The Brain and Cranial Netves

12/1/21, 1:03 AM Labs 15-17 Assignment Labs 15-17 Assignment Due: 11:59pm on Monday, December 6, 2021 Exercise 15 Review Sheet: The Brain and Cranial Nerves In the embryo, the central nervous system develops from a cylindrical structure called the neural tube. The cephalic end of the tube begins to grow at a faster rate than the caudal end and after four weeks of development the three primary brain vesicles (brain regions) have formed. A week later, two of these vesicles subdivide giving rise to the five secondary brain vesicles, from which all adult brain structures form. The remarkable developmental feature of the primate, and in particular, the human brain, is the rapid growth of the telencephalon, which becomes the cerebrum. To complete this Review Sheet, please complete the questions and activities below. Part A - Questions 1-5 Drag and drop the structure names at the left to match the appropriate descriptions at the right. Some labels may be used more than once or not at all. See reference figure below. Drag the terms on the left to the appropriate blanks on the right to complete the sentences. ANSWER: Reset Help 1. This space is filled with cerebrospinal fluid: D - Subarachnoid space 2. This is the innermost meningeal layer: B - Pia mater 3. Hematomas around the brain can occur when damaged meningeal veins leak blood into this space: A- Subdural space 4. This structure drains venous blood from the brain: E - Dural sinus 5. This is the middle meningeal layer: C - Arachnoid mater 6. This the internal surface of the skull. F - Endosteal layer All attempts used; correct answer displayed Part B - Questions 6-10 Drag and drop structures into the appropriate bins to identify brain regions origins. Drag the appropriate items to their respective bins. ANSWER: 1/72 1/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Help Frontal lobe Third ventricle Basal nuclei Corpora quadrigemina Cerebellar cortex Medulla oblongata Mamillary body Corpus callosum Correct Part C - Question 11 Drag the labels onto the diagram to identify the brain structures. Drag the appropriate labels to their respective targets. ANSWER: 2/72 2/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Help Frontal lobe Parietal lobe Occipital lobe Temporal lobe Cerebellum Pons Medulla oblongata Correct Part D - Questions 12-14 Drag the labels to the table to identify the brain’s grooves. Drag the appropriate labels to their respective targets. ANSWER: 3/72 3/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Help Central sulcus Lateral sulcus Transverse fissure Correct Part E - Question 15 Hyrocephalus is an overaccumulation of cerebrospinal fluid in the brain ventricles or subarachnoid space. Which of the following can cause hydrocephalus? ANSWER: Blockage or reduction in the normal drainage of CSF from the brain at the arachnoid granulations Malformation of the aqueducts leading to decreased circulation of CSF Overproduction of CSF from the choroid plexus All the answers are correct. Correct Part F - Question 16 A patient comes to the clinic complaining of irregular skeletal muscle contractions. You explain this is an example of ataxia, an inability to voluntarily control muscle movements. This patient is likely suffering from a lesion affecting which part of the brain? ANSWER: Hypothalamus Superior colliculi Basal nuclei Inferior colliculi 4/72 4/72 12/1/21, 1:03 AM Labs 15-17 Assignment Correct Part G - Questions 18-24 All of the labeled structures in the photo are cranial nerves, except for one. Drag the structure names to the appropriate locations. Drag the appropriate labels to their respective targets. ANSWER: Reset Olfactory tract Trochlear nerve Help Optic nerve Trigeminal nerve Vagus nerve Accessory nerve Correct Part H - Questions 25-29, Part 1 Drag and drop to match the correct skull opening at the left to the appropriate cranial nerve description at the right. Some labels may be used more than once or not at all. See reference figure below. 5/72 5/72 12/1/21, 1:03 AM Labs 15-17 Assignment Drag the terms on the left to the appropriate blanks on the right to complete the sentences. ANSWER: Reset Help 1. This cranial nerve supplies voluntary motor nerve fibers to the muscles of mastication: B- Foramen ovale 2. This cranial nerve supplies autonomic motor fibers to the heart: C- Jugular foramen F- Internal acoustic meatus 3. This cranial nerve contains sensory fibers for vision: D- Optic canal E- Superior orbital fissure 4. This cranial nerve contains sensory fibers from the upper teeth and gums: A- Foramen rotundum 5. This cranial nerve supplies voluntary motor fibers to the tongue: G- Hypoglossal canal Correct Part I - Questions 30-34 If there was an injury to the cranial nerves listed at the left, drag and drop each nerve to match the correct possible symptom at the right. Drag the terms on the left to the appropriate blanks on the right to complete the sentences. ANSWER: 6/72 6/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Help 1. Dizziness: Vestibulocochlear (VIII) nerve 2. Partial loss of smell: Olfactory (I) nerve 3. Loss of sensation in the skin covering the cheek: Maxillary branch of trigeminal (V) nerve 4. Loss of taste sensation on the anterior two-thirds of the tongue: Facial (VII) nerve 5. Difficulty shrugging the shoulders: Accessory (XI) nerve Correct Clinical Case Study: Mysterious Episodes of Mary: A Case on Neuroanatomy Episode 1 Mary Lazarro, a 44-year-old mother of two, made an appointment with her physician after experiencing a prolonged episode of numbness in her chin and lower lip. Two days prior to her appointment, she felt a prickling sensation like "pins and needles" at the right corner of her mouth. The sensation extended to her lower lip and chin. The examination revealed only a superficial hypoesthesia of the chin and lower lip (numb chin syndrome). There was no clinical evidence of palpable regional lymph nodes or other systemic or neurologic abnormalities. Her physician scheduled her for a CT scan of the affected region. These tests showed no abnormalities in the jaw, neck, or pharynx. The numbness and hypoesthesia spontaneously disappeared gradually over a few weeks. Episode 2 Four months later, while eating dinner with her family, Mary felt a stabbing pain in her upper jaw and teeth that radiated out to the side of her nose. Over the next several days, she experienced several more episodes of this intense pain. A visit to the dentist revealed no abnormalities and she was referred to her physician for an evaluation. Prior to her appointment, she noticed that the symptoms were subsiding as they had previously. Her physician scheduled an appointment for a complete neurological exam the following week. Episode 3 Three nights prior to her scheduled visit to the neurologist, Mary stopped at an intersection and experienced intense double vision when looking to the right to check for traffic. The double vision was less intense when looking forward, and her vision when looking left was unaffected. Her husband noticed that her right eye appeared to be turned slightly inward when she looked straight ahead. A day later, Mary noticed that the vision in her left eye started to blur. The neurologist later suggested that the two visual problems she was experiencing were related. The double vision when looking right was found to be caused by cranial nerve palsy-a form of muscle paralysis caused by a dysfunction in one of the cranial nerves. The problem with the left eye was diagnosed as optic neuritis (inflammation). Both of these signs and symptoms, along with the previous episodes, pointed to a diagnosis of multiple sclerosis (MS). The neurologist prescribed oral steroids and ordered an MRI. As with her previous episodes, Mary's visual symptoms began to diminish over time. Finale The results of the MRI, shown below, were consistent with a diagnosis of relapsing-remitting multiple sclerosis (RRMS). Relapsing-remitting multiple sclerosis is a form of MS in which symptoms randomly flare up (Mary's episodes) and then resolve on their own. The lesions seen on the MRI on the left were associated with another episode in which Mary experienced sensory and motor disjunction in her left lower extremity. A subsequent MRI (image on the right) appeared to show improvement after three months. Part A Mary has experienced symptoms and effects associated with many parts of the human nervous system. Which of the following parts of her nervous system DOES NOT appear to show any effects? Hint 1. The division that does not appear to be affected is part of the peripheral nervous system. ANSWER: 7/72 7/72 12/1/21, 1:03 AM Labs 15-17 Assignment central nervous system sensory division of the peripheral nervous system autonomic nervous system (ANS) within the motor division somatic nervous system within the motor division Correct Part B All of Mary's symptoms were related to cranial nerve functions associated with the head and neck region. Which is the only cranial nerve that extends beyond the head and neck to the thorax and abdomen? Hint 1. This nerve is a critical component of the parasympathetic nervous system. ANSWER: VIII (vestibulocochlear) XII (hypoglossal) IX (glossopharyngeal) X (vagus) Correct Part C Which of the following cell types are responsible for the improvement that you see in Mary's MRI following one of her episodes? Hint 1. The improvement seen in the MRI is the result of repair to the axons of the neurons in this region of the brain. ANSWER: oligodendrocytes Schwann cells sensory neurons motor neurons Correct Part D In which region of the brain do cranial nerves III-X originate? Hint 1. The pons and medulla are found in this region of the brain. ANSWER: brain stem cerebral hemisphere diencephalon cerebellum 8/72 8/72 12/1/21, 1:03 AM Labs 15-17 Assignment Correct Part E As part of the neurological exam, the physician placed her hands on the side of Mary's head and asked her to rotate her head against resistance. The neurologist then pressed down on Mary's shoulders while Mary was asked to shrug. Which of Mary's cranial nerves is being evaluated with this exam? Hint 1. The muscles associated with these movements are the sternocleidomastoid and trapezius. ANSWER: VIII (vestibulocochlear) XII (hypoglossal) XI (accessory) VI (abducens) Correct The accessory nerve innervates the sternocleidomastoid and trapezius muscles. These muscles are associated with the actions of turning the head and shrugging the shoulders. Part F Related to Episode 1: What is hypoesthesia? How does it differ from paresthesia? Hint 1. The suffix -esthesia comes from a Greek word meaning sensation or feeling. ANSWER: 3350 Character(s) remaining Hypoesthesia refers to a reduced sense of touch or sensation, or a partial loss of sensitivity to sensory stimuli; in layman's terms, it's numbness. Paresthesia is a sensation of tingling, tickling, pricking, or burning of a person's skin with no apparent and obvious long-term physical effect. The difference is "numbness" is common to hypoesthesia, whereas the sensation of "pins and needles" or of a limb "falling asleep" is common to paresthesia. Submitted, grade pending Part G Related to Episode 1: Using the flowchart, identify the part of the human nervous system that is usually associated with symptoms of hypoesthesia and paresthesia. Hint 1. The suffix -esthesia comes from a Greek word meaning sensation or feeling. ANSWER: 9/72 9/72 12/1/21, 1:03 AM Labs 15-17 Assignment 3650 Character(s) remaining Hypoesthesia and paresthesia are both related to sensory function. The sensory division of the peripheral nervous system is affected in this episode. Submitted, grade pending Part H Related to Episode 1: Which of Mary's cranial nerves is affected in this episode? Hint 1. This is a very complex nerve, so be specific regarding the part that is affected. ANSWER: 3210 Character(s) remaining The trigeminal nerve (V) is a sensory nerve that innervates most of the face. It contains three branches. The upper branch is called the ophthalmic division and receives sensory input from the skin of the anterior scalp, upper eyelid, and nose. The middle branch is called the maxillary division and receives sensory input from the maxilla, skin of the cheek, upper lip, and lower eyelid. The lower branch is called the mandibular division and receives sensory input from the chin, lower teeth, and mandible. In this episode, the mandibular division of the trigeminal nerve is affected. Submitted, grade pending Part I Related to Episode 2: Which of Mary's cranial nerves is affected in this episode? Hint 1. This is a very complex nerve, so be specific regarding the part that is affected. ANSWER: 3212 Character(s) remaining The trigeminal nerve (V) is a sensory nerve that innervates most of the face. It contains three branches. The upper branch is called the ophthalmic division and receives sensory input from the skin of the anterior scalp, upper eyelid, and nose. The middle branch is called the maxillary division and receives sensory input from the maxilla, skin of the cheek, upper lip, and lower eyelid. The lower branch is called the mandibular division and receives sensory input from the chin, lower teeth, and mandible. In this episode, the maxillary division of the trigeminal nerve is affected. Submitted, grade pending Part J Related to Episode 3: Name all of the cranial nerves that are involved with eye movements. Hint 1. There are a total of three cranial nerves involved with eye movements. ANSWER: 10/72 10/72 12/1/21, 1:03 AM Labs 15-17 Assignment 3709 Character(s) remaining Cranial Nerve III – Ocularmotor; Cranial Nerve IV – Trochlear; Cranial Nerve VI - Abducens Submitted, grade pending Part K Related to Episode 3: Which of Mary's affected cranial nerves is responsible for her double vision when looking right? Why does she not experience double vision when looking left? Hint 1. The muscle that is involved in pulling the eye laterally is called the lateral rectus. ANSWER: 3257 Character(s) remaining The abducens nerve (VI) is affected in this episode. It is primarily a motor neuron that innervates the lateral rectus muscle which helps “pull” the eye laterally. Only the right branch of the abducens is affected, so when looking right, the right eye is unable to rotate laterally, and double vision results. The medial rectus muscle of the right eye is responsible for pulling the eye medially when looking left. The oculomotor nerve (III) is responsible for innervating this muscle, and in this episode, cranial nerve III is unaffected. Submitted, grade pending Part L Related to Episode 3: Which of Mary's affected cranial nerves is responsible for her blurred vision? Hint 1. Blurred vision suggests that the affected nerve is a sensory neuron. ANSWER: 3553 Character(s) remaining The optic nerve (II) is purely a sensory neuron responsible for the transmission of sensory input from the retina. In optic neuritis, the inflammation of the optic nerve interrupts the proper transmission of this input, and blurry vision results. Submitted, grade pending Part M Related to Finale: In the MRI images shown in the case, you can see the lesions as bright "white spots" on the brain. Using what you know about the structure of a neuron, explain what is causing this spot to appear in the MRI. Hint 1. Focus your attention on what you know about the structure of the axon. ANSWER: 11/72 11/72 12/1/21, 1:03 AM Labs 15-17 Assignment 3509 Character(s) remaining During Mary's episodes, the protective insulating sheath covering the axons of the neurons is damaged in an inflammatory response by the body's own immune system. This sheath is made of myelin, a mixture of lipids and protein. The lesions are regions in which axons have been demyelinated. Submitted, grade pending Part N Related to Finale: Three months later, you can see that the spots in the MRI appear to be smaller. Using what you know about the structure of a neuron, explain what is happening to the neurons in the area where the lesions are disappearing. Hint 1. Focus your attention on what you know about the structure of the axon. ANSWER: 3485 Character(s) remaining During Mary's episodes, the protective insulating sheath covering the axons of the neurons is damaged in an inflammatory response by the body's own immune system. This sheath is made of myelin, a mixture of lipids and protein. Between episodes, when the inflammatory process has eased, the axons are remyelinated. Submitted, grade pending Lab Manual Exercise 15 Pre-lab Quiz Question 1 Part A The brain and spinal cord are covered by connective tissue membranes called ________. ANSWER: fissures sulci meninges lobes Correct Lab Manual Exercise 15 Pre-lab Quiz Question 2 Part A Which of the following correctly lists the meninges in order from deep to superficial? ANSWER: 12/72 12/72 12/1/21, 1:03 AM Labs 15-17 Assignment dura mater, pia mater, and arachnoid mater pia mater, arachnoid mater, and dura mater dura mater, subarachnoid space, and pia mater arachnoid mater, dura mater, and pia mater Correct Lab Manual Exercise 15 Post-lab Quiz Question 1 Part A The ________ is the fold of the dura mater that separates the cerebral hemispheres. ANSWER: tentorium cerebelli falx cerebri falx cerebelli endosteal layer Correct Art-labeling Activity: Meninges (Lateral View) Part A Drag the labels to the appropriate location in the figure. ANSWER: Reset Dural sinus Help Dura mater (endosteal layer) Dura mater (meningeal layer) Subdural space Arachnoid mater Subarachnoid space Cerebral cortex Pia mater Correct 13/72 13/72 12/1/21, 1:03 AM Labs 15-17 Assignment Lab Manual Exercise 15 From the Book Pre-lab Quiz Question 1 Part A During this laboratory exercise, you will be dissecting a brain from what animal? ANSWER: sheep pig cat cow Correct Lab Manual Exercise 15 From the Book Pre-lab Quiz Question 2 Part A The outermost meningeal layer that surrounds the brain and spinal cord is the arachnoid mater. ANSWER: True False Correct Art-labeling Activity: Superior Surface Structures of the Brain Part A Drag the labels to the appropriate location in the figure. ANSWER: 14/72 14/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Left cerebral hemisphere Right cerebral hemisphere Central sulcus Help Parieto-occipital sulcus Frontal lobe Parietal lobe Temporal lobe Occipital lobe Longitudinal fissure Lateral fissure Insula Correct Lab Manual Exercise 15 Pre-lab Quiz Question 3 Part A The ________ separates the two cerebral hemispheres. ANSWER: transverse cerebral fissure lateral sulcus longitudinal fissure central sulcus Correct Lab Manual Exercise 15 Pre-lab Quiz Question 4 Part A The three parts of the brainstem are the ________. ANSWER: midbrain, cerebellum, and the medulla oblongata olfactory bulb, pons, and the medulla oblongata pituitary gland, pons, and the medulla oblongata midbrain, pons, and the medulla oblongata 15/72 15/72 12/1/21, 1:03 AM Labs 15-17 Assignment Correct Lab Manual Exercise 15 From the Book Pre-lab Quiz Question 3 Part A In both human and the sheep brain, the cerebellum is the most prominent structure. ANSWER: True False Correct Art-labeling Activity: Internal Structures of a Midsagittal Section of the Brain Part A Drag the labels to the appropriate location in the figure. ANSWER: Reset Cerebrum Cingulate gyrus Help Pineal body Thalamus Corpus callosum Cerebellum Fornix Hypothalamus Medulla oblongata Mamillary body Midbrain Pons Correct Lab Manual Exercise 15 Pre-lab Quiz Question 5 Part A The ________ regulates the autonomic nervous system and the pituitary gland. ANSWER: 16/72 16/72 12/1/21, 1:03 AM Labs 15-17 Assignment cerebrum pineal gland hypothalamus cerebellum Correct Lab Manual Exercise 15 Post-lab Quiz Question 2 Part A The "tree-like" white matter of the cerebellum is referred to as the ________. ANSWER: arbor vitae medulla oblongata cingulate gyrus corpus callosum Correct Lab Manual Exercise 15 Post-lab Quiz Question 3 Part A What is the structure that is responsible for secreting the hormone melatonin? ANSWER: pineal gland cingulate gyrus medulla oblongata mammillary body Correct Lab Manual Exercise 15 From the Book Pre-lab Quiz Question 4 Part A What type of section is the classic view for examining the internal anatomy of the brain? ANSWER: parasagittal transverse frontal midsagittal Correct 17/72 17/72 12/1/21, 1:03 AM Labs 15-17 Assignment Dissection Video Activity: Sheep Brain (3 of 7) Watch the animation, then answer the questions. Part A What structure connects the right and left cerebral hemispheres? Hint 1. The right and left cerebral hemispheres are connected by a commissure. ANSWER: Septum pellucidum Corpus callosum Vermis Intermediate mass Correct Correct. The corpus callosum is a large fiber tract of axons connecting the right cerebral hemisphere to the left cerebral hemisphere. Part B Which of the following areas form the central core of the brain? Hint 1. The diencephalon is found in this region. ANSWER: Hypothalamus Thalamus Epithalamus Cerebellum Correct Correct. The thalamus is the central region of the diencephalon and forms the central core of the brain. The thalamus is enclosed by the cerebrum. Part C Where is the arbor vitae located? Hint 1. The term arbor vitae means “tree of life.” ANSWER: 18/72 18/72 12/1/21, 1:03 AM Labs 15-17 Assignment Cerebrum Cerebellum Brain stem Diencephalon Correct Correct. The white matter in the cerebellum has a branching arrangement that resembles a tree. This structure is named for its appearance. The term arbor vitae means “tree of life.” Part D What part of the corpora quadrigemina is clearly observed in a midsagittal section? Hint 1. The corpora quadrigemina is made up of 4 bump like projections. ANSWER: Optic chiasm Inferior colliculus Superior colliculus Corpus callosum Correct Correct. The superior colliculus is clearly observed in the transverse fissure on the back of the midbrain. It is involved with directing eye movement. Part E Which region of the brain is necessary for consciousness? Hint 1. This region is the largest region of the brain. ANSWER: Cerebrum Cerebellum Brain stem Diencephalon Correct Correct. The cerebrum is involved in higher order functions such as consciousness, personality, and intellect. Dissection Video Activity: Sheep Brain (6 of 7) Watch the animation, then answer the questions. 19/72 19/72 12/1/21, 1:03 AM Labs 15-17 Assignment Part A How many major regions are contained within the diencephalon? Hint 1. The diencephalon makes up the central core of the brain. ANSWER: 4 3 2 1 Correct Correct. The diencephalon consists of 3 regions, the thalamus, the epithalamus, and the hypothalamus. Part B Which part of the diencephalon is connected to the pituitary gland? Hint 1. There are 2 glands associated with the diencephalon. Think about the physical proximity of the pituitary gland to the diencephalon. ANSWER: Thalamus Midbrain Epithalamus Hypothalamus Correct Correct. The hypothalamus is connected to the pituitary gland by the infundibulum. Part C Which region acts as a relay center for sensory messages ascending to the cerebrum? Hint 1. What part of the diencephalon is located directly inferior to the cerebrum? ANSWER: 20/72 20/72 12/1/21, 1:03 AM Labs 15-17 Assignment Pons Corpus callosum Thalamus Hypothalamus Correct Correct. The thalamus acts as a filter, sending the most important sensory messages on to the correct location in the cerebrum. Part D Which region of the diencephalon contains the pineal body? Hint 1. The pineal body is located close to the transverse fissure. ANSWER: Hypothalamus Epithalamus Midbrain Corpora quadrigemina Correct Correct. The epithalamus is a region posterior to the thalamus that contains the pineal body. Part E The pineal body secretes melanocyte stimulating hormone (MSH). Hint 1. The pineal body secretes a hormone that is a derivative of the amino acid, tryptophan. ANSWER: False True Correct Correct. The pineal body secretes the hormone melatonin which is secreted when light is not entering the eyes (typically at night). Part F The diencephalon is found in between the brain stem and the cerebrum. Hint 1. Think about the special relationship between the 4 major regions of the brain. ANSWER: False True Correct The diencephalon forms the core of the brain, housed between the cerebrum and brainstem. 21/72 21/72 12/1/21, 1:03 AM Labs 15-17 Assignment Dissection Video Activity: Sheep Brain (4 of 7) Watch the animation, then answer the questions. Part A Which ventricles are divided by the septum pellucidum? Hint 1. The septum pellucidum is found within the cerebrum. ANSWER: Lateral and third ventricle First and second ventricles Third and fourth ventricles Lateral ventricles Correct Correct. The lateral ventricles are cavities within the cerebrum. The right and left lateral ventricles are separated on midline by the septum pellucidum. Part B What type of tissue makes up the cerebral cortex? Hint 1. The cerebral cortex is the outer surface of the cerebrum. ANSWER: Nerves White matter Meninges Gray matter Correct Correct. The cerebral cortex is composed of gray matter. Gray matter is primarily neuron cell bodies. Part C What is the function of white matter? Hint 1. Think about the composition of white matter. What is white matter made of? ANSWER: 22/72 22/72 12/1/21, 1:03 AM Labs 15-17 Assignment Processes information Transmits messages Supports neurons Produces cerebrospinal fluid Correct Correct. White matter is predominately myelinated axons, which transmit information (action potentials). Part D The composition of gray matter includes neuron cell bodies. Hint 1. Gray matter makes up the cerebral cortex. ANSWER: False True Correct Correct. Gray matter consists of neuron cell bodies, unmyelinated axons, and neuroglial cells. Part E White matter has a fatty consistency. Hint 1. White matter is composed of mainly myelinated axons. ANSWER: True False Correct White matter consists mainly of myelinated axons. Myelination is created by the membrane of a neuroglial cell wrapping many times tightly around an axon. Recall the plasma membrane is a lipid bilayer, therefore white matter contains a lot of fat. The high amount of fat gives white matter it’s characteristic glossy white appearance. Part F The brain is a solid organ that lacks cavities. Hint 1. Does the brain contain any cavitites? ANSWER: True False Correct Correct. The brain is not completely solid; it contains cavities called ventricles. Dissection Video Activity: Sheep Brain (1 of 7) 23/72 23/72 12/1/21, 1:03 AM Labs 15-17 Assignment Watch the animation, then answer the questions. Part A Which of the following ventricles is found under the corpus callosum? Hint 1. These are C shaped cavities. ANSWER: Fourth ventricle Third ventricle Fornix Lateral ventricles Correct Correct. The lateral ventricles lie side by side under the corpus callosum, separated by the septum pellucidum. Part B Which passageway connects the third and fourth ventricles? Hint 1. Narrow passageways interconnect all of the ventricles. ANSWER: Cerebral aqueduct Interventricular foramen Septum pellucidum Central canal Correct Correct. The cerebral aqueduct is the narrow passageway that connects the third and fourth ventricles. It can sometimes be observed on a midsagittal section. Part C Identify the passageway found in the spinal cord that is continuous with the ventricles. Hint 1. This is a narrow passageway found on midline. ANSWER: 24/72 24/72 12/1/21, 1:03 AM Labs 15-17 Assignment Central canal Interventricular foramina Cerebral aqueduct Choroid plexus Correct Correct. The central canal is the canal found in the spinal cord that originates off of the fourth ventricle. Part D Cerebrospinal fluid is produced within the ventricles. Hint 1. Recall the actual tissue that produces cerebrospinal fluid. ANSWER: True False Correct Correct. The choroid plexus produces cerebrospinal fluid. It is found in each of the ventricles. Part E The ventricles are all interconnected. Hint 1. Are the ventricles isolated and independent of each other? ANSWER: True False Correct Correct. Narrow passageways connect the ventricles together, so that cerebrospinal fluid flows freely inside the ventricular system. Dissection Video Activity: Sheep Brain (2 of 7) Watch the animation, then answer the questions. Part A Identify cranial nerve I. 25/72 25/72 12/1/21, 1:03 AM Labs 15-17 Assignment Hint 1. Cranial nerve I exits off of the forebrain. ANSWER: Oculomotor nerve Optic nerve Olfactory nerve Optic tract Correct Correct. Cranial nerve I is the olfactory nerve. Part B Which of the following areas takes visual information from one side of the body and conveys it to the opposite side? Hint 1. This region crosses midline. ANSWER: Optic tract Olfactory bulbs Optic nerve Optic chiasm Correct Correct. The optic chiasm is where the optic nerves cross midline, so that sensory information from one side of the body is processed on the opposite side of the brain. Part C Which of the following glands can be observed on the ventral surface of the sheep brain? Hint 1. One gland is easily observed on the ventral surface. ANSWER: Mammillary body Pineal gland Pituitary gland Olfactory bulb Correct Correct. The pituitary gland can be seen on the ventral surface of the brain. It can easily be removed with the meninges if care isn’t taken to keep it attached. Part D Which of the following structures attach the pituitary gland to the brain? Hint 1. This is a small stalk like structure. ANSWER: 26/72 26/72 12/1/21, 1:03 AM Labs 15-17 Assignment Hypothalamus Pia mater Infundibulum Optic chiasm Correct Correct. The infundibulum attaches the pituitary gland to the hypothalamus. It contains axons that originate in the hypothalamus and end in the posterior pituitary. Part E All three regions of the brain stem can be observed on the ventral surface of the brain. Hint 1. The brain stem is made up of the midbrain, pons and the medulla oblongata. ANSWER: False True Correct Correct. All 3 regions of the brain stem, the midbrain, pons, and medulla oblongata, can be observed on the ventral surface. Part F The cerebellum is present on the ventral surface of the sheep brain. Hint 1. Was the cerebellum a highlighted structure in the video? ANSWER: True False Correct Correct. The cerebellum is not a ventral structure. It is located on the dorsal surface of the brain. Dissection Video Activity: Sheep Brain (5 of 7) Watch the animation, then answer the questions. Part A Name the membranous encasement surrounding the brain. 27/72 27/72 12/1/21, 1:03 AM Labs 15-17 Assignment Hint 1. This encasement also surrounds the spinal cord. ANSWER: Meninges Epineurium Choroid plexus Lamina propria Correct Correct. The meninges encase the central nervous system. Part B Which of the following regions cannot be observed superficially? Hint 1. Consider what structures were observed in the video, compared to deeper structures that can’t be seen. ANSWER: Cerebellum Diencephalon Longitudinal fissure Cerebrum Correct The diencephalon forms the central core of the brain and cannot be seen from the surface of the brain. Part C Which region of the brain contains gyri and sulci? Hint 1. Gyri and sulci are the convolutions commonly associated with the appearance of the brain. ANSWER: Cerebellum Diencephalon Brain stem Cerebrum Correct Correct. The cerebral cortex has a convoluted surface. The ridges are known as gyri and the grooves that separate the gyri are sulci. Part D Which of the following landmarks separate the cerebrum from the cerebellum? Hint 1. What is the name for a deep division in the brain? ANSWER: 28/72 28/72 12/1/21, 1:03 AM Labs 15-17 Assignment Longitudinal fissure Central sulcus Corpus callosum Transverse fissure Correct Correct. The transverse fissure is the separation found between the cerebrum and the cerebellum. Part E Which of the following landmarks divides the cerebrum in half? Hint 1. The 2 halves of the cerebrum are known as the cerebral hemispheres. ANSWER: Transverse fissure Longitudinal fissure Vermis Lateral sulcus Correct Correct. The longitudinal fissure is easily observed right along midline dividing the cerebrum into the right and left cerebral hemispheres. Part F The meninges consist of ___ layers. Hint 1. The meninges encase the central nervous systems. ANSWER: 1 2 3 4 Correct Correct. The dura mater, arachnoid, and pia mater make up the 3 layers of the meninges. Part G Which of the following is the outer layer of the meninges? Hint 1. Is the outer, middle, or inner layer of the meninges most apparent prior to removing the meninges? ANSWER: 29/72 29/72 12/1/21, 1:03 AM Labs 15-17 Assignment Pia mater Dural sinus Dura mater Arachnoid Correct Correct. The outer layer of the meninges is the dura mater. The dura mater is easily seen surrounding the outside of the brain. Dissection Video Activity: Sheep Brain (7 of 7) Watch the animation, then answer the questions. Part A How many regions make up the brain stem? Hint 1. The brain stem is the lowest region of the brain. ANSWER: 1 2 4 3 Correct Correct. The brain stem consists of the midbrain, pons, and medulla oblongata. Part B Which area of the brain stem is in contact with the spinal cord? Hint 1. The spinal cord is continuous with the lowest most part of the brain stem. ANSWER: Cerebellum Pons Medulla oblongata Midbrain 30/72 30/72 12/1/21, 1:03 AM Labs 15-17 Assignment Correct Correct. The medulla oblongata is the lowest region of the brain stem. It is continuous with the spinal cord at the foramen magnum of the skull. Part C Which region contains the corpora quadrigemina? Hint 1. The corpora quadrigemina are 4 bump like projections that can be seen in the transverse fissure. ANSWER: Midbrain Epithalamus Medulla oblongata Pons Correct Correct. The corpora quadrigemina are found on the posterior surface of the midbrain. They can be observed by looking into the transverse fissure. Part D Which ventricle is located within the brain stem? Hint 1. There are 4 ventricles in the brain, which are all interconnected. ANSWER: First ventricle Second ventricle Fourth ventricle Third ventricle Correct Correct. The fourth ventricle is located anterior to the cerebellum. It is continuous with the third ventricle through the cerebral aqueduct at its superior border and continuous with the central canal at its inferior border. Part E The foramen magnum marks the border between the medulla oblongata and spinal cord. Hint 1. Think about the physical proximity of the 3 anatomical structures mentioned in the question. ANSWER: True False Correct Correct. The medulla oblongata is the lowest region of the brain stem. It is continuous with the spinal cord at the foramen magnum of the skull. Part F The inferior colliculi are part of the corpora quadrigemina. 31/72 31/72 12/1/21, 1:03 AM Labs 15-17 Assignment Hint 1. The corpora quadrigemina is a collection of 4 bumps on the posterior surface of the midbrain. ANSWER: False True Correct Correct. The corpora quadrigemina is a collection of 4 bumps on the posterior surface of the midbrain. It is composed of the 2 superior colliculi and the 2 inferior colliculi. Art-labeling Activity: The Internal Structures from a Coronal Section of the Brain Part A Drag the labels to the appropriate location in the figure. ANSWER: Reset Corpus callosum Cerebral cortex Help Lateral ventricles Septum pellucidum White matter Internal capsule Basal nuclei Correct Lab Manual Exercise 15 Pre-lab Quiz Question 6 Part A What is the name of the structure that connects the left and right cerebral hemispheres, allowing for interhemispheric communication? ANSWER: corpus callosum cerebral cortex internal capsule lateral ventricles 32/72 32/72 12/1/21, 1:03 AM Labs 15-17 Assignment Correct Lab Manual Exercise 15 From the Book Pre-lab Quiz Question 5 Part A When the internal anatomy of the brain is viewed from a coronal section, the white matter, which is located deep to the cerebral cortex, can be identified. ANSWER: True False Correct Art-labeling Activity: Brain Structures Involved with the Production and Drainage of Cerebrospinal Fluid Part A Drag the labels to the appropriate location in the figure. ANSWER: Reset Help Cranium Choroid plexus Dura mater Superior sagittal sinus Arachnoid granulation CSF movement Fourth ventricle Subdural space Arachnoid mater Subarachnoid space Pia mater Cerebral cortex Correct Art-labeling Activity: Ventricles of the Brain (lateral view) Identify the ventricles of the brain. Part A Drag the labels to identify the ventricles of the brain. 33/72 33/72 12/1/21, 1:03 AM Labs 15-17 Assignment ANSWER: Reset Help Lateral ventricles Interventricular foramen Third ventricle Aqueduct of the midbrain Fourth ventricle Correct Lab Manual Exercise 15 Pre-lab Quiz Question 7 Part A The ________ are a series of interconnected cavities that are filled with cerebrospinal fluid. ANSWER: lobes hemispheres meninges ventricles Correct Lab Manual Exercise 15 Pre-lab Quiz Question 8 Part A Which of the following cell types produces cerebrospinal fluid? ANSWER: astrocytes oligodendrocytes ependymal cells microglia Correct 34/72 34/72 12/1/21, 1:03 AM Labs 15-17 Assignment Lab Manual Exercise 15 Post-lab Quiz Question 9 Part A Cerebrospinal fluid produced in the lateral ventricles flows next to the ________. ANSWER: cerebral aqueduct of the midbrain fourth ventricle third ventricle choroid plexus Correct Lab Manual Exercise 15 Post-lab Quiz Question 10 Part A The ________, located in each of the ventricles, produce cerebrospinal fluid. ANSWER: arachnoid granulations interventricular foramina basal nuclei choroid plexuses Correct Lab Manual Exercise 15 From the Book Pre-lab Quiz Question 6 Part A The aqueduct of the midbrain is a narrow channel that connects the two lateral ventricles. ANSWER: True False Correct Lab Manual Exercise 15 Pre-lab Quiz Question 9 Part A There are ________ pairs of cranial nerves. ANSWER: 35/72 35/72 12/1/21, 1:03 AM Labs 15-17 Assignment 5 12 31 4 Correct Lab Manual Exercise 15 Post-lab Quiz Question 4 Part A Which of the cranial nerves originate in the nasal cavity? ANSWER: oculomotor nerve (CN III) olfactory nerves (CN I) trigeminal nerve (CN V) optic nerves (CN II) Correct Lab Manual Exercise 15 Post-lab Quiz Question 5 Part A Which of the following is a correct listing of the cranial nerves that originate from the medulla oblongata? ANSWER: glossopharyngeal, trigeminal, accessory, and abducens glossopharyngeal, vagus, accessory, and olfactory glossopharyngeal, vagus, trochlear, and oculomotor glossopharyngeal, vagus, accessory, and hypoglossal Correct Lab Manual Exercise 15 Post-lab Quiz Question 11 Part A Electric impulses generated by brain activity can be detected and then recorded on a/an _____. ANSWER: spirogram electroencephalogram electrocardiogram electromyogram Correct 36/72 36/72 12/1/21, 1:03 AM Labs 15-17 Assignment Lab Manual Exercise 15 Post-lab Quiz Question 13 Part A Which of the following electroencephalogram wave patterns would you not expect to identify if your subject is asleep? ANSWER: alpha waves theta waves beta waves delta waves Correct Lab Manual Exercise 15 Post-lab Quiz Question 12 Part A Which of the following electroencephalogram wave patterns would you expect to identify when your lab partner opened his or her eyes and tried not to blink? ANSWER: theta waves high-frequency, low-amplitude waves delta waves low-frequency, high-amplitude waves Correct Art-labeling Activity: The Origins of Cranial Nerves III - XII Part A Drag the labels to the appropriate location in the figure. ANSWER: 37/72 37/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Help Oculomotor nerve (III) Trochlear nerve (IV) Trigeminal nerve (V) Abducens nerve (VI) Facial nerve (VII) Vestibulocochlear nerve (VIII) Glossopharyngeal nerve (IX) Vagus nerve (X) Accessory nerve (XI) Hypoglossal nerve (XII) Correct Art-labeling Activity: The Origins of Cranial Nerves I and II Part A Drag the labels to the appropriate location in the figure. ANSWER: 38/72 38/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Help Olfactory tract Optic chiasm Olfactory nerve (I) Olfactory bulb Optic nerve (I) Correct Lab Manual Exercise 15 Pre-lab Quiz Question 10 Part A Which of the following cranial nerves is associated with the sense of smell? ANSWER: optic nerve (CN II) olfactory nerve (CN I) oculomotor nerve (CN III) vagus nerve (CN X) Correct Lab Manual Exercise 15 Post-lab Quiz Question 6 Part A Which of the following activities would be altered by damage to the olfactory nerve? ANSWER: using your eyes to follow the movements of a dancer smiling at your lab partner smelling roses tasting a salty dill pickle 39/72 39/72 12/1/21, 1:03 AM Labs 15-17 Assignment Correct Lab Manual Exercise 15 From the Book Pre-lab Quiz Question 7 Part A There are 10 pairs of cranial nerves. ANSWER: True False Correct Lab Manual Exercise 15 Post-lab Quiz Question 7 Part A Which of the following cranial nerves may be damaged if your lab partner cannot distinguish between salty and sugary tastes? ANSWER: olfactory nerve facial nerve oculomotor nerve optic nerve Correct Lab Manual Exercise 15 From the Book Pre-lab Quiz Question 8 Part A All of the following cranial nerves innervate the extrinsic eye muscles except the ANSWER: trochlear nerve (IV). optic nerve (II). abducens nerve (VI). oculomotor nerve (III). Correct Lab Manual Exercise 15 Post-lab Quiz Question 8 Part A Which of the following cranial nerves innervates the muscles that move the tongue? ANSWER: 40/72 40/72 12/1/21, 1:03 AM Labs 15-17 Assignment accessory facial abducens hypoglossal Correct Lab Manual Exercise 15 From the Book Pre-lab Quiz Question 9 Part A During this laboratory exercise, you will identify salty and sweet tastes to test the sensory function of which cranial nerve? ANSWER: facial nerve (VII) accessory nerve (XI) vestibulocochlear nerve (VIII) trigeminal nerve (V) Correct Art-labeling Activity: Skull Openings for the Cranial Nerves Part A Drag the labels to the appropriate location in the figure. ANSWER: 41/72 41/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Help Cribriform plate of the ethmoid bone Optic canal Foramen rotundum Foramen ovale Superior orbital fissure Internal acoustic meatus Jugular foramen Hypoglossal canal Correct Lab Manual Exercise 15 From the Book Pre-lab Quiz Question 10 Part A During this laboratory exercise, you will insert pipe cleaner into various skull openings to identify the destinations of the cranial nerves. ANSWER: True False Correct Exercise 16 Review Sheet: The Spinal Cord and Spinal Nerves Along its course the spinal cord gives rise to 31 pairs of spinal nerves. The ventral branches of many spinal nerves form plexuses or nerve networks. The four spinal nerve plexuses are summarized in the following table: Plexus Spinal Nerve Contributions Cervical plexus C1 - C5 Distribution Portion of the head, neck, and shoulders Brachial plexus C 5 - T1 All structures in the upper limb Lumbar plexus T12 - L4 Abdominal wall, external genitalia, part of lower limb Sacral plexus L 4 - S4 Buttocks, perineum, part of lower limb Each plexus gives rise to peripheral nerves that contain contributions from two or more spinal nerves. For example, the sciatic nerve, which supplies structures in the lower limb, originates from the sacral plexus. It contains components from spinal nerves L4–S3. 42/72 42/72 12/1/21, 1:03 AM Labs 15-17 Assignment To complete this Review Sheet, please complete the questions and activities below. Part A - Question 1 Which of the following structures or structural features is/are always present in the spinal cord, but missing from the brain? ANSWER: Subarachnoid space Epidural space Pia mater Arachnoid mater Correct Part B - Questions 2-10 Drag the labels onto the diagram to identify the structures in this spinal cord cross section. Drag the appropriate labels to their respective targets. ANSWER: Reset Help Dorsal root ganglion Gray matter Spinal nerve White matter Dorsal root Dorsal ramus Ventral ramus Ventral root Rami communicantes Correct Part C Inferior to L1, the nerve roots must travel inferiorly through the vertebral canal to exit at the correct vertebral levels. These bundles of fibers are collectively known as the __________. ANSWER: conus medullaris lumbar enlargement filum terminale cauda equina Correct Part D - Question 12 43/72 43/72 12/1/21, 1:03 AM Labs 15-17 Assignment The results of a two-point discrimination test on four skin areas are given in the table. Complete the table by dragging and dropping the appropriate numbers to rank the skin areas 1–4 according to the relative densities of sensory receptors (1 = highest density, 4 = lowest density). In the figure of the sensory homunculus, drag and drop the four skin regions, A, B, C, and D, based on your ranking of sensory receptor density. Drag the appropriate labels to their respective targets. ANSWER: Reset A B C Help D 3 2 4 1 Correct Part E - Question 13 The following peripheral nerves are derived from the lumbar plexus: Peripheral Nerve Ilioinguinal nerve Genitofemoral nerve Lateral femoral cutaneous nerve Femoral nerve Spinal Nerve Contributions L1 L 1 , L2 L 2 , L3 L 2 , L 3 , L4 During clinical assessments you find that your patient has a loss of both sensory and motor function of the entire thigh (femoral) area, but no changes in the function of the abdominal muscles. Using this information, which of the peripheral nerves below would be affected? ANSWER: Femoral nerve only Lateral femoral cutaneous nerve and ilioinguinal nerve Ilioinguinal nerve only Genitofemoral nerve, lateral femoral cutaneous nerve, femoral nerve Correct Art-labeling Activity: The Spinal Nerve Plexuses Part A 44/72 44/72 12/1/21, 1:03 AM Labs 15-17 Assignment Drag the labels to the appropriate location in the figure. ANSWER: Reset Help Cervical plexus Brachial plexus Lumbar plexus Sacral plexus Sciatic nerve Correct Art-labeling Activity: Spinal Meninges and Associated Structures Part A Drag the labels to the appropriate location in the figure. ANSWER: 45/72 45/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Help Pia mater Spinal cord Arachnoid mater Dura mater Subarachnoid space Epidural space Denticulate ligaments Correct Lab Manual Exercise 16 Pre-lab Quiz Question 1 Part A The spinal cord is protected by three layers of connective tissue membranes called the ________. ANSWER: plexuses dermatomes meninges vertebrae Correct Lab Manual Exercise 16 Pre-lab Quiz Question 2 Part A ________ is an area on the body monitored by a single sensory neuron. ANSWER: A dermatome The conus medullaris The filum terminale A receptive field Correct 46/72 46/72 12/1/21, 1:03 AM Labs 15-17 Assignment Lab Manual Exercise 16 Pre-lab Quiz Question 9 Part A The ________ connect(s) the pia mater to the dura mater of the spinal cord. ANSWER: conus medullaris spinal nerves denticulate ligaments filum terminale Correct Lab Manual Exercise 16 Pre-lab Quiz Question 10 Part A The area between the dura mater and the vertebrae is known as the ________. ANSWER: conus medullaris subarachnoid space epidural space filum terminale Correct Lab Manual Exercise 16 Post-lab Quiz Question 1 Part A One difference between the meninges of the brain and the spinal cord is that ________. ANSWER: the denticulate ligaments of the dura mater anchor the meninges to the arachnoid mater denticulate ligaments connect the pia mater of the brain to the dura mater of the brain the dura mater of the spinal cord is not attached to the inner surface of vertebrae, but the dura mater of the brain is attached to the inner surface of the cranial bones There are no differences between the meningeal layers of the brain and spinal cord. Correct Lab Manual Exercise 16 Post-lab Quiz Question 2 Part A What is the role of the adipose tissue in the epidural space? ANSWER: 47/72 47/72 12/1/21, 1:03 AM Labs 15-17 Assignment There is no known function of the adipose tissue in the epidural space. The adipose tissue of the epidural space produces myelin. The adipose tissue conducts nerve impulses. The adipose tissue in the epidural cushions dura mater and protects the nerves and blood vessels that it surrounds. Correct Lab Manual Exercise 16 From the Book Pre-lab Quiz Question 8 Part A The spinal cord ends between the T12 and L1 vertebrae. ANSWER: True False Correct Art-labeling Activity: Gross Anatomy of the Spinal Cord (longitudinal section) Part A Drag the labels to the appropriate location in the figure. ANSWER: Reset Help Spinal cord origin Cervical enlargement Conus medullaris Spinal nerves Lumbar enlargement Cauda equina Correct 48/72 48/72 12/1/21, 1:03 AM Labs 15-17 Assignment Art-labeling Activity: The Gray and White Matter of the Spinal Cord Part A Drag the labels to the appropriate location in the figure. ANSWER: Reset Help Posterior horn Posterior white column Lateral white column Gray commissure Anterior white column Lateral horn Anterior horn Correct Art-labeling Activity: The Roots and Branches of a Spinal Nerve Part A Drag the labels to the appropriate location in the figure. ANSWER: 49/72 49/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Dorsal root Dorsal root ganglion Help Beginning of a spinal nerve Dorsal primary ramus Ventral primary ramus Ventral root Rami communicantes Correct Lab Manual Exercise 16 Pre-lab Quiz Question 3 Part A In the spinal cord, the grey matter is ________ to the white matter. ANSWER: deep superficial inferior superior Correct Lab Manual Exercise 16 Pre-lab Quiz Question 5 Part A How many pairs of spinal nerves are there? ANSWER: 8 5 12 31 50/72 50/72 12/1/21, 1:03 AM Labs 15-17 Assignment Correct Lab Manual Exercise 16 Pre-lab Quiz Question 6 Part A Spinal nerves are classified as mixed nerves because they ________. ANSWER: contain motor nerve fibers only contain neither sensory nor motor nerve fibers contain both sensory and motor nerve fibers contain sensory nerve fibers only Correct Lab Manual Exercise 16 Post-lab Quiz Question 10 Part A The cone-shaped terminal end of the spinal cord is called the ________. ANSWER: filum terminale conus medullaris epidural space subarachnoid space Correct Lab Manual Exercise 16 From the Book Pre-lab Quiz Question 6 Part A A spinal nerve begins where the two nerve roots unite. ANSWER: True False Correct Lab Manual Exercise 16 From the Book Pre-lab Quiz Question 7 Part A Spinal nerves are classified as mixed nerves because they contain both sensory and motor nerve fibers. ANSWER: 51/72 51/72 12/1/21, 1:03 AM Labs 15-17 Assignment True False Correct Lab Manual Exercise 16 Pre-lab Quiz Question 4 Part A The bony structure that encloses and protects the spinal cord is called the ________. ANSWER: vertebral canal conus medullaris cauda equina dura mater Correct Lab Manual Exercise 16 Pre-lab Quiz Question 7 Part A First-order neurons ________. ANSWER: carry sensory information from a receptor to the central nervous system transmit motor information from a receptor to the central nervous system travel to the thalamus and synapse on third-order neurons travel from the thalamus to the cerebral cortex Correct Lab Manual Exercise 16 Pre-lab Quiz Question 8 Part A A sensory cutaneous region, innervated by a single pair of spinal nerves, is called a ________. ANSWER: plexus receptive field sensory neuron dermatome Correct Lab Manual Exercise 16 Post-lab Quiz Question 3 52/72 52/72 12/1/21, 1:03 AM Labs 15-17 Assignment Part A In a two-point discrimination test, the distribution of sensory receptors is ________ related to the distance between the compass points. ANSWER: inversely seldom not directly Correct Lab Manual Exercise 16 Post-lab Quiz Question 4 Part A During lab class, you conducted a two-point discrimination test on your lab partner. At the tip of the index finger, the two-point discrimination was 5 mm. On the dorsal surface of the hand, the two-point discrimination was 10 mm. Given the results of this test, which of the following statements is true? ANSWER: The density of skin receptors is equal in both areas tested. The density of skin receptors is greater on the dorsal surface of the hand than on the tip of the index finger. The density of skin receptors is greater at the tip of the index finger than on the dorsal surface of the hand. There is not enough information to draw a conclusion about the density of skin receptors in the areas that were tested. Correct Lab Manual Exercise 16 Post-lab Quiz Question 6 Part A Consider the sensory homunculus. Why is a large portion of the sensory area dedicated to the hands and fingers? ANSWER: There are fewer sensory receptors in the hands and fingers than in other parts of the body. There are a larger number of sensory receptors in the hands and fingers than in other parts of the body. Sensory receptors are equally distributed in all body areas. Sensory receptors are larger in the hands and fingers than in other parts of the body. Correct Lab Manual Exercise 16 Post-lab Quiz Question 7 Part A Which of the following statements explains why sensations felt on the left side of the body are received by the right cerebral hemisphere? ANSWER: 53/72 53/72 12/1/21, 1:03 AM Labs 15-17 Assignment Axons of third-order neurons cross over to the opposite side of the CNS. Axons of second-order neurons in a sensory pathway cross over to the opposite side of the CNS. First-order neurons cross over to the opposite side of the CNS. There is no explanation for this occurrence. Correct Lab Manual Exercise 16 Post-lab Quiz Question 9 Part A What would be the most immediate consequence of damage to a first-order sensory neuron? ANSWER: Sensory information would not be transmitted to the cerebral cortex. Motor function would be lost. This type of damage would not affect the organism. Sensory information from the receptive field nearest the damaged area would not be transmitted to the CNS. Correct Lab Manual Exercise 16 From the Book Pre-lab Quiz Question 2 Part A During this laboratory exercise, what piece of equipment will you use for the two-point discrimination test? ANSWER: tuning fork goniometer reflex hammer measuring compass Correct Lab Manual Exercise 16 From the Book Pre-lab Quiz Question 3 Part A The primary sensory area is located in the frontal lobe of the cerebrum. ANSWER: True False Correct Lab Manual Exercise 16 From the Book Pre-lab Quiz Question 4 54/72 54/72 12/1/21, 1:03 AM Labs 15-17 Assignment Part A In a two-point discrimination test, the greater the distance between two pins at which two distinct sensations can be felt, the greater the density of skin receptors. ANSWER: True False Correct Lab Manual Exercise 16 From the Book Pre-lab Quiz Question 5 Part A The body parts map in the primary sensory area is called the sensory homunculus. ANSWER: True False Correct Lab Manual Exercise 16 From the Book Pre-lab Quiz Question 9 Part A If two pins touch your skin simultaneously and you detect only one sensation, the pins touched the skin in the same receptive field. ANSWER: True False Correct Art-labeling Activity: Major Nerves of the Brachial Plexus Part A Drag the labels to the appropriate location in the figure. ANSWER: 55/72 55/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset Help Nerve roots of brachial plexus Musculocutaneous nerve Median nerve Ulnar nerve Radial nerve Correct Lab Manual Exercise 16 Post-lab Quiz Question 5 Part A Which spinal nerve is linked to the skin covering the deltoid muscle? ANSWER: C6 C7 C8 C5 Correct Lab Manual Exercise 16 Post-lab Quiz Question 8 Part A Your lab partner does not feel the stick of a needle in the sural region of the leg. Which spinal nerve may be damaged? ANSWER: 56/72 56/72 12/1/21, 1:03 AM Labs 15-17 Assignment S2 L5 L3 C2 Correct Lab Manual Exercise 16 From the Book Pre-lab Quiz Question 1 Part A During this laboratory exercise, what piece of equipment will you use to test sensory function in dermatomes? ANSWER: reflex hammer measuring compass tuning fork goniometer Correct Lab Manual Exercise 16 From the Book Pre-lab Quiz Question 10 Part A There is very little variability in the distribution of dermatomes among individuals. ANSWER: True False Correct Exercise 17 Review Sheet: Human Reflex Physiology Motor neurons in the primary motor area or precentral gyrus of the frontal lobe initiate all voluntary motor functions. The motor pathways contain two types of motor neurons. The cell bodies of upper motor neurons are located in the primary motor area. Axons from these cells travel to nuclei in the brainstem or spinal cord, where they synapse with lower motor neurons. Axons of lower motor neurons travel in cranial and spinal nerves and innervate skeletal muscles. Along their pathways, upper motor neurons cross over to the opposite side either in the brainstem or spinal cord. Thus, the motor area on the right side of the brain directs motor function on the left side of the body, and vice versa. The primary motor area can be divided into body regions represented by a motor homunculus. This is a body parts map that correlates a cortical region with the body part it controls. Notice that body regions in the motor homunculus are proportioned differently from the body itself. For instance, your hand is much smaller than your torso, but the cortical region that controls your hand is relatively large while the cortical region that controls your torso is relatively small. To complete this Review Sheet, please complete the questions and activities below. Part A - Question 1 Which of the following best describes the primary motor area? ANSWER: 57/72 57/72 12/1/21, 1:03 AM Labs 15-17 Assignment A map of body regions controlled by various portions of the brain. This is the primary muscle responsible for initiating motion in a body region. A region of the brain that receives information from the opposite side of the body. Motor neurons in the frontal lobe that control voluntary movements. Correct Part B - Question 2 Which of the following best describes the motor homunculus? ANSWER: A diagram showing the physical regions of the cerebrum assigned to interpreting stimuli from various body regions A diagram showing the physical regions of the cerebellum assigned to body regions for motor function A diagram showing the physical regions of the cerebrum assigned to body regions for motor function A specific region of the frontal lobe that crosses over to control the opposite side of the body Correct Part C - Question 3 Which of the following would be important in assessment of an individual’s motor proprioception? ANSWER: How far the person can lift an arm Whether or not the person speaks when spoken to Whether or not the person can touch their nose with a finger Whether the person feels full after eating Correct Part D - Question 4 Which of the following is a role of the cerebellum? ANSWER: Throwing a baseball to home plate while running in from the outfield. Relaying sensory information to the cerebral cortex. Hearing a noise and turning toward the noise. Figuring out an alternate path home because the road is blocked. Correct Part E - Question 5 One evening as you are reading a book by your favorite author, there is a power outage in your neighborhood. Which of the following tasks involves proprioception? ANSWER: Feeling the pain as you stub your toe on the coffee table. Moving the book from your right hand to your left hand to place it on an end table. Feeling your stomach growl in hunger. Hearing the crackle of the fire in the fireplace in a nearby room. 58/72 58/72 12/1/21, 1:03 AM Labs 15-17 Assignment Correct Part F - Questions 6-10 Drag and drop the letters, at the left, of the corresponding diagrammed structures to match the appropriate descriptions of reflex arc components, at the right. Drag the terms on the left to the appropriate blanks on the right to complete the sentences. ANSWER: Reset Help 1. This structure contracts as a result of a stimulus: E 2. Located in the CNS, this receives sensory impulses and sends out motor impulses: C 3. This cell delivers nerve impulses to an effector organ: D 4. This structure responds to a stimulus: A 5. This cell delivers nerve impulses to the CNS: B Correct Part G - Question 11 Transverse myelitis is a CNS disease that is caused by inflammation of the spinal cord. It can affect one or several levels of the spinal cord. Which of the following would NOT be a possible symptom of this disease? ANSWER: Partial paralysis A weaker reflex Numbness in a limb A stronger reflex Correct 59/72 59/72 12/1/21, 1:03 AM Labs 15-17 Assignment Lab Manual Exercise 17 Pre-lab Quiz Question 3 Part A After consuming several servings of a beverage containing alcohol, your roommate is unable to maintain the balance required to walk in a straight line. What can this behavior be attributed to? ANSWER: Beverages containing alcohol affect the nervous system but do not impair balance. Alcohol temporarily alters proper functioning of the cerebellum. Alcohol temporarily alters proper functioning of the cerebrum. Beverages containing alcohol have no effect on the nervous system. Correct Lab Manual Exercise 17 Post-lab Quiz Question 9 Part A Proprioception plays an important role in the ability to ________. ANSWER: maintain hand-eye coordination navigate through a dark home maintain balance while under the influence of alcohol or drugs climb a rope Correct Lab Manual Exercise 17 Post-lab Quiz Question 10 Part A Which of the following explains how the motor area on the right side of the brain controls motor function of the left side of the body? ANSWER: Lower motor neurons cross over to the opposite side. Upper motor neurons synapse with lower motor neurons in the brainstem or spinal cord. The precentral gyrus contains the cell bodies of upper motor neurons. Upper motor neurons cross over to the opposite side. Correct Lab Manual Exercise 17 From the Book Pre-lab Quiz Question 2 Part A During this laboratory exercise, you will analyze your lab partner's coordination and balance. These activities will test the function of what brain region? ANSWER: 60/72 60/72 12/1/21, 1:03 AM Labs 15-17 Assignment cerebrum cerebellum thalamus hypothalamus Correct Lab Manual Exercise 17 From the Book Pre-lab Quiz Question 3 Part A Proprioception is a general sensory awareness of position and movement of your own body parts. ANSWER: True False Correct Lab Manual Exercise 17 From the Book Pre-lab Quiz Question 4 Part A During the laboratory exercise, you will assess coordination by ANSWER: both (a) and (c). touching the tip of your nose. walking in a straight line, heel to toe. standing erect, adjacent to a vertical line. Correct Lab Manual Exercise 17 From the Book Pre-lab Quiz Question 5 Part A During this laboratory exercise, you will assess balance by ANSWER: walking in a straight line, heel to toe. both (a) and (b). standing erect, adjacent to a vertical line. moving your arms forward and bringing your fingertips together. Correct Art-labeling Activity: The Components of a Reflex Arc Part A 61/72 61/72 12/1/21, 1:03 AM Labs 15-17 Assignment Drag the labels to the appropriate location in the figure. ANSWER: Reset Sensory neuron Help Integration center Sensory receptor Motor neuron Effector organ Correct Lab Manual Exercise 17 Pre-lab Quiz Question 1 Part A A ________ is an automatic, involuntary, and predictable response to a stimulus. ANSWER: effector neuron plexus reflex Correct Lab Manual Exercise 17 Pre-lab Quiz Question 2 Part A The sensory and motor impulses of a reflex follow a specific pathway that consists of a sensory receptor sensory neuron, integration center, motor neuron, and effector organ. This pathway is known as a ________. ANSWER: 62/72 62/72 12/1/21, 1:03 AM Labs 15-17 Assignment reflex reflex arc muscle spindle stretch reflex Correct Lab Manual Exercise 17 Pre-lab Quiz Question 4 Part A Which component of a reflex arc responds to stimuli (either external or internal)? ANSWER: integration center sensory receptor sensory neuron motor neuron Correct Lab Manual Exercise 17 Pre-lab Quiz Question 5 Part A Which element of a reflex arc is responsible for carrying out an action in response to a stimulus? ANSWER: sensory neuron effector organ motor neuron sensory receptor Correct Lab Manual Exercise 17 Pre-lab Quiz Question 6 Part A Which element of a reflex arc is responsible for receiving and processing sensory information and transferring it to motor neurons? ANSWER: motor neuron sensory neuron integration center effector organ Correct 63/72 63/72 12/1/21, 1:03 AM Labs 15-17 Assignment Lab Manual Exercise 17 Pre-lab Quiz Question 7 Part A Which of the following elements of a reflex arc is responsible for delivering sensory impulses from the receptor to the central nervous system? ANSWER: integration center motor neuron sensory neuron sensory receptor Correct Lab Manual Exercise 17 Pre-lab Quiz Question 8 Part A Which of the elements of a reflex arc is responsible for delivering motor impulses from the central nervous system to effector organs? ANSWER: integration center motor neuron sensory neuron sensory receptor Correct Lab Manual Exercise 17 Pre-lab Quiz Question 9 Part A Stretch reflexes are triggered by engagement of sensory receptors called ________. ANSWER: sensory receptors muscle spindles skeletal muscles muscle fascicles Correct Lab Manual Exercise 17 Pre-lab Quiz Question 10 Part A Reflexes help clinicians assess the functional integrity of the ________. ANSWER: 64/72 64/72 12/1/21, 1:03 AM Labs 15-17 Assignment CNS PNS and CNS PNS muscular system Correct Lab Manual Exercise 17 Post-lab Quiz Question 1 Part A The biceps reflex tests the function of levels ________ of the spinal cord. ANSWER: L2, L3, and L4 S1 and S2 C5 and C6 C7 and C8 Correct Lab Manual Exercise 17 Post-lab Quiz Question 3 Part A The triceps reflex tests the function of levels ________ of the spinal cord. ANSWER: C5 and C6 L2, L3, and L4 S1 and S2 C7 and C8 Correct Lab Manual Exercise 17 Post-lab Quiz Question 4 Part A What would be the clinical significance of an absent or weak triceps reflex? ANSWER: sensory or motor neuron damage along spinal nerves C7 and C8 motor neuron damage along spinal nerves C7 and C8 sensory neuron damage along spinal nerves C7 and C8 sensory or motor neuron damage along spinal nerves S1 and S2 Correct 65/72 65/72 12/1/21, 1:03 AM Labs 15-17 Assignment Lab Manual Exercise 17 Post-lab Quiz Question 6 Part A Which of the following is a normal response to the plantar reflex test in an adult? ANSWER: slight flexion of the forearm extension of the great toe and spreading of the other toes plantar flexion of the foot slight extension of the forearm Correct Lab Manual Exercise 17 From the Book Pre-lab Quiz Question 1 Part A During this laboratory exercise, what piece of equipment will you use to perform spinal reflex tests? ANSWER: goniometer tuning fork reflex hammer measuring compass Correct Lab Manual Exercise 17 From the Book Pre-lab Quiz Question 6 Part A Stretch reflexes involve the activity of sensory receptors called muscle spindles. ANSWER: True False Correct Lab Manual Exercise 17 From the Book Pre-lab Quiz Question 9 Part A Stretch reflexes are important because the protect muscles from damage caused by overextension. ANSWER: True False Correct 66/72 66/72 12/1/21, 1:03 AM Labs 15-17 Assignment Lab Manual Exercise 17 From the Book Pre-lab Quiz Question 10 Part A The biceps reflex test assesses the function of the and segments of the spinal cord. ANSWER: True False Correct Pre-lab Video Coaching Activity: Stretch Reflexes Watch the following Pre-lab Video: Stretch Reflexes, and complete the activity below. Part A - Overview of Reflexes Drag and drop the correct terms on the left to complete the sentences. Words may be used once, more than once, or not at all. Hint 1. What is a reflex arc? A reflex arc is the neural pathway traveled by impulses producing a reflex action. Hint 2. What does intrinsic refer to? Intrinsic refers to a natural or essential component. ANSWER: 67/72 67/72 12/1/21, 1:03 AM Labs 15-17 Assignment Reset reflexes Intrinsic reflexes Help are inborn and serve to protect the body. learned reflexes Reflexes are rapid, predictable, and involuntary motor responses to stimuli. intrinsic reflexes reflex arcs Reflex arcs are neural pathways composed of five basic components. Riding a bike and driving a car are examples of learned reflexes . Correct Intrinsic reflexes are divided into two functional categories: autonomic and somatic reflexes. Part B - Autonomic and Somatic Reflexes Determine whether the following items describe somatic reflexes or autonomic reflexes. Hint 1. Motor neurons of somatic reflexes Somatic reflexes are mediated through the somatic motor neurons of the somatic nervous system. The effector organs of the somatic nervous system are responsible for body movements. Hint 2. Motor neurons of autonomic reflexes Autonomic (or visceral) reflexes are mediated through the visceral motor neurons of the autonomic nervous system. The effector organs of the autonomic nervous system are responsible for involuntary actions, such as digestion and blood pressure. ANSWER: Reset activate skeletal muscles activate glands pull hand away from hot stove activate smooth muscles patellar reflex Help activate cardiac muscles All attempts used; correct answer displayed We are generally not aware of autonomic reflexes that regulate body functions such as digestion, elimination, blood pressure, salivation, and sweating. Part C - Reflex Arc Drag the labels to identify the five basic components of a reflex arc. Hint 1. Where is the integration center? The integration center is located in the central nervous system. Hint 2. What is the difference between sensory and motor neurons? Sensory neurons transmit impulses from receptors to the central nervous system (CNS), and motor neurons transmit impulses away from the CNS. 68/72 68/72 12/1/21, 1:03 AM Labs 15-17 Assignment Hint 3. What does an effector do? The effector responds to the efferent impulses by contracting, if a muscle, or secreting a product, if a gland. ANSWER: Reset receptor Help sensory neuron integration center effector synapse motor neuron Correct Most reflexes are polysynaptic (more than one synapse) and involve the activity of interneurons in the integration center. Few reflexes are monosynaptic (one synapse) and involve only two neurons—one sensory and one motor. Since there is a delay in the impulse at synapses, the more synapses in a reflex arc, the slower the response. Part D - The Patellar Reflex Stretch reflexes are important for maintaining and adjusting muscle tone for posture, balance, and locomotion. Recall from the video that the patellar reflex is a specific example of a stretch reflex test. Which of the following components is the integration center of the patellar reflex arc? Hint 1. What is the muscle spindle? Recall from the video that the muscle spindle receives the sensory information (stimuli). It detects a change in the length of the muscle (the stretch). ANSWER: quadriceps femoris synapses in the L2–L4 segments muscle spindle patellar ligament 69/72 69/72 12/1/21, 1:03 AM Labs 15-17 Assignment Correct Reflex testing is an important diagnostic tool for assessing the condition of the nervous system. Stretch reflexes tend to be hypoactive or absent in cases of peripheral nerve damage or ventral horn disease and hyperactive in corticospinal tract lesions. They are absent in deep sedation and coma. Art-labeling Activity: Examples of Stretch Reflex Tests Part A Drag the labels to the appropriate location in the figure. ANSWER: Reset Biceps reflex test Triceps reflex test Patellar reflex test Ankle jerk reflex test Help Plantar reflex test Correct Lab Manual Exercise 17 Post-lab Quiz Question 2 Part A What would be the clinical significance of a positive Babinski sign in an adult? ANSWER: incomplete myelination sensory neuron damage in the spinal cord damage to the descending (motor) tracts in the spinal cord, indicating possible spinal cord damage muscle spindle damage Correct Lab Manual Exercise 17 Post-lab Quiz Question 5 Part A Which of the following is a normal response to the patellar reflex test? ANSWER: 70/72 70/72 12/1/21, 1:03 AM Labs 15-17 Assignment contraction of the quadriceps femoris muscles and slight extension of the leg spreading of the toes plantar flexion contraction of the gastrocnemius and soleus coupled with slight plantar flexion Correct Lab Manual Exercise 17 Post-lab Quiz Question 7 Part A Which of the following is a normal response to the plantar reflex test in an infant? ANSWER: slight extension of the forearm plantar flexion of the foot extension of the great toe and spreading of the other toes slight flexion of the forearm Correct Lab Manual Exercise 17 Post-lab Quiz Question 8 Part A Which of the following explains the difference in response to the plantar reflex test in infants and adults? ANSWER: destruction of motor neurons incomplete myelination of nerve fibers altered sensory processing in the integration center destruction of sensory neurons Correct Lab Manual Exercise 17 From the Book Pre-lab Quiz Question 7 Part A The normal response for the patellar reflex test is a slight flexion of the leg. ANSWER: True False Correct Lab Manual Exercise 17 From the Book Pre-lab Quiz Question 8 71/72 71/72 12/1/21, 1:03 AM Labs 15-17 Assignment Part A The normal response for both the plantar reflex and the ankle jerk (Achilles) reflex is dorsiflexion of the foot. ANSWER: True False Correct Score Summary: Your score on this assignment is 94.3%. You received 115 out of a possible total of 122 points. 72/72 72/72