Composition of the Meninges

Brain meninges: name and distribution from the most superficial to the deepest. pia mater- most deep; This is the inner layer, closest to your brain tissue arachnoid mater- this is the middle layer dura mater- most superficial; the outer layer, closest to your skull Composition of the Meninges dura mater, arachnoid mater, pia mater What are the dural septa? What is the location? falx cerebri: in the longitudinal fissure, in between the cerebral hemispheres tentorium cerebelli: the superior borders of the petrous part of the temporal bone falx cerebelli: between the cerebellums of the cerebellum diaphragma selae: the roof of the pituitary fossa Where is CSF made? choroid plexus in ventricles what structures make the CSF? formed by filtration and secretion from networks of capillaries, called choroids plexuses, in the ventricles. What are the functions of CSF? mechanical protection, chemical protection, circulation Excess CSF flows into the arachnoid villi, then drains into the dural venous sinuses. The greater pressure on the CSF How does the CSF circulate and return in the subarachnoid space ensures that to the blood (place of absorption)? CSF moves into the venous sinuses without permitting venous blood to enter the subarachnoid space. Through which space does the CSF flow both in the brain and spinal cord? 1/9 subarachnoid space What is the blood brain barrier? a filtering mechanism of the capillaries that carry blood to the brain and spinal cord tissue, blocking the passage of certain substances. What glial cells are involved in the blood brain barrier? Astrocytes and microglia What is the purpose of the blood brain to protect brain from harmful substances barrier? in blood The white matter is found in the inner layer of the cortex, the optic nerves, the central and lower areas of the brain or brainstem, and surrounding the central shaft of gray matter in the spinal cord. the structure of the cerebellum and its functions (location of gray and white mater) cerebellar white matter What is the arbor vitae? Know the lobes of the brain and their main important functions. frontal: motor control, emotion, speech production temporal: auditory processing (hearing, language comprehension, memory brainstem: involuntary responses parietal: touch perception, body orientation and sensory distinction occipital: sight, visual reception and interpretation cerebellum: balance and coordination What sulci separated the different lobes of the cerebrum? The central sulcus 2/9 midbrain, pons, medulla oblongata 3 parts of the brain stem Midbrain Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion. pons A brain structure that relays information from the cerebellum to the rest of the brain medulla oblongata Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion. The grey matter contains the cell bodies, dendrites and the axon terminals, differences between white and gray matwhere all synapses are. The white matter ter is made up of axons, which connect different parts of grey matter to each other. function of limbic system emotion and memory functions of white matter in the cerebrum facilitates information transfer; helps the body process info What is the corpus callosum? a broad band of nerve fibers joining the two hemispheres of the brain. The diencephalon is located deep in the brain underneath the cerebrum, and it is the link between the nervous system and the endocrine system. It includes the location and general functions of the di- thalamus and hypothalamus. The thalaencephalon mus relays signals to and from the brain and body. -acts as a primary relay and processing center for sensory information and autonomic control. thalamus, epithalamus, hypothalamus 3 parts of the diencephalon In the brain, grey matter is mainly found in the outer layers, while in the spinal 3/9 cord it forms the core 'butterfly' shape. difference in the distribution of gray and White matter refers to the areas of the white matters between the brain and the CNS which host the majority of axons, spinal cord the long cords that extend from neurons. What are the basal ganglia? Islands of gray matter deep within the white matter of the cerebrum basal ganglia function motor control Gross Anatomy of the Spinal Cord Extends from the Foramen Magnum to L1 or L2 Cervical and lumbar enlargements (plexuses) contain the cell bodies of the many spinal nerves to the limbs Cauda Equina The Nerve roots of lumbar and sacral Spinal nerves. Ascending and descending white matter tracts carry information to/away from brain abt 18in Long and 1/2in wide Where does the spinal cord begin and begins at foramen magnum and ends at end? L1/L2 Five Segments of the Spinal Cord cervical (C1-C8), thoracic (T1-T12), lumbar (L1-L5), sacral (S1-S5), coccygeal The delicate inner layer is the pia mater. The middle layer is the arachnoid, a web-like structure filled with fluid that cushions the brain. The tough outer layer what are the three meninges and their is called the dura mater. function? where do the meninges end at the level of the spinal cord? foramen magnum Name the spaces Between the Meninges epidural space, subarachnoid space, and the subdural space. 4/9 Sensory information enters the spinal cord through the dorsal root. This comwhat type of information enters the spinal ponent of the nervous system contains cord and where it enters sensory axons that relay information regarding pain, temperature, touch, and proprioception. the type of information and location of the exit in the spinal cord (sensory vs motor information) The nerve roots exit the spinal canal through the intervertebral foramen, small hollows between each vertebra. motor information in the upper part of the pons, in the lateral part of the reticular formation location of the somatic sensory nuclei in the brain stem visceral sensory nuclei location the medial portion of the brainstem. somatic motor nuclei location how white and gray matters are organized functionally in the spinal cord In the spinal cord, gray matter is functionally organized into horns, while white matter is organized into columns. ascending= carrying sensory info (i.e. pain up to the spinal cord to the brain) 5/9 the basics of ascending (sensory) and descending (motor) pathways descending= carrying motor info (i.e. movement of arm/leg from the brain down to the spinal cord to the body) definition of tract bundle of axons in the CNS Definition of nerve bundle of axons in PNS definition of ganglion a knot-like swelling in a nerve where neuron cell bodies are concentrated in the PNS Definition of Nucleus Control center of eukaryotic cells (contains DNA) What is the peripheral nervous system (PNS)? This is the part of the nervous system outside the CNS. These are the nerves that extend from the brain and spinal cord Ex: Spinal nerves - carry impulses to and from the spinal cord Ex: Cranial nerves - carry impulses to and from the brain Sensory nerves are responsible for carrying information from the body to the brain, while motor nerves are responsible for carrying information from the brain difference between the sensory and moto the body. tor divisions. What type of information do sensory divisions= transmits impulses each carry? from peripheral organs to the CNS motor division= transmits impulses from the CNS out to the peripheral organs to cause an effect or action What is a sensory receptor? part of the nervous system that detects a stimulus i.e. interoceptors (present at the termini of the peripheral sensory ganglia) sensation= ability to detect senses (i.e. What is the difference between sensa- taste, touch). perception= brain processtion and perception? ing and communication of the sense to the rest of the body 6/9 12 cranial nerves I. Olfactory II. optic III. Oculomotor IV. Trochlear V. Trigeminal VI. Abducens VII. Facial VIII. Vestibulocochlear IX. Glossopharyngeal X. Vagus XI. Accessory XII. Hypoglossal (I) olfactory nerve sensory, smell sensory only (II) optic nerve sensory, vision sensory only (III) Oculomotor nerve motor, eye movement (IV) Trochlear nerve motor, eye movement (V) Trigeminal nerve has both sensory and motor components. it is the main sensory nerve to the head, relaying sensation of touch, pain, and temperature Abducens (VI) Lateral Rectus Muscle of the Eye (Somatic Motor) (VII) Facial nerve sensory for taste; motor fibers to the face Vestibulocochlear (VIII) Equilibrium and Hearing (Special Somatic Sensory) sensory only IX Glossopharyngeal Nerve sensory for taste; motor fibers to the pharynx (X) Vagus nerve Sensory, motor and autonomic functions of viscera (glands, digestion, heart rate) (XI) Accessory nerve motor fibers to neck and upper back (XII) Hypoglossal motor, tongue movement Which cranial nerves carry parasympathetic fibers? III (oculomotor), VII (facial), IX (glossopharyngeal), X (vagus) 7/9 Which cranial nerves move the eyeball? III (oculomotor), IV (trochlear), and VI (abducens) Which cranial nerves are involved in taste? CN VII (facial) for the anterior 2/3s of tongue; CN IX (glossopharyngeal) for the posterior 1/3 of the tongue; CN X (vagus) for the taste buds scattered over the epiglottis and pharynx. spinal nerves 31 pairs 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal What is a plexus? a network of nerves or vessels in the body How are plexuses formed? from the merging of the anterior rami of spinal nerves and blood vessels Name the 4 nerve plexuses 1. cervical plexus (Serves the Head, Neck and Shoulders) 2. brachial plexus (Serves the Chest, Shoulders, Arms and Hands) 3. lumbar plexus (Serves the Back, Abdomen, Groin, Thighs, Knees, and Calves) 4. sacral plexus (Serves the Pelvis, Buttocks, Genitals, Thighs, Calves, and Feet) Define dermatome an area of the skin supplied by nerves from a single spinal root What is a reflex arc? Involuntary response to an external stimulus. Direct connection between sensory and motor neuron without connection to brain How do we classify reflexes? either autonomic (unconscious movement) or somatic (conscious movement) 8/9 polysynaptic reflexes are mediated through at least two synapses and one How do mono- and polysynaptic reflexes interneuron. differ one sensory and motor neuron, it is referred to as a monosynaptic reflex what is the reflex arc (ipsilateral) If an afferent neuron delivers a stimulation to an efferent neuron on the same side, this is called a ipsilateral reflex. If these neurons are not on the same side, the resulting reflex is contralateral. the contraction of a muscle in response the contraction of a muscle in response to stretch of that muscle to stretch of that muscle flexor reflex (withdrawal reflex) initiated by painful stimulus like touching something hot and causes quick withdrawal/flexion of limb crossed extensor reflex opposite limb supports body during withdrawal of injured limb the Babinski reflex Infant reflex where if its foot is stroked, the baby's toes fan out (adults the same) 9/9