Lab 9 Sensory Organs Eye and Ear

Anatomy & Physiology 1 Lab Lab 9: Sensory Organs: Eye and Ear Objectives for this Lab: 1. Differentiate between general senses and special senses. 2. List the extrinsic muscles of the eye. 3. Identify the following structures of the eye on pictures and classroom models: the sclera, cornea, choroid layer, iris, pupil, ciliary bodies, lens, retina, fovea centralis and optic nerve. 4. Describe the functions of the following structures of the eye: sclera, cornea, iris, pupil, lens, fovea centralis and optic nerve. 5. Describe the difference between the rods and cones of the retina. 6. Differentiate between the different regions of the ear. 7. Identify the following structures of the ear on pictures and classroom models: auricle, external auditory meatus, tympanic membrane, auditory tube, incus, malleus, stapes, cochlea, semicircular canals and vestibulocochlear nerve. 8. Describe the functions of the following structures of the ear: auricle, tympanic membrane, auditory tube, auditory ossicles, cochlea, semicircular canals and vestibulocochlear nerve. 9. Determine the purpose of the papillae found on the tongue and the type of cells found in our taste buds. 10. Describe the 3 types of cells that comprise our olfactory epithelium. Overview: In order to maintain homeostasis in our body, it is necessary for our brain to receive constant input from our internal and external environment. We have many different types of sensory receptors (nerve endings) found throughout our body in our skin and internal organs. This would be classified as our general senses. Receptors in the skin may send information to the brain regarding temperature, pressure or pain. Receptors lining our blood vessels will detect changes in pressure, stretch and chemical composition. Our brain must receive this information in order to determine if a response is necessary and what that response should be. This allows us to maintain a state of equilibrium. We also have specialized sensory organs found in our head that will send information to the brain about olfaction (smell), gustation (taste), vision, hearing and equilibrium. In lab today, we will be discussing the special senses of olfaction, gustation, vision and hearing. We will focus primarily on identifying the structures and functions of the Eye and Ear. 144 Anatomy & Physiology 1 Lab Pre Pre-La -La -Lab bQ Que ue uestio stio stions ns ns:: 1. What type of sensations do our somatic sensory receptors detect? sight, sound ______________________________________________________________ smell 2. What does the sense of Olfaction detect? _______________________________ 3. Which of the following structures are part of the middle layer of the eye? (check all that apply) _✔_ pupil _ _ sclera _ _ retina _✔_ iris _✔_ lens _ _ cornea 4. What is the function of the pupil of the eye? controls the amount of light entering the eye ______________________________________________________________ 5. Where are the rods and cones found? in the retina ___________________________________ 6. True/False: The fovea centralis is the region of highest visual acuity. true ________ 7. What structure separates the outer ear from the middle ear? ear drum ____________________________________________ 145 Anatomy & Physiology 1 Lab 8. List the 3 auditory ossicles (bones) found in the middle ear. Incus: shaped like an anvil; Malleus: shaped like a hammer; Stapes: shaped like a stirrup ______________________________________________________________ 9. What type of information does the vestibulocochlear nerve transmit to the brain? nerve signals to the brain associated with balance, equilibrium and hearing ______________________________________________________________ 10.What are the 5 basic taste sensations? sweet, salty, sour, bitter and umami (savory, meat) ______________________________________________________________ 146 Anatomy & Physiology 1 Lab Lab Exercises: Exe Exerci rci rcisse 9. 9.1 1: Iden entify tify the Extr xtrins ins insiic Muscle scless of the EEye: ye: 147 Anatomy & Physiology 1 Lab Exe Exerci rci rcisse 9.2 .2:: Ide dentif ntif ntifyy the fo follow llow llowing ing sstru tru tructu ctu ctures res o off the Ou Outer ter LLaayer o off th the e E ye - Sclera Cornea (Clear) sclera cornea Question: 2. What type of tissue is the sclera made up of? epithelium with collagen fibers in between ____________________________________ 148 Anatomy & Physiology 1 Lab Exe Exerci rci rcisse 9. 9.3 3: Id Iden en entify tify the follo ollowi wi wing ng str truct uct ucture ure uress o off the Middl iddle e LLay ay ayer er of the Eye - Choroid Layer Iris Pupil Ciliary Body Lens lens cilliary body iris 149 Anatomy & Physiology 1 Lab pupil Question: 1. What is the function of the lens? focuses image directly onto the retina by changing its shape _____________________________________________________________________ 150 Anatomy & Physiology 1 Lab Exe Exerci rci rcisse 9. 9.4 4: Id Iden en entify tify the follo ollowi wi wing ng str truct uct ucture ure uress o off the Inner LLaayer o off th the e Eye - Retina Fovea Centralis Optic Nerve Optic Disc retina optic nerve Fovea Centralis optic disc retina Question: 1. Why is the optic disc referred to as the “blind spot”? there are no visual receptors here. _____________________________________________________________________ 151 Anatomy & Physiology 1 Lab Exe Exerci rci rcisse 9. 9.5 5: Id Iden en entify tify the follo ollowi wi wing ng str truct uct ucture ure uress o off the Oute terr EEar ar - Pinna (Auricle) External Auditory Meatus Tympanic Membrane external auditory canal pinna/ auricle? tympanic membran Question: 1. What is the purpose of the tympanic membrane? to seperate outer and middle ear. sound waves cause vibrations of membrane and causes the ossicles (bones) to vibrate. _____________________________________________________________________ 152 Anatomy & Physiology 1 Lab Exe Exerci rci rcisse 9. 9.6 6: Id Iden en entify tify the follo ollowi wi wing ng str truct uct ucture ure uress o off the Middl iddle e EEar ar - Auditory (Eustachian) Tube Ossicles: o Incus o Malleus o Stapes Auditory tube incus malleus 153 Anatomy & Physiology 1 Lab stapes Question: 1. What 2 structures does the auditory tube connect? nasal pharanyx and auditory ossicles _____________________________________________________________________ 154 Anatomy & Physiology 1 Lab Exe Exerci rci rcisse 9. 9.7 7: Id Iden en entify tify th the e follo ollow wing ssttruc ructur tur tures es of the IInne nne nnerr EEar ar - Cochlea Semicircular Canals Vestibulocochlear Nerve vestibulocochlear nerve semicircular canals cochlea Question: 1. What are the functions of the Inner Ear? hearing and equilibrium balance _____________________________________________________________________ Exe Exerci rci rcisse 9. 9.8 8: Visua isuall A Acu cu cuity ity ity:: Snellen Test An Emmetropic (normal) eye can take the light from an object 20 feet away and focus it directly on the retina. If the shape of the eye, lens or cornea is irregular, this image will be focused in front of or behind the retina. The Snellen (E) Chart is used to test normal acuity. Normal acuity (20/20 vision) would allow an individual to see line 8 on the chart from 20 feet away. 1. Stand 20 feet from the Snellen Test and cover one eye at a time while you read as much of the chart line by line. 155 Anatomy & Physiology 1 Lab Post-Lab Questions: 1. What organs (or organ systems) do you think contribute to balance and equilibrium? inner ear- (all parts) _____________________________________________________________________ 2. Why would a respiratory infection potentially cause an ear infection? swelling, inflammation, mucous in Eustachian tubes from URI/allergy can block them causing accumulation of fluids in middle ear. Bacterial/oral infection of fluid is what gives 3. If the semicircular canals of the inner ear are damaged, how might this affect an individual? They are sensory receptors that detect proprioception and equilibruim posture balance, movement awareness _____________________________________________________________________ 4. Explain what “far-sightedness” and “near-sightedness” are. Far sighted- cant see far away near sighted- cant see? _____________________________________________________________________ 5. What causes an astigmatism and how do we test for it? common condition/blurred vision _________________________________________________________________ 156