Chapter8-review_sheet.docx

Chapter 8 : The Special Senses Name the 5 special senses. Taste – gustation Smell – olfaction Sight Equilibrium – balance Hearing Name the 2 that are chemical senses. Taste and Smell Label the drawing below: Define gustation. Begins in the mouth when food is dissolved by enzymes in slaiva Roughly 10...

Chapter 8 : The Special Senses Name the 5 special senses. Taste – gustation Smell – olfaction Sight Equilibrium – balance Hearing Name the 2 that are chemical senses. Taste and Smell Label the drawing below: Define gustation. Begins in the mouth when food is dissolved by enzymes in slaiva Roughly 10K taste buds, most of which are on the tongue Located in small bumps called Papillae Different areas of the tongue contain different taste buds Tip of the tongue – taste buds for sweet foods Anterior sides = taste buds for salty foods are near the tip of the tongue Posterior sides – taste buds for sour foods Back of tongue – taste buds for bitter things When stimulated, taste bud receptor cells send information on to the brain, where the overall taste of the food we are eating is determined Explain olfaction. Sense of smell Olfactory receptors – cells containing the olfactory hairs Olfactory hairs – respond to odors The olfactory receptors respond to odor molecules Impulses generated are sent by the axons from the olfactory receptors to the olfactory bulbs in the brain allowing the sense of smell Olfactory glands – glands in nasal mucosa that produce mucus Support cells Olfactory cells are located in the nasal mucosa Write a function for each for each of these: olfactory receptor, olfactory bulb - sense types of smells, olfactory gland. Label the drawing below: Fibrous layer Outer coat of the eyeball Divided into the sclera in the back of the eye and the cornea in the front of the eye Describe the two areas in which the fibrous layer is divided. Sclera – The white of the eye It is a tough layer that gives the eyeball its shape Protects the inner parts of the eye Cornea – transparent covering over the front of the eyeball Admits and refracts light What does the vascular layer contain? Middle layer of the eyeball It is composed of the choroid, ciliary body and iris Choroid – lines the internal surface of the sclera; contains blood vessels and absorbs light Iris – colored part of the eye; regulates amount of light that enters the eyeball Pupil – opening in the iris Ciliary body – secretes aqueous humor and moves the lens Define lens Oval shaped structure made of protein Attached to ciliary body It moves to reflect light to the retina Changing of the Len’s shape to view nearby objects is called accomodation What does the nervous layer of the eye contain? Retina – contains severaly layers of neurons Ganglionic cells – Bipolar cells – Photoreceptors - Rods – black and white vision in dim light Contain the photo pigment rhodopsin Cones – work in bright light (color vision and sharpness) 3 types of cones – red, blue, and green, allow us to see color A reduced number or lack of one of the types of cones results in color blindeness Macula lutea – area of the retina that has a high concentration of cones What is located in the anterior cavity? Contains a watery fluid called aqueous humor Vitreous is vitreous humor and where is it located? Vitreous chamber – contains a gel-like fluid that holds the retina in place Explain the nearsighted eye, farsighted eye and astigmatism eye. Near sighted eye – Myopia Close objects seen clearly Distant objects out of focus Long eyeball cause image to focus in front of retina Corrected Concave lens – causes light rays to diverge so that the image focuses on the retina Farsighted eye – Distant objects seen clearly Close objects out of focus Short eyeball causes image to focus behind retina Corrected Convex lens – causes light rays to converge so that the image focuses on the retina Astigmatism – Image blurred Irregular curvature of cornea or lens causes light rays to focus unevenly Corrected Uneven lens – focuses entire image on retina Differentiate between rods and cones. Explain the physiology of sight. Optic nerve – enters the back of the eyeball, the area where it enters is the blind spot Light enters the eye. Muscles in the iris adjust the size of the pupil to let in more or less light. The photoreceptors (rods and cones) at the very back of the eye react to incoming light. Changes in the excitability of photoreceptors are passed along to other neurons in the retina. Photoreceptors pass the light impulse on to interneurons which communicate with ganglion cells I the retina. Ganglion cells send visual input from the retina to the brain via the optic nerve. Label the diagram below: What are the 3 functional parts of the ear? Outer Ear – receiver Middle Ear – amplifier Inner Ear - transmitter Name the 3 parts of the outer ear. Pinna – external flap that directs sound waves to tympanic membrane Auditory Canal – lined with hairs; contains glands that secrete wax Tympanic Membrane – ear drum, vibrates in response to sound waves pushing the auditory ossicles The bones of the middle ear are called: Auditory ossicles – bones of middle ear that transfer sound waves to the inner ear Malleus – Incus – Stapes – Eustachian (Auditory) tube – connects middle ear to nasopharynx and equalizes pressure on both sides of the ear drum Semicircular canals, ampulla, vestibule and cochlea are part of the ______ Inner ear Semicircular canals – contain ducts filled with fluid Ampulla – swelling at the base of the semicircular canals that contain fluid and a receptor called crista ampullaris Contains receptor for rotational (dynamic) equilibrium called the crista ampullaris When the head rotates the movement of fluid moves the cupula (jelly like substance) which stimulate hair cells that produce an impulse that is sent to the brain Vestibule – contains utricle, saccule and a receptor called macula Chamber between that ampullae and cochlea Contains 2 sacs called the utricle and saccule Define oval and round window pertaining to the inner ear. Oval window – membranous structure the auditory ossicles press against Round window – membranous structure that equalizes pressure in the inner ear What is the function of the Vestibularcochlea nerve? Conducts impulses to the brain Auditory Nerve Vestibular branch – balance Cochlear branch - hearing Define macula. Is a receptor for gravitational (static) equilibrium found in both the utricle and saccule Contains hair cells that are covered by a membrane with calcium carbonate crystals When the head bends movement stimulates the hair cells which generate an impulse The 3 canals in the cochlea. Cochlea – looks like a snail, contain the receptor for hearing Contains 3 canals Vestibular canal – upper canal, contains fluid Cochlear canal – middle canal, contains fluid and the receptor for hearing called the organ of corti Tympanic canal – lower canal, contains fluid Define organ of corti. Receptor for hearing Located in the cochlear duct Contains hair cells and supporting cells Tectorial membrane – gelatinous membrane above the hair cells Basilar membrane – membrane below the organ of corti that moves when fluid flows through the tympanic canal Explain the physiology of hearing in four steps. Sound waves travel through the auditory canal to the tympanic membrane causing it to vibrate Vibrations move the auditory ossicles Auditory ossicles press against the oval window which causes pressure waves to form in the fluid of the cochlea Movement of fluid in the cochlea stimulate hair cells that generate an impulse that moves to the brain so we can hear