CONCEPT REVIEW ( Special Senses) Flashcards
The special senses include smell, taste, ………., hearing, and equilibrium. …………… for these senses are located in complex sensory organs of the head.
VISION , RECEPTORS
The special senses include smell, taste, vision, hearing, and equilibrium. Receptors for these senses are located in complex sensory organs of the head.
The receptors for olfaction, olfactory receptor cells, are in the …………………………………. in the superior area of the …………… cavity.
olfactory epithelium, nasal
The receptors for olfaction, olfactory receptor cells, are in the olfactory epithelium in the superior area of the nasal cavity.
Olfactory hairs respond to ?
inhaled chemicals, or odorants
What do supporting cells do?
detoxify chemicals, electrically insulate receptors, and provide support and nourishment
What do Basal cells do?
continually divide to produce new olfactory receptor cells
What do Olfactory glands do?
Olfactory glands produce mucus to dissolve odorants.
What’s the role of Olfactory receptors?
Olfactory receptor cells are excited by odorant molecules binding to odorant binding proteins. This results in production of a generator potential, which may lead to an action potential.
Does Olfaction have a low or high threshold?
Olfaction has a low threshold; only a few molecules are needed to be perceived as an odor. Adaptation to odors occurs rapidly.
Explain the last process of Olfaction
Bundles of axons of olfactory receptor cells pass through foramina in the cribriform plate of the ethmoid bone and form the left and right olfactory nerves, which convey impulses of smells to the olfactory bulbs, olfactory tracts, limbic system, and cerebral cortex (temporal and frontal lobes).
How do Impulses for Gustation travel?
Impulses for taste propagate along the facial, glossopharyngeal, and vagus nerves to the brain.
Gustation involves distinguishing five tastes:
bitter, sour, salty, sweet, and umami.
MISSING WORDS
Receptors for taste are located in……………….. Taste buds are found on the tongue in …………………,
fungiform, ……………, and filiform papillae. …………….. increase friction with food to help manipulate it. Each taste bud consists of supporting cells, ………………, and gustatory receptor cells that have a gustatory hair projecting from the cell through a taste pore to the surface.
Taste buds, vallate, foliate, Papillae, basal cells
What do Tastants do? How does the Gustation system react to them?
Tastants dissolve in saliva and bind to gustatory hairs, stimulating the receptor cells to have a receptor potential that stimulates the release of neurotransmitter, which can generate action potentials in firstorder neurons.
Explain how taste varies
The threshold for each of the primary tastes varies, and adaptation to taste occurs quickly.
Three cranial nerves propagate gustation impulses to the medulla oblongata; some then project to
the : 4 other areas…
limbic system, hypothalamus, thalamus, and cerebral cortex (parietal lobe).
MISSING WORD
The eye is protected by eyelids, eyelashes, eyebrows, and a ………………………….?
lacrimal apparatus.
The accessory structures of the eye include ?
eyelids, eyelashes, eyebrows, lacrimal apparatus, and extrinsic eye muscles.
The eyelids shade and protect the eyes, and spread lubricants over the eyeballs. Each eyelid contains ?
the orbicularis oculi, meibomian glands, and conjunctiva.
The lacrimal apparatus includes ?
the lacrimal glands, lacrimal ducts, lacrimal puncta,
lacrimal canals, lacrimal sac, and nasolacrimal duct.
How many extrinsic muscles move each eyeball? What are the names?
6, the superior rectus, inferior rectus, lateral rectus,
medial rectus, superior oblique, and inferior oblique.
MISSING WORD
The eye is constructed of………………. layers.
three
The wall of the eyeball has three layers: name them
the fibrous tunic, vascular tunic, and retina.
The superficial fibrous tunic consists of the
posterior, tough, protective, white sclera
MISSING WORDS
the anterior, curved, transparent ________. The scleral venous___________is at the junction of the sclera
and cornea, and functions to drain aqueous _______.
cornea, sinus, humor
The vascular tunic is between the fibrous tunic and retina. How are nutrients delivered?
The vascular choroid supplies
nutrients to the retina and absorbs scattered light rays
MISSING WORDS
The ciliary body consisting of the _____________ and ciliary muscle that secretes ___________ and controls the shape of the lens, and the ______, which regulates the diameter of its central opening, the _______.
cilliary processes, aqueous humor, iris, pupil
What is the innermost tunic of the eye?
The retina
MISSING WORDS
The outer pigmented layer prevents scattering of ___________. The neural layer contains photoreceptors, bipolar cells, and ____________. The _________ are photoreceptors that are stimulated by even low light and allow night or dim vision. ________ are photoreceptors that are stimulated by bright light and produce color vision.
light rays, ganglion cells, rods , cones
Visual information passes from photoreceptors to
bipolar cells to ganglion cells
Axons of ganglion cells extend to the
optic disc
What is the blind spot of the eye & why?
Optice disc, no rods and cones
Where in the eye are only cones situated?
The central, posterior portion of the retina contains only cones. This area, the fovea centralis, is the area of highest visual acuity.
What is posterior to the pupil and iris?
The lens is posterior to the pupil and iris,
The LENS is transparent and contains proteins called ___________. The lens functions to focus images on the retina.
crystallins
The lens divides the interior of the eyeball into the anterior cavity and the ____________. The anterior cavity, the space anterior to the lens, contains anterior and posterior chambers filled with _____________. The larger vitreous chamber, between the lens and the retina, contains the ________________.
vitreous chamber, aqueous humor, vitreous body
Image formation involves refraction of light rays, accommodation, pupil constriction, and ________?
convergence.
Light rays entering the eye undergo __________, the bending of light rays at each surface of the cornea and the lens, which focuses an inverted image on the fovea centralis of the retina.
refraction
What is Accommodation?
an increase in the curvature of the lens for near vision.
An ___________ eye is a normal eye that can refract light rays so that a clear image is focused
on the retina. _________ (nearsightedness) is the inability to focus properly on distant objects. __________ (farsightedness) results in the inability to focus on nearby objects
emmetropic, Myopia, Hyperopia
When there is an irregular curvature to the cornea or lens that causes parts of an image to be out of focus or distorted?
Astigmatism
Human eyes have __________ to allow depth perception. When objects move closer, the eyes must move medially and undergo _________, so that light rays from the object can strike the same points on both eyes.
binocular vision, convergence
The neural pathway of light is photoreceptors →
bipolar cells → ganglion cells → optic nerve → primary visual cortex.
Photoreceptors have photopigments that transduce light energy into a receptor potential. Rods have the photopigment ___________; cones have three different cone photopigments that absorb different colors of light.
rhodopsin
Photopigments contain two parts: the glycoprotein _______, and retinal, the lightabsorbing part of photopigments. When retinal absorbs light, it changes shape from cis to trans in a process called __________ . The transretinal separates from opsin during bleaching. The photopigment finally undergoes regeneration when cisretinal binds to opsin.
opsin, isomerisation
Light adaptation occurs when photoreceptors adjust to a brighter environment by decreasing their sensitivity as increasing amounts of ___________ are bleached.
photopigment
____________ occurs when photoreceptors increase sensitivity by increasing photopigment regeneration. Only rods function at low light intensity.
Dark adaptation
Light striking the retina activates enzymes that lead to a receptor potential in the photoreceptors, then receptor potentials in ____________ that synapse on photoreceptors.
bipolar cells
Bipolar cells transmit receptor potentials to ganglion cells, which generate action potentials. Ganglion cell axons exit the eyeball as the optic nerve. When optic nerve axons pass through the _________, they either cross to the opposite side or continue straight ahead, forming the optic tract that enters the ___________. Optic radiations allow for projection to the primary visual areas of the cerebral cortex.
optic chiasm, thalamus
The pathway of sound is tympanic membrane → ?
ossicles → oval window → cochlea → vestibulocochlear nerve → primary auditory cortex.
Sound waves are alternating _________________regions traveling in a medium.
high and low pressure
