Chr. 17 - The Special Senses Flashcards
(176 cards)
1
Q
[17.1] What is olfaction?
A
The sense of smell.
2
Q
[17.1] What is the olfactory epithelium?
A
Epithelium in the superior part of the nasal cavity, covering the inferior surface of the cribriform plate.
3
Q
[17.1] What are the kinds of olfactory epithelium cells?
A
- Olfactory receptor cells.
- Supporting cells.
- Basal cells.
4
Q
[17.1] Describe olfactory receptor cells.
A
First order bipolar neurons laying in the epithelial tissue in the superior nasal concha. Axons extending through the cribriform plate towards the brain and dendrites contain olfactory cilia.
5
Q
[17.1] What are olfactory cilia?
A
Nonmotile cilia on dendrites of olfactory receptor cells where transduction of stimulus occurs.
6
Q
[17.1] How is a transduction formed in olfactory cilia?
A
Olfactory receptor proteins within cilia detect inhaled chemicals and bind them, generating receptor potential. These chemicals are called odorants.
7
Q
[17.1] What is an odorant?
A
Chemicals that bind to and stimulate olfactory receptors in the olfactory cilia.
8
Q
[17.1] What is a supporting cell in olfactory epithelium?
A
Columnar epithelial cells of the mucous membrane providing support, nourishment, and insulation.
9
Q
[17.1] What are basal cells in olfactory epithelium?
A
Stem cells located between bases of supporting cells undergoing cell division to produce new olfactory receptor cells.
10
Q
[17.1] What are olfactory glands?
A
Glands within connective tissue producing mucus. This mucus is carried to the epithelial surface by ducts.
11
Q
[17.1] Which nerve innervates supporting cells and olfactory glands?
A
Facial VII nerve.
12
Q
[17.1] What sort of adaptation exists in olfaction?
A
Rapid adaptation.
13
Q
[17.2] What is gustation?
A
The sense of taste.
14
Q
[17.2] What are the five primary tastes?
A
Salty, sweet, sour, bitter, and umami.
15
Q
[17.2] What is a taste bud?
A
An oval body consisting of gustatory receptors, supporting cells, and basal cells.
16
Q
[17.2] Describe the anatomy of a taste bud.
A
An oval body consisting of supporting cells surrounding groups of 50 gustatory receptor cells with basal cells laying near the connective tissue layer. Gustatory microvilli project from gustatory receptor cells through the taste pore.
17
Q
[17.2] Describe the function of basal cells in a taste bud.
A
Basal cells lay near the connective tissue layer and differentiate into supporting cells. These supporting cells eventually develop into gustatory receptor cells.
18
Q
[17.2] What is a papillae with respect to the tongue?
A
An elevation on the tongue containing taste buds/
19
Q
[17.2] What are the types of papillae?
A
- Vallate papillae.
- Fungiform papillae.
- Foliate papillae.
- Filiform papillae.
20
Q
[17.2] Describe vallate papillae.
A
12 large, circular papillae forming an inverted V at the back of the tongue. Contain 100-300 taste buds.
21
Q
[17.2] Describe fungiform papillae.
A
Mushroom shaped elevations across the tongue, contain 5 taste buds.
22
Q
[17.2] Describe foliate papillae.
A
Located in small trenches but irrelevant because they disappear in early childhood.
23
Q
[17.2] Describe filiform papillae.
A
Pointed, thread-like structures with tactile receptors and providing friction but lacking taste buds.
24
Q
[17.2] What are tastants?
A
A chemical stimulating gustatory receptors.
25
[17.4] What are the accessory structure of the eye?
The eyelids, eyelashes, eyebrows, lacrimal apparatus, and extrinsic eye muscles.
26
[17.4] What is the function of the eyelids?
Shade eyes during sleep, protection, and lubrication.
27
[17.4] What is the muscle responsible for moving the eyelid?
Levator palpebrae superioris.
28
[17.4] What is the space between the upper and lower eyelids?
Palpebral fissure.
29
[17.4] What are the angles of the palpebral fissure of the eye?
Lateral commissure and medial commissure.
30
[17.4] What is the lacrimal caruncle?
A small, reddish elevation on the medial commissure.
31
[17.4] List the layers of the eyelid from superficial to deep.
Epidermis,
Dermis,
Subcutaneous tissue,
Fibers of orbicularis oculi muscle,
Tarsal plate,
Tarsal glands,
Conjunctiva.
32
[17.4] What is a tarsal plate?
A thick fold of connective tissue giving form to eyelids.
33
[17.4] What are the tarsal glands?
Elongated, modified sebaceous glands secreting fluid to prevent eyelids from adhering to each other.
34
[17.4] What is the conjunctiva?
A thin protective mucous membrane composed of nonkeratinized stratified squamous epithelium and containing goblet cells.
35
[17.4] What is the palpebral conjunctiva?
Conjunctiva lining the inner eyelids.
36
[17.4] What is the bulbar conjunctiva?
Conjunctiva passing from eyelids onto the surface of the eyeball and covering the sclera.
37
[17.4] What are eyelashes?
Hair projecting from the eyelid.
38
[17.4] What are eyebrows?
Hair on the bony arch above the eyelids
39
[17.4] What are sebaceous ciliary glands?
Glands at the base of hair follicles releasing lubricating fluids into follicles.
40
[17.4] What is the lacrimal apparatus?
A group of structures that produces and drains lacrimal fluid.
41
[17.4] What is lacrimal fluid?
Water based fluid containing salts, mucus, and lysozyme.
42
[17.4] What are lacrimal glands?
Glands that produce lacrimal fluid and secrete it onto the surface of the palpebral conjunctiva.
43
[17.4] What is the lacrimal puncta?
Small openings in the medial portion of the eye draining lacrimal fluid into canaliculi.
44
[17.4] What are the lacrimal canaliculi?
Ducts passing to the lacrimal sac.
45
[17.4] What is the lacrimal sac?
A sac of lacrimal connecting to the nasolacrimal duct.
46
[17.4] What is the nasolacrimal duct?
A duct carrying lacrimal fluid to the nasal cavity inferior of the inferior nasal conchae.
47
[17.4] What is periorbital fat?
A layer of fat surrounding the orbit.
48
[17.4] How many extrinsic eye muscles are there?
Six.
49
[17.5] What are the layers of the eyeball?
1. Fibrous tunic.
2. Vascular tunic.
3. Retina.
50
[17.5] What is the fibrous tunic?
The superficial layer of the eyeball consisting of anterior cornea and posterior sclera.
51
[17.5] What is the cornea?
A triple-layered transparent coat covering the coloured iris
52
[17.5] Describe the composition of the layers of the cornea.
Outer layer: nonkeratinized statified squamous epithelium.
Middle layer: collagen fibers and fibroblasts.
Inner surface: simple squamous epithelium.
53
[17.5] What is the sclera?
A layer of dense connective tissue mostly made of collagen fibers and fibroblasts.
54
[17.5] What is the scleral venous sinus?
An opening at the junction of sclera and cornea.
55
[17.5] What is the vascular tunic?
The middle layer of the eyeball composed of choroid, ciliary body, and iris.
56
[17.5] Describe the choroid.
The posterior portion of the vascular tunic containing a high number of blood vessels as well as melanocytes.
57
[17.5] Describe the ciliary body.
Middle portion of the vascular tunic composedof ciliary processes and ciliary muscles. Extends from the ora serrata to just posterior of the junction between sclera and cornea.
58
[17.5] What is the ora serrata?
The jagged anterior margin of the retina.
59
[17.5] What are ciliary processes?
Protrusions on the internal surface of the ciliary body containing blood capillaries supplying aqueous humor.
60
[17.5] What are zonular fibers?
Suspensory ligaments attaching to the lens from the ciliary body. Composed of thin, hollow fibrils resembling elastic connective tissue fiber.
61
[17.5] What is a ciliary muscle?
A circular band of smooth muscle altering the shape of the lens by tightening or loosening zonular fibers
62
[17.5] What is the iris?
The coloured portion of the eyeball suspended between the cornea and lens, attached on the periphery to ciliary processes. Contains melanocytes and smooth muscle fibers (circular and radial)
63
[17.5] What is the function of the iris?
To regulate the amount of light that enters the pupil.
64
[17.5] What is the pupil?
A hole in the center of the iris.
65
[17.5] What are circular muscles?
Muscles of the iris innervated by the parasympathetic system that contract to limit light entering the pupil.
66
[17.5] What are radial muscle?
Muscles of the iris innervated by the sympathetic system to contract resulting in dilation of the pupil.
67
[17.5] What is the retina?
The inner layer of the eyeball and beginning of the visual pathway.
68
[17.5] What is the optic disc?
The site where the optic III nerve exits the eyeball.
69
[17.5] What is the central retinal artery?
A branch of the ophthalmic artery bundled with the optic nerve.
70
[17.5] What is the central retinal vein?
The main vein collecting blood from the veins of the eyeball, bundled with the optic nerve.
71
[17.5] What are the layers of the retina?
Deep to superficial - the pigmented layer and a neural layer.
72
[17.5] What is the pigmented layer of the retina?
A sheet of melanin-containing epithelial cells between the choroid and the neural layer. Absorbs stray light rays.
73
[17.5] What is the neural layer of the retina?
A multilayered outgrowth of the brain processing visual data extensively before sending impulses through the optic nerve.
74
[17.5] What are the layers of retinal neurons?
Deep to superficial - photoreceptor cell layer, bipolar cell layer, and ganglion cell layer.
75
[17.5] What are the zones separating the layers of retinal neurons?
The outer and inner synaptic layers.
76
[17.5] Explain how impulses are generated when light enters the eye.
Light enters the eye and passes through, in order, the ganglion layer, the outer synaptic layer, the bipolar layer, the inner synaptic layer, and reaches the photoreceptor layer. Once activated, the photoreceptor layer generates a signal and sends it up to the ganglion layer, where it transmits down to the optic disc and onto the brain.
77
[17.5] What are horizontal cells and amacrine cells?
Cells forming laterally directed neural circuits within the bipolar layer of the retina.
78
[17.5] What is the function of horizontal cells and amacrine cells?
Modify signals transmitted along the pathway from photoreceptor layer to ganglion layer.
79
[17.5] What are the types of photoreceptor cells?
Rods and cones.
80
[17.5] What are rods?
Rods allow for dim vision light and do not receive colour.
81
[17.5] What are cones?
Cells producing colour vision from bright light - blue, red, and green.
82
[17.5] What is the blind spot of the eye?
The region on the retina producing no vision due to the exit of the optic III nerve.
83
[17.5] What is the macula lutea?
The exact center of the posterior portion of the retina at the visual axis of the eye.
84
[17.5] What is the fovea centralis?
A small depression in the center of the macula lutea containing only cones, exposed without cover of the bipolar and ganglion layer.
85
[17.5] What is the lens?
A refractive layer made of crystalins enclosed by clear a connective tissue capsule laying behind the pupil and iris.
86
[17.5] What is the function of the lens?
Focus images on the retina to facilitate clear vision.
87
[17.5] What are the cavities of the eyeball?
Anterior cavity and posterior cavity.
88
[17.5] Where does the anterior cavity lay?
In front of the lens.
89
[17.5] What are the sections of the anterior cavity of the eye?
The anterior chamber and posterior chamber.
90
[17.5] Where does the anterior chamber lay?
Between the cornea and iris.
91
[17.5] Where does the posterior chamber lay?
Between the iris and zonular fibers/lens.
92
[17.5] What is aqueous humor?
Fluid filling the anterior cavity that nourishes the lens and cornea.
93
[17.5] What is the posterior cavity?
Known as the vitreous chamber, laying behind the lens and in front of the retina.
94
[17.5] What is the vitreous body?
A transparent jellylike substance within the vitreous chamber holding the retina flush against the choroid.
95
[17.5] What is the hyaloid canal?
A narrow channel inconspicuous running through the vitreous body from the optic disc to the lens.
96
[17.5] What is intraocular pressure?
Pressure in the eye maintained aqueous humor and the vitreous body.
97
[17.6] What are the three processes of image formation?
1. Refraction of light by lens and cornea
2. Accommodation, change in the shape of lens
3. Constriction of pupil.
98
[17.6] What is refraction?
Light changes direction at junctions of different adjacent substances with different densities.
99
[17.6] Describe the refraction of light rays processes in the eye.
Light rays enter the eye and are refracted at both ends of the cornea and lens to focus on the retina. Images are inverted and flipped as it projects onto the retina.
100
[17.6] Describe accommodation in the eye.
The ability of the lens to increase or decrease curvature, changing the degree to which light is refracted.
101
[17.6] What is the near point of vision?
The minimum distance from the eye an object can be focused on.
102
[17.6] What is an emmetropic eye?
A normal eye.
103
[17.6] What are abnormalities of refraction?
Myopia, hyperopia, and astigmatism.
104
[17.6] What is myopia?
An abnormality where the eyeball is too long compared to the cornea and lens, or the lens is thicker. resulting in nearsightedness - inability to properly see distance objects.
105
[17.6] What is hyperopia?
An abnormality where the eyeball is too short compared to the cornea lens, or the lens is thinner than normal. Results in farsightedness - inability to properly see near objects.
106
[17.6] What is astigmatism?
An abnormality where either the cornea or lens has irregular curvature resulting in out-of-focus vision.
107
[17.6] What is convergence in relation to eyes?
Medial movement of both eyeballs directed toward the object.
108
[17.6] What is binocular vision?
The characteristic of both eyes focusing on one set of objects.
109
[17.6] What is a photopigment?
A coloured protein undergoing structural changes when absorbing light. Found in outer segment of photoreceptors.
110
[17.6] What is rhodopsin?
A photoreceptor, present in rods and cones, and the only photoreceptor present in rods.
111
[17.6] What are cone photopigments?
Photopigments found in cones, three varieties present: one for green, one for blue, and one for red.
112
[17.6] What is opsin?
A glycoprotein making up half of a photopigment.
113
[17.6] What is retinal?
A derivative form of vitamin A composing half of a photopigment.
114
[17.6] What are the steps of the cyclical process in which photopigments respond to light?
1. Isomerization
2. Bleaching
3. Conversion
4. Regeneration
115
[17.6] Describe the isomerization step of photopigments responding to light.
The straightening of retinal from its resting shape, initiated by a photon of light being absorbed. One isomerized, the outer segment experiences a colour-changing chemical process leading to a receptor potential.
116
[17.6] Describe the bleaching step of photopigments response to light.
The changed retinal separates from opsin causing opsin to appear colourless.
117
[17.6] Describe the conversion step of the photopigments response to light.
An enzyme, retinal isomerase, converts retinal back to its resting shape.
118
[17.6] Describe the regeneration stage of a photopigments response to light.
Retinal rebinds to opsin, forming the function photopigment.
119
[17.7] What is hearing?
The ability to perceive sounds.
120
[17.7] List the main regions of the ear.
1. External ear
2. Middle ear
3. Internal ear
121
[17.7] List the parts of the external ear.
Auricle,
External auditory canal,
Tympanic membrane
122
[17.7] Describe the auricle.
A flap of elastic cartilage covered by skin, composed of the helix and the lobule. Attached to the head by ligaments and muscles.
123
[17.7] Describe the external auditory canal.
A curved tube about 2.5cm long in the temporal bone leading to the tympanic membrane. Contains ceruminous glands.
124
[17.7] What are ceruminous glands?
Specialized sweat glands that secrete cerumen, a wax meant to prevent dust and foreign objects.
125
[17.7] Describe the tympanic membrane.
A thin, semitransparent partition between external auditory canal and middle ear. Connective tissue covered by epidermis and lined by simple cuboidal epithelium.
126
[17.7] Describe the middle ear.
An air-filled cavity of the petrous portion of the temporal bone lined by epithelium and containing the auditory ossicles; separated from the inner ear by a bony partition.
127
[17.7] List the auditory ossicles.
Incus, stapes, and malleus.
128
[17.7] Describe the malleus.
A hammer shaped bone in the middle ear attaching to the tympanic membrane and articulating with the incus.
129
[17.7] Describe the incus.
Anvil-shaped bone in the middle ear articulating with the malleus and the stapes.
130
[17.7] Describe the stapes.
A stirrup-shaped bone in the middle ear articulating with the incus and fitting into the oval window.
131
[17.7] What is the oval window?
One of two windows connecting the middle ear to the inner ear. Fits the stapes.
132
[17.7] What is the round window?
One of two windows connecting the middle ear to the inner ear. Contains the secondary tympanic membrane.
133
[17.7] What is the tensor tympani?
A muscle supplied by mandibular trigeminal V nerve, limits movement and increases tension of eardrum to protect inner ear from loud noises.
134
[17.7] What is the stapedius?
A muscle supplied by the facial VII nerve dampening vibrations of the stapes and protecting the oval window. Decreases sensitivity of hearing if paralyzed.
135
[17.7] What is the auditory tube?
A channel connecting the middle ear with the nasopharynx, lined by bone and elastic cartilage.
136
[17.7] What are the divisions of the inner ear?
The outer bony labyrinth, and an inner membranous labyrinth.
137
[17.7] Describe the bony labyrinth.
A series of cavities in the petrous portion of the temporal bone, divided into three areas and lined with periosteum and containing perilymph.
138
[17.7] What are the areas of the bony labyrinth?
The semicircular canals, the vestibule, and the cochlea.
139
[17.7] Describe the semicircular canals.
Three bony projections laying at right angles from each other and contain semicircular ducts of the membranous labyrinth.
140
[17.7] What is the ampulla?
A swollen enlargement of the end of each semicircular canal.
141
[17.7] What is the vestibule?
An oval central portion of the bony labyrinth between the cochlea and semicircular canals. Holds the utricle and saccule of membranous labyrinth.
142
[17.7] What is perilymph?
Fluid similar to cerebrospinal fluid surrounding the membranous labyrinth.
143
[17.7] What is the membranous labyrinth?
A series of epithelial sacs and tubes inside the bony labyrinth housing receptors for hearing and equilibrium.
144
[17.7] What is endolymph?
A fluid high in potassium found within the membranous labyrinth.
145
[17.7] What is the vestibular ganglion?
Cell bodies of sensory neurons in the ampullary, utricular, and saccular nerves of the vestibular branch of the vestibulocochlear VIII nerve.
146
[17.7] What is the cochlea?
A bony spiral canal resembling a snail shell.
147
[17.7] What is the modiolus?
The central bony core of the cochlea.
148
[17.7] What are the divisions of the cochlea?
The cochlear duct, the scala vestibuli, and the scala tympani.
149
[17.7] What is the cochlear duct?
A continuation of the membranous labyrinth into the cochlea. Filled with endolymph.
150
[17.7] What is the scala vestibuli?
A channel in the bony labyrinth deep to the cochlear duct, extending from the oval window and containing peri lymph.
151
[17.7] What is the scala tympani?
A channel in the bony labyrinth superficial to the cochlear duct, extending from the round window and containing perilymph.
152
[17.7] What is the helicotrema?
The opening of the cochlea just after the round window and oval window before the cochlea begins.
153
[17.7] What is the vestibular membrane?
A membrane separating the cochlear duct from the scala vestibuli.
154
[17.7] What is the basilar membrane?
A membrane separating the cochlear duct from the scala tympani.
155
[17.7] What is the spiral organ?
A coiled sheet of epithelial cells, mostly supporting cells and hair cells, resting on the basilar membrane.
156
[17.7] List and describe the groups of hair cells.
Inner hair cells, arranged in a single row - receptors for hearing.
Outer hair cells, arranged in three rows - increase sensitivity of inner hair cells.
Both synapse with first-order sensory neurons and motor neurons of the cochlear branch of the vestibulocochlear VIII nerve.
157
[17.7] What are stereocilia?
Long, hair-like microvilli extending from apical tips of each hair cell extending into endolymph.
158
[17.7] What is the spiral ganglion?
Cell bodies of the sensory neurons in the cochlea branch of the vestibulocochlear VIII nerve.
159
[17.7] What is the tectorial membrane
A flexible gelatinous membrane covering hair cells of the spiral organ.
160
[17.7] What is a sound wave?
Alternating high-and-low pressure waves travelling in the same directions though a medium.
161
[17.7] What is frequency?
The length of a period of a sound wave. Measured in Hertz, the number of waves in 60 seconds.
162
[17.7] What is intensity as it relates to sound waves?
The size or amplitude of sound waves. Measured in decibels, a scale measuring loudness of a scale where 1 decibel represents a ten-fold increase in sound with 0 as a baseline.
163
[17.7] Describe the event of hearing.
Sound waves travel down the external auditory canal and strike the tympanic membrane causing it to vibrate. The malleus picks up the vibrations of the TM and they travel down the incus to the stapes which vibrates in the oval window. This transmits the vibrations, now amplified, transfer into perilymph of the scala vestibuli and ultimately to the perilymph of the scala tympani and round window. As the scala vestibuli and scala tympani resonate, it vibrates the cochlear duct and the endolymph, successively vibrating the basilar membrane, moving the spiral organ and the tectorial membrane, generating receptor potentials in the inner hair cells, beginning the action potential of first-order neurons.
164
[17.8] What is equilibrium?
Sense of balance.
165
[17.8] What is the receptor organ for equilibrium?
The vestibular apparatus.
166
[17.8] What makes up the vestibular apparatus?
The utricle, the saccule, and the semicircular ducts.
167
[17.8] What are otolithic organs?
The utricle and the saccule.
168
[17.8] What is the macula?
A small, thickened region attaching to the inner walls of the utricle and saccule. Responsible for sensing linear acceleration/deceleration and head tilt.
169
[17.8] Describe the composition of the macula.
Hair cells acting as sensory receptors, and supporting cells.
170
[17.8] Describe hair cells of the macula.
Similar to hair cells of the basilar membrane in the cochlea, aninner hair cell accompanied by three outer hairs cells, whilte containing a kinocilium, forming a "hair bundle"
171
[17.8] What is the otolithic membrane?
A thick, gelatinous glycoprotein layer secreted by supporting cells.
172
[17.8] What are otoliths?
A dense layer of calcium carbonate crystals extending over the surface of the otolithic membrane.
173
[17.8] On the semicircular ducts, what is the crista?
An elevation on the junctionto the ampulla.
174
[17.8] What is the composition of cristae?
Hair bundles covered by cupula.
175
[17.8] What is cupula?
A gelatinous material covering cristae.
176
[17.8] How is equilibrium sensed?
Motion of the head (acceleration/deceleration/tilting) occurs with a lag in movement of endolymph. As the endolymph moves belatedly, it causes drag pulling on cupula and the otolithic membrane. As the cupula and otolithic membrane moves, it shifts kinocilium stimulating them and producing receptor potential.
