1. what are olfactory receptor cells, supporting cells, and basal cells?

1. Olfactory receptor cells are bipolar neurons (1 main dendrite and 1 axon) with dendrites and an axon projecting through cribriform plate that ends in olfactory bulb

Olfactory receptor cells respond to chemical stimulation of an odorant

by producing a generator potential, thus initiating olfactory response

2. Supporting cells

• Columnar epithelial cells of mucous membrane lining nose

• Provide physical support, nourishment, and electrical insulation for olfactory receptor cells

• Help detoxify chemicals that come in contact with olfactory epithelium

3. Basal cells

• Stem cells located between bases of supporting cells

• Continually undergo mitosis

• produce new olfactory receptor cells

2.What is the function of the Bowman’s glands?

a. Produce mucus that is carried to surface of epithelium by ducts

b. Secretion moistens surface of olfactory epithelium

i. dissolves odorants so that transduction can occur (conversion of odor to electrical impulse)

3.Olfactory pathway to brain.

1. Through the cribriform plate

2. Synapse with the olfactory bulb

3. Impulses travel along the olfactory tract

4. Interpretation in the primary olfactory area in the cerebral cortex (temporal lobe)

4.Steps to olfactory transduction. G protein, cAMP, Na+ ion influx, depolarization. Know order.

I. Binding of an odorant to an olfactory receptor protein in olfactory cilium stimulates membrane protein called G protein

II. Binding of an odorant to an olfactory receptor protein in olfactory cilium stimulates membrane protein called G protein

III. cAMP opens a Na+ channel and Na + enters cytosol which causes depolarization

IV. If depolarization reaches threshold, action potential is generated along axon of olfactory receptor

V.

5. What is gustation? Where are gustatory receptors located?

Gustation is a chemical sense

5 primary tastes: sour, sweet, bitter, salty, and umami (“meaty” or “savory”)

Umami-the taste of flavor enhancers added to food to accentuate savoriness, such as monosodium glutamate (MSG)

6. What are gustatory receptor cells? Supporting and basal stem cells?

Gustatory cells-

1. Single long microvillus projects from each cell

2. to the external surface through taste pore (an opening in the taste bud)

Basal cells

3. Stem cells found at periphery of taste bud

4. Produce supporting cells which then develop into gustatory receptor cells

7. What are the 3 types of papaillae that contain taste buds and where are they located on the tongue? What type of papillae contain tactile receptors but no taste buds?

1. Vallate papillae (back of tongue; about 12 that contain 100–300 taste buds)

2. Fungiform papillae (scattered over the tongue with about 5 taste buds each)

3. Foliate papillae (located in lateral trenches of the tongue

} Filiform papillae cover the entire surface of the tongue. Contain tactile receptors but no taste buds

8. Gustatory pathway to brain. From taste buds, nerve impulses propagate along cranial nerves to medulla oblongata to where? Thalamus From this point, where do nerve signals travel to in the cerebral hemisphere (e.g., primary gustatory area)? See figure.

From the taste buds:

• nerve impulses propagate along 3 cranial nerves to medulla oblongata

From medulla oblongata:

1. axons carry taste signals to thalamus

2. where it enters the primary gustatory area in parietal lobe

3. Gives rise to conscious perception of taste

9. Facial (VII) nerve carries taste information from:

anterior 2/3 of the tongue

10. Glossopharyngeal (IX) nerve carries taste information from:

posterior 1/3 of the tongue

11. Vagus (X) nerve carries taste information from:

taste buds on the epiglottis and in the throat

12. What are the conjunctivia, palpebral fissure, lateral and medial commissure, and palpebrae? What are their functions?

} Eyelids (palpebrae)

◦ Shade eyes during sleep, protect eyes from excessive light

} Palpebral muscles control eyelid movement (under eyelid)

} conjunctiva- a thin, protective mucous membrane

◦ lines the eyelids and covers the sclera

} Palpebral fissure-space between upper and lower eyelid

} Lateral and medial commissure-angles of palpebral fissure

13. What is lacrimation?

Group of structures that produces and drains lacrimal fluid (tears) (protective mechanism)

14. Wall of the eyeball consists of 3 layers. What is each layer called and what structures make up each layer?

1. Fibrous tunic (superficial layer)

1. Cornea-transparent coat

1. covers colored iris and helps focus light onto retina

2. Sclera- “white” part; covers entire eyeball except the cornea

1. gives shape to eye

2. Vascular tunic (middle layer)

3. Choroid-highly vascularized and lines most of sclera

1. contains melanocytes that produce melanin which absorbs stray light rays and prevents reflection and scattering of light within eyeball

4. Iris-regulates amount of light that enters eyeball

5. Ciliary body-consists of ciliary muscles (smooth muscle) that alter shape of lens

6. Ciliary processes- folds on ciliary body that contain blood capillaries that secrete aqueous humor

7. Contraction or relaxation of ciliary muscle:

1. changes tightness of elastic fibers which alters shape of lens

3. Retina

◦ Lines the posterior three-quarters of the inner layer of the eyeball

◦ Optic (II) nerve is also visible

15. What is the function of the cornea, sclera, choroid, ciliary body, iris, and retina?

Iris- regulate amount of light entering pupil

Cornea- covers colored iris and helps focus light onto retina

Sclera- gives shape to eye

Choroid - contains melanocytes that produce melanin which absorbs stray light rays and prevents reflection and scattering of light within eyeball

Ciliary body - alter shape of lens

Retina- detects light and color

16. What is the macula lutea? Fovea centralis?

Macula lutea- exact center of the retina

In its center is the fovea centralis(area of highest visual acuity; most CONES are here!)

17. What are rods and cones?

◦ Rod– allow us to see in dim light and not in color (120 million). Only register black and white; more light sensitive. Several rods share a ganglion, so you don’t get real detail (just basic shape)

◦ cones – bright light stimulates cones and provide us with color vision (6 million) Each cone gets its own ganglia, so you get more detailed description

18. Where do light rays refract(bends) within the eye? There are 2 locations.

Cornea and lens

19. What is the anterior chamber, posterior chamber, aqueous humor, vitreous chamber, vitreous humor?

- Anterior chamber (between the iris and cornea) is filled with aqueous humor (a clear, watery liquid)

- Posterior chamber lies behind the iris and in front of the lens and is also filled with aqueous humor

- vitreous chamber (behind posterior chamber) filled with a transparent, gelatinous substance, called the vitreous humor

- Aqueous Humor - thin, watery fluid that fills the space between the cornea and the iris

• produced by the ciliary body

• fluid nourishes the cornea and the lens and gives the eye it's shape

- Vitreous humor - clear gel that fills the space between the lens and the retina

• maintains structural stability of eye

20. Know the pathway light takes from cornea to retina. See figure.

Light passes through:

1. cornea (refracts)

2. anterior chamber

3. pupil

4. posterior chamber

5. Lens (refracts)

6. vitreous humor

7. and is projected onto the retina

21. What is emmetropic, myopia, and hyperopia?

• The normal (emmetropic) eye will refract light correctly and focus a clear image on the retina.

• Myopia (nearsightedness) - eyeball is longer than it should be and the image is focused in front of the retina. See close objects sharply, but perceive distant objects as blurry. A concave lens (thinner at center) is used to correct the vision

• Hyperopia (farsightedness) also known as hypermetropia - eyeball is shorter than it should be and the image is focused behind the retina. See distant objects clearly, but have difficulty with close objects

22. Where is the image forming in reference to the retina in nearsighted people? How about far-sighted people?

Nearsightedness- Image is focused in front of retina

Farsightedness- the image is focused behind the retina

23. How does light make its way to the retina? What about refraction?

As light rays enter eye: rays are refracted at cornea and lens so they come into exact focus on retina. Images focused on retina are upside down and reversed. Brain corrects this image

24. What structures make up the outer ear, middle ear, and inner ear?

} External ear- Contains the auricle (pinna), external auditory canal and the tympanic membrane (eardrum). Ceruminous glands secrete cerumen (earwax) to protect the canal and eardrum

} Middle ear- Contains 3 auditory ossicles; Malleus, incus, and stapes. Sound vibrations are transmitted from the eardrum: through these 3 bones to the oval window into which the stapes fits. Auditory tube (Eustachian tube) extends from the middle ear into the nasopharynx to regulate air pressure in the middle ear

} Inner ear - Cochlea- translates vibrations into neural impulses that brain can interpret as sound. Semicircular canals - work with the cerebellum for balance and equilibrium

lie at approximately 90 deg angles to each other

25. What does the auricle (pinna), external auditory canal, tympanic membrane (eardrum), and chochlea do?

-Auricle captures sound .

-External auditory canal transmits sound to the eardrum.

-Tympanic membrane (eardrum)-

- Cochlea- translates vibrations into neural impulses that brain can interpret as sound.

26. How does sound enter the ear and how does it translate into electrical signals? Know the steps. See figures.

1. Auricle directs sound waves into external auditory canal

2. Waves strike and vibrate tympanic membrane

3. Vibrations continue along malleus, incus, and then to stapes (inner ear)

4. Vibrations continue through oval window

5. Movement of stapes set up fluid pressure waves in perilymph in cochlea into scala vestibuli(channel above cochlea duct)

27. How do sound impulses enter the brain? See flowchart and figure.

Cochlear nerve fibers form part of vestibulocochlear (VIII) nerve

1. Axons synapse with neurons in medulla oblongata and pons

1. Midbrain (inferior colliculi)

Impulses travel to thalamus and end in the primary auditory area of the temporal lobe

28. What structure of the inner ear functions in dynamic equilibrium?

Semicircular canals

29. What structure of the ear functions in static equilibrium?

Otolithic Organs- Saccule and Utricle

Walls of both utricle and saccule contain thickened region called macula

2 maculae are receptors for static equilibrium

30. Equilibrium pathway. How do nerve impulses reach the brain?

Nerve impulses pass along axons of sensory neurons and form vestibulocochlear nerve and enter the medulla and pons of brain

Thalamus and inferior colliculi

Temporal lobe for

processing