Eye and Cells Olfactory Neurons

Chapter 15 The Special Senses

Olfaction
A.
1. Olfactory epithelium
Specialized cells lining the olfactory recess
2. Olfactory bulbs (#1)
Axons of olfactory neurons project through the cribriform plate (#1) to these structures
Where the olfactory nerves synapse with mitral & tufted cells
3. Olfactory vesicles bulbous enlargements of the dendrites of olfactory neurons
4. Olfactory hairs
Have chemoreceptors (#5) that bind to odorants, resulting in action potential production
5. Basal cells olfactory neurons lost from the olfactory epithelium are replaced by these cells

B.
1. Olfactory nerves
Formed by axons from the olfactory neurons
2. Olfactory bulb
3. Olfactory tracts
Structures that project from the olfactory bulbs to the cerebral cortex
4. Olfactory cortex
Where the olfactory tracts terminate
5. Lateral olfactory area
Part of olfactory cortex involved with the conscious perception of smell
6. Medial olfactory area
Part of olfactory cortex responsible for visceral & emotional reactions to odors
7. Intermediate olfactory area
Part of olfactory cortex that modifies input from the olfactory bulb
Taste
A.
1. Vallate papillae
Largest but least numerous papillae; surrounded by a groove or valley
2. Fungiform papillae
Mushroom-shaped papillae; appear as small, red dots scattered irregularly over the tongue
3. Foliate papillae
Leaf-shaped papillae; distributed over the sides of the tongue & containing the most sensitive taste buds
4. Filiform papillae (#4)
Filament-shaped papillae; most numerous papillae, but with no taste buds; provide a rough surface on the tongue

B.

C.
1. Tastants
Substances dissolved in saliva that cause taste cells to depolarize
2. Salt (#3)
Taste that results from the diffusion of Na+ into taste cells
3. Acid
Taste that results from H+ diffusing into taste cells, binding to ligand-gated K+ channels, or binding to ligand-gated channels that let positive ions into taste cells.
4. Sweet, Bitter, Umami (savory)
3 tastes that result from the activation of G protein mechanisms
Accessory Structures of the Visual System

A.
B.
C.
1. Lacrimal Gland
2. Lacrimal ducts
3. Puncta
4. Lacrimal canaliculi
5. Lacrimal sac
6. Nasolacrimal duct

D.

Anatomy of the Eye

A.
1. Fibrous layer (#7)
Outer layer of the eye, consisting of the sclera & cornea (#8)
2. Vascular layer (#7) middle eye layer; the choroid, ciliary body, & iris.
3. Nervous layer (#7) inner layer of the eye, consisting of the retina
4. Sclera firm 5. Cornea (#9)
Avascular, transparent structure; permits light entry
B.
C.
D.

Functions of the Complete Eye

A.
1. Visible light
2. Refraction (#10)
Bending of light rays as they pass into a new medium, such as light passing from air into water
3. Convex
4. Concave
5. Focal point
6. Focusing
7. Reflection

B.
1. S
2. E
3. Ciliary muscles (#11)
Structures that contract & reduce the tension on the lens, allowing it to assume a more spherical shape

Structure & Function of the Retina

A.

B.

C.

D.

E.

F.
(#12, order of layers of neurons in the sensory retina as they encountered light passes from the vitreous humor through the sensory retina)
(1)Photoreceptor layer--- (2) Bipolar layer)--- (3) Ganglionic layer
1. Photoreceptor cells
2. Bipolar cells
3. Ganglion cells
4. Optic nerve
5. Interneurons neurons

Neuronal Pathways for Vision
A.
B.

Clinical Applications
A.
B.

Auditory Structures & Their Functions
A.
B.
C.
D.
1. Bony labyrinth
2. Cochlea
3. Scala vestibuli (#15)
Cochlear chamber that contains perilymph & extends from the oval window to the helicotrema
4. Scala tympani
5. Helicotrema
6. Vestibular membrane
E.
F.
G.

Neuronal Pathways for Hearing

Balance
A.
1. Static labyrinth
2. Macula
3. Otoliths
4. Semicircular canals
5. Crista ampullaris (#14)
Specialized sensory epithelium located in each ampulla
6. Cupula