A&P CH 17
Terms
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- 3 Types of cells of the Olfactory Epithelium
- Olfactory Receptors, Supporting Cells, and Basal Stem cells.
- The first order neurons of the Olfactory Pathway, Bipolar neuron.
- Olfactory Receptor
- Cilia that project from the dendrite, and the sites of olfactory transduction
- Olfactory Hairs
- Columnar epthelial cells of the mucous membrane lining the nose. They provide physical support, nourishment, and electrical insulation for the olfactory receptors.
- Supporting Cells
- Lie between the bases of the supporting cells and continually undergo cell division to produce new olfactory receptors, which live for only a month of so before getting replaced.
- Basal stem cell
- Produce mucous that is carried to the surface of the epithelium by ducts.
- Olfactory (Bowman's) Gland
- Physiology of Olfaction
-
1. Production of cAMP
2. Opening of Na ion channel
3. Inflow of Na
4. Depolarizing generator potential
5. Nerve impulses arise and propagate along axon of olfactory receptor. - DEcreasing sensativeity, about 50% in the first second of stimulatin of olfaction
- Adaptation
- Reduced ability to smell, affects half of those over 65 and 75% over 80.
- Hyposmia
- 40 bundeles of axons collectively form the right and left olfactory nerves
- Cranial nerve I
- Primary tastes
- Sour, Sweet, Bitter, Salty, and Umami
- Location of taste buds
- Tounge, soft palate, pharynx, and Epiglottis.
- 3 Types of Epithelial cells of the taste bud.
- Supporting Cells, Gustatory Receptor Cells, and Basal Cells
- Found at the periphery of the tase bud near the connective tissue layer, produce supporting cells.
- Basal Cell
- Developed from supporting cells with a lifespan of about 10 days. Synapse with dendrites of the First-order neurons that form the first part of the gustatory pathway
- Gustatory Receptor Cells
- Provide a rough texture, and the location of the taste buds.
- Papillae
- Types of Papillae
- Vallate Papillae, Fungiform Papillae, Foliate Papillae.
- Chemicals that stimulate gustatory receptor cells.
- Tastants
- The three cranial nerves that include axons of first order neurons from taste buds.
- Facial Nerve (VII), Glossoparyngeal nerve (IX), and Vagus Nerve (X).
- The 3 structures of the wall of the eyeball.
- Fibrous Tunic, Cascular Tunic, and Retina.
- Superficial avascular coat of the eyeball, consists of the anterior cornea and posterior sclera.
- Fibrous Tunic
- Transparent coat that covers the colored Iris.
- Cornea
- The 3 layers of the Cornea
-
Outer: nonkeratinized stratified squamous epithelium.
Middle: collagen fibers and fibroblasts.
Inner: simple squamous epithelium. - The white of the eye, a layer of dense connectie tissue made up of collagen fibers and fibroblast. Gives the eye shape.
- Sclera
- The junction of the sclera and cornea, secretes a fluid called aqueous humor into the sinus.
- Scleral venous sinus (Canal of Schlemm)
- 3 parts of the vascular tunic.
- Charoid, Ciliary body, and Iris
- Highly vascularized posterior portion of the vascular tunic, lines most of the internal surface of the sclera. It provides nutrients to the posterior surface of the retina.
- Charoid
- The anterior portion of the vascular tunic
- Ciliary Body
- Protrusions or folds on the internal surface of the ciliary body. They contain blood capilaries that secrete aqueous humor.
- Ciliary Processes
- Extend from the ciliary process and attach to the lens.
- Zonular Fibers (Suspensory Ligaments)
- Circular band of smooth muscle that alters the shape of the lens, adapting it for near or far vision.
- Ciliary Muscle
- Regulates the amount of light entering the vitreous chamber fo the eyeball through the pupil.
- Iris
- When bright light stimulates the eye, parasympathetic neurons stimulate this muscle of the iris to contract, causing the pupil to constrict.
- Circular Muscles (Sphincter Pupillae)
- Muscles that cause the Iris to recede, and the pupil to dialate.
- Radial Muscles (Dilator Pupillae)
- Third and inner coat of the eyeball
- Retina
- Site where the optic nerve exits the eyeball.
- Optic Disc
- Layers of the optic part of the Retina.
- Pigmented Layer and Neural Layer
- Sheet of melanin containing epithelial cells located between the charoid and the neural part of the retina.
- Pigmented Layer
- Absorbs stray light rays, which prevents reflection and scattering of light within the eyeball.
- Melanin in the charoid and in the Pigmented layer.
- Multilayered outgrowth of the brain that extensively processes visual data before sending nerve impulses into axons that from the optic nerve.
- Neural Layer
- 3 Layers or retinal neurons
- Photoreceptor layer, bipolar layer, and Ganglion Cell Layer.
- These cells form lateraly directed neural circuits that modify the signals being ransmitted along the pathway from photoreceptors to bipolar cells to ganglion cells.
- Horizontal Cells and Amacrine Cells.
- Low light threshold, allowing us to see in dim light, such as moonlight.
- Rods
- Stimulated by brighter light, and has a higher threshold and produce color vision.
- Cones
- Exact center of the posterior portion of the retina, at the visualaxis of the eye.
- Macula Lutea
- Area of highes visual acuity or resolution. Small depression near the center of the macula lutea, contains only cones.
- Central Fovea
- The optic disc contains no rods or cones, so it is also known as
- Blind Spot
- Helps focus images on teh retina to facilitate clear vison. Made up of protiens called crystallins, perfectly transparent and lacks blood vessels.
- Lens
- The lens divides the interior of the eyeball into two cavities.
- Anterior Cavity and Vitreous Chamber
- A watery fluid that nourishes the lens and cornea.
- Aqueous Humor
- Pressure in the eye, produced mainly by the aqueous humor and partly by vitrous body. Maintains the shape of the eyeball and prevents the eyeball from collapsing.
- Intraocular Pressure
- Degenerative disorder of the retina and pigmented layer in persons 50 years of age and older.
- Age-related macular disease (AMD)
- Increase in curvature of the lens of the lens for near vision.
- Accomodation
- Where 75% of the total refraction of light occurs.
- Cornea
- Provides the remaining 25% of focusing power and also changes the focus to view near or distant objects.
- Lens
- Light rays any closer than this distance are divergent rather than parallel, so they must be refracted more if they are to be focused on the retina.
- 6m or 20ft
- With aging, the lens loses elasticity and thus its ability to accomodate.
- Presbyopia
- A normal eye is known as
- Emetropic
- The eyeball is too long relative to the focussing power of the cornea adn lens, Nearsightedness.
- Myopia
- The eyeball length is short relative to the focusing power of the cornea and lens, Farsightedness
- Hypermetropia/Hypermyopia
- Both eyes focus on only one set of objects. Allows perception of depth andan appreciaton of the 3D nature of objects.
- Binocular Vision
- Binocular vision occurs when
- Light rays from an dobject strike corresponding points on the two retinas.
- Medial movement of both eyeballs so that both are directed toward the object being viewed.
- Convergence
- In rods and cones, transduction of light energy occurs in the
- Outer Segment
- The first step in visual transduction is absorption of light by a
- Photopigent
- Light absorption initiates the events that lead to the production of a
- Receptor Potential
- The photopigments in rods
- Rhodopsin
- 2 Parts of photopigments associated with vision
- the glycoprotein Opsin and the vitamin A dirivative retinal
- The light absorbing part of all visual photopigments
- Retinal
- Photopigments respond to light in the following cyclical process
-
1. Isomerization
2. Bleaching
3. Retinal Isomerase
4. Regeneration - The frequency of a sound vibration is the
- Pitch
- The louder the sound is the higher the
- Intensity
- The production of receptor potentials in the ear is caused by a bending of the
- Stereocilia
- to close transduction channels, allow repolarization or even hyperpolarization to occur, and reduce neurotransmitter release from the hair cells.
- Bending of the stereocilia in the opposite direction
- Inaudible sound produced by the cochlea
- Otoacoustic Emissions
- Receptor organs for equilibrium
- Saccule, Utricle, and Semicircular ducts
- Receptors for static equilibrium, also detect acceleration and deceleration in dynamic equilibrium
- Maculae
- Two types of cells of Maculae
- Supporting cells (Sensory receptors) and hair bundles