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137 Cards in this Set
- Front
- Back
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define proprioreceptors
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special senses located within body muscles, joints, or bones.
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What is the mechanoreceptor for hearing?
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Organ of Corti (hair cells)
in the cochlea detects vibration inner ear |
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What are the mechanoreceptors for balance in the inner ear?
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maculae and cristae (hair cells)
in the vestibular apparatus detects deflection inner ear |
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Olfactory cells and gustatory cells are what kind of receptors?
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chemoreceptors.
in superior nasal cavity dorsum of tongue and pharynx |
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Name the three layers of the wall of the eye.
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1. outer: sclera & cornea: tough fibrous
2 middle: choroid - iris - ciliary body: highly vascular 3. retina - contain light receptors |
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Describe the fluid fill cavities of the eye.
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Anterior Cavity: has anterior chamber (bt the iris and cornea) AND posterior chamber (bt the iris and lens)
- both have watery aqueous humor. |
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Describe the location and fill of the posterior CAVITY of the eye
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between the lens and retina
contains jelly vitreous humor |
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What two layers of smooth muscle control the iris?
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sphincter muscles: constrict pupil
and dilator muscles: makes pupil larger |
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What is the "white" of the eye?
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the visible portion of the sclera.
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What is the function of the cornea?
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Refracts light
helps focus light onto the retina. |
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What is the function of the sclera?
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Maintains shape of eye
Protects eye Site of muscle attachment |
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What is the function of the iris?
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Controls the amount of light passing through the pupil.
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What is the function of the ciliary body?
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Changes shape of lens aka accommodation
Secretes aqueous humor. |
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What is the function of the choroid?
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Absorbs light
Contains blood vessels for eye structures. |
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What is the function of the retina?
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Absorbs light & stores vitamin A
Detects light & forms image for transmission to brain. |
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What is the function of lens?
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Refracts light
Important in accommodation (changing shape of lens) |
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What is the function of anterior cavity?
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Maintains shape of eye
Refracts light through vitreous humor. |
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What is the function of posterior cavity?
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Maintains shape of eye
Refracts light through aqueous humor |
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What is the function of aqueous humor?
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Fills anterior cavity.
Helps maintain shape of eye Refracts light Maintains intraocular pressure |
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What is the function of vitreous humor?
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Fills posterior cavity
Maintains intraocular pressure Shapes eye. Keeps retina firmly pressed against choroid. Refracts light. |
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Describe the two layers of the retina.
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1. outer pigmented layer, adheres to choroid.
2. inner layer of nerve tissue (the retina proper) |
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Describe the three layers of the retina's nerve tissue.
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1. Receptor neurons (closest to choroid) 100 million rods, 700 million cones.
2. Bipolar neuron layer 3. Ganglionic neurons attach directly to the optic nerve. |
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Describe "rod" vision
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Dim light.
Form outlines or silhouettes of objects. Twilight vision. |
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Describe "cone" vision
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most accurate if light permits close, detailed vision.
Daylight vision. Color and Detail. |
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Describe the eye's fovea centralis
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Small indentation in center of retina.
Cones are most concentrated. To see clearly, focus on fovea centralis. Fewer cones as you move away. |
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Where can you see movement and twilight vision most clearly?
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Periphery of retina, where rods are more concentrated.
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What is the visual pigment?
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Rhodopsin.
Derived from Vitamin A Light energy causes changes in the shape of the protein. Starts nerve impulses in bipolar and ganglion cell layers. |
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What is accommodation?
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The process of light focusing based on lens elasticity.
Distant object - lens flattens Close object - lens rounded (convex) Ciliary muscle acts on suspensory ligaments to change lens shape. RELAXES to reduce tension, lens more convex. |
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What parts of the eye refract light?
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lens
cornea aqueous humor vitreous humor focus and converge on fovea centralis. |
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Describe external visual field
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The area served by an eye.
Overlaps. Allows 3D vision. |
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What is strabismus?
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Cross eyes
see to images bc muscle movements of eye do not work together. |
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What happens in nearsightedness?
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Rays focus in front of lens.
Need concave lens to correct. Caused by elongation of eyeball or Lens that does not adjust properly |
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What happens in astigmatism?
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Rays do not focus on fovea.
Need an uneven lens in glasses to correct. = the inability to separate two closely placed point. |
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What is hyperopia?
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Farsightedness.
Image forms behind the retina. |
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What is farsightedness?
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Image forms behind retina.
Eyeball is too short. Lens too flat. Happens w age as lens loses elasticity. |
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What is colorblindness.
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Cones cannot react to certain colors.
Sex linked genetic trait, carried by females, expressed most often in males. |
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What is the purpose of the ear?
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To gather sound waves and transmit them to nerve cells in the inner ear.
Cortex of temporal lobe. |
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What are the parts of the external ear?
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Pinna (auricle)
External auditory canal & meatus. Tympanic membrane (eardrum) |
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What is the function of the external auditory canal?
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Amplifies & channels sound waves
A few hairs Ceruminous (sweat) glands secretes earwax. Prevent dust & foreign objects from entering ear. |
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Name the parts of the middle ear?
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- small, air filled cavity
- Tympanic Membrane and Windows are the boundaries. - Auditory Ossicles (malleus, incus, stapes) - Tensor Tympani - Eustachian Tube |
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What is the function of the tympanic membrane?
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Eardrum
Vibrates Transforms the sound energy into the mechanical energy |
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Which CN supplies the tensor tympani?
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- CN V: trigeminal.
- limits movement of and - increases tension on eardrum - to prevent damage to inner ear from loud noises |
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What is the function of the eustachian tube?
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- from middle ear to pharynx
- helps maintain air pressure on both sides of the eardrum. - normally closed. opens when swallowing, yawning, allowing air to enter/leave middle ear. equal pressure. |
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What causes otitis media?
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Ear infection.
- pathogens travel through eustachian tube from nose and throat to middle ear. |
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Name the two major divisions of the inner ear
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1. Bony labrynth: vestibule, cochlea, semicircular canals.
2. Membranous labrynth |
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Name the three channels in the cochlea.
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1. scala vestibuli
2. scala tympani 3. cochlear duct |
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Where are the receptors for equilibrium located?
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Bony labyrinth
- semicircular canals - vestibule |
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Where are the receptors for hearing located?
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cochlea
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What is the membranous labyrinth?
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- contains endolymph
- series of epithelial sacs and tubes inside the bony labyrinth. - high level of Potassium ions. |
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What does the bony labyrinth contain?
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- contains perilymph.
- similar to Cerebrospinal Fluid - surrounds the membranous labyrinth. |
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What structures are in the vestibule?
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Vestibule is the oval central part of bony labyrinth.
- two sacs: utricle saccule. - connected by small duct. |
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What are vestibular ganglia?
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Cell bodies of sensory neurons of CN VIII - vestibulocochlear nerve.
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What is the helicotrema?
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Scala vestibuli (top - ends at oval window)
Scala tympani (bottom - ends at round window) Cochlear duct (in middle) At end of cochlea all join. Perilymph around all. |
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Describe the Organ of Corti
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aka spiral organ.
- coiled sheet of epithelial cells (supporting cells) - 16,000 hair cells - receptors - inner hair cells: single row - outer hair cells: three rows At tip of hair, are 40-80 stereocilia (microvilli) several rows of graded height. - tectorial membrane covers - bodies rest on basilar membrane |
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Describe the tectorial membrane.
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tector=covering
- flexible, gelatinous membrane, covers the hair cells of the cochlea. |
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Define pitch.
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Pitch = frequency. The number of air vibrations per unit of time. Cycles per second.
higher frequency = higher pitch. humans: 100-5000 Hertz 1HZ=1cycle per second. |
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Define Intensity
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intensity = amplitude
decibels dB 0 - 1000 HZ uncomfortable at 120, painful at 140 |
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Define timbre
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timbre=quality. overtones vary with object producing the sound
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What is the role of the basement membrane?
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certain regions vibrate to certain sound waves. each segment is "tuned" for a particular pitch.
- narrow & stiff at window = high pitched sounds. |
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What are the receptor organs for static equlibrium?
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Macula in saccule and utricle are perpendicular to each other
- position of head and = linear acceleration & deceleration - have supporting cells, hair cells & otolithic membrane (jelly) & otoliths (stones) |
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What are the receptor organs for dynamic equilibrium?
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3 semicircular ducts (canals)
- detects rotational acceleration /decelearation - ampulla has crista. - each crista has supporting cells & hair cells. - covering crista is cupula (jelly) - hair cells move, endolymph lags behind. - hair bends... produces AP VIII |
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Where are the cell bodies of sensory neurons located for
a. hearing b. equilibrium |
a. spiral ganglia
b. vestibular ganglia |
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Describe symptoms and causes of
cataracts |
loss of transparency of lens.
caused by aging, UV rays, injury, meds (steroids), diabetes, smoking |
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Describe symptoms and causes of
glaucoma |
High intraocular pressure due to buildup of aqueous humor in the anterior cavity.
- puts pressure on neurons of retina, eventually destroyed.. blind. race, age, family history, injuries |
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Describe symptoms and causes of
sensorineural deafness |
impairment of hair cells in cochlea or damage to VIII nerve.
- caused by atherosclerosis (reduces blood to ears), loud noise, drugs (aspirin, streptomycin) |
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Describe symptoms and causes of
conduction deafness |
- can't transmit sounds.
otosclerosis (new bone forms around oval window), earwax, injury, aging (stiffens ossicles & thickens eardrum) |
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Describe symptoms and causes of
Meniere's disease |
- Increased endolymph enlarges membranous labyrinth.
- vertigo, tinnitus, and fluctuating hearing loss (basilar membrane is distorted) |
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Describe symptoms and causes of
otitis media |
- infection of middle ear
- bacteria from eustachian tube - in children e. tube is horizontal.. decreases drainage. |
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Describe taste buds.
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- located in tiny elevations - papillae
- sweet, sour, bitter, salty, umani - individual taste cell is within the taste bud. |
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Where are the tastes located on the tongue?
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back: bitter
lateral front: sour lateral back: salt front: sweet & salty pharynx: umami |
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CN for taste are?
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Facial
Glossopharyngeal. medulla- thalamus-temporal lobe |
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Describe visual convergence
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medial movement of the two eyeballs so that both are directed toward the object being viewed.
eg. pencil - crosseyed |
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Describe the steps in visual transduction.
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1. photopigment absorbs light.
(rhodopsin in rods, three different forms for cones) rhodopsin = opsin + retinal (vit.A) retinal part absorbs light 2. isomerization (cis-to-trans) 3. bleaching - trans-retinal separates from opsin. 4. enzyme retinal isomerase converts trans-retinal back to cis- 5. regeneration. cis- can bind to opsin |
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What is the neurotransmitter in the eye?
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glutamine
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What are the three types of tastebud papillae?
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1. Vallate papillae - 12 in V at back of tongue. each has 100-300 buds
2. Fungiform papillae: entire surface, have 5 taste buds each 3. Foliate papillae: small trenches on lateral margins. die in early childhood. also 4. Filiform papillae: pointed, threadlike: for tactile reception and increase friction so food can move. |
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What CN are involved in taste?
What is the pathway? |
VII Facial (front 2/3)
IX Glossopharyngeal (back 1/3) X Vagus (buds in throat and epiglottis) - to gustatory nucleus in medulla - to limbic, hypothalamus, thalamus. from thalamus to parietal lobe. |
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Describe the olfactory receptors.
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- 1st order, bipolar neuron.
- knob shaped dendrite - axon goes through cribriform plate to olfactory bulb. - olfactory hairs project from the dendrite. |
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Besides the sensory neurons, what other cells are in the nose?
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- Supporting cells: columnar epithelial cells. support, nourishment, electrical insulation, detoxify chemicals.
- Basal cells: stem cells renew every month (nerve cells regenerating!) |
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What are olfactory (Bowman's) glands?
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- produce mucus.. carried to surface by ducts.
- moistens surface and dissolves odorants so transduction can occur. |
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What CN innervates olfactory cells?
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CN VII Facial
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What happens in the olfactory bulb?
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Axons of receptors synapse with dendrites/cell bodies of olfactory bulb neurons.
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What is unusual about the olfactory nerve pathway?
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DO NOT first synapse in thalamus.
- go to olfactory ares of cortex (inferior/medial temporal lobe) - lymbic system & hypothalamus (emotions = smells) - frontal lobe (id smells) |
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What are steroid hormones?
Name some. |
- lipids made from cholesterol.
cortisol, cortisone estrogen, progesterone testosterone |
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What are the four kinds of non-steroid hormones?
Give examples. |
1. Proteins: chains of aa
insulin, calcitonin (thyroid), pituitary hormones, somatotropin, prolactin 2. Peptides: shorter chains of aa ADH and oxytocin 3. Amines: derived from aa throxine (thyroid), nor-epi & epinephrine (adrenal) 4. glycoproteins: FSH, LH, TSH |
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Describe the action of steroid hormones.
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- readily pass through cell membranes
- combine with proteins - stimulate synthesis of proteins which cause chang |
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Define hormone
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A molecule that is released in one part of the body but regulates the activity of cells in other parts of the body.
- bloodstream usually delivers. - bind to receptors on target cells. - some can be neurotransmitters & hormones (eg norepi) |
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Name some exocrine glands
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- secrete products into ducts
sudoriferous (sweat) glands subaceous (oil) glands mucous digestive glands |
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Name the endocrine glands
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pituitary
thyroid parathyroid adrenal pineal also, hypothalamus, thymus, pancreas, ovaries, testes, kidneys stomach, liver, small intest, skin, heart, adipose tissue, placenta |
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Lipid Soluble Hormones
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1. Steroid: from cholesterol
2. Thyroid: T3 and T4 3. NO nitric oxide (hormone & neurotransmitter) |
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Water Soluble Hormones
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1. Amine Hormones
epi, norepi, dopamine, histamine, serotinin, melatonin 2. Peptide Hormones/Protein Hormones ADH, oxytocin, Human Growth, insulin 3. Eicosanoid Hormones |
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What does insulin do?
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Stimulates synthesis of glycogen in liver cells.
and synthesis of triglycerides in adipose cells. |
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What are some responses to hormones?
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- synthesis of a new molecule (insulin)
- change the permeability of plasma membrane - stimulate transport of a substance into or out of target cells. - alter the rate of metabolic reactions - cause contraction of smooth or cardiac muscle. |
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Where are receptors for hormones located?
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- lipid soluble: inside target cells
- water soluble: plasma membrane |
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What are first messenger, second messengers?
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Water solubile
binds to receptor on membrane = first messenger (G protein) causes production of a second messenger inside the cell. A common 2nd messenger is cyclic AMP |
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Water Soluble Hormone Process
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1. 1st mess. binds to membrane
2. G protein activates 3. adenylate cyclase 4. converts ATP into cAMP (2nd) 5. activates protein kinases - cause reactions. 6. cAMP inactivated by phospho di esterase |
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List 3 factors that influence the responsiveness of a target cell to a hormone...
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1. hormone concentration
2. number of cell hormone receptors. 3. influences of other hormones. |
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Synergistic effect
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When two hormones acting together have a greater effect than either acting alone.
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Antagonistic effect
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when one hormone opposes the action of another.
eg. insulin: promotes synthesis of glycogen by liver cells. glucagon: stimulates breakdown of glycogen in liver |
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How are hormone secretions regulated (3)?
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1. signals from the nervous system.
2. chemical changes in the blood. 3. other hormones. most are negative feedback cycles. except oxycotin in childbirth. |
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Adenohypophysis
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Anterior pituitary (75%)
control of ITS hormones is through releasing hormones inhibiting hormones FROM the hypothalamus |
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Neurohypophsis
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Posterior pituitary
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How do hypothalamic hormones reach the anterior pituitary?
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Through a PORTAL system.
two capillary beds with a vein between them. wo passing through the heart. ANTERIOR pituitary only. |
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The hypothalamus is part of which system of the body?
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BOTH endocrine and nervous
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What does the anterior pituitary release?
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7 hormones
hGH (growth hormone) TSh (thyroid stim hormone) FSH (follicle stim hormone) LH (luteinizing homone) PRL (prolactin) - initiates milk ACTH (adreno-cortoco-tropic) - stim adrenal to produce cortisol MSH (melanocyte stim hormone) |
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How are anterior pituitary secretions controlled?
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1. hypothalamus secretes 5 releasing hormones AND 2 inhibiting hormones.
2. negative feedback from hormones released by target glands. |
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Human Growth Hormone
hGH |
hGH most plentiful hormone
- increases mitosis - prevents growth plates from closing - stimulate metabolism - stimulate growth of muscles & bones. - repair - lasts for whole life. receptors on almost all cells of body. |
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What does excess hGH cause?
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- hyperglycemia...pancreas secretes insulin continuousy... may lead to burn out of cells and diabetes.
- giant: thick bones: acromegaly |
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What does too little hGH cause?
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pituitary dwarf. normal proportions. tom thumb
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What controls hGH production?
(human growth hormone) aka somatotropin |
Hypothalamus
1. GHRH - growth hormone releasing hormone - promotes 2. GHIH - growth hormone inhibiting hormone - supresses THESE are regulated by blood glucose level. |
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What is hypoglycemia and what does it cause?
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hypoglycemia: abnormally low blood glucose concentration.
- stimulates GHRH - goes through portal veins - hGH released - blood glucose raised - too high, inhibits release of GHRH |
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ADH
antidiuretic hormone (vasopressin) |
made by hypothalamus, stored in posterior pit.
- acts on kidney tubules. - regulates reabsorption of water - effects BP |
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What disease is associated with under (hypo) secretion of ADH?
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Diabetes insipidus
excessive urine production, excessive thirst |
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Oxytocin
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made by hypothalamus,
stored in posterior pit stimulates uterine contractions & milk secretion. |
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TSH
thyroid stimulating hormone |
- anterior pituitary
- regulates development of thyroid gland. - stimulates uptake of iodine controls synthesis & release of thyroid hormones T3 & T4 |
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ACTH
adreno cortico tropic hormone |
- released by anterior pituitary
- target is cortex of adrenal gland tissue growth - increase of hormones called glucocorticoids. |
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Prolactin
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- Anterior Pituitary
- acts on mammary glands. milk |
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FSH
follicle stimulating hormone |
- Anterior Pituitary
- target is ovaries and testes. female development of follicle, male production of sperm. |
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LH
Luteinizing Hormone in male called ICSH interstitial cell stimulating hormone |
- Anterior Pituitary
- female: stim corpus luteum secrete estrogen & progesterone - male: testosterone |
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What is the isthmus?
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thyroid gland lobes connected by a band of tissue called the isthmus.
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What are the functional units of the thyroid gland called?
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follicles.
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What are three hormones that the thyroid produces?
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1. thyroxine T3
2. triiodothyronine T4 both increase metabolism 3. calcitonin (made by parafollicular cells) - regulates level of calcium in blood. Antagonistic to parathyroid hormone made by parathyroid gland. |
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What does low secretions of thyroxine (T3) cause?
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Cretinism in children
stunted growth, thick face, retardation, lethargy - Myxedema in adults: weight gain, slow pulse, lack of energy, weakness, decreased metabolic rate. |
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What does too much T3 and T4 cause?
throxin and triiodothyronine |
Graves Disease (goiter)
often due to a tumor in thyroid weight loss, rapid pulse, increase appetite and inc metabolic rate. Bulging Eyes sometimes seen. |
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What does calcitonin do?
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made by thyroid.
- regulates level of CA in blood - antagonistic to PTH - lowers CA in blood, increase level of CA in bone. |
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Parathyroid gland: what does it secrete?
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- 4 tiny masses on posterior thyroid.
- secretes PTH (parathroid hormone or parathormone) - increases CA (antagonistic to calcitonin) by stimulating osteoclases. - also tells kidneys to reabsorb calcium from kidney tubules. |
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What does the pancreas do?
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Digestive and Endocrine Functions.
- digestive: produce enzymes - endocrine: produce insulin and glucagon in the Islets of Langerhans. |
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What does Insulin do?
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- produced by pancreas
- throughout body - glucose into cells (and so decrease blood levels of glucose) - antagonistic to glucagon |
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What is diabetes mellitus?
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- No insulin.
- glucose can't enter cells - no energy - excess glucose goes into urine. - kidneys must expel more water to dilute glucose... pee a lot.. thirsty a lot. |
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What does glucagon do?
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- produced by pancreas
- when you haven't eaten. - stimulates breakdown of glycogen in liver - increases blood glucose - antagonistic to insulin |
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Adrenal medulla produces hormones that...
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- hormones complement Sympathetic NS
- catecholamines (epi and norepi) |
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Adrenal Cortex produces hormones that...
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- regulate mineral balance, energy balance & reproductive functions
- mineralocorticoids (aldosterone) concentration of electrolytes (NA/K) - glucocorticoids (cortisol/cortisone) anti-inflammatory, metabolism of carb, pro, fats, constrict blood vessels. Regulated by ACTH from anterior pit. - negative feedback. - Steroids: sex characteristics |
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Hyposecretion of Adrenal Cortex hormones causes..
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Addison's Disease
dehydration, hypotension, weakness, Na/K imbalance |
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Hypersecretion of Adrenal Cortex hormones causes..
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Cushing's Syndrome:
puffy face, high BP, muscle weakness. |
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What does the pineal gland produce?
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melatonin: day/night cycle
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What does the thymus gland produce?
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thymosins:
maturation and development of T-lymphocytes. immune system. Is large in babies, decreases w age. |
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What does the corpus luteum produce?
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progesterone
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What are the three layers of the adrenal cortex?
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zona glomerulosa
zona fasciculata zona reticularis |
