Term
| What kind of receptors are utilized in the auditory system? What are they bathed in? |
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Definition
-hair cells
-endolymph
-in the cochlear duct |
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Term
| What is the key stimulus of the auditory system? |
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Definition
| -the vibrations of sound waves through air |
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Term
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Definition
| -the 3 bones in the inner ear |
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Term
| Outline the stimulus of the auditory system |
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Definition
| -vibrations of sound waves go through air=> through tympanum=> through tympanum=>causes basilar mem to vibrate=> makes hair cells move (embedded in tectorial mem)=> epens mech gated K+ channels=> Glutamate neurotransmitter released=> dendrites of CN VIII take signal to spiral ganglion=> through internal acoustic meatus=> joins vestibular n to make vestibulocochlear n=> enter medulla=> to medial geniculate body of thalamus=> enter auditory cortex in temporal lobe |
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Term
| True or False: The signals of the Auditory System are diffuse and unilateral. |
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Definition
| FALSE: diffuse and bilateral |
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Term
| What is the clinical difficulty often found when subjectively diagnosing hearing problems in the vet clinic? |
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Definition
| -animals often respond to action, not noise (thus ask owners to do it while the animal is asleep) |
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Term
| What is the most efficient method of diagnosing hearing issues in the vet clinic? |
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Definition
-Brainstem Auditory Evoked Response (BAER)
-physioligal way to assess hearing that measures electrical activity
=>can differentiate where the lesion is |
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Term
| What are the 4 causes of deafness? |
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Definition
-Inherited deafness: permanent
-Toxic deafness: permanent deafness
-Infections: not necessarily permanent
-Aging: usually permanent |
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Term
| What occurs in inherited deafness? In what population is it common? |
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Definition
-loss of hair cells, loss of endolymph, hair cell degeneration
-common in albino animals |
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Term
| What often causes toxic deafness? |
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Definition
-aminoglycosides (antibiotics)
-platinum drugs (used in cancer treatment) |
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Term
| True or False: Deafness due to infections is usually bilateral. |
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Definition
| FALSE: usually unilateral |
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Term
| How does aging cause deafness? |
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Definition
| -degeneration of hair cells or arthritis of ossicles |
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Term
| What is the neurologically concerned feature of the eye? |
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Definition
|
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Term
| What are the 5 layers of the retina? |
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Definition
-Photoreceptors (outer layer): rods and cones
-Bipolar cells
-Ganglion cells
-Horizontal cells: outer layer
-Amacrine cells: inner layer |
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Term
| What is the function of horizontal cells and amacrine cells? |
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Definition
| -to spread signal horizontally |
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Term
| What is the clinical significance of the retina? |
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Definition
| -it is the only part of the "brain" we can see |
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Term
| Outline the 3 neuron train of the vision system. |
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Definition
| photoreceptor=> bipolar n=> ganglion cell |
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Term
| Outline the path of light through the vision system. |
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Definition
| light hits eye=> hits photoreceptors=> bipolar cells=> ganglion cells=> horizontal cells=> amacrine cells=>tapetum=>ganglion cells form optic n |
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Term
Definition: Tapetum
-Function? |
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Definition
-the shiny thing in the caudal part of the eye (scary thing on cats, gators, opossum, etc)
-Function: reflects light that is there thus improving night vision |
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Term
| How do rods and cones differ? |
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Definition
| -by shape, pigment contents, and their synaptic connections |
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Term
| Rods have ______ spatial resolution and is _________ to light. What occurs with loss of rods? |
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Definition
-low spatial resolution
-very sensitive to light
-loss of rods= night blindness |
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Term
| Cones have ________ to light and _______ resolution. What occurs when cones are lost? |
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Definition
-insensitive to light
-high resolution
-loss of cones= blindness |
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Term
| What is the special function of ones? |
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Definition
|
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Term
| Outline the reception of light |
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Definition
| photons of light are absorbed=> activate (conf change) the pigments (including rhodopsin)=>activates a protein transducing (G-coupled receptor protein)=> releases CTP bound subunit=> act phophodiesterase=> cleaves cGMP=> opens a Na channel which depolarizes the photoreceptor, thus channel is closed, hyperpolarizing the receptor=> leads to a graded release of glutamate from photoreceptor on to bipolar cells |
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Term
| Light causes a change in ________ of photoreceptors (rods and cones) and an associated change in neurotransmitter release onto the ________ neurons |
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Definition
-membrane potential
-bipolar neurons |
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Term
| True or False: Light depolarizes, not hyperpolarizes receptors. Thus in light, more transmitter is released. |
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Definition
| FALSE, light hyperpolarizes, not depolarizes, receptors. In light, less transmitter is released. |
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