physio quiz special senses

Study Questions for Oct 14 Quiz:

1.     What is the consequence of glutamate binding to mglur6 receptor of an “on” bipolar cell?
Calcium channel closes, cell polarizes and doesn’t release any neurotransmitters (means no light)

2.     Does CGMP PDE turns off the depolarization events of cGMP?

Yes, it breaks down cGMP, causing no Na+ and Ca2+ to enter the cell -> no depolarization

3.     All of the photoreceptor cells are in vitreous humor

False; photoreceptor cells are found in the retina

4.     Guanylyl cyclase is always active in light or dark?

Dark

5.     In what way is the concentration of cGMP-PDE regulated?

Light comes in ->retinal (part of opsin) goes from cis ->trans configuration -> activates membrane bound effector protein transducin -> activates cGMP phosphodiesterase (degrades cGMP and polarizes cell membrane -> no neurotransmitters); light dependent process

6.     Can you graph the function of light on [PDE] ([ ] means concentration)?

Dark -> low pde

Light -> high pde

7.     Graph the function of light on [cGMP.

Dark -> high cGMP

Light -> low cGMP

8.     Are Ganglion cells myelinated ? Why or Why not?

Ganglion cells are not myelinated in the eye but they are myelinated in the brain; why not in the eye? ->because if the axons were covered by fat, how would light get through all the way to the retina

9.     What kind of external lens (glasses) should be used to take the focal point more anterior?

Biconvex lenses

10.   Can you illustrate the consequence of prolonged stimulus on Phasic and tonic sensory neurons

Phasic -> rapidly adapting (action potentials then stop)

Tonic -> slowly adapting (less frequent action potentials over time)

11.  Which nerve is more metabolically efficient.... Tonic or Phasic neuron? Why?

Phasic neurons are more metabolically efficient because they do not keep doing action potentials (using atp)

12.   What’s the value of the choroid?

Dark pigment to absorb light rays at the back of the eyeball; includes iris, ciliary muscle & zonular fibers = suspensory ligaments

13.   Increasing the parasympathetic innervation to the ciliary muscles will have what effect on the shape of the lens, and  therefore enable on to see at closer distances?

Ciliary muscle will pull, lens will round and get wider -> see closer distances

Need to round to refract light at close distance

14.   If there are neurotransmitters at the synapse of the OFF Bipolar cell to Ganglion cell, what light conditions exist?

Dark conditions exist

15.  If the ON bipolar cell is depolarized, what is the state of neurotransmitter concentration at the photoreceptor On Bipolar synapse ?

There are neurotransmitters

16.  What happens when wavelength of light is 280 nm? Will there be neurotransmission on the photoreceptors OFF bipolar synapse cells? Is NMDA voltage or ligand gated?

We can’t see 280nm, yes neurotransmitters on off bipolar cells; NMDA is ligand gated

17.  In cells that can perform long-term potentiation, what is the most plausible consequence if there are AMPA channels and NMDA channels at the post-synaptic membrane, as well has a high concentration of glutamate in the synapse of the AMPA

Extended long term potentiation (glutamate binds ampa and nmda -> na+ and ca2+ enter, depolarization, long lasting increase in glutamate receptors and sensitivity & long lasting increase in glutamate synthesis and release

18.  What is the role of the choroid ?

Being able to focus on far distances vs short distances

19.  Trick Question: What is the voltage threshold for an action potential on the OFF bipolar cell

No action potentials!!!

20.  If the on bipolar cell is in a state of polarization,   is it light or dark?

dark

21.  T or F.    AMPA channel is a voltage-gated receptor .

false

22.  What does the m mean in the mGLUR6

metabotropic

23.  What do metabotropic receptors indicate?

G-protein coupled receptors

24.  If each cone is stimulated equally,   what color would the brain ‘see’.

white

25.  T or F.     Receptors of sound stimulus generate action potentials.

false

26.  What color is when the on and off bipolar are sending the same amount of glutamate?

gray

27.  Of the somatic receptors,  which receptor is not encapsulated ?

none

28.  Which of the somatic receptors detects temperature?

   Free nerve endings

29.  What phenomenon describes referred pain

Convergence

30.  Moving the stereocilia of the inner hair cells of the cochlea toward the kinocilia will do what?

Depolarize, release neurotransmitters

31.  When (or by what mechanism) will the dendrite of the inner hair cell of the cochlea open a cation channel?

Moving the stereocilia of the inner hair cells of the cochlea toward the kinocilia will do what

32.  Taste buds can be regenerated.   T or F

true

33.  The hair cells of the ampula are constantly depolarized and also able to send enough neurotransmitters to have the afferent neurons fire action potentials.    T or F

true

34.  The saccule is able to assess what kind of accelerations?

Vertical acceleration

35.  The semicircular canals are filled with ________.

endolymph

36.  Of the rods and cones,  what was anatomist  Mr. Cones’ s first name ?

frank

37.  What wavelengths do we “see” in ?

400-750 nm

38.  What is an Epley Manoever ?

Maneuver used to get otoliths back on saccule and utricle

39.  What do the otoliths do ?

Make gelatinous substance thicker so that hair cells can shear in either direction -> depolarization event

40.  Where on the tongue are you most likely to detect Umami?

   Everywhere

42.  What sensory cells can generate action potentials?

Olfactory cells and ganglion cells

43.  How does the compression and rarefaction of sound waves impact
the hair cells of the cochlea ? Tell a story .

Zones of compression-> basilar membrane vibrates (pressure increases) ; SC->KC -> depolarization

Zones of rarefaction-> basilar membrane vibrates (pressure decreases); SC away from KC -> polarization event

44.  Change in velocity when your head is in the horizontal position will
stimulate what vestibular organ ?

utricle

46.  T or F.  The basilar membrane is thick and narrow at the windows and broad and thin at the helicotrema

true

47.  Where are these hair cells ? What is KC ? What is SC ? It looks
like these cells are generating action potentials...

In the ampulla; kc= kinocilia; sc= sterocilia

49.  Can one regenerate hair cells of the cochlea ?    

no

50.  Can one regenerate retina ?    

no

51.  Can one regenerate taste buds?

yes

52.  If I smell something,  does that mean the actual element (like rose or garlic pizza) embedded in the nasal mucosa ????

No, but odorants do