6.2 Nervous System Flashcards Preview

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Flashcards in 6.2 Nervous System Deck (45)
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1
Q

afferent neurons

A
  • transmit into CNA from receptors at their peripheral endings
  • single process from the cell body splits into
    1) long peripheral process (axon in PNS
    2) short central process that enters CNS
2
Q

efferent neurons

A
  • transmit niformation out of the CNA to effector cells, particularly muscles, glands, neurons and other cells
  • cell body with multiple dendrites and small segments of axons are in the CNS
  • most of the axon is in the PNS
3
Q

internuerons

A
  • function as integrators and signal changers
  • integrate groups of afferent and efferent neurons into reflex circuits
  • lie entirely within the CNS
  • account for >99% of all neurons
4
Q

all pain activates what subcortical level of brain?

A

reticular formation

5
Q

somatotopy means?

A

orderly arrangement of cortical areas that correspond to body areas

6
Q

is the primary motor cortex or somatosensory cortex more anterior?

A

primary motor cortex

7
Q

declarative vs procesdural memory

A

declarative

  • put into words
  • short term= hippo and temp lobe
  • long term= areas of cortex
  • *SWS sleep (short wave)

procedural memory

  • how to do things, hand/eye skill
  • short term= widely distributed
  • long term= basal nuclei cerebellum and premotor cortex
    • REM sleep (long wave)
8
Q

neocortex does what?

A

causes the hippocampus to replay stuff in slow wave sleep

9
Q

two examples of neural plasticity?

**what does this do?

A

1) long-term potentiation
2) neural facilitation

**increases speed, strength and efficiency of synapses and neural transmission

10
Q

what are the 5 basic sensory receptor types?

A

1) mechanoreceptors
2) thermoreceptors
3) pain receptors AKA nociceptors
4) photoreceptors
5) chemorecptors

11
Q

where are the two most common places to find sensory receptors?

A

1) on fere nerve ending

2) on a receptor cell

12
Q

what is unique about receptor cells?

A

NO action potentials on these cells! only graded that lead to action!

13
Q

divergence vs convergence

A

divergance= one afferent neuron onto ONE interneurons

convergence= one afferent neuron onto MANY interneurons

14
Q

changes in membrane permeability generate?

**exception?

A

depolarizing receptor potential (a graded potential)

** exception is photo-receptor

15
Q

what two senses have RAPID adaptation?

**Note that all receptors eventually?

A

olfaction
taste

**All mechanorecptors probably adapt completely given sufficient time, with extinction times ranging from seconds (pacinian corpuscles) to days (aropeceptors)

16
Q

what is the only receptor that does NOT adapt?

A

pain

17
Q

tonic vs rapid adapting receptors

A
slow adapting (tonic) receptors
-continuous input on body status is needed "balance"

rapidly adapting receptors
-monitor rate/movement while it is OCCURING “on or off”

18
Q

what are the two primary determinates of cnoduction velocity?

A

1) larger diameter increases velocity

2) more myelination increases velocity

19
Q

what is the conduction of A-alpha, A-gamma, and C fibers

A

Aa= 100 m/sec

Ag= 10 m/sec

C= 1 m/sec

20
Q

what are the two primary sensory pathways in the spinal cord that we will focus on?

A

1) dorsal column-medial lemniscal pathway

2) anterolateral spinothalamic pathway

21
Q

what is the proper order of pons, medulla,spinal cord, midbrain?

A

spinal cord > medulla > pons > midbrain

22
Q

dorsal column-medial lemniscal pathway transmits information for?

A
fine touch
vibration
position
movement against skin
fine pressure
  • large myelinated neurons
  • 1st neurons to medulla
  • many 3rd order neurons synapse at somatosensory cortex
23
Q

anterolateral spinothalamic pathway

A
pain
warmth
cold
crude tactile sensations
tickle and itch
sexual sensations
  • smaller, myelinated neurons
  • 1st neuron to dorsal horn
  • fewer 3rd order neurons synapse at somatosensory
24
Q

how much of somatosensory cortex is hand and feet?

A

40-50%

25
Q

pathway of DCML?

A

1) 1st order= post horn to medulla
- –ipsilateral
2) 2nd= medulla, thru lemniscus to thalamus
- –contra
3) thalamus to cortex

26
Q

pathway of anterolateral spinothalamic sensory pathway?

A

1) dorsal root to horn
- –ipsilateral
2) immediately cross body! dorsal horn up BOTH anterior and lateral spinalthalmic tracts to terminate in thalamus
- –contra
3) 3rd= FEW to cortex
- – contra

27
Q

entry of sensory information for the face and oral cavity vs the body/neck/back of head?

A
  • face and oral cavity= enter into the CNS at the pons via trigeminal nerve
  • body/neck/back= enter into the CNS at the spinal cord via dorsal nerve roots
28
Q

where all does joint movement/speed processing happen?

A

spinal cord, thalamus, and DCML pathway

29
Q

1) cold receptors
2) warmth receptors
3) pain receptors

A

1) A-delta
2) C fibers
3) primarily by polymodal nocicetors and C fibers

30
Q

How is pain classified?

A

duration
-acuts, subacute, chronic

etiology
-malignent or nonmalignent

initiation
-nociceptive or neuropathic

quality
-A-delta (fast) or C (slwo)

31
Q

biphasic pain response

A
  • first you get fast pain as A-delta

- secondly you get slow pain from C-fibers

32
Q

fast pain

A

A-delta fibers

  • rapid
  • neospinalthalmic tract of anterolateral pathway
  • noxious mechano-stimulation
  • unimodal
  • intense (sharp or stabbing)
  • localized
  • NOT felt in deep tissue
33
Q

slow pain

A

C fibers

  • begins 1 second or more after stimulus
  • paleospinalthalmic tract of anterolateral pathway
  • noxious mechano-, chemo- and thermo- stimulation
  • polymodal
  • burn, ache or throb, nausea
  • poorly localized
  • deep tissue
  • tissue destruction and unbearable suffering
34
Q

what does lidocaine do?

A

stabilizes the neuronal membrane (preventing depolarization) by inhibiting ionic fluxes required for the initiation and conduction of impulses, thereby effecting local anesthetic action

35
Q

Lidocaine blocks _______ channels and prevents neural propagation?

A

voltage-gated sodium channels

*prevents membrane depolarization

36
Q

takes longer to numb a myelinated or unmyelinated axon?

A

mylinated! must first spread to nodes of R

37
Q

central sensitization is an example of?

A

neuropathic pain

38
Q

neuropathic pain is the end result of?

A

pathological neuroplasticity

39
Q

long term potentiation increases the amount of?

A

synaptic terminals and dendrites over a long period of time, EASILY ACTIVATED

40
Q

nociceptive vs non-nociceptive pain?

A

nociceptive= activate nociceptors which activate central pain areas

non-nociceptive pain= nociceptors are NOT firing, but something else is activating central pain areas

41
Q

how is central sensitization, sleep deprivation, anxiety and depression related?

A

they all reinforce each other

42
Q

central sensitization is initiated by peripheral nociceptors, why can you NOT simply blunt this?

A

bc it’ll stop learning from happening! You need this to make new short term synapses

43
Q

define referred pain

A

pain is percieved at a site that is remote from the noxious stimuli trigger-point (heterotopic pain)

44
Q

what is the one thing that all functioning theories on referred oain have in common?

A

afferent convergance

45
Q

what is the ‘poster child’ for referred pain?

A

myocardial ischemia

-insufficient BS to heart