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A&P I 2024 > Exam 2 (CNS) > Flashcards

Exam 2 (CNS) Flashcards

1
Q

If someone has brain cancer, what type of cell would it likely be, and why?

A

Glial cell; rapid multiplication of cell

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2
Q

What is responsible for the prolonged cardiac action potential peak?

A

L-Type Voltage Gated Ca2+ channels allowing an influx of Ca2+.

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3
Q

What HR do we consider normal for A&P? What would this heart rate be without parasympathetic activity?

A

70-72 bpm
100-110 bpm without parasympathetic activity (Vagus nerve blocked through antimuscarinic drugs).

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4
Q

What are the subunits of the Adult NMJ nACh receptors?

A

Alpha-1 x 2
Beta-1
Delta
Epsilon

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5
Q

In broad strokes, what is the process for how adult NMJ nACh receptor works? What does this process initiate?

A

ACh binds to two subunits.
This binding causes the m-gate to open exposing the (-) charged pore.
Na+ floods through pore due to charge and concentration gradient.
H-gate closes due to time delay (no outside stimulus), preventing further ion movement.

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6
Q

How do Schwann cells insulate axon’s? Is this CNS or PNS?

A

Schwann cells form a wrapping myelin sheath that squeezes out water from around the axoplasm to provide insulation and prevention of loss of signal, electrons, and ions. Provides speed, protection, and insulation.
Schwann cells insulate axons in the PNS.

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7
Q

What compound is a precursor to myelin?

A

Sphingomyelin

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8
Q

Do smaller or larger diameter nerves have more resistance?

A

Smaller

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9
Q

What example did Schmidt give in class regarding small diameter nerves?

A

Low voltage lights

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10
Q

What example did Schmidt give in class regarding large diameter nerves?

A

An air conditioner wire

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11
Q

What proteins make up Gap Junctions? What is their purpose? Are these junctions unidirectional?

A

Gap Junctions are composed of 6 Connexin proteins that form a Connexon.
Connexon’s allow free flow of ion’s between adjacent cells for muscular or neurological action potential transmission.
Gap Junctions are bidirectional meaning a signal can pass both ways with very low resistance.

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12
Q

Are gap junctions in the heart? If so, where?

A

Yes. Throughout the heart there are many gap junctions to spread action potentials rapidly.

There is a low number of gap junctions in the pacing area of the heart. This gives the functional pause that is needed between beats.

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13
Q

What are the causes of demyelinating disease talked about in class?

A

Multiple Sclerosis
Guillain-Barre Syndrome
Genetics
Autoimmune hyperreactivity
Infection
Polyneuropathies

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14
Q

What is Multiple Sclerosis? What is the pathophysiology?

A

Multiple Sclerosis is a Central Nervous System disease of demyelination occurring within the motor neurons.
Over time, the myelin sheath is degenerated. Na/K-are pumps fill the gap where myelin once was, leading to excess energy use, excess sodium being pumped out of the cell, leading to a squelched action potential —> Paralysis.

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15
Q

What is Guillan Barre Syndrome (GBS)? What usually causes this syndrome?

A

GBS is a demyelinating disease of the PNS (Peripheral Nervous System)
GBS is often caused by overreaction of the immune system to an infection or from a vaccine (i.e. Covid)

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16
Q

What is Saltatory Conduction?

A

An action potential traveling between nodes of ranvier

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17
Q

What is a Node of Ranvier?

A

Nodes between myelinated sections of an axon

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18
Q

Are dendrites myelinated? Why or why not?

A

No, they are not myelinated.
The dendrites have to be available for excitatory/inhibitory stimulus, so they have no myelin.

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19
Q

What is the pathophysiology behind alcohol withdrawal related seizures in relation to the axon hillock?

A

The Axon Hillock is non-myelinated, and is more electronegative than the soma. It has an inhibitory receptor for GABA on it. Alcohol can enter the CNS, and can bind to this GABA inhibitor receptor. In doing so, chloride permeability is increased, leading to a MORE negative Vrm, depressing the nerve cell.

When alcohol is removed after a long period of time, the body does not produce the normal amount of GABA to “act as the brakes of the nervous system,” leading to profound excitability of the neuron, which then leads to jitters —> seizures.

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20
Q

In demyelinating disease, does anything fill the gap of the missing myelin? If so, why is this significant?

A

Yes. Na/K-ase pumps fill the axon where myelin used to be. This effectively kills the action potential, as all of the sodium coming in through rapid V-G channels are pumped out before the action potential reaches the intended target. This leads to paralysis.

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21
Q

Where are V-G sodium channels concentrated on a healthy nerve cell?

A

Node of Ranvier

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22
Q

If ischemia is present in the nervous system, will myelinated nerves last longer than non-myelinated nerves? Why or why not?

A

If you have a block of perfusion, myelinated neurons will last longer than non-myelinated nerve cells due to decreased energy use. Myelinated nerve cells have improved efficiency due to lack of excess Na/K pumps found on non-myelinated nerve fibers.
i.e. heart, brain

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23
Q

Are myelin producing glial cells harder to replace in the CNS or PNS?

A

CNS. The myelin producing cells in the CNS are Oligodendrocytes.

24
Q

If we lose the myelin sheath of the Optic nerve, what problems might we have?

A

Cloudy vision; low peripheral vision; delayed vision

25
Q

What cells are the “vacuum cleaners” of the CNS? What does this mean?

A

Microglial cells; these cells act as macrophages of the CNS and clear virus, bacteria, etc.

26
Q

What glial cell produces CSF? Where is it located? What pump in these cells produces CSF? Do they have a motility structure?

A

Ependymal cells produce CSF (through network called choroid plexus).
They are located throughout the entirety of the brain and spinal cord.
CSF is produced by Na+ pumps
They have cilia to help move CSF

27
Q

What are the important functions of astrocytes?

A

-Most abundant type of glial cell
-Regulation of metabolic environment - can tuck electrolytes away and use them to act as an electrolyte buffer;pH buffer
-Repair neuron after neuronal injury
-Regulation of Blood Brain Barrier.
-Provide supporting structure

28
Q

What cell is the most common glial cell?

A

Astrocytes

29
Q

What anatomical feature determines if an action potential is transmitted down the axon from the dendritic portion of the neuron?

A

The axon hillock

30
Q

What should be known about Category C neurons? What do they ennervate? What sensory information do these neurons transmit?

A

Unmyelinated
Smaller and slower
Spinal cord to ANS ennervation.
These neurons transmit:
Aching slow pain
Temperature
Crude touch and pressure

31
Q

Where is acetylcholine can be inhibitory? What is the pathway from the CNS to the outcome?

A

Inhibitory: heart —> PNS signals down vagus nerve with acetylcholine —> acts on mACh receptor (GPCR) —> Alpha subunit binds to K channel —> Results in efflux of K ions —> Hyperpolarizes cardiac pacer cell —> Slowed HR

32
Q

Where is acetylcholine stimulatory? How does binding work? Can smoking affect this?

A

-nACh receptors of the brain/skeletal muscle
Two Acetylcholine (released from motor neuron) bind to the two binding sites on either side of the “donut”
Fast Na channels open, depolarizing the muscle cell

Nicotine can bind to these receptors, leading to shakiness.

33
Q

In nACh receptors, what ion can sneak out of the channel while it is open?

A

K+; though Na primarily pushes it back in before it has the chance to leave the cell.

34
Q

Where do paralytics work?

A

The neuromuscular junction

35
Q

What is the area of the axon that communicates with the soma of a neighboring neuron called?

A

Presynaptic terminal

36
Q

What is the area of the soma called that communicates with a neighboring axon?

A

Postsynaptic terminal

37
Q

What are the three types of nerve fiber classifications?

A

A – fastest (Myelinated)
B – slower (Light myelin)
C – slowest (Non-Myelinated)

38
Q

Can information from the nervous system be sent faster through a small or large neuron?

A

Large, as there is less resistance. Myelin also helps.

39
Q

What example did Schmidt give in class regarding motor neurons being large and myelinated?

A

Running from a dog that is trying to kill you - you probably want that to be instantaneous.

40
Q

Which nerve classification has four subgroups? What are the subgroups from largest to smallest?

A

The A classification of nerve fibers

Alpha subunits 1
Beta 2
Gamma 3
a-delta

41
Q

Dendrites have excitatory and inhibitory receptors. What is the relationship of electronegativity between the two and the soma of the neuron?

A

Excitatory receptor areas of the dendrite are more positive than the soma.

Inhibitory receptors (including the axon hillock) are more negative than the soma of the neuron.

42
Q

What is the smallest glial cell called, and what does it do?

A

Microglia

Acts as immune system anywhere where there is CSF
Will digest anything that is broken down i.e. dead cell
Microglia function as macrophage and keep CSF clean/free from debris

43
Q

What are the 3 neuron types found in mammals? Which one is not in mammals?

A

Multipolar
Pseudounipolar
Bipolar
True Unipolar not found in mammals.

44
Q

Which neuron type is the most common? What is the defining trait of these?

A

Multipolar
This is the “decision making” neuron.
I.e. Motor neuron; pain sensor tells motor neuron that you touched something hot —> pull away.

45
Q

What is the purpose of pseudounipolar cells? Where are pseudounipolar neurons found? What is the purpose of the nucleus in these cells?

A

Sensory information processing.
They are found in the “corridor immediately outside of the spinal cord” - Schmidt
The nucleus mainly just provides cell support.

DOES NOT MAKE DECISION —> sends to nervous system

46
Q

Where are bipolar neurons found as discussed in class?

A

Think “special organs.”
Bipolar neurons found in the optic nerve & photoreceptors in retina

47
Q

True unipolar neurons are found in lower life forms. What neuron type in humans are true unipolar neurons most like?

A

Pseudounipolar neurons

48
Q

What does somatic mean?

A

Sensible

49
Q

What is an example of a free nerve ending, and what is it used for?

A

Nociceptors - pain

50
Q

How do Pacinial & Messner’s Corpuscle somatic sensory receptors generate an action potential?

A

Flatten out, opens Na channels, causes action potential. These are pressure/stretch sensors.

51
Q

Where are Golgi tendon apparatus somatic sensory receptors located, how do they work, and what do they do?

A

They are located inside tendons.
They work by pressure/stretch (opening Na channels, generating action potential)
They detect how muscles/tendons are working.

52
Q

Where are muscle spindle somatic sensory receptors located, and what do they do?

A

They are wrapped around muscle fibers.
They confirm whether muscle fibers are contracted or not.

53
Q

Golgi tendon apparatus and Muscle spindle somatic sensory receptors are collectively known as

A

Mechanoreceptors

54
Q

How fast does a baroreceptor adapt to a new normal, allowing them to work at different set points to lower BP?

A

Two days.

55
Q

What classification of nerve fiber does tickling go through?

A

Type C; non-myelinated

56
Q

When administering a pharmacological block on a nerve, does it take a higher dose to block a myelinated nerve or a non-myelinated nerve?

A

A myelinated neuron requires more local anesthetic to block due to the high fast sodium channel density at the node of ranvier.

57
Q

What is the ratio between glial cells and neurons in the brain and spinal cord?

A

10:1

A&P I 2024 (18 decks)

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