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A&P > Test 2 🧠 > Flashcards

Test 2 🧠 Flashcards

1
Q

What is the purpose of hyperpolarization of cells?

A

Used by body to suppress activity

Inside cell is more negative, takes more stimulus to turn on

Suppresses electrical activity in excitable cells

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2
Q

What happens in regard to voltage gated Na channels if cell isn’t repolarized?

A

They won’t be able to be used for another action potential

Fewer voltage gated Na channels or no voltage gated channels = no action potential

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3
Q

Differentiate between voltage gated Na channels and voltage gated Ca2+ channels:

A

Same structure as voltage gated Na channels

Voltage gated Ca channels are slower

Known as slow Ca channels

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4
Q

What is Dihydropyridine?

A

class of calcium channel blockers (blocks DHP receptor)

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5
Q

Why is chloride useful in neurons?

A

Important in CNS

Hyperpolarize/ suppress electrical activity in excitable cells

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6
Q

How are chloride channels opened up to allow for hyperpolarization in the cell?

A

GABA receptors open up chloride channels in neurons

Increase chloride permeability= makes cells more negative and more difficult to excite

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7
Q

Stages of action potentials:

A
  1. Resting
  2. Stimulus causes depolarization to an area
  3. Action potential spreads
  4. Resetting after depolarization
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8
Q

What generates the depolarization during the initial phase of an action potential?

A

Outside force causing area of depolarization–Na coming in through channels

Starts with a small area: outside electrical stimulus,

Ex: electrodes hooked up to a muscle

Ex: taserOu

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9
Q

Where are most of the voltage gated Na channels located?

A

Cell wall

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10
Q

Why are they called voltage gated sodium channels?

A

VG Na channels open up when there is enough initial depolarization

VG Na channels open up when there is a change in membrane voltage (membrane depolarizing)

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11
Q

What happens after VG Na channels open?

A

depolarization spreads and more VG Na channels are activated

action potential is fired

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12
Q

How does an action potential travel?

A

Spreads away from initial area of excitement

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13
Q

What affects how the depolarization wave travels?

A

2 way propogation:
-if initial excitation in middle
-AP travels both way
-shorter amount of time to depolarize
(EX:taser, paddles to chest)

1 way propogation:
-initial excitation is on one end
-potential travels opposite direction from one end to the other
-takes longer to get entire activation

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14
Q

How does repolarization wave travel?

A

Repolarization moves in the same direction as initial depolarization

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15
Q

Describe how actions potential are positive feedback:

A

positive feedback is the basis for normal propagation of action potentials

initial stimulus –> Na comes in–> activates VG Na –> MORE Na comes in

amplifies intial response of letting Na in

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16
Q

Aside from external stimuli, What is another way we could have activation of initial depolarization?

A

Through a process mediated by a neurotransmitter

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17
Q

Motor Neuron

A

Set of neurons that are specialized to talk to skeletal muscles

attach to skeletal muscles and activate them

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18
Q

Where do motor neurons communicate with the skeletal muscles?

A

Each skeletal muscle fiber talks to at least one motor neuron

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19
Q

How do motor neurons communicate with skeletal muscle?

A

neurotransmitters

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20
Q

What would be the process if the brain wants to contract a muscle?

A

Motor neuron activated in spinal cord–> activation produces action potential that moves from brain to spinal cord–>action potential reaches where motor neuron connects with muscle

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21
Q

What is the path that action potential flows through a neuron?

A

action potential flows from top pf neuron down to distal end

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22
Q

What releases neurotransmitter?

A

Motor neurons

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23
Q

What is the NMJ

A

Neuro Muscular Junction: area that connects 2 cells together via neurotransmitter

need receptors on target cell

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24
Q

What are the neurotransmitter receptors on skeletal muscle?

A

nicotinic acetylcholine receptor (nAch)–specialized for skeletal muscle (some in brain)

differ from acetylcholine receptors in other parts of the body

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25
Q

How does acetylcholine bind to the receptor?

A

2 binding sites

each site should be occupied simultaneously for the channel to allow current through it

donut shape protein in cell wall
-lined with amino acids (-) charge–repel negative electrolytes

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26
Q

What are the nAch receptors specific to?

A

specific for charged ions–negative charge on inside of channel created by amino acid lining

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27
Q

What generates majority of current through nAch receptors?

A

Sodium

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28
Q

Describe how nAch receptors enable an action potential:

A

Motor neuron needs to excite skeletal muscle–> sends neurotransmitter –> neurotrans binds to nAch receptor –> nAch receptor opens up and allows Na+ to flood into cell

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29
Q

Why are the nAch receptors called nicotinic?

A

nicotine can stimulate this neurotransmitter

ex: a bunch of nicotine can stimulate acetylcholine being released from motor neurons (causing tremors, shaky)

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30
Q

Why is Na+ the predominant current through nAch and not Ca2+?

A

Na+ is smaller than Ca2+
chemical and electrical current for Na+

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31
Q

Is there other current through nAch channels besides Na+?

A

-Small amount of K+ that can leak out: most is prevented from moving out because there is so much Na+ it boots it to the side

-a little calcium: Comes into cell but much less than Na+ because Ca2+ is big and clunky (doesn’t fit through channel very well)

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32
Q

Where are the voltage gated Na+ channels in relation to the nAch receptors?

A

VG Na+ channels are usually situated next to nAch receptors

initial current though nAch receptor sets off VG Na+ channels since they are close by

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33
Q

Is there potential to run out of nAch receptors in healthy person?

A

in a healthy person this system is robust: way more channels that we actually need, more VG Na+ channels than we need, receptors are in large abundance–so anytime we get acetylcholine release from motor neuron skeletal muscles will contract

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34
Q

Where do paralytics work?

A

Neuromuscular junction

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35
Q

What happens if there is dysfunction relationship between CNS and skeletal muscle?

A

Skeletal muscle is a large compartment of intracellular container

if dysfunction relationship then causes massive problems–things that are not suppose to be sequestered in skeletal muscle leak all over the place

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36
Q

What mediates the interaction at the NMJ?

A

depolarization mediated event

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37
Q

Wha change would be expected in a cell if we are trying to slow something down?

A

Hyperpolarization
(inhibition)

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38
Q

What are mAch-R?

A

Muscarinic acetylcholine receptors

responsive to a chemical called muscarine–found in rainforest

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39
Q

Where in the body are mAch-R located?

A

heart, smooth muscle, lungs

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40
Q

What is the purpose of mAch-R in the heart?

A

Mediate pumping levels of heart and electrical activity by controlling how hyperpolarized the cell is

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41
Q

Where in the heart are mAch-R found?

A

Pacing centers (SA/AV nodes)

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42
Q

Where is the SA node?

A

right side of heart

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43
Q

Where is the AV node?

A

top of the septum

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44
Q

What is the path that actions potentials take in the heart?

A

SA node–>atria–>AV node–> ventricle

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45
Q

What nerves are specialized in communicating with SA/AV nodes?

A

Vagus nerves: come into contact with pacing structures in the heart

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46
Q

Which vagus nerve innervates each node?

A

Right vagus nerve innervates SA node

Left vagus nerve innervates AV node

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47
Q

What neurotransmitter is released by vagus nerve in the nodal area?

A

Acetylcholine

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48
Q

What type of receptor is mAch-R?

A

GPCR

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49
Q

Describe mechanism of action for mAch-R:

A

Acetylcholine binds to receptor–> alpha subunit from muscarinic Ach receptor are now activated –> alpha moves away from receptor–causes K+ channels in cell wall to open

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50
Q

What is a task of the alpha subunit of mAch receptors?

A
  1. communicate with K+ channels in cell wall to open more
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51
Q

What is the relationship between acetylcholine and K+ channels?

A

when there is a lot of acetylcholine around–there are lots of K+ channels open

leaky channels and extra K+ channels that can be activated with Ach

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52
Q

What happens to membrane potential when the cell has more K+ channels open?

A

K+ leaving the cell

cell is more negative

increased electronegativity (makes cell more difficult to excite but can still excite)

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53
Q

What effect does the hyperpolarized Vrm have on the heart?

A

influences how fast pacemakers works

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54
Q

When looking at heart beat, what does the trough between beats indicate?

A

Vrm

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55
Q

What happens in the heart if we adjust Vrm lower than normal?

A

Hyperpolarized: cycle would have lower starting point and will take longer to get up to area where action potential is fired

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56
Q

What is the function of Ach mediated hyperpolarization in the heart?

A

Used by body to pump the breaks on heart

we have alot of Ach being released by vagus nerve all the time–keeps the heart in check

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57
Q

What happens with massive vagal stimulation of the heart?

A

Expect heart rate to slow down:
-K+ permeability increases
-pacemaker cells are hyperpolarized
-HR slows down

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58
Q

What is a side effect of Antimuscarinic meds?

A

side effect: increased HR

blocks acetylcholine from binding to GPCR

alpha subunit no longer active

K+ channels close and makes cell more +

Vrm more +: starting point for heart beat is closer to point where action potential will fire (shorter time between action potential so increase HR)

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59
Q

Describe how basline Ach activity effects the heart:

A

Atropine blocks normal vagus activity on heart

this implies alot of baseline Ach activity normally because if there wasnt baseline activity of Ach through muscarinic receptors then atropine would have no effect

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60
Q

What does atropine do to the heart?

A

blocks normal vagus activity on the heart (inhibits the breaks)

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61
Q

If there was no CNS influence how would resting HR change?

A

without CNS: HR would want to beat 100-110bpm

CNS slows that down with Ach and mAch-R to resting rate 70-72bpm

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62
Q

What is the main thing muscarinic receptors mediate?

A

K+ permeability

(through GPCR alpha subunit)

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63
Q

How is an action potential generated with physical pressure?

A

specialized structure gives off sensor then another structure takes sensor info and passes to CNS

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64
Q

What is an important pressure sensor in the heart?

A

Baroreceptor

lots of pressure sensors in the heart

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65
Q

What happens in regards to action potentials with light vs increased pressure?

A

Repeated action potentials with a lot of pressure

slower action potentials with light pressure or maybe no action potentials

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66
Q

What is the structure of pressure sensors that allows for action potentials?

A

pressure sensitive Na+ channels inside sensor

little pressure: not alot of Na+ permability

when pressure is applied, sensor get flattened out–walls of Na+ channels get wider and more Na+ can come in

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67
Q

Describe how increased physical pressure affects action potentials:

A

more pressure= more open N+ channels= more Na+ comes in and if + enough can create action potential

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68
Q

Why are pressure sensors necessary?

A

CNS uses them to keep an eye on whats going on around us

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69
Q

How are nerves classified?

A

Size
Myelination state

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70
Q

How does diameter of neuron affect action potentials?

A

Small diameter fibers are slower

Larger diameter fiber sends faster

largest neuron diameter 20micometers

smallest neuron diameter 0.5micrometer

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71
Q

How is myelination state categorized?

A

A fibers: heavily myelinated

B fibers: lightly myelinated

C fibers: non myelinated

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72
Q

Give example of nerves in the body that are myelinated:

A

motor neurons: Big and heavily myelinated

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73
Q

What type of info is carried by small unmyelinated fibers?

A

Crude info–ex: cold/warm, tickle

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74
Q

What are the smaller subunits that neurons are divided into?

A

Alpha
beta
gamma
delta
(from largest to smallest category)

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75
Q

Describe the cell body of a neuron:

A

also known as SOMA

all neurons have cell body

contains nucleus, mitochondria, place to build things the cell needs

some synapses on cell body

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76
Q

How does the threshold potential affect the action potential?

A

this is the bar that the stimulus has to get over to create an action potential
- if you barely pass it, it takes longer to have an action potential
- if you fly past the bar then you have an action potential quickly

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77
Q

What causes an extension of action potential in the heart? (the pause)

A

the slow calcium channels

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78
Q

How does extracellular chloride affect membrane potential?

A

It brings negative charges into the cell to make it harder to excite
- also could hyperpolarize the cell
- keeps the “brakes” on the nervous system

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79
Q

How does extracellular calcium affect electrical excitability of the cell?

A

It has two positive charges with a huge chemical gradient - it has a calming affect on the excitability

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80
Q

What does calcium do to the sodium channels?

A

It is BIG and CLUNKY and sits at the entrance of the cell wall and blocks the influx of sodium
- this limits resting sodium permeability through sodium leak channels
- inhibits electrical activity of the cell

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81
Q

How does hypocalcemia affect the excitability of the cell?

A

There is less calcium to block the sodium channels, so more sodium influx makes the cell more positive

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82
Q

Why would giving supplemental calcium to a patient help them?

A

It would block more sodium permeability to make a more negative membrane potential aka make it not as excitable

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83
Q

How does calcium affect skeletal muscle?

A

If a motor neuron is not surrounded by a normal amount of calcium, the membrane potential would be more positive and it would increase the amount of contractions happening in the muscle (tetany or trousseau’s sign)

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84
Q

How does magnesium function?

A

A lot like calcium, it’s large and has a double positive charge
- makes things more hyperpolarized
- reduces electrical activity of a cell or the heart

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85
Q

What are the main things that affect the rate of electrical propagation?

A
  • length of the nerve (longer nerve = longer to get there)
  • width (wider = quicker)
  • insulation (more insulation = faster action potential) ex. myelin sheath
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86
Q

Describe the myelin sheath

A
  • made from sphingomyelin in the cell wall
  • Schwann cells grows and wraps itself in a spiral around the neuron
  • each layer is compacted and the water is squeezed out which leaves a lipid layer for protection
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87
Q

How exactly does myelination help with action potential?

A

It covers up the Na/K pumps which will prevent sodium from coming out - it will keep it in the cell and have to keep moving downstream to make the action potential faster
- this also reduces the energy requirements of the cell
- myelinated neurons are less prone to ischemia

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88
Q

How does a myelinated neuron affect anesthesia?

A

If they’re myelinated, they will need more local anesthetic to block them because of the high density of fast sodium channels at the nodes

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89
Q

What is saltatory conduction?

A

The movement of sodium from one node to the next - since the sodium can’t move out, it must move forward

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90
Q

What are the cells that are responsible for creating and maintaining myelin?

A

Oligodendrocytes and Schwann Cells

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91
Q

Where are oligodendrocytes located?

A

CNS - brain, spinal cord, cranial nerve 2, retinas

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92
Q

Where are Schwann cells located?

A

Peripheral nervous system

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93
Q

What happens if there is demyelination?

A

The stuff (pumps) sitting under the myelin start to disappear
- Fast sodium channels and VG potassium channels start to go away
- this leaves only Na/K pumps that push the sodium out and it cuts the action potential short

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94
Q

What are some common causes of demyelination?

A

Guillain-Barre, infection, MS, autoimmune response to vaccines, genetics

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95
Q

What type of synapses occur at dendrites?

A

Can be excitatory or inhibitory in nature for target

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96
Q

Differentiate excitatory Vs inhibitory interactions at synapse:

A

Excitatory: more positive membrane potential

Inhibitory: lower than average membrane potential–hyperpolarization. more difficult to excite

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97
Q

How many connections can a neuron have with other neurons?

A

Some neurons have connections with over 10,000 of their neighbors

Common with decision making neurons because receiving input from lots of different places)

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98
Q

Why do we not have myelinated dendrites?

A

Messages wouldnt be able to get through to receptors. Myelin would get in the way of the synapses

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99
Q

What is the Axon?

A

specialized to send action potentials quickly

most axons are myelinated

nodes of ranvier

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100
Q

How are action potentials conducted quickly through the axon?

A

Axons are usually myelinated

Nodes of ranvier–Na+ current jumps from one node to the next

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101
Q

Presynaptic terminal

A

tail end of sending portion of neuron (axon)

synapse of target cell

presynaptic portion of next synapse in pathway

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102
Q

What mediates inhibition at the axon hillock?

A

GABA mediated inhibition

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103
Q

Axon hillock

A

Very beginning part of axon

input from other places in nerbous system that suppresses over activity in neurons

4 inhibitory connections–GABA mediatef

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104
Q

How do GABA receptors function?

A

Increase chloride permeability–increase chloride means more inhibition of cell

GABA is key component of controlling electrical activity in CNS

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105
Q

What would happen if all GABA is removed?

A

Inhibition is removed

would expect over the top crazy levels of CNS activity–Seizures

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106
Q

Explain the physiology of an alcoholic going through withdrawals:

A

Alcohol is GABA receptor agonist

Alcoholics who drink alot over a long period of time, body stops producing their own GABA

If you take alcohol away and body isnt producing any of its own GABA–results in massive overactivity of CNS and seizures

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107
Q

How does GABA work at the axon hillock?

A

Makes sure no over activity of axon–CNS break system

no excitatory connection at axon hillock

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108
Q

Why are there no excitatory connection at the axon hillock?

A

They would bypass the rest of the cell–no longer decision makers if cell isnt taking to account all connections with other parts of the nervous system

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109
Q

Difference between glial cells and neurons?

A

glial cells divide/multiple and neurons do not really

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110
Q

If you had a brain tumor what kind of cells would it likely be?

A

Glial

neurons do not divide quickly

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111
Q

List the macroglia cells:

A

Astrocytes
Ependymal cells
Oligodendrocytes
Schwann cells

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112
Q

Astrocytes

A

Star shaped

Appendages connect with outside of endothelial cells

Attach to capillaries in the brain

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113
Q

How do astrocytes function as supporting structures?

A

Projection from cell body of astrocyte (astrocytic end foot) wraps around capillaries surrounding CNS for support

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114
Q

How are astrocytes useful in CNS?

A

Support

Maintain electrolyte balance in CNS–CSF buffer, important in maintaining pH of CSF

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115
Q

Ependymal cell function:

A

Useful in producing CSF and moving CSF around

MAIN SOURCE OF CSF–cilia used to help CSF move downstream and around entire system until it exits

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116
Q

Oligodendrocyte function:

A

Myelin producing cell in CNS

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117
Q

Schwann cell function:

A

Myelin producing cell in PNS

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118
Q

Microglia

A

Small nervous system cell

Immune system for any structure that contains CSF

Good at digesting things that need to be broken down

Function as Macrophages in CSF

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119
Q

What would happen if there is a dead cell in the CSF?

A

Microglia would break it down

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120
Q

Multipolar Neuron

A

Decision making cells

Decide whether or not to fire action potential

Lots of area for communication with other neurons

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121
Q

What is an example of multipolar neuron?

A

Motor neuron

EX: If there are enough pain sensors telling motor neuron something is painful the motor neuron would make decision to move

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122
Q

Bipolar Neuron:

A

Sensory–sense and pass info along

2 projections used in special organs

Optic nerve

photoreceptors in retina send action potentials to brain

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123
Q

Pseudounipolar neuron:

A

Majority of sensory cells parked in spinal cord or immediately outside spinal cord

sensing–cell body does not make decisions

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124
Q

What is the purpose of the cell body in pseudounipolar neurons?

A

Exists as a place to build proteins and replace things in the neuron

cell body supports the rest of the structures

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125
Q

Are decisions made in pseudounipolar neurons?

A

Decisions are made by sensor itself then relays info from dendrite down to axon and pass info to CNS

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126
Q

True unipolar

A

Said we didnt have to know but also said we didnt have to know amino acids SOOOOOO

these neurons are not found in humans (only in lower life forms)

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127
Q

What is another term for sensible / sensing neurons?

A

somatic

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128
Q

What is the purpose of free nerve endings?

A

Pain sensors/ nociceptors

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129
Q

Other examples from lecture of pressure sensors:

A

Pacinian corpuscle

Messiners corpuscle

Golgi tendon apparatus

Muscle spindle

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130
Q

What is the function of the golgi tendon apparatus?

A

Feedback on skeletal muscles

Pressure/stretch sensors integrated in tendons that are connected to skeletal muscle

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131
Q

Muscle spindle

A

Woven skeletal muscle

confirms if a muscle has contracted or not

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132
Q

How do somatic sensory receptors function in the body?

A

Take a physical environmental disturbance and turn into electrical signal that is relayed to rest of the body

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133
Q

What is adaptation of sensors?

A

resetting/ adjustments to new normal

some sensors adapt slow others adapt quickly–some do not adapt at all

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134
Q

Explain reverse adaptation:

A

Really strong stimulus for long period of time–becomes more sensitized to that stimulus

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135
Q

Function of baroreceptors?

A

Monitor and adjust BP for changes from normal

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136
Q

What is the purpose of resetting baroreceptors?

A

Gives the body ability to adjust BP changes from new normal

allows room to change up signal being fed into brainstem

Gives us ability to have a system work at different set points

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137
Q

What would happen if we didnt have baroreceptor adaptation?

A

If baroreceptors kept firing at fast rate with increase BP unadapted system would be limited in response to further changes from new normal

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138
Q

About how long does it take baroreceptors to adapt and is it considered fast or slow?

A

takes around 2 days

slow adaptation

most specialized sensors adapt much quicker

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139
Q

Why do sensors adapt?

A

Often adapt to give ability to sense change

CNS set up this way to be efficient–cut down signals where it can to decrease noise

EX: holding ball example

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140
Q

Somatic sensor blocking variables:

A

attached to neurons of different sizes or myelination

some are easier to block with local anesthetic than others depending on orientation (if on outside of nerve bundle or buried further into nerve )

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141
Q

What dictates how sensitive sensors are with blockage of local anesthesia?

A

Anatomy

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142
Q

What are some other ways for cells to talk to each other?

A

Electrical or Chemical Synapse

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143
Q

What is an electrical synapse made of?

A
  • 6 Connexin proteins assemble to make a Connexon
  • 2 Connexon create a gap junction
  • Connexon sits in the cell wall and connects with a neighboring cell with a connexon
  • this creates a conduit to allow for current to move between the cells
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144
Q

What is a downside to using an electrical synapse?

A

It can operate in both directions - if you have a rogue action potential circling the heart then it could be bad

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145
Q

What is another term for electrical synapse?

A

Gap junctions

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146
Q

What ions can travel through a gap junction?

A

All small ions can travel through, but the majority of the current is sodium

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147
Q

What type of transport is a gap junction?

A

Simple diffusion

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148
Q

What makes up a chemical synapse?

A

Sending cell = presynaptic terminal
Receiving end = postsynaptic terminal

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149
Q
A

A - Telencephalon
B - Diencephalon
C - Brain Stem
D - Cerebellum
C1 - Midbrain
C2 - Pons
C3 - Medulla Oblongata

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150
Q
A

A - frontal lobe
B - Central sulcus
C - Occipital lobe
D - Cerebellum
E - Temporal lobe
F - Lateral sulcus (temporolateral fissure)

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151
Q
A

Longitudinal Cerebral Fissure

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152
Q
A

A- Anterior Rootlets
B- Anterior Root
C- Posterior Rootlets
D- Posterior Root with Spinal Ganglion
E- Spinal Nerve

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153
Q
A

A- Vertebral Arch
B- Superior Articular Process
C- Pedicle
D- Vertebral Notch
E- Lamina (difficult to mark with this view–after the pedicle)
F- Inferior Articular Process
G- Inferior Articular Facet
H- Spinous Process
I- Vertebral Body

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154
Q
A

A- Vertebral Foramen
B- Vertebral Body
C- Pedicle
D- Spinous Process
E- Superior Articular Facet
F- Transverse Process
G- Superior Articular Process

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155
Q

How is sensory info transmitted?

A

Once info is in dorsal horn–it hops over to ascending pathway in white mater to be routed up toward brain and brainstem

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156
Q

What is the dividing point between CNS and PNS?

A

Spinal Nerve

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157
Q

How does motor info travel in the spinal cord?

A

Motor information is sent out the front of the SC through anterior horn

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158
Q

How does sensory info enter the spinal cord?

A

Sensory info enters horizontally through posterior rootlets

Comes in from the side and enters the back of the cord to interact with cell bodies in the dorsal horn

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159
Q

Where are the majority of ascending pathways in the spinal cord located?

A

In the rear of the spinal cord

Some in the front and a few on the lateral sides of the cord

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160
Q

What are examples of signals that get sent through ascending pathways?

A

Sensory stimuli

pressure sensors, pain sensors

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161
Q

What happens at the spinal nerve anatomically?

A

Combination of sensory and motor pathways

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162
Q

How do motor signals contribute to the spinal nerve?

A

Motor signals come out of the cord
Relayed through anterior rootlets
Pass through anterior root
Then joins sensory info from the back of the cord to create the spinal nerve

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163
Q

What is the function of most spinal nerves?

A

Mixed sensory and motor function

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164
Q

What is unique about posterior root compared to anterior root?

A

Posterior root– big lump

Lump is collection of cell bodies from Pseudounipolar (sensing) cells

Bulge area called Spinal Ganglion

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165
Q

Why are there no ganglion in the anterior root?

A

Anterior deals with motor so most of those cells are Multipolar cells–cell bodies will be in the anterior horns

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166
Q

What is primary function for descending spinal tract and where are these pathways located in the spinal cord?

A

Function for motor signal
Pathway on lateral sides of spinal cord and some in anterior

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167
Q

How many spinal nerves do we have?

A

2 spinal nerves at every level of vertebrae

one exiting on left side, one exiting on right side

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168
Q

How many cervical vertebrae do we have? How many cervical spinal nerves?

A

7 vertebrae
8 pairs of spinal nerves

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169
Q

Why do we have more cervical spinal nerves than cervical spinal vertebrae?

A

C1 spinal nerves come out about C1 vertebrae, all of the other cervical spinal nerves exit under the next vertebrae (C2 nerves come out below C1)

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170
Q

How many thoracic vertebrae and spinal nerves?

A

12 thoracic vertebrae
12 pairs of thoracic spinal nerves (exit underneath vertebrae)

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171
Q

How many lumbar vertebrae and spinal nerves?

A

5 lumbar vertebrae
5 pairs of lumbar spinal nerves (exit underneath vertebrae)

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172
Q

How many sacral vertebrae and spinal nerves?

A

At birth we have 5 sacral vertebrae–fuse as we age

5 pairs of sacral spinal nerves associated with original vertebrae

named for vertebrae they originate under

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173
Q

How many coccygeal vertebrae and spinal nerves?

A

Start with 4 coccygeal vertebrae–fuse into 2 coccygeal vertebrae as adults

one extra set of coccygeal spinal nerves

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174
Q

What are dermatomes used for?

A

Dermatomes are different regions of the body that are innervated by spinal nerves–topical map where spinal nerves are routed (dermatome man)

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175
Q

Generically where do the cervical, thoracic, lumbar, and sacral spinal nerves innervate?

A

Cervical nerves: Sensory top of neck and back of head

Thoracic nerves: Chest area

Lumbar Nerves: front of legs

Sacral nerves: back of legs/butt

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176
Q

How can we identify where the spinal nerves are on a person?

A

Use anatomical spine markers-spinal nerves comes out of spinal column

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177
Q

What is the typical spine curvature for a young/healthy person?

A

“S” curvature (front to back curvature)
Neck: Lordosis (anterior curve)
Thoracic: Kyphosis (posterior curve)
Lumbar: Lordosis
Sacral/coccygeal: Kyphosis

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178
Q

Where is the most common place to have abnormal curvature of the spine?

A

Thoracic Kyphosis–common

Occurs with age–posture change–hunch back

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179
Q

What happens with pathologic amounts of curvature in the spine?

A

Destabilizes overall structure of the spine and puts pressure on structures held within the spine

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180
Q

What is scoliosis?

A

Abnormal lateral curvature of spine (left and right)

Common problem–most people that have it don’t even know–sometimes its bad enough to need surgery

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181
Q

Common pathologic spine curvature:

A

Kyphoscoliosis: combo of 2 abnormal curvature

abnormal kyphotic curvature and abnormal scoliotic curvature

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182
Q

What is the shape of the spine at birth and why is development crucial?

A

Only Kyphotic curve at birth
Ex: why its hard for newborn to hold head up–anatomical problem because center of mass on a structure that is incapable of absorbing movement

Cant start walking/balancing until “S” shape curve starts to form crucial development process

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183
Q

What is the point of the vertebral body?

A

Large weight supporting structure

Intervertebral disc sits on vertebral body

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184
Q

How does vertebral body size correlate with different levels of the spine?

A

Higher up in spine= smaller vertebral body

Lower back has a lot of weight to support so need the vertebral body to be bigger

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185
Q

What is the purpose of the vertebral arch?

A

Encases the cord and spinal roots/spinal nerves

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186
Q

What is a process in anatomy?

A

a body extension

Area for vertebrae to connect

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187
Q

What are the palpable bumps on our back?

A

From the spinous process on each vertebrae

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188
Q

How many transverse process do we have per vertebrae?

A

2

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189
Q

How many superior articular processes per vertebrae?

A

2–processes that fit together with processes from the bottom of the vertebrae above

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190
Q

What does the term articular mean?

A

Connecting one thing to another

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191
Q

How many inferior articular processes per vertebrae?

A

2–connect with superior articular processes in vertebrae below

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192
Q

What is the purpose of inferior vertebral notch?

A

Located under the pedicle
Provides an area where spinal nerve can exit on each side of spine

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193
Q

What is the point called where superior articular process and inferior articular process connect?

A

Inferior/superior articular facet–cartilage

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194
Q

What structures are in all cervical vertebrae?

A

Vertebral foramen (wide)
Vertebral arch
Body
Superior articular process
Superior articular facet

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195
Q

What are the specialized structures only found in the neck vertebrae?

A

Bifid spinous process (only in cspine) C2-C5

Transverse foramen

Sulcus in transverse process

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196
Q

Which cervical vertebrae are expected to be bifid?

A

C2-C5 almost always bifid
C6: 50% of the time
C7: 0.3% bifid (usually a single spinous process)

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197
Q

Where is the transverse foramen located and what is its purpose?

A

Located in the transverse processes

Where the vertebral arteries run through
2 vertebral arteries (one of each side of neck)
Supply the back of the brain

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198
Q

What are the blood supplies for the brain and brainstem?

A

2 Vertebral arteries: back of brain
2 Carotid arteries: anterior brain perfusion

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199
Q

Which vertebrae has transverse foramen?

A

All cervical vertebrae

C7 has transverse foramen but vertebral artery doesn’t pass through it

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200
Q

What is the sulcus in the transverse process?

A

Hollowed out groove where cervical spinal nerves can hang out

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201
Q

What is anatomical term for hollowed out spot?

A

Sulcus

“sulcus in transverse process for spinal nerve”

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202
Q

Why is vertebral foramen larger in cervical vertebrae compared to lower back?

A

The spinal cord is wider and larger at the neck compared to lower back

Further down on the cord the less info is sent

More info being sent by the top of the cord so it should be wider

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203
Q

What is the name for C1 vertebrae?

A

Atlas: specialized to create clean attachment to base of skull

specialized vertebrae

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204
Q

What is the name for C2?

A

Axis: unique connection with C1

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205
Q
A

Typical Cervical Vertebrae
A- Spinous Process
B- Vertebral Foramen
C- Lamina
D- Pedicle
E- Transverse process with sulcus for spinal nerves
F- Transverse Foramen
G- Superior Articular Facet
H- Body

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206
Q

What are the fucntions of each lobe?

A
  • Frontal: thinking
  • Parietal: primary somatosensory cortex
  • Occipital: primary visual cortex
  • Temporal: processes hearing and language comprehension
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207
Q

Define these terms:
Sulcus
Fissure
Gyrus

A

Sulcus = groove
Fissure = really deep groove
Gryus = “lump” of tissue - separated by grooves

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208
Q

How does information get from one side of the brain to the other?

A

Corpus callosum bridges the two sides

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209
Q

Where does language comprehension take place?

A

Wernicke’s area (temporal lobe)

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210
Q

Where does word formation take place?

A

Broca’s area (frontal lobe)

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211
Q

Where are emotional responses developed?

A

Limbic system

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212
Q

Why is grey matter in the spinal cord a darker color?

A
  • less myelin
  • has lots of cell bodies where the decisions are usually made
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213
Q

Why is white matter in the spinal cord a lighter color?

A
  • there’s more myelin
  • not as many cell bodies
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214
Q

How does the left and right side of the spinal cord communicate with each other?

A
  • Lamina X in the grey matter
  • Anterior white commissure in the white area
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215
Q

How does CSF travel?

A

It is produced in the brain and travels through the central canal of the spinal cord
- the canal is lined with ciliated cells that pushes CSF down the cord

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216
Q

How does information travel through the spinal cord?

A

Sensory information comes in the back through the dorsal horn and motor function comes out the anterior horns in the front

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217
Q
A

A: Corpus Callosum
B: hypothalamus
C: Pons
D: Medulla oblongata
E: Cerebellum
F: Occipital Lobe

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218
Q
A

A: Dorsal horns
B: Anterior horn
C: Anterior Median Fissure (sulcus)
D: Anterior white commissure
E: Central Canal
F: Posterior median Fissure (sulcus)

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219
Q

What is the name of C1 and where does it come from?

A

Atlas - Mythical god who held the weight of the world on his shoulders

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220
Q

What’s the biggest difference of C1?

A

There’s no vertebral body - it doesn’t need to support as much weight

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221
Q

Where is the “pivot point” in C1?

A

The anterior arch is where C2 connects to C1 and provides a rotational axis

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222
Q

What is the opening at the base of the skull called?

A

Foramen magnum

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223
Q

What are occipital condyle for?

A

Downward projections in the base of the skull that have cartilage to fit together with C1

224
Q

What is the ligament that connects the top of the spine to the base of the skull?

A

Atlantooccipital ligament

224
Q

What does the axis have that’s specific to it?

A

Dens - bony projection that connects to C1
- it creates a connection that allows your skull to rotate

224
Q

What is C2 called?

A

Axis

225
Q

What is different about the ligamentum flava flav?

A
  • they are more stretchy
  • it may feel different if you hit it with a needle
  • could have a midline that’s not fused completely
226
Q

Where is the vertebral prominens?

A
  • it’s the marker in the back of the neck that divides the cervical and thoracic spine
  • if you look in a textbook it will say C7 but Schmidt says it’s more like T1
227
Q

Why don’t you see thoracic spine injuries very often?

A

There’s alot of things connected to this part of the spine so this makes it stronger and more robust

228
Q

Why is the thoracic spine hard to access with a needle?

A

The spinous processes are all angled downward so a midline approach would be hard

229
Q

What are true ribs and where do they connect on the spine?

A
  • the first 7 ribs that connect directly to the sternum from a piece of cartilage
  • they connect to costal facets on the body of the vertebra and the transverse process
230
Q

What are false ribs?

A

Ribs 8, 9 and 10 that don’t have a dedicated connection to the sternum;
- they connect to the cartilage on rib 7

231
Q

What are floating ribs?

A

The last two ribs that aren’t connected to the rest of the thorax
- they are very easy to jar loose from the connecting spots

232
Q

What are the unique structures of the thoracic spine?

A
  • downward facing spinous facet
  • 2 costal facets on the back of the vertebral body (superior and inferior costal facet)
  • the shape of the body is in the shape of a heart & the left side is flatter because it is compressed by the aorta
233
Q

Where do the head and neck of the ribs attach?

A
  • Head attaches to the costal facets of the vertebral body
  • Neck comes in contact with the costal facet of the transverse process at the coastal tubercle
234
Q

Label Atlas

A

A: Superior Articular Facet
B: Posterior Arch
C: Posterior tubercle
D: Transverse process
E: Transverse foramen
F: Anterior arch
G: Anterior tubercle
H: Facet for dens

235
Q
A

A: Occipital Condyle
B: Foramen Magnum

236
Q
A

A: Anterior articular facet
B: Dens
C: Superior articular facet
D: Posterior articular facet
E: Body
F: Transverse process
G: Spinous process

237
Q
A

A: Vertebral foramen
B: Dens
C: Superior articular facet
D: Anterior articular facet
E: Spinous process

238
Q
A

A: Anterior longitudinal ligament
B: Posterior longitudinal ligament
C: Ligamentum flava
D: Interspinous ligament
E: Supraspinous ligament
F: Inter-transverse ligament

239
Q

Characteristic of lumbar spine:

A

Large vertebral bodies—-supports a lot of weight

240
Q

What is the curvature of the lumbar spine?

A

Lordotic (anterior curvature)

241
Q

How can you increase chances of successful spinal access in lumbar spine?

A

Have patient lean forward

242
Q

Where does the lumbar spine connect with the sacrum?

A

Inferior articular process of L5 connects with superior articular process from sacrum

243
Q

Why is lumbar spine popular spot for epidurals/spinal anesthesia?

A

Anatomy is easier to approach with a needle
Spinous processes angle straight back
And intervertebral foramen

244
Q

How are the intervertebral foramen formed?

A

The Pedicles have notches in them—superior and inferior vertebral notches from neighboring vertebrae line up to form Foramen

245
Q

What the the purpose of the intervertebral foramen?

A

Openings between vertebrae where spinal nerves can exit the spine

246
Q

At what point in life does the sacrum become completely fused?

A

Usually by 14-15 years old

247
Q

What are the transverse lines on the sacrum?

A

The points where the vertebrae fused

248
Q

Where does the intervertebral disc sit in the sacrum?

A

Sacral Promontory—weight supporting structure at the top of sacrum

249
Q

What is the purpose of the intervertebral disc on top of the sacrum?

A

Gives a place for L5 body to rest (cushion)

250
Q

Opening down the center of the fused sacrum:

A

Sacral canal

251
Q

What is located in the sacral canal?

A

Spinal nerves and nerve roots hang out in sacral canal before they exit

252
Q

What are the openings in the front and back of the sacrum?

A

Sacral Foramina

253
Q

How many sacral foramina do we have?

A

Anterior and posterior sacral foramina

4 on each side- 8 total anterior and 8 total posterior

254
Q

What is the function of sacral foramina?

A

Places where spinal nerves and nerve roots can exit sacrum

A place to get drugs into sacral canal

255
Q

Posterior sacrum bony prominences that are palpable:

A

Median sacral crest: spinous processes that have fused together (middle back of sacrum)

Lateral sacral crest: transverse processes have fused (one on each side)

Medial sacral crest: fusion of superior and inferior articular processes (between median sacral crest and lateral sacral crest)

256
Q

What is a crest in anatomy?

A

A ridge

257
Q

Opening at the base of the sacrum and purpose for it:

A

Sacral hiatus—exit point for coccygeal spinal nerves (1 pair)

Allows some ligaments to pass through

258
Q

Raised ridges/bumps on either side of sacral hiatus —projections that come off the side

A

Sacral cornua

259
Q
A

A: Inter-transverse ligament
B: Anterior longitudinal ligament
C: Ligamentum flava

260
Q
A

A: Anterior longitudinal ligament
B: Ligamentum flava
C: Interspinous ligaments
D: Inter-transverse ligaments
E: Supraspinous ligament

261
Q

How many coccygeal vertebrae do we have as adults?

A

2

262
Q
A

A: Apex of Dens
B: Posterior longitudinal
C: Anterior longitudinal ligament
D: Nuchal ligament
E: Supraspinous ligament

263
Q

What type of vertebrae is this?

A

Thoracic vertebrae
A: Superior costal facet
B: Inferior costal facet
C: Inferior articular facet
D: Spinous process
E: Transverse process

264
Q
A
265
Q

Most superior ridge of the pelvis; palpable even in obese patients

A

Iliac crest

266
Q

What level vertebrae would you be at if you draw a line on top of 2 iliac crests?

A

Middle of L4
below that line–L4-L5 interspace
above that line–L3-L4 interspace

267
Q

What is the marker of the iliac crests used for?

A

Epidural marker

268
Q

2 palpable bumps on the top back side of the pelvis

A

Posterior Superior Iliac Spines

269
Q

Marker that we use posterior superior iliac spine for:

A

Used for markers to estimate access to S2 posterior sacral foramina

Palpate posterior superior iliac spine–drop down 1cm and move 1cm midline

270
Q

Why S2 and not S1 to get drugs into sacral canal?

A

If moving perpendicular to the body with a needle–S1 opening is very difficult to hit straight on

S1 openings more to the side than is does to the back

271
Q

Bump below superior iliac spines:

A

Posterior inferior iliac spines–much harder to palpate–posterior superior iliac spine is actually visible so it a better marker

272
Q

What are the attachment points of the inguinal ligament?

A

Anterior superior iliac spine
Pubic tubercle

273
Q

Can inguinal ligament be palpated?

A

Should be able to feel for this if not see it even if patient is obese. Would have to tape up pannus with straps ;)

274
Q

Ligament that runs on the front of all vertebral bodies down entire length of spine:

A

Anterior longitudinal ligament

275
Q

Iliolumbar ligament:

A

Connects transverse processes of L4 and L5 to the top of the pelvis

276
Q

Describe anatomical differences in pelvis between men and women:

A

Women have wider opening in pelvis and broader hips

277
Q

What is the cartilage that separates the hip bones that come together at the front of the pelvis?

A

Pubic symphysis

278
Q

Where is the umbilicus marker and what is it used for?

A

The belly button–should be at intervertenbral disc between L3-L4

BUT this is not really used because there is alot of variation with extra weight–better to use bony markers

279
Q

What are the “2 sets of hips” Dr schmidt references in lecture?

A

Greater trochanter of femur
Sides of pelvis

280
Q

Supraspinous ligament

A

Tips of spinous processes all the way down the spine–visualize on posterior pelvis

281
Q

How many intervertebral dics do we have?

A

Between each vertebrae–some disc gets lost if vertebrae are fused (no sacral discs)

282
Q

What is the purpose of the intervertebral discs?

A

Serve as a cushion between the bodies of vertebrae

283
Q

What is the intervertebral disc made out of?

A

Nucleus pulposus: Gel filled center
Anulus Fibrosus: Fibrous housing for nucleus pulposus

284
Q

What are some of the characteristics of the anulus fibrosus?

A

FIbers are structured in a crisscross pattern in front of vertebral bodies
Provides alot of strength in the front of the spine
No crosshatching patter in the back of spine–not as strong

285
Q

What is used to sandwich nucleus pulposus and anulus fibrosus?

A

Hyaline cartilage places on tops and bottoms of vertebral bodies

286
Q

What happens with disc herniation?

A

Injury causing loss of some nucleus pulposus when the anulus fibrosus has a weak spot–leaking out putting pressure on spinal nerve

287
Q

In what direction do most disc herniations occur?

A

Nucleus pulposus almost always get pushed out the back since the front of spine is a lot stronger than the back

288
Q

What are some potential interventions for disc herniation?

A

Discectomy: try to remove part of disc causing issue; minimally invasive

Fusion: Fuse some vertebrae together for stabilization–put plates and screws in from anterior approach

Laminectomy: Create more space so the spinal nerves isnt being compressed

289
Q

What is a downside to spinal fusion?

A

Putting rods/screws into other vertebrae near the issue to stabilize–prevents movement in that area which creates extra stress on levels above and below the fusion

290
Q

Lumbar fusion risks down the road:

A

Even if initial procedure is successful–years later need another surgery on vertebrae above and below that are now messed up from the added stress.

Usually not just one procedure because it reduces integrity of shock absorbing and increases stress on spine

291
Q

How does a laminectomy help with a herniated disc?

A

Create more space so spinal nerve is not being pushed against intervertebral foramen

removing part of the bone to take pressure off–usually remove lamina (the less bone removed more likelihood for lasting solution)

292
Q

How can lower back problems be alleviated without surgical interventions?

A

80% of lower back problem could be fixed with lifestyle changes and PT

Hamstring stretches–hamstrings are tight/rigid these muscles attach to back of spine compresses opening in vertebrae

293
Q

What are the spinal meninges made of?

A

Connective tissue

294
Q

What the are the 3 layers of spinal meninges?

A

1) Pia Mater
2) Arachnoid Mater
3) Dura Mater

294
Q

Spinal Cord Pia Mater:

A

Tight layer stuck to neurons and glial cells in CNS (Neurons and glial cells underneath pia)

295
Q

SC arachnoid mater:

A

Superficial to Pia–superficial to all large blood vessels that perfuse CNS

296
Q

Subarachnoid layer in SC:

A

Underneath arachnoid layer–Where CSF is contained

297
Q

Dura Mater in SC:

A

Outer layer on top of arachnoid mater–tough, robust

298
Q

Subdural space in SC:

A

Between arachnoid and dura–potential space (nothing in this space in SC)

299
Q
A

A: Body
B: Hyaline Cartilage
C: Nucleus Pulposus
D: Anulus Fibrosus

300
Q
A

A: Anterior Longitudinal Ligament
B: Iliolumbar Ligament
C: Anterior Superior iliac Spine
D: Sacral Promontory
E: Inguinal Ligament
F: Anterior Inferior Iliac Spine
G: coccyx
H: Pubic Symphysis
I: Pubic tubercle

301
Q
A

A: Superior Articular Process
B: Promontory
C: Anterior Superior Iliac Spine
D: Anterior Inferior Iliac Spine
E: Pubic Symphysis
F: Pubic Tubercle
G: Anterior Sacral Foramina
H: Posterior Inferior Iliac Spine
I: Iliac Crest

302
Q
A

A: Iliac Crest
B: Sacral Canal
C: Superior Articular Process
D: Median sacral crest
E: Sacral Hiatus
F: Coccyx
G: Posterior Sacral Foramina
H: Posterior Superior Iliac Spines
I: Posterior Inferior Iliac Spine

303
Q
A

A: Sacral Canal
B: Lateral Sacral Crest
C: Median Sacral Crest
D: Medial Sacral Crest
E: Sacral Hiatus
F: Sacral Cornua
G: Posterior Sacral Foramina
H: Superior Articular Facet

304
Q
A

Lumbar vertebrae
A: Spinous Process
B: Transverse process
C: Superior Articular Process
D: Inferior Vertebral Notch
E: Superior Vertebral Notch
F: Intervertebral Foramen
G: Vertebral Body
H: Inferior articular process
I: Inferior articular facet

305
Q

Cells that move portions of electrolytes from blood to CSF:

A

Ependymal cells

306
Q

What is the primary mechanism of ependymal cells for producing CSF?

A

Na+ pump–primary active transport with ATP to pump Na+ into CSF

307
Q

What do ependymal cells separate?

A

Separate CV circulatory system and CSF circulatory system

308
Q

How do anesthetics affect CSF production?

A

Some anesthetics can increase or decrease the speed of sodium pumping

309
Q

How does the ependymal cell get electrolytes to make CSF?

A

Ependymal cells have access to blood for water, Na+, and Cl-

Leaky to Na+ from blood
leaky to Cl- on blood side
water can slip across

310
Q

How does Cl- and water move over to CSF?

A

Chloride passively follows sodium (positive charged Na+pulling negative Cl)

Water passively follows Na+ and Cl-

311
Q

Area where ependymal cells are aggregated together to form a tissue that produces CSF:

A

Choroid Plexus

312
Q

What are the main components of CSF?

A

Na+, Cl-, and water

313
Q

How are K+ levels regulated in CSF?

A

Astrocytes–tuck away more than usual

314
Q

What is a primary location(s) of choroid plexus?

A

Choroid plexus found in all ventricles

315
Q

How many ventricles do we have in the brain/brainstem?

A

4
-2 lateral ventricle
-3rd ventricle
-4th ventricle

316
Q
A
317
Q

Where is the 3rd ventricle located?

A

Where hypothalamus would be in diencephalon (inner part of brain)

318
Q

Where is the 4th ventricle located?

A

Middle of brain stem–anterior to cerebellum

319
Q

Describe the drainage of CSF through the ventricles:

A

lateral ventricles drain into 3rd ventricle
3rd ventricle drains into 4th ventricle
4th ventricle CSF can exit from multiple different places

320
Q

Pathway that allows CSF to flow from lateral ventricles to 3rd ventricle:

A

Interventricular foramen (Foramen of Monroe)

321
Q

Pathway that allows CSF to flow from 3rd ventricle to 4th ventricle:

A

Cerebral Aqueduct (Aqueduct of Sylvius)

322
Q

What the the pathways for CSF from the 4th ventricle:

A

1) Central Canal (in spinal cord)
2) Lateral Aperture (2) (foramen of luschka): horns on either side of 4th ventricle
3) Median Aperture (foramen of magendie): CSF exits out the back of ventricle

323
Q

What is the purpose of the median aperture (foramen of magendie)?

A

Provide CSF circulation around cerebellum

324
Q

Pool of CSF fed by median aperture that circulates CSF around cerebellum

A

Cerebellomedullary cistern (Cisterna Magna)

324
Q

Why would you want to potentially sample CSF from Cerebellomedullary Cistern?

A

CSF is fresh/new–would sample from accessing foramen magnum (not used alot because super invasive)

324
Q

Where is CSF reabsorption occurring?

A

Arachnoid Granulations: infoldings found at top of brain midline above longitudinal fissure

325
Q

Explain how arachnoid granulations work?

A

Mediate majority of CSF reabsorption into CV system: If ICP is too high the arachnoid granulations open up and “blow off” some CSF back to CV system to normalize pressure

326
Q

Where is another place that a small amount of CSF gets reabsorbed?

A

Area surrounding the spinal cord

327
Q

What happens to CSF production if the exit paths get occluded?

A

CSF is still produced at the same rate–but nowhere for it to go so ventricles enlarge and push on other important structures surrounding the ventricles

328
Q

If the cerebral aqueduct is occluded, what consequence would this have on brain?

A

CSF volume would increase in 3rd ventricle/lateral ventricles

(volume above exit point expect to grow in size and compress neurons and glial cells)

329
Q

What is the most common CSF occlusion site and why?

A

Cerebral Aqueduct–narrow pathway (tumor or something could get lodged there easily)

330
Q

Temporary fixes for non-communicating hydrocephalus:

A

provide path for CSF–Ex: bolt/drain to divert CSF (invasive and issues if they dont work)

331
Q

Non communicating vs communicating hydrocephalus:

A

non communicating: blocked pathways CSF uses to exit

communicating: open pathways but CSF isnt being reabsorbed like it should be

332
Q

Difference in the physical appearance of the brain with non communication and communicating hydrocephalus:

A

Non-communicating hydrocephalus–ventricle size increase

communicating hydrocephalus: No ventricle enlargement–just increase ICP

333
Q

What would you expect to happen if a patient had a stroke and there are blood clots in the arachnoid granulations?

A

Would expect pressure throughout the system to be elevated because the arachnoid granulations are not functioning properly and CSF isnt being reabsorbed

Communicating hydrocephalus

334
Q

What is the function of the cerebellum?

A

Part of brain responsible for coordinating complex motor tasks (coordinated movement)

335
Q

What are the cranial sinuses responsible for perfusing?

A

The brain and spinal cord

336
Q

What is a sinus?

A

a big vein

337
Q

What is the sinus on top of the skull that runs midline in the sagittal plane?

A

Superior Sagittal Sinus

338
Q

Where are arachnoid granulations located?

A

they sit on top of superior sagittal sinus

339
Q

Sinus that runs below the most superior sinus in the same plane:

A

Inferior sagittal sinus

340
Q

Connective tissues between superior and inferior sagittal sinuses:

A

Falx cerebri: fan structure, rigid separates left and right hemispheres

341
Q

What is the tentorium Cerebelli?

A

extension of the Flax Cerebri down to back of the brain–provides a place for occipital lobe to sit (like a shelf)

342
Q

What is below Tentorium Cerebelli?

A

Cerebellum

343
Q

Straight sinus:

A

Connects superior and inferior sagittal sinuses–tail end of inferior sagittal sinus (where it straightens out)

344
Q

Where does blood go after the straight sinus?

A

Blood can flow in lateral path either to right or left of skull: provides exit point for all venous blood returning through superior and inferior sagittal sinuses

345
Q

Sinus Confluence:

A

Area where superior sagittal sinus, inferior sagittal sinus, and straight sinus connect to use lateral exit point

346
Q

How many transverse sinus do we have?

A

2–one on each side

347
Q

What is the purpose or transverse sinus?

A

Lateral exit point for superior and inferior sagittal sinuses

348
Q

What is the structure of the sigmoid sinus?

A

“hairpin turn”

349
Q

What is the function of the sigmoid sinus?

A

Blood moves to lateral sides of the skull and then takes a turn (sigmoid sinus) before moving to internal jugular veins

350
Q

Venous collection pool int he front/middle part of the brain:

A

Cavernous Sinus

351
Q

Where does the venous blood in the cavernous sinus come from?

A

Venous run off from face and front of the brain–it would join sigmoid sinus and then exit cranium via internal jugular veins

352
Q

what the is function of external jugular veins?

A

For more superficial structures on the side of the head

353
Q

What are the 4 vessels feeding arterial circulation of the brain and brainstem?

A

Vertebral arteries (2)
Internal carotid arteries (2)

354
Q

Where are the vertebral arteries and carotid arteries located?

A

Vertebral arteries: running up back of neck (supply posterior of brain)

Internal carotid arteries: feed anterior portion of brain

355
Q

what is the function of the external carotid artery?

A

In charge of giving blood supply to more superficial structures

356
Q

What is normal arterial blood flow in the brain?

A

750mL/min

357
Q

What determines blood flow in the brain?

A

blood flow is due to high metabolic rate of the brain

358
Q
A

A: Superior articular facet
B: Costal facet (transverse process)
C: Intervertebral disc

359
Q

How much of our body weight does the brain account for?

A

2-3% of our overall body weight

reason why its lopsided that our brain required 15% of our cardiac output compared to its small size

360
Q

What is the brain blood flow rate based on tissues?

A

50mL/min/100g of tissue

361
Q

How much of blood flow in brain is supplied to white vs grey matter?

A

Grey matter: 80%
white matter: 20%

362
Q

Why is there an increase in blood flow to grey matter?

A

decision making happens here so very important

main metabolic requirement of CNS is to get blood flow to grey matter where decision are make and all action is happening

363
Q

How can the white matter of the brain function without as much blood flow?

A

White mater is efficient for sending messages (myelinated) without using a ton of activity

364
Q
A

A) Transverse Sinus
B) Sinus Confluence
C) Superior Sagittal Sinus
D) Straight Sinus
E) Tentorium Cerebelli
F) Cavernous Sinus
G) Sigmoid sinus

365
Q
A

A:Costal tubercle
B: Neck
C: Head

366
Q

What cells help regulate the contents of the CSF?

A

Astrocytes

367
Q

In what order are the layers of the meninge?

A

Pia mater: directly on top of neurons and glial cells
Arachnoid: on top of pia
Dura mater: robust top layer filled with fat tissue and blood vessels

368
Q

Where is a good location to do a spinal block?

A

It’s better to go in an an area where there’s less spinal cord - the neck has a thick cord so this is not ideal
- lower back has projections with more space around them so this is safer

369
Q

How long is the spinal cord?

A

It goes from the medulla to the level of L1

370
Q

What is the end of the cord at L1 called?

A

Conus medullaris?

371
Q

What are the two enlargements of the spinal cord and why are they enlarged?

A

Cervical enlargement - feeds into the brachial plexus
Lumbar enlargement - feeds into the sciatic nerve and lumbar plexus
- they are larger because they have alot of innervations for all of the muscles that need to be controlled

372
Q

What is the collection of nerve roots at the bottom of the cord called?

A

Cauda equina (horse’s tail) - roots that haven’t combined yet to form the spinal nerves

373
Q

What is the filum terminale and it’s function?

A

extensions of the pia layer - helps keep the spinal cord anchored to the natural position in the spinal canal

374
Q
A

A) Dura mater
B) Pia mater
C) Sinus confluence
D) Arachnoid Granulations
E) Superior sagital sinus

375
Q

Describe the difference between the filum terminale internum and the filum terminale externum -

A

Internum - inside the dural sac
Externum - starts at the dural sac and goes down to the coccyx

376
Q

Why is the filum terminale so important?

A

The growth of the bones in the spine occur faster than the spinal cord, so these ligaments prevent the cord from retracting up as you grow

377
Q

What is the lumbar cistern?

A

Also called the dural sac
- storage area where CSF can circulate around the cauda equina
- extends from conus medullaris to the cauda equina
- makes for a good target for a CSF sample

378
Q

What is the downside of taking a CSF sample from the lumbar cistern?

A

The CSF down there can get pooled up down there and isn’t well circulated so it can get stale - take these results with a grain of salt because the CSF is older

379
Q
A

A) Falx Cerebri
B) Inferior Sagittal Sinus
C) Superior sagittal sinus
D) Straight sinus
E) Sinus Confluence
F) Transverse sinus
G) Sigmoid sinus
H) Cavernous Sinus
I) Tentorium cerebelli

380
Q

What are some typical access points in the spine?

A
  • Anatomical marker for L4 - above or below
    -Sacral hiatus - base of the sacrum
  • Posterior sacral foramina
381
Q

If a patient has a skull fracture, where would you suspect a bleed and why?

A

Epidural bleed - the dura is the layer closest to the skull so the and the fracture can rupture an artery running through it

382
Q

What types of bleeds are more dangerous, why?

A

Epidural and Subarachnoid
- these are usually arterial so they will bleed faster and cause more damage

383
Q

What is the supportive structure that keeps the space between the arachnoid and pia layer?

A

arachnoid trabecular

383
Q

Explain the contents of CSF -

A

pH: around 7.31
Sodium: around 140
Chloride: higher than plasma - close to sodium (140)
Potassium: 40% less than plasma
Magnesium: higher than plasma
Glucose: around 60 meq/dL
Clear

384
Q
A

A) Lateral ventricle
B) Cerebral Aqueduct
C) Interventricular foramen (foramen of monroe)
D) 3rd ventricle
E) Corpus Callosum
F) 4th ventricle
G) Lateral Aperture (foramen of luschka)
H) Central canal
I) Median Aperture (Foramen of magendie)

385
Q

Why do the CSF contents vary from plasma?

A

the higher chloride, lower potassium and higher mag makes the cell more negative and “keep the brakes” on the central nervous system

386
Q

Why is the CSF pH lower than blood?

A

The brain has it’s own buffer system with bicarb to buffer the CO2 that’s being produced
- bicarb is lower than in the blood

387
Q
A

A) 3rd ventricle
B) Right lateral ventricle
C) Cerebral aqueduct (aqueduct of Sylvius)
D) 4th ventricle

388
Q

What are the cerebral sinuses made from?

A

Wall of sinuses are made up of dura mater–they are robust and rigid compared to other veins in the body

389
Q

what is the average amount of CSF in the body?

A

150 ml

390
Q

How much CSF is produced per day?

A

500 ml
- replaced about 3x day on average

391
Q
A

A: Dura mater
B: Arachnoid mater
C: Tentorium cerebelli

392
Q
A

A: Epidural hematoma
B: Arachnoid
C: Arachnoid trabeculae
D: Pia mater
E: Subarachnoid space
F: Subdural hemorrhage
G: Dura mater

393
Q

What is brain blood flow rate dependent on?

A

cerebral metabolic activity in the brain

394
Q

Describe what happens to cerebral blood flow when we are active vs inactive:

A

If we are using out brain for alot of things–blood flow increases

If we are in a coma–low neurological activity and would expect low brain blood flow

395
Q

Is there potential for increase in brain blood flow under homeostasis?

A

usually do not get extra brain blood flow when things are working normally

396
Q

What is the circle of willis and its purpose?

A

A continuous structure that wraps around where arteries connect to anatomy–provides a pathway that will increase likelihood of collateral circulation in the brain if there is a problem in one of the arteries

397
Q

What happens if there is a blockage in one of the arteries in the circle of willis?

A

If one artery if blocked then the blood should have another pathway to take to get to tissue that needs to be perfused

398
Q

What is the name of the artery formed by the merging of both vertebral arteries?

A

Basilar Artery

399
Q

At what point on the brain surface do the vertebral arteries merge to become the basilar artery?

A

Inferior to the pons

400
Q

Where does the basilar artery feed into the circle of willis?

A

Posterior midline

401
Q

What are the 3 large cerebral arteries?

A

Posterior cerebral artery
Middle cerebral artery
anterior cerebral artery

402
Q

Where is the posterior cerebral artery located?

A

stems of basilar artery on the back of circle of willis

403
Q

What part of the brain is perfused by posterior cerebral artery?

A

Back and far lateral brain perfusion

404
Q

What is the largest cerebral artery?

A

Middle cerebral artery

405
Q

What part of the brain is perfused by the middle cerebral artery?

A

majority of lateral and middle part of the brain

406
Q

Where are the anterior cerebral arteries?

A

front of brain

407
Q

What area of the brain does the anterior cerebral artery perfuse?

A

front and medial parts of the frontal lobe primarily

408
Q

Name the sections of the anterior cerebral artery:

A

Post-communicating part of cerebral artery (A2)

Pre-communicating part of cerebral artery (A1)

409
Q

The small artery that connects the two anterior cerebral arteries:

A

Anterior communicating artery

410
Q

What is it important to have anterior communicating artery in the circle of willis?

A

Its the only way to have left to right cross talk in the front of the circles of willis

allows for anterior cerebral arteries to communicate

411
Q

What name is given to the internal carotid arteries once they become a part of the circle of willis?

A

Name changes to middle cerebral artery

412
Q

Name the sections of the posterior cerebral artery:

A

Post communicating posterior cerebral artery (P2)

Pre communicating posterior cerebral artery (P1)

413
Q

What is the structure that connects posterior cerebral arteries to middle cerebral arteries?

A

POsterior communicating artery

414
Q

What are the arteries for the cerebellum?

A

Superior cerebellar artery

Anterior inferior cerebellar artery

Posterior inferior cerebellar artery

415
Q

Where is the superior inferior cerebellar artery?

A

Projects from top of basilar artery

416
Q

Where is anterior inferior cerebellar artery?

A

middle portion–arises from basilar artery

417
Q

Where is posterior inferior cerebellar artery?

A

Furthest back–arise from each of the vertebral arteries (below the pons)

418
Q

Why are subarachnoid bleeds more difficult than other intracranial bleeds?

A

usually arterial- blood is infiltrating some of the neurons and glial cells in are of hemorrhage

hard to remove blood without injuring underlying structures

419
Q

What causes subarachnoid bleeds?

A

Genetics/lifestyle

alcoholism: BVs are thin and dont handle abuse very well. Or if person has HTN long periods of HTN make aneurysm more prone to burst

420
Q

What is the top byproduct of metabolism that is involved in regulation of brain blood flow?

A

CO2

421
Q

What is the correlation with CO2 and brain blood flow?

A

CO2 is produced by metabolism

The more CO2 we produce the higher the brain blood flow

422
Q

How does increase CO2 cause increased blood flow to brain?

A

Local areas of the brain that have high activity are producing lots of CO2

CO2 moves into BVs surrounding that tissue and causes vasodilation

423
Q

What is brain/blood flow autoregulation?

A

System that can maintain constant brain blood flow under changing conditions

423
Q

How can the body gage how much perfusion it needs to the brain?

A

CO2 levels

We need as much perfusion as it takes to wipe out the CO2 that is being produced

once we get that done then blood flow will not increase any further

424
Q

What drives blood flow?

A

systemic blood pressure

425
Q

If there is an increase in systemic BP in a healthy person, what would happen to cerebral blood flow?

A

brain blood flow would not change (autoregulation is working)

426
Q

How does the brain adjust to prevent over perfusion?

A

increases vascular resistance (vasoconstriction)

427
Q

If feed vessels in the circle of willis have higher than normal pressure what will happen?

A

The vessels will constrict to limit any over perfusion that might come from increased BP

428
Q

How does the brain prevent under perfusion during low BP?

A

brain blood vessels must relax to help maintain normal amounts of blood flow (dilation)

429
Q
A

A: External carotid artery
B: Common carotid artery
C: Vertebral artery

430
Q

What type of relationship would we see between brain blood flow and BP if autoregulation was not present?

A

linear

increase blood flow with increase bp

decrease blood flow with decrease BP

431
Q

What would be a potential issue from unregulated cerebral over perfusion?

A

Risk of blowing up any aneurysm in the brain

432
Q
A

A: Anterior communicating artery
B: Pre-communicating anterior cerebral artery (A1)
C: Post-communicating posterior cerebral artery (P2)
D: Pre-communicating posterior cerebral artery
E: Vertebral artery
F: Basilar artery
G: Posterior communicating artery
H: Middle cerebral artery
I: Post-communicating anterior cerebral artery (A2)

433
Q

What would happen with unregulated cerebral under perfusion?

A

cell death

434
Q

What is the BP range that cerebral blood flow autoregulation functions best at?

A

50-150

435
Q

Why does autoregulation fail when outside allocated BP range?

A

If BP is lower (below 50) the bvs really cant dilate any further

if they cant relax any more then there will be further drop in BP causing a decrease in blood flow

436
Q

What does LLA represent?

A

Lower limit of autoregulation (50)

437
Q

What does ULA stand for?

A

Upper limit of autoregulation (150)

438
Q

What happens to autoregulation in a patient with chronically elevated blood pressure?

A

Autoregulation adapts and shift new normal limits to higher values

439
Q

What is a physical adaptation to chronic HTN?

A

Atherosclerosis: blood vessel harden up then they can can try to clamp down and prevent hyper perfusion

BVs can clamp down better but wont dilate very well

440
Q

How does atherosclerosis in the brain occur?

A

It is a biproduct of HTN but also an adaptation to prevent over perfusion

441
Q

How can autoregulation relate to patients overall health?

A

Autoregulation is used to gage health of cerebral circulation

Ability of vessel to dilate is related to cardiovascular health

442
Q

In a healthy person, How does brain blood flow overcome blood clot of ischemia?

A

Vascular beds are capable of solving problems by opening up collateral circulation–if a vessel is clogged there other open vessels in the area should relax and help increase perfusion to affected area

443
Q

If a patient has atherosclerosis from HTN what would happen in regards to cerebral blood flow if they had an ischemic stroke?

A

Blood vessels dont relax

They will have a much larger area of injury since the BVs dont relax and create collateral flow

444
Q

How can we check vascular health?

A

Look at the blood vessels ability to dilate

445
Q

Do we have collateral blood flood in the brain if we are healthy?

A

Yes-we have collateral brain flow all through life

we wouldnt notice any difference since the brain is finding ways to perfuse the tissue

446
Q

What happens to cerebral blood flow in a patient with uncontrolled diabetes or hypertension?

A

Blood vessels do not have ability to dilate–which is why these patients have more serious diseases or strokes then you would otherwise

447
Q

What are some drugs that alter autoregulation?

A

Volatile anesthetics–take some of the autoregulation offline

not a flat line with normal autoregulation, more of a slope

448
Q

How is impaired autoregulation depicted in a graph representing pressure and blood flow relation?

A

The steeper the slope–the more autoregulation is affected by drug

449
Q

What determines whether a motor neuron is turned on or not?

A

amount of stimulus it gets in the anterior horn

450
Q

What happens once the action potential reaches the end of the neuron?

A

Slow voltage gated calcium channels open (P-type calcium channel)

451
Q

When do P-type calcium channels open?

A

when an action potential is sensed/ in response to depolarization and allows Ca2+ into motor neuron

452
Q

What happens once Ca2+ enters into motor neuron?

A

Storage vesicles move to cell wall and excrete neurotransmitter

453
Q

What is another name for the acetylcholine storage vesicles?

A

VP-1 storage vesicles
VP-2 storage vesicles

454
Q

What does VP stand for?

A

Vesicular Pool

455
Q

Where is the different between VP-1 vs VP-2 vesicles?

A

VP-1: not ready to go yet (May be away from cell wall or not full of neurotransmitter yet)

VP-2: Storage vesicles are ready to go (ready to be activated by Ca2+ and secrete neurotransmitter to NMJ)

456
Q

Which acetylcholine vesicles are there more of?

A

Lots of VP-1
smaller number of VP-2 that are ready to go

457
Q

What happens when Ca2+ comes into cell after action potential?

A

Ca2+ causes vesicles to move to cell wall–fuse with it and empty contents into NMJ

458
Q

What shuts of vesicles from fusing and dumping neurotransmitter into NMJ?

A

Ca2+ pumps: take Ca2+ that moved in from P-type calcium channel and removes it from neuron

Need ATP–very fast process

459
Q

What happens to the vesicles when calcium is pumped out of the neuron?

A

removing calcium gets acetylcholine vesicles to stop fusing and emptying neurotransmitter

460
Q

What helps reset a neuron?

A

Na/K ATPase

Voltage gated K+ channels: open when action potential passes through to help reset cell

Ca2+ sensitive K+ channels: K+ channel in motor neuron that is Ca2+ dependent K+ channel

461
Q

What do acetylcholine receptors on skeletal muscles look like?

A

function a cylinders

2 binding sites for aCH–when both occupied the channel opens

462
Q

Where are the nAch receptors on skeletal muscles located?

A

Located on target cell at the synapse–close to motor neuron

463
Q

How many receptors are there at each NMJ?

A

millions of nAch receptors at each NMJ–concentrated area at this area of the motor neuron

464
Q

What is end plate potential?

A

Depolarization that is happening in the muscle d/t nAch receptors opening up

end plate potential is the initial stimulus and then an action potential follows

465
Q

Does end plate potential always lead to action potential?

A

end plate potential in health muscles always leads to action potential–will always open fast Na+ channels

466
Q

When does end plate potential turn into action potential?

A

When voltage gated Na+ channels are opened

467
Q

Where are voltage gated sodium channels located in skeletal muscle?

A

fast Na+ channels are located right next to nAch receptors–when these are open the action potential can spread down the length of skeletal muscle

468
Q

What are action potentials mediated by?

A

Voltage gates Na+ channels

469
Q

What is the approximate bare minimum of nAch receptors that need to be activated for an end plate potential?

A

500,000 activated receptors–not an issue because we have vast excess receptors and neurotransmitter than we actually need

470
Q

What happens after voltage gated Na+ channels open on skeletal muscle?

A

muscle contraction with the spread of action potential down the skeletal muscle

471
Q

What are skeletal muscles important for besides muscle contraction?

A

Important to keep body temp up

472
Q

What do anesthetics do to skeletal muscles?

A

Takes them “off line”

Volatile anesthetics tend to reduce amount of muscle activity

473
Q

What is the largest container within the body?

A

Skeletal muscles

lots of internal volume

474
Q

What is associated with every skeletal muscle?

A

A motor neuron

475
Q

How many motor neurons per skeletal muscle cell?

A

Vast majority of skeletal muscles have cells that are innervated my just one motor neuron

some muscles in the body are innervated by more than one motor neuron

476
Q

On average, how many motor neurons control each skeletal muscle cell?

A

one motor neuron

477
Q

What is an example of muscles in the body that are innervated by more than one motor neuron?

A

Ocular muscle in the eye socket are controlled by more than one motor neuron

478
Q

How can motor neuron cell bodies be excited?

A

Descending spinal pathways

Reflex Arcs

479
Q

How can an reflex arc elicit a muscle contraction?

A

Sensory pathway feeds into reflex system

strong pain signal coming into the cord–reflex arc can get involved

strong pain signal might elicit a muscle to contract to withdraw from pain

480
Q

What is a fiber?

A

Term for cell in skeletal muscles

481
Q

How are fibers in muscles arranged?

A

Fibers are arranged in groups within the muscle itself

482
Q

What are the contractile elements of the skeletal muscles and how are they arranged?

A

Actin and myosin

arranged in tubelike structures

483
Q

What does the prefix Sarco- denote?

A

muscle

484
Q

What is the sarcoplasmic reticulum?

A

Specialized ER in skeletal muscles where calcium is stored

485
Q

If a skeletal muscle needs calcium to contract, where does the calcium come from?

A

usually from internal stores in the SR

486
Q

What happens to calcium in the skeletal muscle after muscle has contracted?

A

It gets quickly tucked back into SR through calcium pumps

487
Q

What is the function of the transverse tubules (T-tubules)?

A

Perpendicular pathway (infolding) that allows action potential to move deep into the muscle cell

makes sure deep parts of muscle cell are activated

488
Q

What happens when calcium is liberated in the skeletal muscle?

A

Drives actin and myosin cross-bridge cycling–muscle contraction

489
Q

What physical change happens to muscle fibers when they contracted?

A

Muscle fiber shortens with contraction

490
Q

How big is the NMJ in relation to size of skeletal muscle?

A

NMJ is a small area compared to size of skeletal muscle

Each spot where motor neuron innervates skeletal muscle has one neuromuscular junction

491
Q

How many neuromuscular junctions are there in each skeletal muscle?

A

Probably tons

Every fiber has different NMJ associated with it

492
Q

What causes skeletal muscles cells to look cross-hatched or zebra like pattern?

A

Actin and Myosin filaments

493
Q

How does the muscle get needed energy?

A

There are lots of mitochondria in the muscles close to the neuromuscular junction

494
Q

What would be the result in the target cell if there is large release of acetylcholine from the motor neuron?

A

Skeletal muscle would have lots of depolarization and should follow through with action potential (in healthy tissue)

495
Q

What are clefts?

A

Infoldings at the NMJ on the skeletal muscle

496
Q

What is the difference between primary and secondary clefts?

A

Primary Clefts: just one infolding

Secondary Clefts: more than one infolding

497
Q

Are there Acetylcholine receptors located throughout the clefts in the post synaptic terminal?

A

acetylcholine receptors are toward the surface of the clefts–at the beginning part to keep receptors closer to neuron

498
Q

Where is the primary location of voltage gated Na+ channels on skeletal muscles?

A

Concentrated on inside the clefts but also continue down the length of the skeletal muscle

499
Q

What is the enzyme that breaks down acetylcholine and what components is it broken down into?

A

acetylcholinesterase enzyme–breaks acetylcholine down into acetyl (acetate) and choline

500
Q

What is the purpose of acetylcholinesterase?

A

limits the length of depolarization from contact with the motor neuron

helps shut target down to reset things for another stimulus from motor neuron

501
Q

Where is acetylcholinesterase produced and stored?

A

produced by skeletal muscles

it is fastened to skeletal muscle itself (parks at NMJ)

502
Q

What enzymatic reaction occurs with the action of acetylcholinesterase?

A

Hydrolysis

503
Q

What happens to the broken down components of acetylcholine?

A

No longer has an effect on the receptors on skeletal muscles
so its recycled by the motor neuron

504
Q

Where is choline produced?

A

Motor neuron–specific enzymes that assemble acetylcholine

505
Q

What myelinates motor neurons?

A

Schwann cells

506
Q

Where are schwann cells in motor neurons located?

A

At the terminal end of motor neurons–manage the myelination of the motor neuron all the way back to spinal cord

507
Q

How many nACh-Rs receptors at typical NMJ?

A

5 million

508
Q

How many nACh-Rs are activated in a typical synaptic response?

A

500,000

509
Q

What precent of nACh-Rs open in response to acetylcholine during a typical response?

A

10%

510
Q

What is the bare minimum acetylcholine release to maintain muscle contraction?

A

at least 1 million acetylcholine molecules

since receptor needs 2 bound to activate probably release closer to 2 million acetylcholine molecules

511
Q

What can happen to acetylcholine when trying to cross NMJ?

A

Acetylcholinesterase breaks it down before it reaches the target

512
Q

What type of response is elicited when nACh-receptor has one unoccupied binding site?

A

No response–channel remains closed/ inactive

513
Q

How many subunits do nACh-Receptors have?

A

5 subunits

2 of 5 have acetylcholine binding sites

514
Q

How do nACh-R antagonists block acetylcholine?

A

Bind to sites on nACh-r; only need to block one of the binding sites to block the channel

515
Q

What is Curare?

A

Naturally occurring paralytic–most non depolarizing paralytics are modeled after

Old acetylcholine receptor antagonist

Biologic found in rainforests used to paralyze prey when hunting

516
Q

What causes exocytosis during the process of a muscle contraction?

A

Exocytosis is mediated by calcium interacting with storage vesicles

517
Q

What channels are primarily involved in generating a normal looking action potential in the skeletal muscle?

A

VG Na+ and VG K+

518
Q

How do skeletal muscles know what to do when an action potential is being transmitted?

A

Voltage sensors (DHP receptors) in the cell wall that can detect action potentials

519
Q

What occurs when DHP receptors sense an action potential come through?

A

DHP receptor open up calcium release channels in the SR

520
Q

Where is the sarcoplasmic reticulum located?

A

SR is close to the cell wall and in proximity to the transverse tubules; also very close to voltage sensors (DHP)

521
Q

What is DHP?

A

Dihydropyridine receptor–not a receptor but a voltage sensor

some calcium channel blockers are DHP calcium channel blockers

522
Q

How do DHP receptors function in skeletal muscle?

A

DHP receptors are tethered to the door keeping calcium release channel closed

They facilitate release of calcium from the SR when an action potential is sensed

523
Q

How do DHP receptors open door to SR?

A

A physical spring like attachment from receptor to SR door

action potential comes through and sensor tugs on calcium release channel to liberate calcium inside “pops the cork”

524
Q

Where does majority of calcium that is used for muscle contraction come from?

A

Sarcoplasmic reticulum

a little calcium can come in through DHP voltage sensors

525
Q

How are voltage gates Ca2+ channels and DHP voltage sensors different?

A

Voltage gated Ca2+ channels allow for large amount of calcium to enter compared to DHP voltage sensors which only have a small amount of calcium enter the cell

526
Q

Where are the 2 places DHP voltage sensors are located?

A

Cell wall

Transverse Tubule

Sensors in both of these places have a physical attachment to calcium release channel in SR

527
Q

What is another name for calcium release channels that are attached to DHP receptors?

A

Ryanodine Receptor (RyR)

Does not function as a receptor buts its reactive to a chemica

sensitive to a chemical called ryanodine–chemical will open channel

528
Q

A patient has hypocalcemia and is displaying trousseaus sign. This is primarily due to the effects of hypocalcemia in:

A

A) The skeletal muscle
B) The brain
C) The motor neuron
D) The mitochondria

answer: C: hypocalcemia would cause neuron membrane potential to be depolarized increasing activity of neuron that increases activity of skeletal muscle

skeletal muscles can contract without needing outside calcium–because they have lots of calcium tucked away in the skeletal muscle

529
Q

How does calcium get put back into SR in skeletal muscles?

A

SERCA (calcium pump): sarcoplasmic endoplasmic reticulum calcium ATPase

530
Q

What type of transport is SERCA?

A

Primary active transport–burns ATP directly to put calcium into container it doesnt want to go into (expends energy to do so)

531
Q

What is another term for intracellular fluid in skeletal muscle?

A

Sarcoplasm

532
Q

How is choline transported from the synapse it is liberated in back to the motor neuron?

A

ATPase mediated pump (choline pump)

Choline sodium transporter–choline follows Na+ gradient

533
Q

Where is acetate resynthesizes?

A

In the mitochondria in the neuron–lots of mitochondria in neuron and skeletal muscle (supply ATP for all ion transporters in neuron)

534
Q

Where can choline be stored?

A

In cell wall as phosphatidylcholine

535
Q

What are some examples of things that can go wrong in a motor neuron?

A

Myasthenia gravis and LEMS

536
Q

What is myasthenia gravis?

A

Condition where the body develops antibodies to the nACh receptor
- these antibodies bind and destroy the receptor

537
Q

What usually causes myasthenia gravis?

A

Inflammation or genetic anomaly to the thymus gland

538
Q

What are some treatments for myasthenia gravis?

A
  • remove the thymus gland
  • plasmapheresis
  • Stigmine drugs
539
Q

How do stigmine drugs work?

A
  • target the acetylcholinesterase enzymes
  • inhibit the breakdown of acetylcholine will prolong activity at the NMJ and increase chances that nACh receptors will be activated
540
Q

What is LEMS? (Lambert-eaton myasthenic syndrome)

A
  • typically neoplastic
  • body develops antibodies to P-type calcium channels
  • this reduces the calcium coming into the cell and ACh isn’t released
541
Q

What are some treatments for LEMS?

A
  • plasmapheresis
  • remove lung tumor
  • potassium channel blockers
542
Q

How do potassium channel blockers work and why are they dangerous?

A

They close VG potassium channels or prevent them from opening - results in depolarization
- longer depolarization of the MN allows for more time for calcium channels to be open
- they are dangerous because they are not specific for motor neurons, they also affect the potassium channels in the heart

543
Q

What are some examples of potassium channel blockers?

A
  • TEA: tetraethylammonium
  • Diaminopyridine
  • Amiodarone (fairly safe cause it sucks at it’s job)
544
Q

How do NON-depolarizing muscle relaxants work?

A

They are receptor antagonists - prevents action potential from happening
- you only need to bind one out of two sites to cause paralysis

545
Q

How do depolarizing muscle relaxants work?

A

Succinocholine = 2 acetylcholine are attached to each other
- it causes sustained depolarization by keeping nACh receptors open for an extended period of time

546
Q

Why doesn’t acetylcholinesterase break down succinylcholine?

A

It normally breaks down the ester bonds in the native acetylcholine, with succinylcholine the 2 acetylcholine are super stuck together so the enzyme has a hard time getting in to break the ester bond

547
Q

Why is there muscle twitching when giving succinylcholine?

A

Because the medication causes a depolarization and creates an action potential that causes a small contraction

548
Q

What is an important side effect of giving succinylcholine?

A

Elevated potassium in the blood - Sodium is constantly coming in and makes the membrane potential more positive and it will push potassium out of the cell to try and make the cell more negative
- usually increases by .5

549
Q

What category of drug is Succinylcholine? (more specific than paralytic)

A

nACh-receptor agonist

550
Q
A

A) Anterior Atlanto-occipital ligament
B) Posterior tubercle
C) Intervertebral Disc
D) anterior longitudinal ligament
E) Posterior longitudinal ligament
F) External occipital protuberance
G) Dens
H) Posterior antlanto-occipital ligament
I) nuchal ligament
J) Ligamenta Flava
K) Vertebral arch
L) intervertebral foramen
M) spinous process
N) interspinous ligament
O) supraspinous ligament

A&P (5 decks)

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