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Flashcards in Physio - Nerve and Muscle Deck (135):
1

On which surface is the Na K ATP pump located?

apical vs basal

basal

2

How many Na does the Na/K - ATPase pump? And from where to where?

3
From: inside
To: outside

3

How many K does the Na/K - ATPase pump? And from where to where?

2
From: outside
To: inside

4

What is the importance of Na/K - ATPase pump? (3)

1. Establish normal ionic gradients

2. Helps maintain cellular volume (because water follows Na)

3. Help establish membrane potentials

5

Identify the main factor involved in the movement of water across body compartments

Osmotic pressure difference

6

What is the major determinant of the ECF osmolality? And how do you calculate it?

Sodium is the major determinant.

Plasma osmalality = 2 x Plasma Na+

7

Plasma osmolality reflects the osmolality of (ECF or ICF). Why?

Both.

ECF and ICF are isotonic

8

What 2 forces determines fluid exchange in capillaries?

Hydrostatic pressure

Osmotic pressure/plasma oncotic pressure

9

What is the cause of hydrostatic pressure?

due to the pumping of the heart and gravity, especially in the lower extremities

10

What is the cause of osmotic pressure?

due to plasma proteins

11

Will hypo protenemia cause edema or dehydration?

Edema - the hydrostatic pressure overcomes the osmotic pressure

12

What is osmotic pressure and how is it determined?

Pressure to oppose/stop osmosis

Based on NUMBER of molecules ONLY

13

What is oncotic pressure and how is it determined? Why is it important?

Osmotic pressure (pressure to stop osmosis) generated by large molecules like proteins.

Important for movement of fluid across capillaries from interstitial space back to capillaries.

14

Synapses occur between

_ and _
_ and _

Neuron to neuron

Neuron to muscles

15

What are the two types synapses?
And which is the more predominant?
What is their mechanism?

Chemical
most predominate
neurotransmitters

Electrical
gap junctions

16

Where do you see electrical synapses? Why?

Give two examples

In cells in which you need to work together - syncytium

1. cardiac
2. smooth muscle

17

What is the difference between IPSP and EPSP?

IPSP - hyperpolarizes the cell (further from threshold)

EPSP - depolarizes the cell (closer to threshold)

18

Is the electrical synapse found in the CNS?

Yes

Cerebellum

19

What is the triggers a chemical synapse?

An electrical potential reaches the presynaptic neuron

20

What are the major steps the the operation of a chemical synapse?

1. Electrical potential reaches the presynaptic neuron

2. Ca channels open

21

What are the major steps the the operation of a chemical synapse? (Pre and post synapse only)

1. Electrical potential reaches the presynaptic neuron

2. Ca channels open and enters the presynaptic terminal

3. Ca attaches to neurotransmitter containing vesicles

4. Vesicles release neurotransmitters to synaptic gutter

5. Neurotransmitters bind to receptors in the postsynaptic cell

22

In order, what are the two most predominate ions in the ECF?

1. Na+
2. Ca+

23

What role does Ca play in the chemical synapse?

Ca attaches to neurotransmitter containing vesicles allowing them to release contents into synaptic gutter

24

What are two types of postsynaptic receptors?

1. Ionotropic receptors

2. Metabotropic receptors aka G protein coupled receptors

25

Characteristics of ionotropic receptors

- opens ion channel
- fast acting
- shorter duration
- single action

26

Characteristocs of metabotropic receptors

- activation of second messengers
- slow acting
- longer duration
- performs many functions

27

Which stays open longer?

A) Open ionotropic receptor opened ion channels
B) Metabotropic opened ion channels

B) Metabotropic opened ion channels

28

What is the moa of metabotropic receptors?

1. Open ion channels
2. They will cause cascade of events through secondary messengers to phosphorylation of intracellular proteins (activation)

29

Where are synaptic receptors found?

1. Presynaptic membrane
2. Postsynaptic membrane

30

What is the purpose of of synaptic receptors in the presynaptic membrane?

Acts as inhibitory mechanism for the release of neurotransmitters.

31

Presynaptic receptors may bind what? 3

1. transmitter that is has released
2. transmitter released by another presynaptic terminal
3. nonsynaptically acting neurotransmitter

32

What are the 3 types of neurotransmitters?

1. small molecule neurotransmitters (Ach)

2. neuropeptides

3. gaseous neurotransmitters

33

What is the fate of small molecule neurotransmitters?

1. reuptake
2. degradation (Ach only)

34

What is the fate of Ach if it does not bind to a postsynaptic receptor?

Ach is degraded to Acetyl CoA and Choline.

Choline is the only part reuptaken.

35

Which is synthesized in a larger amount?

A. small molecule neurotransmitters

B. neuropeptides

A. small molecle neurotransmitters

36

How do neuropeptides differ from small molecules transmitters?

- synthesized in smaller amounts
- larger molecule
- immediately released upon synthesis

37

What is the fate of neuropeptides?

They bind preferentially to post synaptic or extra synaptic g protein coupled receptors. They will simple diffuse.

38

What is a gaseous transmitters?

Nitrous oxide

39

EPSP

a. decrease negativity
b. increase negativity

a. decrease negativity - increases chances of reaching threshold, always depolarizing

40

What are the mechanisms of EPSP? Which is most used?

1. Opening of Na+ channels (widely used)

2. Depressed conduction through the Cl- and/or K+ channels

41

What are the mechanisms of IPSP?

1. binding of neurotransmitter to postsynaptic receptor

Cl- or K+ channels open

42

IPSP

a. decrease negativity
b. increase negativity

b. increase negativity

43

What are the sub units coupled to the GPCR

alpha, beta, gamma

44

What is attached to alpha subunit of GPCR when it is inactivated?

a. GDP
b. GTP

a. GDP

45

What happens to alpha subunit of GPCR when a neurotransmitter binds?

GDP is replaced by GTP activating the alpha subunit. The alpha subunit will dissociate from beta and gamma subunits and bind with and effector protein.

46

What are the usual effector proteins of GPCR? Which is more common and where are they found?

1. Adenylate cyclase - most common, most cells

2. Phospholipase C - smooth muscles

47

What is the most common cascade effect of GPCR?

1. neurotransmitter binds to post synaptic GPCR

2. ADP is replaced with ADP on alpha subunit of GPCR

3. alpha subunit activates effector protein - most common is adenylate cyclase in cell membrane

4. adenylate cyclase produces cAMP

5. cAMP activates the enzyme PKA (protein kinase A)

6. PKA phosphorylates intracellular proteins

48

What is the second most common cascade of GPCR?

1. neurotransmitter binds to post synaptic GPCR

2. ADP is replaced with ADP on alpha subunit of GPCR

3. alpha subunit activates effector protein- phospholipase C

4. Phospholipase C creates IP3 (inositol triphosphate) and DAG (diacylglycerol ->

5a. IP3 promotes release of Ca from sarcoplasmic reticulum

5b. DAG (diacyl glycerol) -> PKC (protein kinase C) & aracadonic acid

5bi. Arachidonic acid + cyclo oxygenase pathway -> prostagladins, thromboxane, prostacycline

5bii. Arachidonic acid + lipo oxygenase pathway -> leukotriene

49

What are the major secondary messenger of phospholipase C?

inositol triphosphate, IP3 (promote release of Ca from sarcoplasmic reticulum)

diacylglycerol DAG -> protein Kinase C and arachidonic acid

50

What are the two pathways for arachidonic acid?

1. cyclooxygenase
2. lipooxygynase

51

What hydrolyzes cAMP?

Phosphodiesterase

52

What hydrolyzes cAMP? And why?

Phosphodiesterase to stop signaling in cell

53

What are the products of the cyclooxygenase pathway and their roles?

1. prostagladins - fever

2. thromboxane - platelet aggregation

3. prostacycline - opposes the action of other two

54

What are the products of lipooxygenase and their roles?

1. leukotrienes - allergic reaction

55

What are the biogenic amine neurotransmitters?

epinephrine
norepinephrine
dopamine

56

Amino acid neurotransmitters?

glutamate - excitatory
glycine - inhibitory

57

Purine neurotransmitters?

ATP

58

Glutamate

a. excitatory
b. inhibitory

a. excitatory

59

Glycine

a. excitatory
b. inhibitory

b. inhibitory

60

Are hypothalamic releasing hormones neurotransmitters?

Yes, a neuropeptide

61

enkephalin

a. small molecule
b. neuropeptide
c. gaseous

b. neuropeptide

62

endorphin

a. small molecule
b. neuropeptide
c. gaseous

b. neuropeptide

63

ACTH, GH, FSH, LH

a. small molecule
b. neuropeptide
c. gaseous

b. neuropeptide

64

glutamate

a. small molecule
b. neuropeptide
c. gaseous

a. small molecule

65

ATP

a. small molecule
b. neuropeptide
c. gaseous

a. small molecule

66

acetylcholine

a. small molecule
b. neuropeptide
c. gaseous

a. small molecule

67

Site of synthesis

Small molecule
Peptide
Gasesous

Small molecule - presynaptic terminal

Peptide - nerve cell body

Gasesous - presynaptic terminal

68

Duration of Action

Small molecule
Peptide

Small molecule - fast acting, less potent

Peptide - slow acting, more potent

Gasesous

69

Amount Released

Small molecule
Peptide

Small molecule - large

Peptide - small

70

Kinds released from neuron

Small molecule
Peptide

Small molecule - single

Peptide - single or multiple

71

Removal from synapse

Small molecule
Peptide
Gasesous

Small molecule - diffusion, enzymatic destruction (Ach), reuptake

Peptide - diffusion

Gasesous - terminated by binding top superoxide anion or the scavenger proteins

72

Examples of gaseous neurotransmitters

NO and CO2

73

Fate of vesicles

Small molecule
Peptide

Small molecule - reused

Peptide - autolyzed

74

Factors that affect synaptic transmission

- fatigue
- pH
- hypoxia

75

Main cause of fatigue

- depletion of neurotransmission

76

Causes of fatigue (3)

1. main cause is exhaustion/depletion of stores of transmitter substance in the presynaptic terminals

2. progressive inactivation of many postsynaptic membrane receptors

3. build-up of abnormal concentration of ions inside the postsynaptic neurons which causes an inhibitory effect on the postsynaptic neuron

77

Alkalosis effect on synaptic transmission on neuronal excitability

a. decrease
b. increase

b. increase

78

Acidosis effect on synaptic transmission on neuronal excitability

a. decrease
b. increase

a. decrease

79

Coma happens at this pH and why?

When pH is <7.0 due to decrease of neuronal excitability

80

What is the effect of hypoxia on synaptic transmission?

decreased oxygen supply will decrease the excitability of neurons

81

What causes negative resting potential?

Conduction of K+ to outside through K-Na leak channels

82

What are the different phases of the action potential and the main ions responsible?

1. Depolarization - Na influx due to fast acting channels

2. Repolarization - Na ion channels begin to close and slow K efflux as channels begin to open

3. Hyperpolarization - persistent K conductance, channel closes slowly

83

K-Na leak channels are more permeable to what and by how much?

K-Na leak channels are 100x more permeable to K

84

How does the Na channel work?

Resting, depolarization, repolarization

Resting - A gate close, IA gate open

Depolarization - A gate open, IA gate open

Repolarization - A gate open, IA gate close

85

When does K channel open and it's relationship to Na channel?

Repolarization - after Na A gate opens and before Na IA gate fully closes

86

What is the cause of absolute refractory period?

Na IA gates are still closed

87

What is the cause of the relative refractory period?

Some Na IA gates are still open

88

What is the reason for hyperpolarization?

Because K channels close slowly

89

Why does the cell return to normal ionic state?

K channels are closed

90

What is the neurotransmitters in the presynaptic terminal of the NMJ?

ach

91

The stimulus in NMJ is always

chemical
electrical

electrical

92

How is end plate potential made in NMJ?

opening of Na channel

93

EPSP is to neurons as

_____ is to NMJ

End plate potential

94

What are the events during excitation-contration coupling?

1. action potential to t tubules

2. t tubles as a continuation of the SR stimulates the released of Ca

3. Ca is required for muscle contraction

95

T tubles are a continuation of

sarcoplasmic riticulum

96

What types of excitation occurs in the NMJ?

a. electrochemical
b. electromechanical

electromechanical excitation

97

Why is it electromechanical excitation?

There is a physical movement of the RYR away from the terminal cisterna of SR and the conformational change of the DHPR

98

The RYR reacts with what receptors?

DHPR receptors when there is a conformational change

99

What is the source of Ca in skeletal muscle?

ONLY from SR

100

What is the role of Ca in skeletal muscle?

cross-bridges to form between actin and myosin filaments in the myofibrils

101

In skeletal and cardiac muscles, how is contraction regulated?

a. thick filament
b. thin filament

b. thin filament - actin

102

What is the role of SERCA?

Actively pump Ca ions back into the SR

103

Ca binds to

a. actin
b. myosin
c. tropomyosin
d. troponin

d. troponin - troponin c

104

What is the thin filament?

Actin

105

What makes the cross bridge?

a. actin
b. myosin
c. tropomyosin
d. troponin

b. myosin

106

Ca binds to

a. troponin c
b. troponin i
c. troponin t

a. troponin c

107

Myosin has what type of function?

ATPase function - binds ATP and dephosphorolate to ADP

108

When does myosin head detach from actin?

When new ATP attaches to myosin

109

What causes muscle relaxation?

Ca is reuptaken into SR

110

Which requires energy to occur?

a. muscle contraction
b. muscles relaxation

BOTH

111

SERCA transports (#) of Ca in the lumen for (#) ____ hydrolyzed

It transports two Ca++ into the lumen for each ATP hydrolyzed

112

SERCA transports (#) of Ca in the lumen for (#) ____ hydrolyzed

It transports two Ca++ into the lumen for each ATP hydrolyzed

113

Sources of energy of energy muscle contraction and their uses?

- ATP from
glycolysis, short term

- phosphocreatine, fast source of high energy

- glycolysis, anaerobically

- oxidative metabolism, sustained long term contraction

114

Muscle shortens

Isometric
Isotonic

Isometric - no

Isotonic - yes

115

Tone changes

Isometric
Isotonic

Isometric - yes, increases

Isotonic - no, constant

116

Skeletal vs cardiac contraction

Connection between sarcoplasmic reticulum and T tubules are less developed in cardiac

Heart requires extracellular calcium to contract

117

What modulates the forces of contraction in cardiac muscles?

changes intracellular Ca levels

118

What causes the prolonged action potential in cardiac muscles?

slow inward Ca++ current

119

Electrical signal originates from

skeletal
cardiac

skeletal - NMJ
cardiac - SA node

120

Cardiac muscle is

electrochemical
electromechanical

electrochemical - the Ca from the ECF needed to release the Ca from the SR

121

Cardiac Ca

ECF = __ %
SR = __ %

30% ECF
70% SR

122

What causes relaxation of cardiac muscles?

- 70% Ca sequestered into SR

- 3 Na/1 Ca channel pumps 30% of Ca to ECF

123

What regulates the the force of cardiac contraction (not Ca)

1. sympathetic stimulation - B1 receptors

2. stretch - frank starling law

124

cAMP activates what?

PKA

125

What is the Frank Sterling law?

heart increases its force of contraction when stretched

126

What is special about contraction of smooth muscle?

Has calmodulin instead of troponin

127

ECF Ca

cardiac muscles
skeletal muscle

cardiac muscles - required

skeletal muscle - not required

128

Action potential length

cardiac muscles
skeletal muscle

cardiac muscles - longer

skeletal muscle - shorter

129

Type of coupling

cardiac muscles
skeletal muscle

cardiac muscles - electrochemical

skeletal muscle - electromechanical

130

Increase of contraction

cardiac muscles
skeletal muscle

cardiac muscles - stretch and sympathetic stimulation

skeletal muscle - recruitment and tetany

131

The following detects what?

muscle spindle
golgi tendon

muscle spindle - muscle length

golgi tendon - force/tension

132

Smooth muscle is regulated by

thick filament
thin filament

thick filament

133

calmodulin-calcium complex does....

activates the myosin light chain kinase

134

how many Ca bind to Calmodulin

4

135

What is a unique of smooth muscle contraction?

- electrochemical
- hormones
- sustained/self paced