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Physiology Test 1 > Membrane Potential And Excitbility > Flashcards

Membrane Potential And Excitbility Flashcards

1
Q

Ca2+ outside vs inside cell

A

Ca2+ kept very low inside cell, and high outside cell
*** Ca2+ kept under severe control

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2
Q

Na-K Pump

A
  • uses ATP
  • 3 Na out
  • 2 K in

*** purpose/fn of Na|K ATPase is to establish Na|K gradient inside/outside the cell

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3
Q

Ca2+ Pump

A
  • requires ATP
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4
Q

Ca2+ used for:

A
  • conformational changes
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5
Q

Ohm’s Law

A

V=IR

I=VxG
Current = voltage x conductance

Amount of current you get = push (voltage) x how easy it is to go a->b (conductance)

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6
Q

Pores

A

Checks amino acids as filter

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7
Q

T|F At Nernst Potential there’s current for X ion?

A

F
- when at equilibrium, there is no current for the ion at equilibrium

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8
Q

Current can only occur when Voltage is

A

Different from NERST potential

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9
Q

Action Potential

A

Electrical signature responsible for all electrical activity in the body

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10
Q

Gating of Sodium Channels
(2 types)

A

M: ACTIVATION gate; opens
H: INACTIVATION gate; almost immediately closes; can’t open again until resets

  • transitions between resting, activated, and inactivated states are dependent on membrane potential and time
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11
Q

BEFORE AP

A
  • @ resting potential K+ at highest [inside], Na+ at highest [outside]
  • Na|K pumps use ATP to maintain these gradients across the plasma membrane
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12
Q

Resting State

A
  • more K channels open than Na
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13
Q

Depolarization

A
  • some Na channels open depolarize game the membrane
  • K channels are closed
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14
Q

Rising Phase of AP

A
  • nearly all Na channels open, sharply raising the AP towards Ena
  • K channels remain closed
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15
Q

Repolariziation

A
  • Na close, K open, pulling membrane potential towards Ek
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16
Q

Undershoot

A
  • overly depolarizes, pulling membrane potential towards Ek, past resting potential
  • Voltage-gated K channels close to restore RP
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17
Q

Going to + NERST
Going to - NERST

A

+: Na|Ca
-: MUST be K

Na\K resets everything

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18
Q

Heart AP

A

AP held longer because Ca2+ helps hold K in

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19
Q

Catecholamines

A

Increase pacemaker rate by increasing cAMP which opens HCN channels increasing If sodium current during phase 4. That increases the slope of phase 4 thus the rate

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20
Q

CNS Overview

A

Brain & Spinal Cord
Afferent Division: sensory stimuli; visceral stimuli : input to CNS from periphery
Efferent Division: autonomic NS; somatic nervous system
Autonomic NS: sympathetic; parasympathetic NS : smooth|cardiac muscle; exocrine|endocrine glands
Somatic NS: motor neurons; skeletal muscle

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21
Q

Where is the ANS controlled?

A
  • controlled centrally in brain regions including hypothalamus, midbrain, pons, medulla
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22
Q

ANS
Function|innervates

A

Function: Involuntary: sympathetic; parasympathetic; enteric
Innervates: cardiac muscles; smooth muscles; glandular epithelia

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23
Q

Somatic Motor Neuron

A
  • originates from spinal cord
  • directly innervates skeletal muscles
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24
Q

Autonomic Motor Neurons

A

-Preganglionic neuron ( most are myelinated): cell bodies in spinal cord
- postganglionic neuron (unmylinated): cell bodies in autonomic ganglia

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25
Q

Parasympathetic NS

A
  • ganglion located close to target organ
  • sympathetic chain ganglion: located in two sympathetic chains running alongside spinal cord
    - short pre; v. Long post
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26
Q

Ganglion (Sympathetic Chain)

A
  • located in two sympathetic chains running alongside spinal cord
  • short pre, very long post
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27
Q

Sympathetic Subdivision also includes:

A

Innervation of adrenal medulla, which then secretes epi & norepi which are important for flight|flight reponse

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28
Q

Adrenal Medulla

A

Regulates release of epi|norepi

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29
Q

Ganglion

A

Intermediate before target organ

30
Q

Reciprocal functions of the sympathetic|parasympathetic actions on the heart

A
  • each target organ is reciprocally regulated by both symp|parasymp systems
31
Q

Sympathetic Ganglia of the Heart

A
  • located in symp chain
32
Q

Parasymp ganglia are located
(Cardiac plexus)

A

Close to the target organ

33
Q

SA node & AV node are innervates by

A

Both parasymp|symp systems

34
Q

Dual innervation by symp|parasymp systems to target organs allows for

A

Balanced regulation of physiological functions

35
Q

2 pathways originating from the hypothalamus important for body’s stress response

A
  • sympatho-adrenal axis: releases epi|norepi = adrenaline rush during fight|flight
  • HPA axis
36
Q

Enteric Nerbous System inputs

A

Symp & parasymp

37
Q

Enteric NS composed of

A
  • local neural networks that receive inputs from both symp|parasymp systems
38
Q

Enteric NS includes

A
  • submucosa plexus
  • myenteric plexus
39
Q

Submucosal Plexus

A

Enteric NS
- groups of neurons located in submucosa of GI tract

40
Q

Myenteric Plexus

A

Enteric NS
- groups of neurons located between 2 smooth muscle layers of GI tract

41
Q

The ANS includes

A
  • sympathetic and parasympathetic divisions
42
Q

The sympathetic division mobilizes the body for ___________ and controls the _________

A
  • mobilizes the body for activity
  • controls the “fight|flight” response
43
Q

The sympathetic system also innervates the ___________ ___________, which secretes…

A
  • innervates the adrenal medulla
  • which secretes epi|norepi important for the fight|flight response
44
Q

The parasympathetic division…

A
  • relaxes the body; rest|digest
45
Q

Ying|Yang Regulation

A

Symp|parasymp

46
Q

The Enteric NS contains the _______ & _____ and is controlled by both the ________ & __________ divisions

A
  • myenteric plexus & submucosal plexus
  • sympathetic|parasympathetic divisions
47
Q

Wiring the autonomic NS

A
  • reiprocal regulation between symp|parasymp
48
Q

2 main synapse types:

A
  • electrical: faster
  • chemical: allow for more levels of regulation by using diff NT & different receptors
49
Q

Electrical Signals

A
  • v. Fast (cardiac)
50
Q

Trafficking Pathways in the Nerve Terminal

A
  • precursors of synaptic vesicles get loaded with neurotransmitters, then dock at active zone and become primed to be released in response to an action potential
  • vesicles undergo endocytosis to be recycled & reused
  • pre-synaptic vesicles loaded with NT; AP releases vesicles into space
  • recycle vesicles back in after signal completion
51
Q

NT vs Hormone

A

NT: acts locally at the synapse

Hormone: released into blood and can affect distant organs

Some substances can be both (norepi)

52
Q

What defines a neurotransmitter?

A
  • must be present in the presynaptic neuron
  • must be released in response to presynaptic depolarization
  • specific receptors for the substance must be present on the postsynaptic cell
53
Q

Neurotransmitter

A
  • substances synthesized in the presynaptic neuron (MUST be present in presynaptic neuron)
  • released in response to an AP
  • act on specific receptors on postsynaptic cells
54
Q

NT Important for peripheral NS

A
  • Acetylcholine
  • Norepi
55
Q

3 Catecholamines

A
  • adrenaline
  • noradrenaline
  • dopamine
56
Q

NT release at the synaptic terminal

A
  • NT release is in response to an AP which triggers Ca2+ influx
57
Q

Chemical Synapse effect on time

A
  • process of synaptic transmission at the chemical synapse causes a slight time delay
58
Q

What is significant about the delay with chemical synapses

A

Acts as regulation

59
Q

2 Broad Types of Postsynaptic Receptors

A
  • ionotropic
  • metabotropic: regulate target response through secondary messenger pathways
60
Q

Ionotropic Rececptor

A
  • Nicontinic
  • all postganglionic neurons; adrenal medullary cells and neuromuscular junctions of the skeletal muscle: causes excitation
61
Q

Nicotinic Acetylcholine Receptors
(NAchR)

A
  • specifically activated by nicotine
  • IONOTROPIC
  • permeable to Na|K (and sometimes Ca)
62
Q

Nicotine Poisoning
- where receptors are located
- what can nicotine affect

A
  • nAchRs: located on skeletal muscles, post ganglion is neurons & adrenal medullary cells
  • nicotine can affect the somatic, symp|parasymp NS depending on dosage
  • e cigs can cause nicotine poisoning
63
Q

Metabotropic Receptors

A
  • GPCR signaling pathways: can lead to different downstream pathways depending on specific G proteins bound to the receptors
64
Q

Muscarinic Acetylcholine Receptors
(MAchRs)

A
  • Metabotropic
  • have different subtypes: can activated different downstream pathways depending on which Gproteins bound
  • mainly expressed on target organs of parasympathetic pathways
65
Q

mAchRs
- agonist vs antagonist

A
  • agonists will mimic the actions of the parasympathetic system
  • antagonists will inhibit the parasympathetic system
66
Q

Parasympathetic System Overall Effect

A
  • decreased heart rate
  • decreased BP
  • increased digestion
  • contracts bladder wall muscles

Rest|Digest

67
Q

Adrenergic Receptors

A
  • all activated by epi|norepi
  • lead to diverse intracellular signaling pathways
68
Q

Types of Adrenergic Receptors

A
  • a1: smooth muscle contraction
  • a2: inhibition of transmitter release; smooth muscle contraction
    -B: heart muscle contraction; smooth muscle relaxation; glycogenolysis
69
Q

Adrenergic Receptor Antagonists

A
  • mainly expressed in sympathetic target organs
  • will counter the action of the sympathetic system
  • NE
70
Q

Somatic NS (illustration)

A

Somatic NS ——————————-Ach

71
Q

Parasympathetic Nervous System (illustration)

A

Parasymp NS ———————-Ach [ganglion] ————-Ach

72
Q

Sympathetic Nervous System (illustration)

A

Symp NS —-Ach [Ganglia] —————————— NA
— Ach [Ganglia] ——————————Ach
—Ach [Ganglia] Adrenal Gland - - - - - -> ADR

Physiology Test 1 (2 decks)

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