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Physiology > Lecture 6-8 > Flashcards

Lecture 6-8 Flashcards

(71 cards)

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1
Q

Myocyte

A

muscle cell

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2
Q

Sarcoplasmic Reticulum

A

ER in muscle cells that stores calcium

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3
Q

Striated and Non-striated Muscles

A

S- skeletal and cardiac

Non- smooth

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4
Q

Muscle Fibers

A

long, thin cell with multiple nuclei and myofibrils

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5
Q

Myofibrils

A

consist of many sarcomeres surrounded by sarcoplasmic reticulum and t-tubule system

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6
Q

Sarcomere

A

functional unit of muscle

smallest part of muscle that can still perform its function

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7
Q

Contractile Protein Structure

A

thick and thin filaments

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8
Q

Thick Filaments

A

myosin

heavy chains w/ globular heads that bind actin and have ATPase activity

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9
Q

Thin Filaments

A

Actin- 2 strands of F actin in a helix
Tropomyosin
Troponin Complex

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10
Q

F Actin

A

made of G actin

has myosin binding sites

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11
Q

Tropomyosin

A

double stranded helix around actin

covers myosin binding site

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12
Q

Troponin Complex

A

binds to tropomyosin

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13
Q

Troponin T

A

binds complex to tropomyosin

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14
Q

Troponin I

A

Holds tropomyosin in myosin binding site

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15
Q

Troponin C

A

binds calcium, uncovers myosin binding site

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16
Q

Dystrophin

A

connects sarcomere to sarcolemma and ECM

mutations cause muscular dystrophy

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17
Q

Nebulin

A

holds thin filaments apart from each other

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18
Q

Alpha- Actinin

A

holds thin filaments to z-disc

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19
Q

Titan

A

spring that runs through heavy chain and connects it to z-disc

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20
Q

M Line

A

bisects sarcomere and bare zone

right down the middle

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21
Q

Bare (H) Zone

A

only heavy chains

center, no heads

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22
Q

A Band

A

thick and thin filaments

dark striation

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23
Q

I Band

A

only thin filaments

light striation

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24
Q

Z-Disc

A

borders- connects individual sarcomeres

bisects I band

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25
Terminal Cisternae
ends of sarcoplasmic reticulum | has RyR receptor
26
RyR Receptor
RyR, calcium release channel
27
Triad
t-tubule and SR (2 terminal cisternae)
28
Changes of DHPR
changes RyR shape due to tight packing in t-tubule system
29
Calcium Binding Proteins
keep free Ca low in SR
30
Calcium reuptake and release
reuptake- longitudinal sections | release- terminal areas
31
Cross Bridge Cycling
myosin binds actin and pulls it toward M line
32
Sliding Filament Theory
actin and myosin slide past each other, pulling z-discs together force transferred to CT around fiber entire muscle eventually shortens and moves bones
33
Cross Bridge Cycling at rest
tropomyosin cover binding site on actin | myosin has bound ATP and is cocked; has high affinity for actin
34
Cross Bridge Cycling- calcium binding
Ca binds TnC, moves tropomyosin off actin's myosin binding pocket myosin - ATP to ADP and binds actin
35
Cross Bridge Cycling- power stroke
myosin releases ADP and ratchets, pulling actin toward M line
36
Cross Bridge Cycling- reloading
myosin binds ATP and releases actin; recocked
37
Cross Bridge Cycling- Relaxation
Ca stays in SR by SERCA, no Ca to bind tropomyosin covers actin binding site contraction stops
38
Tetanus
recruiting multiple units or stim same unit multiple times to get mvmt
39
Isotonic Contraction
enough force is generated to move weight | force velocity relationship
40
Isometric Contraction
same length not enough force to move weight length tension relationship
41
Smooth Muscle
``` no control no sarcomere operate effectively when stretched fatigue resistant make resting tone- stay partially contracted ```
42
Single Unit
``` Smooth M cells linked by gap junction little inn some can make own AP contract together ```
43
Multi Unit
Smooth M each cell has own inn function as distinct muscle cell
44
E-C Coupling in Smooth M
Ca enters cytoplasm- depolarization cytoplasm releases Ca from SR Ca binds to Calmodulin, which activates MLCK
45
MLCK
controls cross bridge cycling in smooth muscle
46
Calcium Entry into Smooth M
2nd Messenger Gated Channels NT activate Gq receptors which make IP3 IP3 channels open on SR IP3 dependent Ca opens other Ca channels
47
Cross Bridge Cycling in Smooth M
Ca binds and activates calmodulin calmodulin activates MLCK MLCK phosphorylates myosin, increasing its ATPase activity
48
Relaxation in Smooth M
when MLCK is no longer active low ICF Ca myosin dephosphorylated by myosin phosphatase
49
Phasic Contractions
spike of Ca, single contraction, relaxation
50
Tonic Contractions
spike of Ca, maintain force | latch state
51
Latch State
allows for resting muscle tone to be generated at lower metabolic cost
52
Length- Tension Relationship of Smooth M
cant overstretch smooth m can generate max force at any length no sarcomeres allow for proper alignment at all preload
53
Force- Velocity Relationship of Smooth M
velocity of contraction increases with more myosin phosphorylated
54
Hypercalcemia
threshold more negative | less excitable
55
Hypocalcemia
threshold less negative | more excitable
56
Cardiac Muscle
``` gap junctions at intercalated disk contract on its own longer AP fatigue resistant- more mitochondria RMP -90mV ```
57
Cardiac M AP Phase 4
RMP same as other cells | K leak channels
58
Cardiac M AP Phase 0
Upstroke | Na channels open
59
Cardiac M AP Phase 1
early repolarization | K channels open
60
Cardiac M AP Phase 2
Plateau Ca channels open SR dump
61
Cardiac M AP Phase 3
late repolarization | K channels open
62
Absolute Refractory Period of Cardiac M
200 msec | prevents tetany
63
Opening RyR channels in cardiac m
need ECF Ca | phase 1 and 2
64
Effective Refractory Period
no conducted potential can generate AP
65
Relative Refractory Period
AP can fire if a greater than norm stim is provided | shorter plateau
66
Supranormal Period
cell is more excitable than normal | not yet reach RMP
67
Frank Starling Law
heart generates more force when preload is increased
68
Cardiac Pacemakers
``` electrical conduction system of heart Sinoatrial Node no SR unstable RMP depolarize at set rate ```
69
Phases of Cardiac Pacemakers
4- Unstable RMP; K close, Na and Ca open 0- Fire AP; Ca open 3- Repolarize- K open
70
PNS Synapses of SA Node
M2 receptors | increase K, decrease Na and Ca
71
SNS Synapses of SA Node
B1 receptor | increase Na and Ca

Physiology (17 decks)

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