hbod2test3lecture Flashcards
(146 cards)
1
Q
how does skeletal muscle maintain blood glucose?
A
takes glucose out of blood and stores as glycogen
2
Q
difference between sarcolemma and endomysium
A
endomysium is the innermost CT layer, wraps each muscle cell. Sarcolemma is the cell membrane of a muscle cell
3
Q
function of endomysium
A
separates muscle cells from each other, allows for sliding/gliding during contraction, the connection of axon terminals
4
Q
does endomysium, perimysium, epimysium ever merge? if so, where and why?
A
Yes, at the myotendinous junction, to funnel coalesce force onto skeletal system
5
Q
how does skeletal muscles regulate body temperature?
A
produce heat during contraction
6
Q
point of contact of muscle to bone
A
enthesis
7
Q
CT wrappings/layers from most superficial to most deep
A
epimysium, perimysium, endomysium
8
Q
what type of collage dominates the epimysium layer
A
majority it is Type 1 collagen
9
Q
Which -mysium layer encases fascicles. What is encased in these fascicles?
A
Perimysium. Fascicles of the perimysium include type 1 and 2 collagen, encase blood vessels and nerves endomysium and individual muscle cells
10
Q
endomysium consists of what strong or delicate collagen fibers encasing each individual muscle cell?
A
delicate
11
Q
1 neuron has how many axon terminals?
A
hundreds
12
Q
1 axon terminal innervates how many muscle cells?
A
1 muscle cell
13
Q
Type 1 collagen connects muscle cells to what cell at the NMJ?
A
fibroblasts
14
Q
immature muscle cells called _____ join together to form ____ and then become one long muscle cell called a ____
A
myoblast, myotube, myocyte
15
Q
inside of a skeletal muscle cell includes
A
ICF(sarcoplasm), multiple nuclei, organelles, myofibirils
16
Q
which organelle makes up a majority of the skeletal muscle cell?
A
myofibrils
17
Q
myofibrils contain
A
sarcomeres which contain many actin and myosin filaments
18
Q
how is the number of muscle cells ‘modulated’
A
genes. a protein called myostatin limits muscle growth(only sk. muscle). this gene expression can change through natural selection
19
Q
name the structure located in the ECF(between the endomysium and the sarcolemma)
A
basallamina, connective proteins that stay connected during contraction and relaxation
20
Q
deep to superficial, what is the layer of structures surrounding the myofibrils
A
sarcoplasmic reticulum, reticular mitochondria
21
Q
function of sarcoplasmic reticulum
A
surrounds myofibrils, holds large amount of Ca2+, turns AP into muscle contraction(electrical to mechanical)
22
Q
function of the reticular mitochondria
A
allows sliding/change of shape during contraction, weird shape increases SA
23
Q
superficial to deep Endomysium to Actin/Myosin(9 things)
A
endomysium, ECF, basallamina, sarcolemma, sarcoplasm, reticular mitochondria, sarcoplasmic reticulum, myofibrils, myofilaments
24
Q
special end of the sarcolemma that recieves action potentials from axon terminals is called
A
motor end plate
25
EPSP of a skeletal muscle cell is called a
EPP-excitatory plate potential
26
nicotinic ACh receptors are found on axon terminal or motor end plate
motor end plate
27
nACh receptors bind ACh, what is the movement of ions
K+ exits, Na+ flows in
28
how is the neuromuscular junction and motor end plate related
neuromuscular junction includes the axon terminal at the endomysium, the ECF, and the motor end plate
29
how does the shape of the motor end plate compare to the rest of the muscle cell
it is wavy to increase surface area
30
specialized region of the sarcolemma that creates the EPP(end plate potential)
motor end plate
31
waviness of the motor end plate, where are nACh receptors found, and where are ACh-ase found?
nACh receptors are found at the 'peaks' of sarcolemma, ACh-ase is found in the valleys
32
What is a motor unit?
single somatic motor neuron and all the skeletal muscle fibers it innervates
33
large motor units containing 1 motor neuron for ~200 muscle fibers are good for strength but lack some precision
small motor units containing 1 motor neuron for ~3muscle fibers are good for fine control, but lack force
34
Resting membrane potential of -90mV in a skeletal muscle cell has an Excitatory plate potential when ACh binds to nAChr and what flows into the sarcoplasm?
Na+
35
Increased flow of Na+ into the sarcoplasm opens up what to let more Na+ in, resulting in conduction of AP along sarcolemma
Voltage gated Na+ channels
36
is ATP used at the motor end plate receiving an action potential?
no
37
where does the AP go on the skeletal muscle cell after it has been 'received' at the motor end plate?
in all directions and spreads quickly along sarcolemma and into T-tubules of the cell
38
excitation includes
creation and spread of AP
39
contraction includes
sarcomere shorting
40
Are L-type Ca2+ channels that same as Voltage Gated channels?
Yes
41
main purpose of sarcoplasmic reticulum
store Ca2+ for release and reuptake
42
timing of Calcium movement in the Sarcoplasmic reticulum is dependent upon what
Action Potential
43
Inside the myofibril, calcium interacts directly with actin or myosin
actin, binding to troponin C
44
Calcium allows myosin to interact with actin T/F
true
45
how can the duration of a contraction be controlled?
controlling Calcium release/reuptake
46
Calcium reaches actin how?
diffusion
47
what are T-tubules
rings of the ECF that surround myofibrils at their Z-line. This provides that the AP reaches all myofibrils in the muscle cell easily
48
myofilaments/contractile proteins (myosin and actin) are located in the
myofibrils
49
myofibrils are encased in ____ which is encased in _____ for what purposes?
sarcoplasmic reticulum to proximity of Calcium diffusion for contraction, and reticular mitochondria for proximity of ATP for energy
50
what protein binds Calcium in the sarcoplasmic reticulum
calsecquestran, concentrated heavily at the terminal cisternae
51
terminal cisternae
on the myofibrils at the end of SR near the T-tubules
52
longitudinal cisternae
SR that runs the length of myofibrils(odd shape for SA)
53
terminal cisternae start or end the Calcium release
start
54
Calcium's target once released is actin, what triggers their release?
Action Potential at the NMJ
55
do myofibrils have membranes?
no, a tight collection of sarcomeres in there
56
sarcomeres are defined as
contractile units, measured from Z line to Z line of a myofibril
57
AP in T-tubules stimulates Calcium release...which 2 channels are used in the steps between these?
DHPR(dihydropyrimidine receptor) and RYR channel
58
what is unique about DHPR
AP in T-tubules stimulates DHPR which is a L-type Ca2+ channel(long lasting, open close slowly). In cardiac muscle Ca2+ does and needs to flow in, in skeletal muscle, Ca2+ doesn't really flow in....hmmmm
59
interaction between DHPR and RYR
AP in T-tubules leads to DHPR channel opening(conformational change) which influences RYR on the sarcoplasmic reticulum to open
60
The opening of RYR is necessary for muscle contraction because
it permits Ca2+ efflux from Sarcoplasmic Reticulum into the Sarcoplasm(ICF) and myofibrils
61
Calcium binds to what part of what myofilament
troponin C on actin
62
the rotation of tropomyosin revealing myosin binding sites on actin is caused by
binding of Calcium(from SR) to troponin C
63
what three places is ATP produced?
mitochondria, sarcoplasm(glycolysis), and creatine phosphate(P+ADP > ATP)
64
if skeletal muscles don't have access to enough oxygen, they fatigue easily. What type of respiration do they turn to?
anaerobic respiration
65
type 2 skeletal muscle cells do what type of respiration, for slow or fast twitch?
anaerobic, fast twitch
66
Troponin T of the troponin complex does what
binds the troponin complex to tropomyosin
67
Troponin I on the troponin complex does what
inhibits myosin-actin binding
68
Troponin C is reponsibile for
binding 2 calciums
69
When calcium binds to troponin C on the troponin complex on tropomysin, what happens next?
troponin complex undergoes conformational change, troponin i is displaced from and exposes myosin binding sites on actin
70
cross bridge cycling is controlled by what?
Action Potential at the NMJ and the spread of the AP along the sarcolemma, including T-tubules
71
Cross Bridge: myosin binding sites on actin are revealed, myosin heads bind to actin. Is ATP required?
no ATP is required
72
myosin heads contain two binding sites for:
actin and ATP
73
long tail of myosin ends at the M-line or Z-line
M-line
74
myosin or actin can hydrolyze ATP
myosin hydrolyzes ATP into Pi and ADP at the ATP binding site(clamp)
75
sliding filament theory is a result of the cross bridge cycling, what part of the muscle cell shortens?
Sarcomere shortens
76
myofilaments and their function
myosin binds to actin. For each myosin, there are six actin
77
titan function
protein that stabilizes myosin in contraction
78
nebulin function
protein that stabilizes actin
79
how does nebulin aid in growth of actin?
adds G-actin(lengthens)
80
A-band is the length of what
all of myosin
81
H-zone is the length of what
only myosin, no overlap of actin
82
I-band is the length of what
only actin
83
During contraction, what bands/zones disappear?
I-bands and H-zone, H-band can disappear
84
the sarcomere shortens toward the...
M-line
85
ATP is required in cross bridge cycling for
release of myosin head from actin. ATP binds to myosin head
86
what is necessary for the myosin head to cock towards the Z-line
ATP that is attached to myosin to be hydrolyzed
87
After ATP is hydrolyzed by myosin, ADP and Pi are present on mysoin head, what is myosin's interaction with actin at this point?
myosin head lightly binds actin
88
When myosin head lightly binding actin, what must take place for Calcium to bind to troponin C on the troponin complex and revela myosin binding sites on actin, for tight binding to occur?
AP must travel down sarcolemma, DHPR opening influences opening of RYR on the SR which permits calcium to flood into sarcoplasm
89
When myosin heads are bounded tightly to actin, the cross bridge forms-what forcefully rotates causing the power stroke?
myosin heads rotate, pulling actin toward M-line
90
SERCA pumps function
remove Ca2+ from sarcoplasm
91
Once the sarcolemma repolarizes, what rotates to cover myosin binding sites?
Tropomyosin covers myosin binding sites on actin
92
systole or diastole is longer?
Diastole
93
systole includes filling of ventricles or contraction/pressurizing ventricles
contraction and pressurizing of ventricles
94
diastole includes filling of ventricles or contraction/pressurizing of ventricles?
filling of ventricles
95
diastole includes atrial contraction or nah?
atrial contraction occurs during diastole
96
electrical conduction components of the heart
SA Node > Bachman Bundles, internodal fibers > AV Node > Bundle of His > L/R Bundles > Purkinje fibers
97
what causes valves to open and close?
pressure differences
98
EKG waveform pieces
P-wave, QRS complex, T-wave, isoelectric periods
99
What takes place during isoelectric periods?
Action Potential travels through AV node and Bundle of His
100
What happens when the SA node depolarizes?
AP flows to the Left atrium and the internodal fibers to the AV node
101
P-wave represents
SA node and internodal fibers depolarizing
102
What takes place during PQ isoelectric period?
atria contract, AP travels through AV Node and Bundle of His
103
QRS complex: What takes place at R peaking?
depolarization of R/L bundle branches, muscle contraction follows, atria repolarize
104
QRS complex: what takes place R-S
Purkinje fibers depolarize, ventricle contraction, atria repolarize
105
pericardial fluid
ultrafiltrate of blood, filled bu blood vessels in serious/visceral pericardium
106
Superficial to deep pericardial layers:
external fibrous pericardium, parietal layer of serous pericardium, pericardial fluid, visceral layer of serous pericardium
107
Pericardial sac(serous pericardium) makes the pericardium. It is filled with pericardial fluid.
What surrounds the pericardial sac?
external fibrous pericardium
108
function of pericadial sac
allows heart to beat freely and prevents sticking
109
Heart(myocardium) layers superficial to deep
epicardium, myocardium, endocardium
110
myocardium is made of 2 types of cells:
work cardiomyocytes and pacemaker cells
111
main function of work cardiomyocytes
contract and generate force
112
main function of pacemaker cells
spontaneously depolarize, generate, initiate AP faster than other cells
113
echtopic heartbeat is caused by
other cells(non pacemaker) generating AP
114
endocardium is made of what types of cells, for what function
simple squamous epithelium barrier, prevents diffusion and reduces turbulence, is continuous with blood vessels
115
myocardium hold work cardiomyocytes to generate force, this causes a change in what in the chambers
increase pressure and decrease volume
116
Endocardium holds simple squamous, Epicardium hold what kinds of cells?
mesothelium(specialized simple squamous)
117
within the myocardium is found
conductile fibers, blood vessels, lymph vessels
118
When does blood flow into blood vessels in the myocardium? Systole or diastole?
diastole, blood vessels aren't closed
119
Contractility influences force generation in pumping blood-what causes this?
initial myocyte length, the greater initial length, the greater force
120
work cardiomyocytes have more or less nuclei than skeletal muscle cells?
less, 1-3 nuclei per cell
121
branching occurs in work cardiomyocytes to aid in
communication with other cells
122
work cardiomyocytes include what in their intercalated discs between their cells
gap junctions
123
gap junction in intercalated discs permit what
electrical synapse(flow of Na+ between cells)
124
inside work cardiomyocytes
myofibrils>myofilaments>sarcomeres
125
T-tubules conduct electrical synapse or AP
AP, electrical synapse is between cells
126
how to work cardiomyocytes utilize/bind oxygen
myoglobin
127
what is the advantage of myoglobin over hemoglobin
myoglobin can bind oxygen at low concentrations, has higher affinity, it reaches saturation quicker. Hemoglobin more easily loses oxygen to tissues
128
SA nodal cells are work cardiomyocytes or pacemaker cells
pacemaker cells
129
SA node is the primary pacemaker of the heart, determines Heart Rate. what is the seconda pacemaker?
AV node
130
SA node would fire at 100-110 bpm without influence from the
Autonomic nervous system
131
Resting heart rate is 72bpm...ANS tone at rest if high sympathetic or parasympethetic?
parasympethetic(vagal)
132
SA node structure superficial to deep
SA nodal cells, transitional cells, conductile fibers
133
SA nodal cells transmit AP to
transitional cells
134
transitional cells transmit AP to
first conductile fibers
135
conductile fibers are the cells that make up the
Right atrium
136
How do SA nodal cells differ from cardiomyocytes
they don't have sarcomeres
137
SA node location
near junction of SVC opening and right auricle opening
138
where is glycogen stored
liver and muscle
139
myostatin inhibits or accelerates muscle growth
inhibits
140
where are SERCA channels found?
found in sarcoplasmic reticulum
141
do SERCAs use ATP?
yes, to resequester calcium into SR
142
L-type calcium channels DHPr need what to open
Action Potential from neuromuscular junction
143
what takes the place of motor end plate/NMJ in skeletal muscles?
gap junctions
144
voltage gated sodium channels are found where along sarcolemma
all over, including T-tubules
145
power stroke includes
myosin heads swiveling towards the M-line
146
reticular mitochondria is found where at in the muscle cell
surrounding myofibrils
