Exam 2 my Qs Flashcards
(119 cards)
1
Q
What kind of signal is contact dependent needs direct surface contact, signal chemical may use CAMs (cell adhesion molecules)
A
local
2
Q
What 2 categories do gap junctions fall under
A
local and electrical
3
Q
what kind of communication is distant diffuse, hormones are secreted by endocrine glands into blood, only target cells with receptors for hormone respond to the signal
A
endocrine
4
Q
What kind of hormone is secreted by a neuron and diffuses across blood
A
neurohormone
5
Q
What kind of filaments make the H band/ zone
A
only thick, no overlap
6
Q
What is the latent period
A
The delay between the muscle AP and beginning of muscle tension. Time needed for Ca calcium release and binding to troponin.
7
Q
What is a multiunit smooth muscle
A
smooth muscle in which cells are not linked electrically and each muscle fiber is controlled individually
8
Q
What does nebulin do
A
inelastic giant protein that aligns filaments of sarcomere
9
Q
What is phosphocreatine
A
muscle molecule that stores energy in high energy phosphate bonds
10
Q
What is ryanodine receptor channel, where is it
A
ca calcium release channel of sarcoplasmic reticulum in striated skeletal muscles
11
Q
What is a single unit smooth muscle
A
smooth muscle fibers that are electrically coupled by numerous gap junctions
12
Q
What does titin do?
A
maintains spatial structure of myofibrils
13
Q
What does tropomyosin do?
A
blocks the myosin binding site on actin
14
Q
Troponin
A
complex of 3 proteins associated with tropomyosin, binds to Ca calcium controls action of tropomyosin
15
Q
What is a z disk
A
sarcomere proteins where actin filaments attach
16
Q
What is a muscle twitch
A
single contraction/ relaxation cycle in a muscle fiber
17
Q
What is an isotonic contraction
A
creates force without movement
18
Q
What is an isometric contraction
A
creates force and moves a load
19
Q
DHP receptor
A
voltage sensing receptors in t tubules that are liked to ca calcium channels skeletal contraction
20
Q
creatine kinase
A
enzyme that transfers a high energy phosphate group from phosphocreatine to ADP
21
Q
calmodulin
A
intracellular 2nd messenger that binds ca calcium
22
Q
What is the A band
A
striated muscle sarcomere whose length equals that of a thick filament
23
Q
What causes acetylcholine to be released into synaptic cleft?
A
action potential arrives at axon terminal
24
Q
What ions enter and exit the motor end plate after an AP
A
Na in, small amount of K out
25
What causes local depolarization of the motor end plate
ion exchange once channels open
26
What enzyme breaks down acetylcholine?
acetylcholinesterase
27
Where do Ca calcium ions go after AP
released into cytosol
28
What are the 4 main characteristics of muscles
excitability, contractibility, extensibility, elasticity
29
Where are skeletal, smooth and cardiac muscles located
skeletal: attached to bones, a few sphincters close off hollow organs
smooth: form walls of hollow organs and tubes some sphincters
Cardiac: heart
30
Which of the 3 muscle types does not have sarcomeres?
smooth
31
which of the 3 muscle types is not striated
smooth
32
What fiber proteins are in skeletal muscle
action, myosin, troponin and tropomyosin
33
What fiber proteins are in smooth muscle
actin, myosin and tropomyosin
34
What fiber proteins are in cardiac muscle
action, myosin, troponin and tropomyosin
35
What fiber protein does smooth muscles lack that the other two have?
troponin
36
Which of the 3 muscle types is multinucleate
skeletal
37
Which of the 3 muscle types has short branching fibers
cardiac
38
What controls skeletal muscle, fibers and where is ca from
ca and troponin
fibers are independent
ca from SR
39
What controls smooth muscle
ca and calmodulin
some electrically linked (gap junctions) others independent
Ca from ECF and SR
calcium
40
What controls cardiac muscle
Ca and troponin
fibers electrically linked gap junctions
ca from ECF and SR
calcium
41
What type of muscle is not controlled by troponin?
smooth
42
What type of muscle has only independently functioning fibers
skeletal
43
What type of muscle gets Ca from SR only
skeletal
44
What type of muscle can be independent or electrically linked in its fibers?
smooth
45
What type of muscle does not have graded force of a single fiber twitch
skeletal
46
What initiates the contraction of skeletal muscle?
acetylcholine
47
What initiates the contraction of smooth muscle?
stretches, chemical signals from pacemaker cells. sometimes autorythmic
48
What causes cardiac muscle to contract?
it is autorythmic
49
What kind of neuron controls skeletal muscles
somatic
50
What kind of neuron controls cardiac and smooth muscle
autonomic
51
What hormone influences the contraction of cardiac muscle
epinephrine
52
What are satellite cells?
PNS glial cells
53
What glial cell is nonmyelinating
satellite
54
What are astrocytes?
branched CNS glial cells that communicate with gap junctions
55
What are microglia
immune cells in the CNS, remove damaged cells and foreign invaders.
56
What are ependymal cells
create selectively permeable epithelial layer separates fluid from CNS
57
Where is Ca stored in the myofibril
in the terminal cisternae
58
What are the non elastic and elastic stabilizers in actin (thin)
nebulin non elastic
| titin elastic
59
What creates the light and dark regions in banding patterns
```
A dark (thick filaments)
I light (thin filaments)
```
60
What are the 3 phases of contraction
latent, contraction, relaxation
61
What ion enters through Ach receptor channel and initiates an AP
Na, sodium
62
What alters the conformation of DHP receptor
AP in t-tubule
63
What does DHP receptor open?
Ryr Ca, calcium release channels in SR
64
What ion binds to troponin to start actin myosin binding?
Ca, calcium
65
How does Ca get back into SR
Ca ATPase pumps it back in
66
What causes troponin to release calcium
decrease in free cytosolic ca
67
When can the power stroke begin?
when tropomyosin moves off banding site
68
What is released during the power stroke?
ADP
69
What causes tension in skeletal muscle
fatigue, fiber length, previous contractions rate of stimulation, thickness of fibers
70
What type of twitch fiber is fast but fatigues easily
fast twitch white
71
What type of twitch fiber has moderate Ca ATPase activity
slow twitch
72
What type of twitch fiber has the longest contraction period
slow twitch
73
What type of twitch fiber can become more oxidative with endurance training
fast twitch red
74
What type of twitch fiber uses aerobic oxidative metabolism
slow twitch
75
Put twitch fibers in order of capillary density
high: slow twitch
medium: fast twitch red
Low: fast twitch white
76
What type of twitch fiber has numerous mitochondria
slow twitch
77
What makes fast twitch glycolytic white muscle white?
the low capillary density
78
What colors are the 3 twitch fibers
slow: dark red
fast oxidative glycolytic: red
fast twitch glycolytic: white
79
put twitch fibers in order of diameter size
slow: small
fast twitch red: medium
fast twitch white: large
80
What type of twitch fiber has slow myosin ATPase activity
slow twitch
81
What type of muscle has torpedo shaped cells
smooth
82
What are the differences between smooth and skeletal muscle
smooth has longer actin and myosin, more actin, no sarcomere arrangement less endoplasmic reticulum
83
What is the major role of smooth muscle ?
homeostatic: control fluid flow, sphincters, tonic contractions
84
What does the contractile response of a multi unit smooth muscles depend on?
number of fibers stimulated
85
What signals the contraction of smooth muscle
cytosolic ca calcium
86
What does calcium bind to in smooth muscle contraction
CAM calmodulin
87
what does the ca-calmodulin complex activate
myosin light chain kinase (smooth muscle only)
88
What does MLCK myosin light chain kinase do?
phosphorylates light chains in myosin heads and increases myosin ATPase activity, smooth muscle
89
What is the first step in smooth muscle relaxation
removal of ca from cytosol
90
What causes muscular dystrophy
mutation on x chromosome
91
What test diagnosis muscular dystrophy
creatine kinase
92
What is myasthenia gravis
abnormal fatigue in muscle, antibody against acetylcholine receptors.
93
how is myasthenia gravis treated?
Ach esterase inhibitors, removal of thymus gland
94
What helps avoid tearing in cardiac muscle?
desmosomes in intercalated disks
95
What restrains the heart valves
chordae tendineae and papillar muscles
96
What prevents blood from flowing backwards?
semilunar valves
97
What are the 2 blood flow circuits?
pulmonary and systemic
98
What are the components of pulmonary circuit
RA and RV to (deoxy) from (oxy) lungs
99
What are the components of systemic circuit
LA LV vessels to from body except lung
100
Blood flow pressure in order of most to least
aorta--> arteries--> arterioles --> capillaries --> venules --> veins --> vena cavae
101
What happens to pressure as blood moves across a vessel
pressure drops when fluid is flowing
102
What kind of pressure does the movement of blood depend on?
pressure difference, not absolute
103
what makes flow faster
the narrower the vessel, the faster if flow is constant
104
Where does an Ap in cardiac muscle contraction come from
adjacent cell
105
What happens to Ca after Ap in cardiac contraction
back into SR or exchanged with Na by NCX antiporter
106
How is sodium gradient maintained in cardiac contraction
na-k-atpase
107
What causes tension in cardiac muscle
calcium levels in cytoplasm
| muscle length at start of contraction as muscle stretches, more force created
108
Who is more flexible skeletal or cardiac muscle
cardiac
109
What percentage of cardiac muscles are contractile and how many are autorythmic
contractile: 99%
| autorythmic (pacemakers) 1%
110
During AP in pacemaker
Net Na in (if opens) --> Ca in (if close) --> Ca in --> K out --> if open k channel closed funny
111
The cardiac cycle between contraction and relaxation: 1) Late Diastole
both sets of chambers are relaxed and fill passively
a. Atrial diastole
b. Ventricular diastole
c. Blood moves from A into V because AV valves are open
112
2) Atrial systole
atrial contraction forces a small amount of additional blood into ventricles
a. Heart sound 1
b. Atria contract add 20% more blood to ventricles
c. Atrial systole
d. Ventricular diastole
113
3) Isovolumic ventricular contraction
a. First phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves.
b. Max blood volume in ventricles = end diastolic volume (EDV)
c. AV valve closes (lub sound), builds pressure allows valve to open later
d. Valves between A and V are closed to avoid backward flow
e. Ventricular systole
f. Atrial diastole
114
4) Ventricular ejection
a. As ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected
b. Open because pressure in V will be greater than the pressure in blood vessels, pulmonic trunk and aorta
c. Heart sound 2
d. Ventricular diastole starts again
115
5) Isovolumic ventricular relaxation
a. As ventricles relax, pressure in ventricles falls
b. Blood flows back into cusps of semilunar valves and snaps them closed
c. AV valves open allowing blood back in, restarting cycle
d. Minimum blood in ventricles = end systolic volume (ESV)
116
Time in cardiac cycle
o Time for complete cycle depends on heart rate
o Rate = 60 beats ( 1 min 60 s) = 1 s per complete beat cycle
o Rate = 75 beats ( 1 min = 0.8 s/ beat cycle)
o Ventricles in diastole 0.5 sec
o In systole 0.3 s
o Total 0.8 s
117
cardiac output
blood pumped per ventricle per unit time
118
P wave
QRS
T wave
P: atrial depolarization
QRS: ventricular depolarization and atrial repolarization
T: ventricular repolarization
119
stroke volume
blood pumped by one ventricle during one contraction
