Exam 4: Muscular System Flashcards
(72 cards)
1
Q
functions of muscular system (4)
A
movement
support
protection
thermoregulation
2
Q
components of muscular system (2)
A
skeletal muscle
tendons
3
Q
tendons
A
attach muscle to bone
4
Q
2 ways to classify muscle tissue
A
structure and function
5
Q
2 ways to classify muscle tissue by structure
A
striated and smooth
6
Q
striated muscle tissue types (3)
A
skeletal: attached to bone, multinucleated
visceral: identical to skeletal, but restricted to soft tissue
cardiac: heart muscle , one nucleus
7
Q
smooth muscle tissue
A
makes up majority of visceral organs
- always one nucleus
8
Q
all tissue has contractile units in them, ______ gives them pattern
A
arrangement of cells
9
Q
2 function types of muscle tissue
A
voluntary and involuntary
10
Q
voluntary muscle tissue
A
skeletal
visceral striated
11
Q
involuntary muscle tissue
A
smooth: cannot control blood vessel walls or digestive system or bladder (sphincters in bladder are visceral striated - voluntary)
cardiac
12
Q
muscle fiber
A
individual cell
13
Q
endomysium
A
wraps around each individual muscle cell
14
Q
fassicle
A
bundle of muscle cells - protective connective tissue
15
Q
perimysium
A
wraps around perimeter of muscle cells
16
Q
epimysium
A
connective tissue around entire functioning organ
17
Q
why are tendons so strong, do not rip?
A
- has endomysium, perimysium, epimysium throughout the ENTIRE organ
- connective tissue throughout entire thing, wrapping all the way through it
- have extensions from all cells
18
Q
what stimulates transformation of mesenchymal cells into myoblasts
A
myogenic regulating factors (MRFs)
19
Q
MRF4
A
blocks the ones that do final differentiation into type of muscle cell you will be
- keep getting lots of myoblasts
20
Q
7th week embryology
A
- starting to get endochondral bone formation
- get condensation of myoblasts
(cannot form bones until endochondral bone formation with perichondral - need dense bone tissue) - once start forming limbs myoblasts migrate to where arms and legs will be
21
Q
myoblasts are spindle-shaped cells that fuse together forming…
A
multi-nucleated myotubes
22
Q
initial myotubes formed by myoblasts migrating to….
A
connective tissue fibers
23
Q
fusion of myoblasts stimulates the production of ____
A
myofibrils
24
Q
what does initial migration and myotube formation provide for the muscle?
A
primary framework
25
what increases muscle size?
innervation of primary fibers causes small contractions which attracts more myoblasts and activated fusion which inc muscle
26
2 things needed to get a good muscle
innervation and a good blood supply
27
poland syndrome
occurs when there is a disruption in blood supply to embryonic tissue
- results in missing or abnormal pectoralis major muscle
- losing muscle
28
why would poland syndrome be unilateral?
can have blood supply to one side but it can also sill reach other side
- recognized at birth (congenital)
not genetic
29
why in Poland syndrome severe cases can you get incomplete formation of limb?
bad blood flow
bones are highly vascular
- not getting signal or blood supply can cause bone to be compromised
30
myosatelite cells
quiescent
| - when there is damage they are activated with growth factors, can help repair damage
31
thick filament in sarcomere
myosin
32
thin filament in sarcomere
actin
33
Binding role of myosin
- can bind 2 things but not at same time (actin and ATP)
- when it binds ATP, it has enzymatic ability and can hydrolyze and release high energy bond allowing for movement (pivot of the head)
34
2 ways myosin is stabilized
1. titin
| 2. myomeseum
35
one long molecule from z line through the filament to another z line
- anchors to both sides of sarcomere
titin
36
protein down the center, secured at the M line
myomesium
37
structure of actin
2 strings of actin twisted in helix around itself
38
how is actin anchored to the Z line?
actinin
- does not go through whole molecule, only attached at one end
- hooks to Z line
39
what is the anchor of actin?
nebulin - hooks to Z line
40
how are actin and myosin regulated?
tropomyosin and troponin
41
tropomyosin
blocks interaction of actin and myosin
42
when muscle is relaxed what form is tropomyosin in?
blocking position
43
what happens with tropomyosin when you want to contract a muscle?
- need to get tropomyosin out of the way
- conformational change in tropomyosin by release of Calcium
- troponin binds Ca and changes shape
- since troponin attached to tropomyosin shape is changes and tropomyosin slides out of the way
44
A band
length of thick filament
| - should not change with contraction bc thick filament dos not change in length
45
I band
z line down center
thin filament not overlapped by thick
- bigger when not contracting
46
what happens to H and I bands when muscle contracts
they get smaller bc they overlap
47
H zone/band
down the center is the M line
on either side is myosin - not overlapped
if not contracting, less thick band has thin pulled over it
just see thick filament!!
48
How do we get the sarcomere to contract? - a few steps
1. get nerve impulse to muscle, depolarizing the membrane which releases internal store of calcium
2. Ca binds troponin
3. conformational changes in troponin moves tropomyosin out of blocking position
4. myosin binding site exposed
49
Cross bridge formation - may steps
1. binding site available, myosin heads have ATP, it hydrolyzes ATP giving it a power stroke, the head comes up and gets closer, eventually get connection
2. myosin heads bind to actin forming cross bridge
3. myosin cross bridges rotate to center of sarcomere
4. as myosin heads bind ATP, the cross bridges detach from actin
50
cross bridge formation: once movement arc done, it will have inc affinity for ATP and release ____ is ATP available
it will bind ATP and the head will go back down and have a higher affinity for ____
myosin
| actin
51
are the heads on the filament synchronized?
NO
| - if they were you would not get any movement
52
the stringer the nerve impulse...
the longer Ca can remain, the longer sites are available for binding, tight contraction
53
when you relax muscles, the signal stops and what happens to the Ca?
it goes back into storage
54
where is Ca stored during muscle relaxation?
terminal cisternae
55
when muscle is stimulated, action potential transmitted to sarcomere by_____
transverse tubule (T tubule)
56
when calcium is released from terminal cisternae, what does it travel to to get to the sarcomere?
open-ended longitudinal tubules
57
sarcoplasmic reticulum
Ca storage
58
Ca pumps in the membrane
- released so much Ca it cannot pull it back in at once
- when depolarization stops, pumps recapture Ca and put back into storage in terminal cisternae - active transport to restore Ca
59
cardiac muscle vs. skeletal muscle
- cardiac = branched
- cardiac is stored in enlarged T-tubules (no triad formation)
- Cardiac requires BOTH intracellular and extracellular sources
60
triad
fusion of T-tubules
| 2 terminal cisternae and 1 t tubule
61
is cardiac considered part of the muscle system?
no
62
if high or low Ca in danger of...
heart attack
63
cardiac has no individual innervation
troponin in heart binds bc of shape one less Ca than in skeletal muscle - can do blood test to see if heart attack - cells die and release contents into blood
64
2 main diff between cardiac and skeletal muscle
- how it stores/uses Ca
| - troponin diff no innervation in cardiac
65
smooth muscle vs. skeletal muscle
- intermediate filaments, vimentin and desmin, connect sarcomeres to dense bodies and desmosomes
- troponin replaced with caldesmon (does not directly bind Ca)
- Ca stored in caveoli (no other sarcoplasmic structures exist)
- smooth contraction dependent on influx of extracellular Ca
65
smooth muscle vs. skeletal muscle
- intermediate filaments, vimentin and desmin, connect sarcomeres to dense bodies and desmosomes
- troponin replaced with caldesmon (does not directly bind Ca)
- Ca stored in caveoli (no other sarcoplasmic structures exist)
- smooth contraction dependent on influx of extracellular Ca
66
vimentin and desmin
help connect to dense bodies
hold sarcomere together
- not z lines but similar
67
What do calveoli do when depolarized in smooth muscle?
release calcium into cytoplasm
NOT directly into sarcomere
- second messenger system binds Ca
68
How is caldesmon diff than troponin?
it is removed off tropomyosin by second messengers like calmodulin
69
which muscle type is the influx of calcium bound by calmodulin?
smooth muscle
70
what are the 2 actions of the calcium-calmodulin complex?
- complex activated myosin light chain kinase (MLCK) and removes caldesmon from tropomyosin
- MLCK activates ATPase activity in myosin head ad cross-bridge formation occurs
71
which muscle type is the only one with individual innervation?
skeletal
