Quiz 2 Muscles Flashcards
Smooth muscle more often responds to which kind of signals?
local and hormonal
What kind of muscle is the diaphragm?
skeletal
What are 5 functions of muscle tissue
- Producing body movements
- Stabilizing body positions
- Regulating Organ Volume
- Flow of substances within the body
- Producing heat
What is extensibility
ability to stretch without damaging the tissue
What is the diameter of muscle fibers?
10-100 microns
What is the sarcolemma
plasma membrane of muscle cell + external lamina
What separates the muscles into fascicles
What seprates muscles fibers from one another
perimysium
endomysium
What kind of fibers make up endomysium/ maybe peri and epimysium as well?
reticular fibers/ type III collagen
light band is isotropic or anisotropic?
Isotropic
what does anisotropic mean?
block light
label, specifically M line
M line represents
attachment of adjacent myosin molecules
What are the 3 types of protein that comprise Myofibrils?
contractile, regulatory, and structural
Out of the three protein types that make up Myofibrils…what kind is Myosin Light Chain Kinase (MLCK)
regulatory
Which kind of muscles use MLCK and why?
smooth, no troponin complex in smooth
what is titin
what does it do
structural protein in myofibrils
starts at Z-line and binds to thick filament. acts as molecular spring
What is myomesin
what does it do
structural protein in myofibrils
.attaches myosin thick filaments at M line
What is nebulin
what does it do
structural protein in myofibrils
Regulates actin length
What is alpha actinin
what does it do
structural protein in myofibrils
anchors actin to Z disk
What is dystrophin
structural protein in myofibrils
What are the three classes of intermediate filaments in myofibrils and where are they
Where are they important
desmin,vinmentin, and syemin
They are inbetween the contractile proteins and
they are particularly importnat at the Z-disk
Troponin T binds to:
Troponin C binds to:
Troponin I binds to:
tropomyosin
calcium
actin and inhibits myosin binding
Each myosin filament has how many actin filaments surrounding it?
6
Myosin heads are N or C terminus?
N
Describe strucure of Myosin II
–How many proteins in myosin head region
and what are they
2 coiled coils of 2 alpha helices
6
2 heavy chains
2 essential light chains
2 regulatory light chains
skeletal muscle has what type of mysoin?
II
myosin thick filaments are ____ _____on the two ends
oppositely polarized
How many molecules of myosin make up one thick filament
300-600
label I H M and A band
During muscle contraction ___ ___ moves towards __ ____
z disk, A band
What decreases in teh sarcomere during muscle contraction?
H and I band
The binding of the myosin to hte myosin-binding site on actin causes release of _____ from the head of the myosin molecule. This results in a conformational change that pulls the actin towards the ____ end of hte actin filament
ADP
minus
waht causes power stroke of myosin
loss of ADP from myosin
t/f release of actin filament requires hydrolysis of ATP
false, just requires the molecule
when in the muscle contraction is ATP hydrolysis requried?
recocking the head
In skeletal muscle, how many many cisternae are there / T tubule
2
SR cisternae are located where in the skeletal muscle sarcomere?
- cardiac
junction b/w the A and I band
.-Z disk
transvere portion of intercalated disks have what kind of junctional complex
fascia adherens/ broad desmosomes
What are smooth muscle cells surrounded by?
reticular fibers
what causes binding of actin/myosin in smooth muscle cells
phosphorylation of myosin light chaisn
wht are the two types of smooth muscle units
visceral and multiunit
which type of smooth muscle type is sparsely innervated and has extensive gap junctions
visercal
