muscle 1 Flashcards
what does the generation of force depend on for all muscle types
conversion of chemical energy (ATP)
what is the pattern of skeletal muscles ?
striated, banded pattern
are skeletal muscles uninucleated or multinucleated
multinucleated
how does skeletal muscle work?
it is primarily voluntary by somatic motor neurons
what is a somatic neuron?
conscious activity within the body
how does cardiac muscle work?
it is primarily involuntary and spontaneous electrical activity
how does cardiac muscle look?
striated and banded
is cardiac muscle uninucleated or multinucleated
uninucleated
what can cardiac muscle be altered by?
autonomic nervous system hormone s
what is smooth muscle ?
primarily involuntary (autonomic control)
provides control off the internal organs
what does smooth muscle look like?
non striated
is smooth muscle uninucleated or multinucleated
uninucleated
what’s the largest muscle group
skeletal muscle
what is skeletal muscle attached to bones by
tendons
where is the origin of a muscle
closest to the trunk
what are antagonistic muscle group
flexor extensor pairs (bicep/triceps)
what does a flexor do
brings bones together
how much % does skeletal muscle take up in body weight
40
what is the cell membrane in muscle
sarcolemma
what’s the functional unit of a skeletal muscle
sarcomere
what’s a thick filament
myosin
whats a thin filament
actin
whats the order of skeletal muscle
- skeletal muscle
- muscle facsicles
- muscle fibre
- myofibril
- sarcomere (made up of myofilaments)
which part of skeletal muscle is there 100s or 1000s of
myofibrils
what binding site is on actin?
thick filaments (myosin)
what’s the backbone of a thin filament and what is its structure?
actin - it is a double stranded helix
what is tropomyosins structure
two identical alpha helices that coil around each other and sit in the grooves of actin
what does tropomyosin do
regulates the binding of myosin to actin
what’s the side structures on actin
tropomyosin and troponin complex
what’s the structure of the troponin complex
3 part protein
T - binds to a single molecule of tropomyosin
C - Ca2+ binding site
I - bound to actin and inhibiting contraction
how many actin molecules in between each troponin complex
7 actin molecules
what is the structure of one myosin molecule
two intertwined heavy chains
each heavy chain consists of 2 light chains
what is the structure of 1 heavy chain head
there is a binding region for actin as well as a site for ATPase
what are the two light chains on a myosin heavy chain
regulatory light chain
essential light chain
what does the regulatory light chain do
regulates ATPase activity
what does the essential light chain do?
stabilizes the myosin head (structural protein)
what are the additional proteins in a sarcomere (accessory structures within the sarcomere)
Nebulin and Titin
what is nebulin
a large protein that interacts with thin filaments
what does titin do
involved in stabilization of of thick filaments and the elastic recoil behaviour of muscles (they help to return muscle fibres back to initial position)
what are transverse tubules
they are an inward extensions of the sarcolemma
what is terminal cisternae
the thick swollen ends of the blue sarcoplasmic reticulum
most calcium is stored in these regions
what’s special about glucose and muscle
it can only be used in skeletal muscle
what is calcium for
we need calcium for muscle contractions
what is the sarcoplasmic reticulum in muscle cells compared to
the endoplasmic reticulum
what does the sarcoplasmic reticulum do?
stores calcium
what does a transverse tubule allow?
they allow an action potential that’s generated in a muscle fibre to be propagated across the sarcolmma and then into the interior of a muscle fibre
where are the sarcoplasmic reticulum, transverse tubules and terminal cistern located
inside a muscle fibre
where is glucose stored?
within the sarcoplasm
