Muscle Physio Flashcards
Skeletal muscle is the predominant site of
Thermogenesis
3 types of muscle tissue
Smooth
Cardiac
Skeletal
Muscle fibers are surrounded by the
Sarcolemma
What is the sarcolemma?
Specialized plasma membrane with an outer coat of polysaccharides and collagen
Skeletal muscle is the largest site for (2)
Blood glucose storage
Lipid oxidation
Sarcoplasm contains (4)
Mitochondria
Ions
Enzymes
Sarcoplasmic reticulum
Where is the main storage site for Ca?
Sarcoplasmic reticulum
What is calsequesterin?
Binds Ca
Maintains Ca in low energy state while in the SR
Where is calsequesterin located?
In the sarcoplasmic reticulum
4 components of myofilaments
A band
I band
H band
Z line/disk
A band
Overlap thick and thin filaments
What is a thick filament
Myosin
What is a thin filament
Actin
I band
Contains actin filaments
H band
Contains myosin
In the light area of the sarcomere
Z line/disk
End boundary of the sarcomere
Anchored to actin
Myosin contains
2 heavy chains
4 light chains
Myosin head contains
ATPase needed for contraction
Actin is made of a double helix of _______ which is made up of _____, _______, and _______
F actin
G actin
Troponin
Tropomyosin
Troponin’s job is to
Shield myosin binding sites on actin
Tropomyosin is the
Binding domain in actin
Troponin I
Actin attachment
Troponin T
Tropomyosin attachment
Troponin C
Ca binding
The motor neuron terminus is ______ and ______
Unmyelinated
Branches into the muscle cell
What is the neuromuscular junction?
Juncture between the motor neuron and muscle tissue
What can alpha motor neurons do?
Convert choline into ACh
How is the ACh signal deactivated?
Acetrylcholinesterase degrades ACh
What are endplate potentials (EPP)?
Sub-threshold membrane depolarizations
What is the job of T tubules
Relays the signal from the sarcolemma deep into the muscle cells
What is DHPR?
Voltage gated Ca channels
Where are DHPRs?
In the T tubule on clusters of ryanodine receptor Ca channels that are embedded in the SR membrane
What’s RyR?
Ryanodine receptor Ca channels
What happens to DHPR as the AP travels down the T tubule?
Undergo conformational change that opens a pore in RyR to allow Ca to flow from the SR lumen to the sarcoplasm
Isotonic contractions
Forceful
Isometric contractions
Non-forceful
Sarcomere shortening and force is generated during an ______ contraction
Isotonic
Sarcomere shortening does not occur during an _____ contraction
Isometric
How is cross-bridge cycling ended? (2)
Decrease Ca concentrations
Decreased sarcoplasmic ATP concentrations