APK Exam3 Ch12 PI

4 Mechanisms of Force Generation in Muscle

Plasma mem of a muscle cell

Cytoplasm of a muscle cell

Endoplasmic reticulum of a muscle cell

4 major components of muscle fiber

Part of a muscle fiber that is a deep invagination of the sarcolemma and is physiologically important for excitation-contraction coupling

Long, thin strand which gives skeletal and cardiac muscle a striated (striped) appearance and which are orderly arranged as sliding thick (myosin) and thin (actin) filaments

Thin filament

Thick filament

A segment of myofibril which is the contractile unit and is the smallest functional unit of a muscle

Part of sarcomere which is a thick filament that forms dark bands

Part of sarcomere which is a thick filament and has no overlap

Part of sarcomere which links thick filaments

Part of sarcomere which links thin filaments

___ is a "filament" or a polymer of G actin, and each G actin has a binding site for myosin

Each ___ of a F actn has a binding site for myosin

Regulatory protein which covers myosin binding sites on actin so that myosin cannot bind to G-actin, inhibiting muscle contraction. It's position is controlled by troponin

Tropomyosin together with troponin, regulate the binding of _____ to ____

A protein complex which is associated with a tropomyosin and consists of 3 polypeptide subunits which each binds to actin, tropomyosin, or calcium

When troponin binds to Ca, it causes _____, which in turn draws tropomyosin away from its blocking position

Myosin head binding sites: (2)

Myosin tail is toward ___ and myosin head is toward ____

Very elastic protein which supports protein in muscle by anchoring thick filaments b/w M line and Z line

During muscle contraction, thick (myosin) and thin (actin) filaments slide over each other instead of shortening

Sequence of events whereby an action potential in the sarcolemma causes contraction

Excitation-contraction coupling requires calcium to be released from ___ and is dependent upon neural input from ___

Synpase b/w motor neuron and skeletal muscle

Receptors on skeletal muscle cells are called ___ and respond to ___ which is released from the motor neuron

During excitation-contraction coupling:
1.) action potential starts in _____,
2.) travels down ______,
3.) then ____ receptors of T tubules open Ca channels (___ receptors) in lateral sacs of SR
4.) Ca increases in cytosol & binds to troponin shifting tropomyosin,
5.) and crossbridge cycling occurs

First source of ATP which is used up very rapidly and can provide 4-5 times the amt of ATP present in cell at rest

Creatine rxn

Primary energy source during light to mod exercise (aerobic) b/c there is enough oxygen avail

How does body maintain adequate oxygen?
1.) Increase ventilation
2.) Increase HR and contraction
3.) ___

During oxidative phosphorylation, where does energy come from during beginning vs later exercise?

Primary source of ATP energy when oxygen supply to muscle is limited:

How many ATP are made per glucose during anaerobic glycolysis?

As a result of anaerobic glycolysis and a limit to glucose availability, what happens in muscles?

After exercise, respiration is still increased b/c ox phosphorylation continues. Sometimes called ____. At this time, ___ and ___ are replenished, and ___ is converted back to ____.