all the muscle cells supplied by one axon's branches
anatomy of a neuromuscular junction?
synaptic knob of the nerve, the motor end plate of the muscle cell membrane and a surrounding Schwann cell
What is the nerotransmitter used for signaling in skeletal muscle?
roles of ligand-gated and voltage gated channels in muscle stimulation?
acetylcholine causes opening of ligandgates which allows entry of sodium which raisesvoltage in the cell. this change in voltage causes voltage gates to open, causing spread of voltage change (depolarization) across the entire cellmembrane
the enzyme that breaks down acetylcholine
describe how T tubules increase the calcium concentration in the muscle cell.
voltage changes in the T tubules cause voltage gated channels in adjacent terminla cisternae to open calcium channels. calcium then flows down its concentration gradient
process in muscle relaxation requires ATP?
pumping calcium back in to terminal cisternae
there is an optimal sacromere length for maximal power of contraction. this is monitored by the brain and is called muscle tone.
describe all or none response as it applies to muscle.
if the voltage change caused by sodium inflow through the ligand gated channels doesn't reach a certain threshold, the muscle will not respond.
what factors decrease the strength of contraction?
cold, increase in acidity, increase or decrease of optimal length-tension relationship, decreased availability of calcium
a sequential increase in strength of contraction caused by incomplete removal of calcium between stimulation
the increase in numbers of nerves stimulated- which increase the number of motor units contracting
role of troponin?
calcium binding site
enzyme that causes ADP+ADP to make ATP+AMP
contains a high energy phosphate bond that can switch to ADP to make ATP
myokinase and creatine. short cut for making ATP used by muscles
binds oxygen and stores it in the muscle cell
provides glucose fragments for anaerobic metabolism
difference between iosmetric and isotinic contraction?
same length- muscle doesn't move
same power- muscle does move
difference between endurance and resistance conditioning?
resistance exercise causes bigger muscles secondary to hypertrophy- does not improve endurance
endurance conditioning increases mitochondria in the muscle cell, increases blood supply to the muscle cell, decreases fatigue of the muscle cell but does not make the muscle bigger
junctions between cardiac muscle cells that provide support, resistance and communication
anatomical differences between skeletal and cardiac muscle cells?
cardiac- shorter, thicker, branched, one nucleus, interacalated discs, rely more on extracellular calcium, does not rely on anaerobic metabolism so doesn't have fatigue
what is the pacemaker conduction system in the heart?
faster autorhythmic cells form a pathway through the heart