A&P muscles

sarcolemma

plasma membrane of a muscle fiber

sarcoplasmic reticulum

smooth ER that forms a network around each myofibril:

Triad

a T tubule and two terminal cisterns associated with it

Thick filaments

made of several hundred myosin molecule, contains globular head

Thin filaments

Fibrous (F) actin: two intertwined strands

Tropomyosin and Troponin (Ca binding) molecules

Elastic filament

• Titin: huge, springy protein

• Run through core of thick filament and anchor it to Z disc and M line

• Help stabilize and position the thick filament

• Prevent overstretching and provide recoil

contractile proteins

myosin and actin

regulatory proteins

tropomyosin and troponin 

Dystropin

Allows for muscle fiber shortening by connecting sarcomere and endomysium

Small motor units

fine degree of control, eye and hand muscles

Large motor units

more strength than control, large muscles

resting membrane potential

about −90 mV in skeletal muscle cells

tetanus

lockjaw) is a form of spastic paralysis caused by toxin Clostridium tetani

flaccid paralysis

a state in which the muscles are limp and cannot contract

botulism

type of food poisoning caused by a neuromuscular toxin secreted by the bacterium Clostridium botulinum

length-tension relationship

the amount of tension generated by a muscle depends on how stretched or shortened it was before it was stimulated

rigor mortis

hardening of muscles and stiffening of body beginning 3 to 4 hours after death, peaks 12 hours after.

Isometric contraction

muscle contraction (“same length”)

Ex) holding a weight

Isotonic contraction

muscle contraction (“same tension”)

Ex) lifting a weight

anaerobic fermentation

• Enables cells to produce ATP in the absence of oxygen

• Yields little ATP and lactate, which needs to be disposed of by the liver

Myokinase

P + ADP → ATP

Creatine Kinase

P + Creatine phosphate → ADP → ATP

Slow twitch fibers

-Endurance, resists fatigue

-Deep red color (myoglobin)

-posture muscles

Fast twitch fibers

-Powerful muscles

-White color

-eye & hand & leg muscles

peristalsis

waves of contraction brought about by food distending the esophagus or feces distending the colon

Fusiform muscle

intermuscular septa

very thick fascia that separate one compartment from another

intrinsic muscle

entirely contained within a region, such as the hand

extrinsic muscle

acts on a designated region, but has one attachment elsewhere

synergist

muscle that aids the prime mover