Body Systems Flashcards
Epimysium
Fibrous connective tissue surrounding more than 430 skeletal muscles
tendon
connects muscle to bone
Fasciculi
grouped muscle fibers located under the epimysium
Perimysium
connective tissue surrounding the fasciculus
Endomysium
connective tissue surrounding an individual muscle fiber
Sarcolemma
encircles and is contiguous with the endomysium. also called the fiber’s membrane
neuromuscular junction
the junction between a motor neuron (nerve cell) and the muscle fibers it innervates - is also called the motor end plate
motor unit
a motor neuron and all of the fibers it innervates
sarcoplasm
the cytoplasm of a muscle fiber, contains contractile components consisting of protein filaments, other proteins, stored glycogen and fat particles, enzymes, and specialized organelles such as mitochondria and the sarcoplasmic reticulum
myofribils
dominate the sarcoplasm. they contain two types of myofilament - actin and myosin
myosin
thick center - consists of a globular head, a hinge point, and a fibrous tail
actin
thin filaments arranged in a double helix
A-band
corresponds with the alignment of the myosin
I-band
corresponds w two adjacent sarcomeres that contain only actin filaments
Z-line
runs longitudinally through the I band
H- zone
where only myosin filaments are present
sarcoplasmic reticulum
where calcium ions are stored. regulation of calcium controls muscular contraction
action potential
an electrical nerve impulse
troponin
a protein that is situated at regular intervals along the actin filament
tropomyosin
another protein molecule, which runs along the length of the actin filament in the groove of the double helix
power stroke
the energy for pulling action - comes from hydrolysis (breakdown) of ATP to ADP and phosphate, a reaction catalyzed by the enzyme myosin ATPase
acetylcholine
neurotransmitter which diffuses across the neuromuscular junction causing excitation of the sarcolemma
tetanus
the maximal amount of force a motor unit can develop
type 1 muscle fibers
generally efficient and fatigue resistant and have a high capacity for aerobic energy supply
type IIa
fast twitch fibers that have a greater capacity for aerobic metabolism and have more capillaries surrounding them than the type IIx
type IIx
fast twitch fibers that have more power and potential for hypertrophy
muscle spindles
proprioceptors that consists of modified muscle fibers enclosed in a sheath of connective tissue
GTO
activated when the tendon attached to an active muscle is stretched inhibiting muscle activation
tricuspid and mitral valve (AV valves) during ventricular contraction (systole)
prevents the flow of blood from the ventricles back into the atria
aortic valve and pulmonary valves (semilunar valves)
prevent back flow from the aorta and pulmonary arteries in the ventricles during the ventricular relaxation (diastole)
sinoatrial (SA) node
the intrinsic pacemaker - where rhythmic electrical impulses are normally initiated
atrioventricular (AV) node
where impulse is delayed slightly before passing into the ventricles
AV bundle
conducts the impulse to the ventricles
purkinje fibers
conduct impulses to all parts of the ventricles
bradycardia
less than 60bpm
tachycardia
more than 100bpm
arterial system
carries blood away from the heart
venous system
carries blood toward the heart
capillaries
facilitate exchange of oxygen, fluid, nutrients, electrolytes, hormones, and other substances between the blood and the interstitial fluid in the various tissues of the body
hemoglobin
responsible for the transport of oxygen
