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Anatomy chapter 9
just kill me now
28
Physiology
Undergraduate 1
02/24/2016

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Term
myoglobin
Definition
red pigment that stores oxygen, located in sarcoplasm,  similar to hemoglobin,
Term
sarcolemma
Definition
plasma membrane of muscle fibers, supplies with blood
Term
sarplasmic reticulum
Definition
elaborate smooth endoplasmic reticulum; interconnecting tubueles surround each myofibril
Term
sarcomere
Definition
smallest contractile unit of a muscle fiber; functional unit of skeletal muscle
Term
fascicle
Definition
groups of muscle fibers surrounded by perimysium
Term
myofibril
Definition
accounts for 80% of cellular volume; contains contractile elements of skeletal muscle cells (sarcomeres)
Term
epimysium
Definition
overcoat of dense irregular connective tissue that surrounds whole muscle
Term
perimysium
Definition
layer of fibrous connective tissue that surrounds each fascicle
Term
endomysium
Definition
whispy sheath of connective tissue that surrounds each individual muscle fiber
Term
skeletal muscle
Definition
attach and cover the bony skeleton; skeletal, striated, voluntary
Term
smooth muscle
Definition
found in walls of hollow visceral organs (ex: stomach), forces fluids and other things through internal body channels; visceral, nonstriated, involuntary
Term
cardiac muscle
Definition
only in heart; cardiac, striated, involuntary
Term
acetylcholine
Definition
neurotransmitter in muscle contraction
Term
acetylcholinesterase
Definition
enzyme located in synaptic cleft
Term
creatine phosphate
Definition
unique high-energy molecule stored in muscles, tapped to regerate ATP
Term
calcium ion
Definition
used in excitation-contraction coupling; secreted by sarcolemma; enters muscle fibers and forces release of acetylcholine in NMJ
Term
potassium ion
Definition
leaves muscle fiber as Na+ enters to produce local channge in membrane potentional (depolarization), in NMJ and AP
Term
sodium ion
Definition
enters muscle fiber as K+ leaves and makes interior of sarcolemma less (-), in NMJ and AP
Term
tetanus
Definition
smooth, sustained muscle contraction resulting from high-frequency stimulation
Term
muscle twitch
Definition
response of a motor unit to single action potential of motor neuron; muscle fibers contract quickly then relax
Term
muscle tone
Definition
relaxed muscles are almost always slightly contracted; due to spinal reflexes; does not produce active movements; keeps muscles firm and ready to respond to stimulation
Term
contraction
Definition
muscle length changes and moves load
Term
contraction
Definition
muscle length changes and moves load; isotonic and isometric
Term
isotonic contraction
Definition
moves load; muscle length changes
Term
isometric contraction
Definition
doesn't move load, muscle tension reaches peak
Term
relaxation
Definition

-initiated by reentry of Ca2+ into SR

-muscle force declines=muscle tension decreases to zero -tracing returns to baseline

-muscle returns to original length

-muscle contracts faster than relaxes

Term
latent period
Definition

first few milliseconds following stimulation when E-C coupling occurs;

muscle tension beginning to increase but no response seen on myogram

Term
maximal summation
Definition
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