Week 3 Quiz Review flashcards

what are the characteristics of muscle cells?

excitability, conductivity, contractility, extensibility, and elasticity

what are the functions of skeletal muscles

body movement, maintaining posture, regulation of body openings, and heat production

what is a skeletal composed of

muscle fibers, connective tissue sheaths, nerves, arteries, and veins

hierarchy of smallest to largest muscle components

myofilament, myfibril, muscle fiber, fascicle, skeletal muscle

whats a myofilament

short contractile which consists of thick and thin proteins

whats a myofibril

cylindrical contractile composed of myofilaments

whats a muscle cell (fiber)

fiber which contains myofibrils

whats a fascicle

group of muscle cells

what is a muscle

multiple fascicles grouped together

connective tissue covering from deep to superficial

endomysium, perimysium, epimysium

what does the endomysium surround

individual muscle fibers

what does perimysium surround

fascicles

what does epimysium surround

entire muscle

what is superficial fascia

the areolar and adipose connective tissue that separates muscle from skin

where does a tendon attach

muscle to bone, skin or another muscle

what is an aponneurosis

a thin flattened sheet some tendons form

what stimulates skeletal muscle contraction

somatic motor neurons

what is the neuromuscular junction

the junction between a motor neuron axon and a muscle fiber

what is a synaptic cleft

the narrow gap between the neuron and muscle fiber

what do synaptic vesicles stores

acetylcholine (ACh), until it’s released

what is acetylcholine

the neurotransmitter that initiates skeletal muscle conntraction

what does acetylcholinestease’s do

break down ACh in the synaptic cleft

what is sacrolemma

the plasma membrane of the skeletal muscle fiber

what is sarcoplasma

the cytoplasm of the skeletal muscle fiber

specialized structures of muscle fibers

t-tubules and the sarcoplasmic reticulum

what do terminal cisternae do

store the calcium needed for contraction

what forms a triad

one t-tubule plus two terminal cisternae

what happens when myoblasts fuse

multiple nuclei in the skeletal muscle fibers

what forms thick filaments

myosin

what forms thin filaments

actin, troponin, and tropomyosin

whats troponin

the protein that binds calcium

what binds to actin during contraction

myosin heads

whats the sarcomere

the functional contractile until of the skeletal muscle

where does the sarcomere extend from

one z-disc to the next z-disc

whats this

z disc

whats #5

i band

whats #1

a band

whats #3

h zone

what does titin/connectin do

helps with muscle elasticity and filament alignment

what are connectins

z-disc proteins that anchor and interconnect thin filament ends

what areas are narrows during contraction

i band and h zone

what areas stay the same during contraction

a band

what areas move closer during contraction

z disc

what is the crossbridge cycle

attach, pivot, detach, return

what does ATP do

provides the energy for myosin movement and cross-bridge cycling

what is passive, not fully active

return of a contracted muscle fiber to resting length

motor neuron recrution helps…

produce more force

distal attachment is

more mobile in appendicular muscles

what are slow oxidative fibers

fatigue resistant and important for posture and endurance

what do fast glycolytic fibers do

produce powerful contractions but fatigue quickly

characteristics of smooth muscles

one nucleus, lacks striations, lacks sarcomeres, and has no z discs

characteristics of cardiac muscles

has striations, usually one nucleus, intercalated discs