Lec 10 - Muscle Histology Flashcards
what are the characteristics of muscle? [ICEE]
irritability
contractility
extensibility
elasticity
what are the classifications of muscle?
skeletal, smooth, cardiac
which muscles are voluntary and multinucleated?
skeltal
which muscles are involuntary and found in the GI tract?
smooth
which muscle is found only in the heart
cardiac
which connective tissues bind muscles to bone
tendons and aponeurosis
which CT binds several muscle groups together
fascia
which surrounds the entire muscle
epimysium
what is the perimysium
surrounds bundles of muscle fibers
what are fascicles
bundles of muscle fibers
what is the endomysium
loose CT that covers individual muscle fibers
what is the sarcoplasm
cytoplasm
what is the sarcolemma
cell membrane
what does the t-tubule do
excites muscle.
tube like extension of sacrolemma which transmits nerve impulses to sarcoplasmic reticulum
what is the sarcoplasmic reticulum
smooth ER that releases calcium during muscle contraction
what are myofibrils?
cylindrical units that run entire length of muscle fiber
what are myofilaments
found in myofibrils, composed of actin (thin) and myosin (thick)
what makes up the sarcomere?
myofilaments
where are actin filaments found on the sarcomere?
end
what makes up the center of the sarcomere
myosin filaments
when muscles contract, what happens to sarcomere?
shortens
what is the all or nothing principle
when a nerve impise travels through a motor unit, ALL fibers contract simultaneously to their max
what are two types of muscle fibers?
red slow twitch and white fast twitch
which type of muscle fibers have aerobic respiration
red slow twitch
which muscles are fatigue resistant?
red slow twitch fibers
which muscles fatigue quickly?
white fast twitch
what are some examples of red slow twitch fibers?
postural muscles, especially lower back.
what are some examples of white fast twitch fibers
muscles of upper limbs, lifting, throwing
what are synergistic muscles
muscles that contract to accomplish a similar movement
what are 2 types of contraction
concentric and eccentric
flexion of the arm is an example of which muscle contraction?
concentric
