week 4 study guide Flashcards
describe cardiac muscle
only in the heart.
is cardiac muscle striated
yes
does the cardiac muscle need nervous system stimulation of contract
no
is cardiac muscle voluntary or involuntary
involuntary
where is skeletal muscle found
organs attached to the bones and skin
what are the fibers of skeltal muscles called
muscle fibers
are skeletal muscles striated
yes
are skeletal muscles under conscous control
yes, they are voluntary
do skeletal muscles require nervous system stimulation
yes
where is smooth muscle found
in the walls of hollow organs like the stomach urinary bladder and airways
is smooth muscle striated
no
does smooth muscle require nervous system stimulation
no
is smooth muscle voluntary
no , it is involuntary
what is excitablity
ability to recieve and respond to stimuli
what is contractability
ability to shorten forceably when stimulated
what is extensibility
ability to be stretched
what is elasticity
ability to recoil to resting length
list the 4 important functions of muscles
movement of bones or fluid
maintaining posture and body position
stabilizing joints
heat generation
list the 3 connective tissue sheaths that protect muscles
epimysium- surrounds entire muscle
perimysium-surrounds fasicles
endomysium-surrounds each muscle fiber
name the 2 kinds of muscle attachments
insertion
origin
what kind of attachment is an insertion
moveable bone
what kind of attachment is an origin
immovable bone
explain sliding filament model
the sliding filament model in contraction- the filaments overlap only at the ends of the A band. Essentially when a muscle is contracting the filaments slide past each other (the thin filament will slide past the thick filament) this causes more overlap because there is more overlap we know that it will have contracted. When there is contraction, the myocin heads connect to the actin and they pull, this causes the sarcomere to contract and shorten. The distance between 2 zdisks will shorten.
what are troponin and trophomyosin
they are regulatory proteins that are bound to the actin. When a muscle fiber is stiumlates, it sets of a whole series of reactions and it removes the trophpmyocen out of the way so that they attachment.
why do we see muscle striations
striations are there because myofibals are lined up in a certain pattern that causes them
describe myacin
myacin filaments -are the thick ones, they extend the length of the a band and connected and the end line. the myacin molecule has heads and tails. each one has a tail made up of interwoven polypeptide chains. it has 2 heads. the heads act as a cross bridge where the muscles contract. when stimulated it uses atp to bind to the binding site on the actin filament. when it binds it creates a cross bridge. myocin is located int he middle and actin is on either side
describe actin
ACTIN- twisted there are subunits have active cites where the myocin can bind . The active site is a place where the myocin can bind to . Only myocin would be able to bind there. Myocin will only be able to get there if it is not blocked by troponen and trophomyocin. when a muscle is relaxed, the active site is blocked by those to . if an action potential is generated, a chemical reaction will take place and move trophomin and tophoomyocin out of the way and myosin will be able to bind to the actin.
