Exam 2 Flashcards
Chapter 9 part 2
after nervous stimulation ends, so does
action potential
after nervous stimulation ends, no calcium release from
SR
during relaxation no calcium bind to
troponin
during relaxation tropomyosin does not move and stays in place
blocking binding site
what is ACh destroyed by
acetylcholinesterase enzyme
what does AChE do
bind to receptor and prevents continues muscle fiver contraction without another stimulation
South American Indian’s Arrowhead Poison
curare
curare is used for
Hunting & Therapeutic Purposes
what does curare weaken
skeletal muscle
curare binds to what and blocks ACh
acetylcholine receptor
do muscles respond to stimulation during curare
no
Mimics Locked in syndrome (Paralysis of all Skeletal muscle VOLUNTARY Contraction)
curare
curare leads to
Asphyxiation & Paralysis DIE
small amount of curare are used in
intubation and surgery as a paralyzing agent
curare is also used for treatment for
Tetanus & Strychnine Poisoning
myasthenia gravis is due to
Ach Receptors being destroyed by AUTOIMMUNE REACTION (Females 20-40)
when thymus is removed in myastenia gravis it will
return to normal
Motor Unit
Functional contractile
unit in Skeletal Muscle
ALL Muscle fibers of Motor Unit
contract at the same time
The Motor Nerve Axon branches at
Terminal and
innervates several muscle
fibers
Motor Units do NOT have same ratio of muscle fibers and
nerve axons
muscle func depends on
ratio
large=
many fibers/ axon
small=
few fibers/ axon
fine motor control=
smaller motor units
strength=
larger motor units
fine motor control would be
fingers, tongue, eye muscles
strength motor units are found
thigh and leg muscles, shoulder and arm muscles, back, and abdomen
skeletal muscle fibers contract in
twitches
twitch lasts
20-40 milliseconds
all muscle fibers innervated contract
simultaneously and maximally
twitch is time from
SR releasing calcium, cross bridge forms, power stroke, sr reuptakes calcium, cross bridge, power stroke stops
after death there is no
ATP production, and cross bridges not detach
muscle stiffening between what hours
3-4 hours post mortem
when are you the most rigid in rigor mortis
12 hours
when does stiffness decrease
48-60 hours
in rigor mortis was causes all cross bridges to form
calcium influx into muscle cells
why do cross bridges not detach
no atp
