Muscle Flashcards
(36 cards)
origin vs insertion
point of attachment closest to middle of body vs point of attachment distant from body
bicep and tricep are
antagonistic muscles
tendon, what contraction does to it
strong connective tissue made of collagen - contraction brings tendons together
movements of joint: flexing, extending, abducting, adducting
flexing: reduce angle of joint
extending: increase angle of joint
abducting: move away from midline
adducting: move toward midline
synergistic muscles
muscles that move joint in same direction
muscle held together by
fascicle
name of muscle cell, type of cell it is, name of membrane of cell
myofiber multinucleate synctia (fusion of multiple cells), surrounded by cell membrane sarcolemma
muscle innervated by ____ nerve ending onto the ____ through a ____ with ___
single
onto motor end plate through NMJ with ACh
sarcomere A band, H zone, I band
A band: length of thick filament
H zone: part of thick filament without thin overlapping (innermost section)
I band: part of thin filament without thick overlapping (outer most section)
sarcomere structure of myosin and actin
coming out from middle M line
coming in from Z lines
steps of power stroke
- crossbridge formed of myson head on actin w ADP w phosphate
- powerstroke, ADP released
- myson head binds to an ATP
- ATP hydrolyzed to ADP
role of Ca2+ in power stroke
when Ca2+ increases, troponin moves tropomyosin out of the way on actin so myosin can bind
NMJ mechanism, starts with action potential
- action potential arrives at axon triggering voltage gated Ca2+
- increase in Ca2+ leads to release of ACh vessicles
- postsynaptic has ACh receptors which are ligand gated Na+ channels (acetyl cholinesterases eat up the rest)
- Na+ influx depolarizes postsynaptic membrane, this is known as end plate potential, which is a combination of MEPPs (mini)
what is a motor unit, motor pool, how does depolarization spread
skeletal muscle fibers and neuron that innervates it
T tubules ensure entire myofiber depolarizes
motor pool: group of motor units used to contract a single muscle
frequency summation, what happens if second contraction happens before refractory period
if second contraction happens immediately after first
no time for SR to uptake Ca2+, leads to stronger, short contraction
length tension relationship
muscle contracts most forcefully at optimum length
type 1 and type 2 skeletal muscle fibers
type 1: slow twitch, high myoglobin/oxygenation
type 2A: fast twitch oxidative fiber, somewhat fatigue resistant
type 2B: fast twitch, explosive force
cardiac vs skeletal muscle
regarding nucleus, Ca2+, how ACh affects, muscle structure
cardiac cells each have a nucleus connected by intercalated disks
gets some Ca2+ from extracellular
ACh released by vagus nerve is parasympathetic
skeletal muscle has multinucleated synctia, Ca2+ only comes from sarcoplasmic reticlum, ACh stimulates contraction
both have striated sarcomeres and T tubules
smooth muscle size, connections, striation, Ca2+, what they use instead of troponin, how it depolarizes
narrower and shorter than skeletal, no need for T tubules
connected by gap junctions like cardiac
no striation thick and thin not organized
no troponin/tropmyosin - calmodulin binds to Ca2+ and activates MLCK which phosphorylates myosin to activate
uses extracellular Ca2+
relies on slow channels to depolarize (no Na+)
fluctuating resting potential
innervated by autonomic motor neurons
bone is made of
connective tissue
fibroblast can become, found in
collagen (fibrous), elastin (stretch), osteocyte, adipocyte, chondrocyte)
found in bone
round part vs long part of bone
epiphysis, diphysis
bone substance made of
bone matrix and ground substance (mostly proteoglycans)
made of collagen + hydroxyapatite
loose vs dense connective tissue is used for
loose: packing tissue
dense: tendon, ligament, bone.
