tendon
tissue connecting muscle to periosteum of bone
what are the layers of connective tissue
- endomysium
-perimysium - epimysium
sarcolemma
muscle cell membrane
sarcomere
runs for z line to z line
functional unit of a muscle fiber (CONTRACTILE UNIT)
what is required for contraction of actin-myosin
- atp: provide energy to cross bridge
- Ca++: uncovering the actin site for actin-myosin connection
each triad contains
- 2 vesicles (terminal cisternae)
- 1 T tubules (transverse tubule)
endomysium wraps each
fiber / cell
perimysium surrounds several fibers and forms bundles called
fasciculi
epimysium surrounds all the bundles to form the entire
muscle
fiber arrangement influences
- force generating capacity
- physiologic cross sections (right angles)
satellite cells
myogenic stem cells located within the sarcolemma (help regenerative cell growth, play a role in hypertrophy
sarcoplamic reticulum
network of tubules and vesicles, provides structural integrity, stores, releases and reabsorbs Ca++
actin filaments lie in ________ pattern around myosin
hexagonal
calcium role in actin-myosin connection
calcium attaches to troponin complex to move tropomyosin off of binding site
ATP role in actin-myosin connection
provides energy for cross-bridge formation, is broken down to create ADP and Pi with ATPase
what transmitter for neuron to neuron connection
positive or negative so could be ach gaba or glycine
what transmitter for neuron to muscle fiber
positive so ach to depolarize
fiber type for endurance athletes
type 1 (slow twitch)
fiber type for speed and power athletes
type 2 (fast twitch a and b)
two distinct fiber types identifiied by characteristics
contractile and metabolic
Slow twitch fiber characteristics
- low myosin ATPase activity
- slower Ca++ release and uptake by sarcoplasmic reticulum
- low glycolytic capacity
- large and numerous mitochondria
fast twitch fiber characteristics
- high capacity for action potentials
- high mysosin ATPase and rapid Ca++ release
- capable of high force generation
- rely on anaerobic metabolism
fast twitch subdivisions
IIa: capacity fot both aerobic and anaerobic energy production
IIb: relies on anaerobic energy production, most rapid shortening velocity
motor unit
one motor neuron and all the fibers it innervates
