Three types of muscle tissue
skeletal, cardiac, smooth
Excitability
ability to receive and respond to stimuli
Contractability
muscle fibers that are stimulated by nerves contract which causes movement
Elasticity
returns to its original resting length after being stretched or contracted
Extensability
ability to be stretched
cardiac muscle location
myocardium of the heart
cardiac muscle cell shape
branched and "Y" shaped
Cardiac muscle # of nuclei
uni- or binucleated
Is cardiac muscle striated?
yes it's striated
Cardiac muscle control
involuntary
Cardiac muscle special features
intercalated discs, autorhythmic
Smooth muscle location
mostly in the walls of visceral organs (think digestive system)
Smooth muscle cell shape
Fusiform
Smooth muscle number of nuclei
uninucleated
Smooth muscle striations?
no striations
Smooth muscle control
involuntary
Smooth muscle special features
Fatigue-resistant
skeletal muscle location
connected to bones
skeletal muscle cell shape
fiber-like (long and cylindrical)
skeletal muscle number of nuclei
multinucleated
skeletal muscle striations?
yes it striated
Skeletal muscle control
voluntary
Skeletal muscle special features
innervated at the NMJ, Vascular
Skeletal muscle functions
movement, maintain posture, temperature regulation, Storage and movement of materials, support abdominal organs, joint stabilization
deep fascia
wraps muscle groups
epimysium
surrounds entire muscle
Perimysium
wraps around a fascicle
Endomysium
wraps muscle cells
tendon
Connects muscle to bone
Muscle-Tendon Connection
collagen fibers of endomysium, perimysium, and epimysium are continuous with tendons
flat tendons
aponeuroses
origin
less movable attachment site
insertion
more movable attachment site
muscle is made up of
fascicles
fascicles are made up of
muscle fibers/ myofibers
Myofibers are made of
myofibrils
Sarcolemma
muscle cell membrane that sends neural pulse through out muscle
Sarcomere
contractile unit of a muscle fiber
Z disc
Separates the sarcomeres from each other
thick filaments
composed of myosin
Grabs a hold of actin during contraction
muscle excitability
Neuron activates Sarcolemma at the neuromuscular junction
thin filaments
actin, troponin, tropomyosin
What happens at the NMJ
Action potential goes through the synaptic end bulb
impulse travels to sarcolemma through synaptic cleft
sarcoplasmic reticulum
Organelle of the muscle fiber that stores calcium.
t tubule
sends pulse to sarcoplasmic reticulum
triad
a T tubule and two terminal cisterns
Terminal cisternae of sarcoplasmic reticulum
Structures within skeletal muscle cells that serve as reservoirs of calcium ions
muscle contraction steps
Calcium is released from the terminal cisternae
calcium attaches to the troponin
actin is now exposed to the myosin
myosin pulls on the actin
muscle relaxtion
calcium is reobsorbed
ATP is required
Rigor Mortis
Death is a process
Tissues continue to live after the brain, heart and lungs fail
A few hours after death, ATP runs out
- myosin cannot detach from actin
- calcium cannot be reabsorbed
-causes continual muscle contraction
After 15-24 hours, myofibrils beg
Tetanus
caused by clostridium tetani
excessive muscle contraction
Botulism
caused by clostridium botulinum
muscular paralysis
botox