Flashcards in Muscle Tissue Ch 9 Deck (53)
Organs that attach to and cover the skeleton
Only in heart
In walls of hollow, visceral organs.
4 Characteristics of Muscle Tissue
4 Major Muscle Functions
Additional functions of muscle
Protect internal organs
Dilate and constrict pupils
Arrector pili in hair follicles
Nerve and blood supply
Generally 1 nerve, 1 artery, and 1 or more veins for each muscle.
3 Connective tissue sheaths of muscle
Epimysium: Surround whole muscle
Perimysium: Surrounds each fascicle
Endomysium: wispy sheath that surrounds each muscle fiber
Direct: fleshy attachments, epimysium is attached directly to outside of bone or cartilage.
Indirect: more common, tissue extends beyond muscle as tendon or aponeurosis and anchors to bone or cartilage.
The attachment at the movable bone
The attachment at the immovable or less movable bone.
Cytoplasm of a muscle cell
Contains large amounts of glycosomes (glycogen) and myoglobin (oxygen).
80% of cellular volume
rod-like cylinders that run the length of the cell
smallest, contractile, functional unit of skeletal muscle.
Dark and light bands that wrap around the myofibril.
Light: I bands
Smaller structures in sarcomeres: think and thin
Length of A band
Extend across I band into A band
rob-shaped protein, spiral around the actin core. Stabilize it and block myosin-binding sites.
TnI: Inhibits, binds to actin
TnT: binds to tropomyosin, positions actin
TnC: binds calcium ions
Giant protein titin
Extends from Z disc
Forms thick filament core
Holds think in place
Helps muscle spring back
Interconnecting tubules surround each myofibril. Regulates calcium
Transverse, at each A band I band junction
Increase muscle fibers surface area
continuous with extra cellular space
Encircle each sarcomere
Ensures synchronized contraction
Perpendicular cross channels at A-I band junctions
Involved in energy production
T tubules, SR and Terminal Cisterns.
T-tubules: act as voltage sensors
SR: gated channels through which terminal cisterns release Ca2+
Sliding filament model of contraction
During contraction thin filaments slide past thick so that the actin and myosin filaments overlap to a greater degree.
Neuromuscluar junction (NMJ)
or end plate, is a synapse between a muscle cell and neuron. Only one per each muscle fiber, located midway.
Neurotransmitter released into the synaptic cleft and open NA+ and K+ channels. Triggers action potential.