Chapter 8 Flashcards
What are the three functions of muscle?
- Movement
- Postural and joint stability
- Production of heat- maintain body temp
What are the 4 properties of all muscle cells?
- Excitability- depolarize to propagate action potential
- Contractility- contract and generate tension
- Extensibility- increase in length
- Elasticity- return to normal resting length
What is conductivity? What muscle cells have this property?
- propagation of action potential from cell to cell via gap junctions with neurotransmitter or receptor
- smooth and cardiac
What is automaticity? what muscle cells have this property?
- self generate an action potential
- only cardiac cells, pacemaker cells in AV and SA nodes
What are the three layers of connective tissue in skeletal muscle?
- Epimysium- outer layer, surrounds whole muscle
- Perimysium- middle layer, surrounds fasciculi
- Endomysium- inner layer, surrounds muscle fibers
A skeletal muscle is a bundle of many ______.
fasciculi
A single fasciculus is a bundle of _______.
20-80 muscle fibers
A muscle fiber is a bundle of ______.
parallel myofibrils
A myofibril is a ______.
series of sarcomeres containing protein myofilaments
Why are skeletal muscle cells called muscle fibers?
they are elongated cells
Why aren’t cardiac and smooth muscle cells called fibers?
they are linked together by intercalated discs to form a large network of branching muscle cells
Why are skeletal muscle fibers striated?
myofibrils have alternating light (I-band) and dark (A-band) bands
What muscle cells are striated?
skeletal and cardiac
Describe the nerve supply to skeletal muscle?
each muscle is supplied by one nerve that has many branching motor neurons, one neuron can innervated many muscle fibers
Describe the blood supply to skeletal muscle?
each skeletal muscle is supplied by one artery which branches into many capillaries which supply the muscle with oxygen and nutrients
one or more veins exit the muscle
