UNIT 2: MUSCLE AND NERVOUS TISSUE (3)

Two contractile proteins in muscle

Actin and myosin

Name this tissue.

Skeletal muscle — Why: Long striated fibers, multiple nuclei at the edges.

Skeletal muscle cells: shape and nuclei

Long, cylindrical, multinucleate

Is skeletal muscle voluntary or involuntary?

Voluntary

Functions of skeletal muscle

Moves the skeleton, maintains posture, produces heat

Name this tissue.

Cardiac muscle — Why: Branched, striated, intercalated discs.

Structures unique to cardiac muscle that join cells end to end

Intercalated discs — Why: Contain desmosomes + gap junctions so the heart contracts as a unit.

Without intercalated discs, heart muscle cells would ___.

Separate (pull apart)

Name this tissue.

Smooth muscle — Why: Spindle-shaped, no striations, one central nucleus.

Smooth muscle cells: shape, striations, nuclei

Spindle-shaped, no striations, single central nucleus

Where is smooth muscle found?

Walls of hollow organs (stomach, intestines, bladder, uterus, blood vessels, airways)

Tissue in the uterine wall that produces labor contractions

Smooth muscle

Muscle that moves food through the GI tract

Smooth muscle

Which muscle types are striated?

Skeletal and cardiac

Which muscle types are involuntary?

Cardiac and smooth

Name this tissue.

Nervous tissue (neurons)

Excitable cell that generates and conducts impulses

Neuron

Neuron process that carries signals TOWARD the cell body

Dendrite

Neuron process that carries signals AWAY from the cell body

Axon

Supporting cells of nervous tissue

Neuroglia (glial cells) — Why: More numerous than neurons; don't transmit impulses.