Skeletal Muscle Part 2

Root Words

Hemoglobin

Pigment in red blood cells that carry oxygen to the rest of the body. Responsible for the red color of blood

Myoglobin

Another pigment synthesized in muscle cell that gives it the reddish-brown color.

Temporarily stores oxygen which reduces need for continuous blood supply during muscle contraction

Muscle Fatigue

A muscle exercised strenuously for a prolonged period may lose ability to contract

Arises from accumulation of lactic acid in the muscle as a result of anaerobic respiration (lack of oxygen)

Threshold Stimulus

A certain amount of stimulation must be applied before a muscle fiber becomes responsive

Once reached, the action potential is generated

Muscle Tone

Sustained contraction, even when muscles appear to be at rest

Constantly stimulated, to maintain poster. If someone loses consciousness, the body collapses.

Sphincter

Muscle that relax and constrict passage ways to release or stop bodily fluids

Over 50 types in the body

Example: Anus, Iris of the eye, stomach, intestine

Smooth Muscle Fibers

Elongated, cell muscles. Also contain myosin and actin.

2 main typesMultiunit Smooth Muscle

Visceral Smooth Muscle

Multiunit Smooth Muscle

Muscle fibers are separate rather than organized into sheets

Found in the irises of the eye and walls of blood vessels.

Only respond to stimulation by motor nerve impulses or certain hormones

Visceral Smooth Muscle

Composed of sheets of spindle-shaped cells in close contact with one another.

Found in the walls of organs such as stomach, intestines, bladder, and uterus

Can stimulate each other, once one is stimulated, the impulse moves to excite adjacent fibers.

Create flash cards of the following major muscle groups using pages 193-

205Front: name of muscle Back: