IBSEHS Topic 1.2 Muscle Notes

Muscle types, functions, properties, and structure

Skeletal Muscle: main features

movement of body, voluntary, generates heat

Skeletal Muscle: location

attached to bones

Skeletal Muscle: type of cells

long, cylindrical, striated (stripes), multinucleated (many nuclei)

Cardiac Muscle: main features

• involuntary

• pumps blood

Cardiac Muscle: location

heart

Cardiac Muscle: types of cells

• short, branched

• striated (stripes)

• single nucleus

Smooth Muscle: main features

• involuntary

• moves substances within the body

• regulates blood flow

Smooth Muscle: location

walls of hollow organs and blood vessels

Main functions of muscles

• movement of the body (skeletal)

• movement within the body (cardiac & smooth)

• posture (skeletal)

• generates heat (skeletal)

Contractility

ability to contract & produce a force

Extensibility

the ability to be stretched or extended

Elasticity

the ability to return to normal length

Excitability

ability to respond to stimuli (usually a nerve impulse or hormone)

Hypertrophy

increase in muscle size

Atrophy

decrease in muscle size

Epimysium

connective tissue covering that surrounds the WHOLE muscle (epi=outer)

Perimysium

The connective tissue that surrounds fascicles.

Endomysium

Connective tissue surrounding a muscle fiber

Fascicle

bundle of muscle fibers and its perimysium

Muscle fibre

muscle cell

Tendon

connects muscle to bone; transmits forces generated by muscles to pull on bones at joints

Blood Vessels

delivers blood to muscles