Human Anatomy Muscles

Types of Muscle Tissues

Smooth, Cardiac, and Skeletal.

Cardiac Muscle Tissue

Found only in the heart.

Smooth Muscle Tissue

Found in the walls of hollow organs.

Excitability

Ability to receive and respond to stimuli.

Contractility

Ability to shorten forcibly when stimulated.

Extensibility

Ability to be stretched.

Elasticity

Ability to recoil to resting length.

Muscle Functions

Produce movement, maintain posture and body position, stabilize joints, generate heat.

Insertion

Attachment of a muscle to a movable bone.

Origin

Attachment of a muscle to an immovable bone.

Sarcolemma

Muscle fiber plasma membrane.

Sarcoplasm

Muscle fiber cytoplasm.

Myofibrils

Actin and myosin myofilaments.

Striations

Stripes formed from repeating series of dark and light bands.

Sarcomere

Unit of function in muscle contraction.

Contraction

The activation of cross bridges to generate force.

Membrane Potential

Electrical potential across the plasma membrane measured in millivolts.

Neurotransmitters

Chemical messengers that transmit information in the nervous system.

Synaptic Cleft

The tiny space separating axon terminals and postsynaptic cells.

Acetylcholine (ACh)

Neurotransmitter stored in synaptic vesicles and released at the neuromuscular junction.

Acetylcholinesterase

Enzyme that breaks down acetylcholine to stop muscle contractions.