Chapter 20- Muscular System and Pathologies

Tendinous attachment on the more movable bone during muscle contraction.

Insertion

Type of contraction in which muscle length remains the same and movement does not occur

Isometric

Type of contraction in which muscle length changes

Isotonic

Main source of energy for muscle contraction

ATP

Principal neurotransmitter involved in muscle contraction

Acetylcholine

Prime mover or muscle causing the desired action

Agonist

Principle stating when a muscle fiber receives a stimulus to contract, it either will contract to its fullest ability or it will not contract at all.

All-or-none Law

Term used to describe the muscle that lengthens while prime movers and their synergists contract and shorten to produce the desired action.

Antagonist

Broad, flat tendon

Aponeurosis

Folded sections of the sarcolemma within neuromuscular junction.

Motor end plate

A single motor neuron and all muscle fibers it innervates

Motor unit

Term synonymous with muscle cells.

Muscle Fibers

Thick filaments located in the center of the sarcomere.

Myosin

Tendinous attachment on the less moveable bone during muscle contraction

Origin

Term to describe a muscle with fibers emerging diagonally from one or more central tendon

Pennate

Body positions maintained by muscle contraction; examples are standing and sitting

Posture

Process of motor unit activation based on need

Recruitment

Cell membrane surrounding muscle fibers

Sarcolemma

Basic unit of muscle contraction

Sarcomere

Most common level arrangement in the body-the load at one end, the pull in the middle, and the fulcrum at the opposite end.

Class 3

Muscle fiber property enabling it to receive and respond to stimulus.

Excitability

Cordlike structure anchoring muscle to bone.

Tendon

Structures made up of proteins called actin, tropomyosin, and troponin.

Thin filaments

Muscle fibers containing large amounts of myoglobin and mitochondria; also called red muscle.

Type 1