A&P ch 10-11

Skeletal muscles

Voluntary muscle attached to bones for movement; fast contraction

Cardiac muscle

Involuntary muscle found in the heart

Smooth muscle

Involuntary muscle in organs; slow contraction

Muscle fiber

Single muscle cell

Myofibril

Structure inside muscle fibers that contains contractile proteins; tiny threads inside muscle fibers

Sacromere

Basic unit of muscle contraction; makes muscles shorten

Actin

Thin filament involved in muscle contraction

Myosin

Thick filament that pulls actin during contraction

Sliding filament theory

Explanation of how muscles contracted by filaments sliding past each other

Neuromuscular junction

Connection between a motor neuron and a muscle fiber

Acetylcholine (Ach)

Neurotransmitter that triggers muscle contraction

Prime mover

Main muscle responsible for a movement

Antagonist

Muscle that opposes the prime mover

Synergist

Muscle that assists the prime mover

Fixator

Muscle that stabilises a body part during movement

Flexion

Bending a joint

Extension

Straightening a joint

Biceps Brachii

Muscle that flexes the arm

Triceps Brachii

muscle that extends the arm

Deltoid

Shoulder muscle that lifts the arm

Rectus abdominis

Abdominal muscle that flexes the spine

Latissimus dorsi

Large back muscle that pulls arms downward

Gluteus maximus

Major hip extension muscle

Quadriceps

Group of muscles that extend the knee

Hamstrings

Group of muscles that flex the knee

Gastrocnemius

Calf muscle that points the foot downward

Causes of muscle fatigue

Low oxygen

Lactic acid buildup

Energy use

Pectoralis major

moves arm across body

obliques

twists body

trapezius

moves shoulders/neck