Chapter 7 - The Muscular System Vocabulary

Anaerobic

(non- oxygen-requiring) process. Used during short intense activities

Complete tetanus

a sustained muscle contraction where the muscle cannot relax at all b/c stimuli come too quickly. Produces maximum tension.

Cross-bridges

Temporary connections between actin and myosin heads which pull the muscle fibers together.

Glycolysis

a process that breaks down glucose to make ATP without oxygen

Think (glyco = sugar, lysis = break)

Insertion

The moveable end of a muscle that attaches to a bone.

Moves toward the origin when the muscle contracts

Isometric contraction

Muscle contracts but does NOT change length

Isotonic contraction

muscle changes length and causes movement

concentric (muscle shortens)

eccentric (muscle lengthens)

Lactic acid

a byproduct of anaerobic respiration when oxygen is low. Causes burning and fatigue in muscles

(ex. sore legs after sprinting)

Motor unit

One motor neuron and all the muscle fibers it controls

smaller motor unit = more precise movement

Myofilaments

Protien filaments inside muscle fibers

Actin (thin)

myosin (thick)

They slid epast each other to cause contraction

Myoglobin

A protien that stores oxygen in muscle cells. Helps muscles work longer during activity

Neuromuscular junction

The synapse between a motor neuron and a muscle fiber.

Where never signals tell muscles to contract

Origin

The fixed end of a muscle attaches to a bone

Prime mover

The main muscle responsible for a specific movement (also called the agonist)

Sarcomere

The basic functional unit of a muscle fiber.

Area between two Z lines where contraction happens.

Sarcoplasmic reticulum

A specialized ER that stores and releases calcium

(calcium triggers muscle contraction)

Synergist

A muscle that assists the prime mover by helping stabilize or reduce unwanted movement

Tendon

String connective tissue that connects muscle to bone. Allows force from muscle to move bones

Transverse tubule (T - Tubule)

Tiny tunnels that carry electrical signals deep into the muscle fiber.

Helps contractions move quickly and easily