Muscular System Over View

Muscles, Organs, Tissues and Energy/Responses


There are three types of muscle tissue: Visceral (Smooth), Cardiac and Skeletal. The skeletal muscle is located in the limbs and voluntarily moves the skeleton. It is multi-nucleated, striated and has cylindrical fibres. It has span joints and attached muscles to skeletons. The smooth muscles are found in the walls of hollow internal organs. They move involuntary and have elongated, spindle shaped fibre with single nucleus. Cardiac muscles are found in the Heart and move involuntarily rhythmic contraction. They are branched, striated fibre with single nucleus and intercalated discs.


There are about 700 different muscles in the muscular system. There are three types of muscle; Skeletal, Cardiac and Smooth. Skeletal muscles are controlled by the Central Nervous System where are the Cardiac an Smooth Muscles are controlled by the Autonomic Nervous System. These muscles can move in about seven different ways; Flexion, Extension, Hyperextension, Abduction, Adduction, Circumdiction and Rotation. The skeletal muscles are moved voluntary (lifting a book), unlike the Smooth and Cardiac which are defined as making Involuntary movements (Heart Beating).


Two Responses:

Twitch; A single brief contraction, not a normal muscle function

Tetanus; one contraction immediately followed by another, Muscle never completely returns to a relaxed state, Effects are compounded

Energy: Stored in the muscle, in form of ATP. ATP comes from glucose being broke down during cellular Respiration. Happens in the Mitochondria.

Exercise and Muscles

ISOTONIC- Muscles shorten and movement occurs (most normal exercise)

ISOMETRIC- Tension in muscles increases, no movement occurs (Pushing one hand against the other)