Unit 1 Muscles

• production of movement
• production of heat
• maintenance of posture

such as the large muscle action required in walking, as well as less obvious motion such as that involved in changing the size of blood vessels or the pupil of the eye

the result of the mechanical contraction. This heat is necessary in the maintenance of the body temperature

ability to hold the boy in stationary positions. This is possible because skeletal muscles are always ina state of partial contraction, called tonus (muscle tone)

state of partial contraction, muscle tone

• cardiac muscle
• visceral muscle
• skeletal muscle

formed exclusively in the heart. This tissue is characterized by its involuntary action and striated appearance when seen under a microscope

associated with internal structures such as blood vessels and the digestive tube. It is also involuntary but it does not have striated appearance

muscle type that attaches to the bones of the skeleton. It is usually voluntary and is striated

• contractility
• irritability - will respond to a stimulus
• extensibility - can stretch
• elastic - comes back to resting length

• muscle belly
• origin
• insertion

• prime mover (agonist)
• antagonist
• synergist
• fixator

• agonist
• major agent that initiates and maintains a particular action

opposes the movement of the prime mover or initiates and maintains the converse of the prime movement

• flexion
• extension
• abduction
• adduction
• rotation
• circumduction