THE MUSCULAR SYSTEM Muscle types Sliding Filament Theory Types of contraction Anatomy diagram

Introduction Our bodies have over 600 muscles, which make up half of our body weight Muscles are used to eat, talk, walk etc Muscles burn lots of calories when they are being used and when resting Muscles burn even more calories when they are “in shape”

MAJOR MUSCLE TYPES SMOOTH MUSCLE: Involuntary and contract automatically CNS adjusts contraction as required They do not tire easily and can stay contracted for long periods of time Ex. Esophagus, stomach, blood vessels

MAJOR MUSCLE TYPES CARDIAC MUSCLE Specialized muscle tissue that comprises the heart Involuntary Striated

MAJOR MUSCLE TYPES SKELETAL MUSCLES: Connect to bones by tendons Voluntary – you control them Most prevalent in human body –> 30-40% of human weight Striated (striped appearance) The engines that pull on bones – causing joints to move

MUSCLES IN ACTION… Muscles work through a process called contraction. Muscle Contraction – result of filaments deep within the muscle sliding over each other This process occurs simultaneously over entire muscle fibre – resulting in contraction

SLIDING FILAMENT THEORY Sequence for contraction: 1.Electrical impulse comes from brain (voluntary) or spinal cord (involuntary) 2.Signal travels along never to muscle site (neuromuscular junction) and attempts to jump the gap.

SLIDING FILAMENT THEORY 3.Chemical reaction takes place deep within the muscle fibre 4.The reaction causes the filaments to “slide” over one another. Thin filament (actin) slide past the thick filament (myosin) 5.Muscle fibre contracts.

Types of Muscle Contraction CONCENTRIC – muscle shortens while working ECCENTRIC – muscle lengthens while working ISOMETRIC – no change in length. Force = resistance.

Skeletal Musculature Origin of a muscle is located at the proximal end (toward the center of the body) Insertion of a muscle is located at the distal end (away from the center of the body) The muscle most directly involved in bringing about a movement is call the agonist A muscle that can slow down or stop the movement is called the antagonist

Agonist v Antagonist

ANATOMY DIAGRAM Complete the chart and diagram

Insertion and Origin Complete the chart along with the website www.