Muscular System

“The power system”

This is what happens without muscles

Nearly half our weight comes from muscle tissue.There are 650 different muscles in the human body.Muscles give us form and shape.Muscles produce most of our body heat.

#One Main Muscle Function

Responsible for all body movement.

#Two Main Muscle Functions

Responsible for body form and shape (Posture)

Responsible for body heat and maintaining body temperature.

#Three Main Muscle Functions

Test Your Gray Matter….

Muscles are responsible for producing most of our : White blood cells, Hormones, Protein synthesis, or Body Heat.

Types of Muscles

Skeletal Muscle

Smooth Muscle

Cardiac Muscle

Attached to bone

Visceral muscle

Found only in the heart

Voluntary Involuntary Involuntary

Skeletal Muscles Attached to bone Striated (striped)

appearance Voluntary Sarcolemma = cell

membrane Contract quickly,

fatigue easily, can’t maintain contraction for a long period of time

Test your skeletal muscles… Open and close

your dominant hand until the teacher tells you to stop.

            

Smooth Muscle Visceral (organ) muscle Found in the walls of

digestive system, uterus, and blood vessels

Cells small and spindle shaped

Involuntary Controlled by the autonomic nervous system

Act slowly, do not tire easily, can remain contracted for a long time.

Cardiac Muscle Found only in the

heart Striated and

branched Involuntary Cells are fused

when one contracts, they all contract

Test your gray matter..

Which of the following muscles are considered “voluntary”

Which kind of muscle forms the walls of the heart?

Striated,cardiac, skeletal,visceral

Cardiac, Skeletal, Smooth, Visceral

Sphincter

Special circular muscles in openings of esophagus and stomach, and small intestine, anus, urethra and mouth

Skill

Working with skeletal muscles

Hand out worksheets for group activity.

Characteristics of Muscles

Contractibility

Excitability

Extensibility

Elasticity

The ability of a muscle to reduce the distance between the parts of its content or the space it surrounds.

The ability to respond to certain stimuli by producing impulses.

The ability to be stretched.

Ability of muscle to return to its original length when relaxing.

Muscle Movement

How do we move?

Muscle Movement Muscle move bones by pulling on them.

As a muscle contracts, it pulls the Insertion one closer to the Origin bone. Movement occurs at the joint between the origin and the insertion.

Rule: A muscle’s insertion bone moves toward its origin bone.

Groups of muscles usually contract to produce a single movement

A. Prime mover muscle whose

contraction is mainly responsible for producing a given movement

B. Antagonist

muscle whose actions oppose the action of prime mover in any given movement.

C. Synergist

helps steady a movement and stabilize joint activity.

When the antagonist muscles contract, they produce a movement opposite to that of the prime movers.

Motor Unit – a motor neuron plus all the muscle fibers it stimulates.

Neuromuscular Junction – the junction between the motor neuron’s fiber which transmits the impulse – and the muscle cell membrane.

Acetylcholine

Fatigue

Oxygen Debt

Muscle chemical neurotransmitter, diffuses across the synaptic cleft (carries impulse across synaptic cleft)

caused by the accumulation of lactic acid in the muscles

after exercise, the amount of oxygen needed by the muscle to change lactic acid back to glucose.

MUSCLE TONE - When muscles are slightly contracted and ready to pull.

DIAPHRAGM – Dome-shaped muscle that separates the abdominal and thoracic cavities, aids in breathing