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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.
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
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
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 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
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.