1. MUSCULAR SYSTEM Nearly half our weight comes from muscle tissue.
There are 650 different muscles in the human body.

2. THREE MAIN FUNCTIONS Responsible for all body movement.
Responsible for body form and shape (posture)
Responsible for body heat and maintaining body temperature.

3. MUSCLE TYPES
SKELETAL
TYPES OF MUSCLES
SMOOTH
CARDIAC

4. Skeletal Muscle Attached to bone VOLUNTARY
Contract quickly, fatigue easily, can’t maintain contraction for long period of time

5. Cardiac Muscle Found only in the heart Involuntary
Creates it’s own stimulus
Cells are fused – when one contracts, they all contract

6. Cardiac Muscle Review of Cardiac Muscle
What is the pacemaker of the heart called?
SA node
What are they vessels that provide O2 to the heart called?
Coronary arteries
When the heart is deprived of O2, what happens? MI

7. Cardiac Muscle
What is the chest pain felt when the heart is deprived of O2?
Angina
What do we call beats that are originated outside of the SA node?
Ectopic beats/arrhythmias
What is the deadliest arrhythmia?
Ventricular fibrillation

8. Smooth Muscle Visceral (organ) muscle
Found in walls of digestive system, uterus and blood vessels
INVOLUNTARY= Autonomic Nervous
System
Act slowly, do not tire easily, can remain contracted for long time

9. SPHINCTER
special circular muscles in openings between the esophagus, stomach and small intestines
What are they called????
Cardiac sphincter pyloric sphincter
Also found at anus, urethra and mouth.

10. CHARACTERISTICS OF MUSCLES
CONTRACTIBILITY – the ability of a muscle to reduce the distance between the parts of its contents or the space it surrounds.
Unique to muscle tissue
EXCITEABILITY (IRRITABILITY) – the ability to respond to certain stimuli by producing impulses.
Only muscle and nervous tissue have this ability

11. CHARACTERISTICS OF MUSCLES
EXTENSIBILITY – the ability to be stretched.
ELASTICITY – ability of muscle to return to its original length when relaxing.

12. Contraction of Muscle Tissue
Muscle contraction occurs as a result of 2 events:
1. “myoneural stimulation” stimulation of the muscle nerve
2. contraction of the muscle
MOTOR UNIT – a motor neuron plus all the muscle fibers it stimulates.