The Muscular System

Study Notes

The muscular system is a complex system that allows for movement, maintains posture, and regulates body temperature.
It consists of approximately 640 muscles, which make up about 40% of the body's total weight.

Skeletal Muscles (Voluntary Muscles):
- Attached to bones and help move the body's skeleton
- Under conscious control
- Examples: biceps, quadriceps, hamstrings
Smooth Muscles (Involuntary Muscles):
- Found in the walls of hollow organs, such as the digestive tract, blood vessels, and airways
- Not under conscious control
- Examples: muscles in the digestive tract, blood vessels, and airways
Cardiac Muscles:
- Found in the heart
- Responsible for pumping blood throughout the body
- Not under conscious control

Movement: enables movement of the body's skeleton
Support: provides support for the body's posture and balance
Stability: helps maintain joint stability
Regulation of Body Temperature: helps regulate body temperature through muscle contraction and relaxation
Protection: protects internal organs by surrounding them with muscle tissue

Muscle Fiber: the basic unit of muscle tissue
Myofibril: a bundle of muscle fibers
Sarcomere: the functional unit of muscle contraction, consisting of actin and myosin filaments

Sliding Filament Theory: the mechanism of muscle contraction, where actin and myosin filaments slide past each other to shorten the muscle
Neuromuscular Junction: the site where a motor neuron terminates and releases neurotransmitters to stimulate muscle contraction

The muscular system is a complex system that allows for movement, maintains posture, and regulates body temperature.
It consists of approximately 640 muscles, making up about 40% of the body's total weight.

Skeletal Muscles: attached to bones, help move the body's skeleton, and are under conscious control.
Skeletal Muscles Examples: biceps, quadriceps, hamstrings.
Smooth Muscles: found in the walls of hollow organs, not under conscious control, and examples include muscles in the digestive tract, blood vessels, and airways.
Cardiac Muscles: found in the heart, responsible for pumping blood throughout the body, and not under conscious control.

Movement: enables movement of the body's skeleton.
Support: provides support for the body's posture and balance.
Stability: helps maintain joint stability.
Regulation of Body Temperature: helps regulate body temperature through muscle contraction and relaxation.
Protection: protects internal organs by surrounding them with muscle tissue.

Muscle Fiber: the basic unit of muscle tissue.
Myofibril: a bundle of muscle fibers.
Sarcomere: the functional unit of muscle contraction, consisting of actin and myosin filaments.

Sliding Filament Theory: the mechanism of muscle contraction, where actin and myosin filaments slide past each other to shorten the muscle.
Neuromuscular Junction: the site where a motor neuron terminates and releases neurotransmitters to stimulate muscle contraction.