Overview of the Human Body

The human body is a complex network of cells, tissues, and organs that enable life. There are ten major organ systems responsible for various bodily functions.

Major Organ Systems

Skeletal System
- Framework of over 200 bones.
- Provides shape, holds the body together, and protects organs.
- Anchors the muscular system.
Muscular System
- Composed of three types of muscles:
  - Skeletal Muscle: Facilitates movement.
  - Smooth Muscle: Found in various organs.
  - Cardiac Muscle: Makes up the heart.
Cardiovascular System (Circulatory System)
- Consists of the heart, blood vessels, and blood.
- Delivers oxygen, hormones, nutrients, and white blood cells throughout the body.
Nervous System
- Communication network made up of nerve cells.
- Includes:
  - Brain: Hub of sensory and intellectual activity.
  - Spinal Cord: Transmits signals to and from the brain.
  - Cranial and Spinal Nerves: Connect the CNS to the rest of the body.

Regulatory Systems

These systems help maintain the body's environment:

Endocrine System
- Consists of glands that regulate bodily processes using hormones.
- Works closely with the nervous system to adjust hormone production based on body needs.
Lymphatic System (Immune System)
- Collection of lymph nodes and vessels.
- Regulates body defenses and transmits healing agents through the bloodstream.
Urinary System (Renal System)
- Includes kidneys, ureters, bladder, and urethra.
- Maintains electrolyte levels and filters waste from the blood, expelling it as urine.

Energy Systems

Respiratory System
- Group of passageways and organs for gas exchange.
- Extracts oxygen from air and expels carbon dioxide.
Digestive System
- Approximately 30 feet of organs converting food into fuel.
- Involves the mouth, esophagus, stomach, and intestines.
- Absorbs nutrients and expels solid waste.

Reproductive System

Responsible for creating life.
Primary organs differ between sexes:
- Women: Ovaries, fallopian tubes, uterus, vagina.
- Men: Testes, sperm channel.
Fertilization leads to organ formation and childbirth.

Conclusion