The Human Body
Vital Organ Systems
Humans have five vital organs that are essential for survival.
These are the brain, heart, kidneys, liver and lungs.
To survive and reproduce, the human body relies on major internal body organs to perform certain vital functions. When two or more organs along with their associated structures work together they become component parts of a body system.
Some of the easily recognisable internal organs and their associated functions are:
The brain is the control centre of the nervous system and is located within the skull. Its functions include muscle control and coordination, sensory reception and integration, speech production, memory storage, and the elaboration of thought and emotion. The human brain is the body's control centre, receiving and sending signals to other organs through the nervous system and through secreted hormones.
The lungs are two sponge-like, cone-shaped structures that fill most of the chest cavity. Their essential function is to provide oxygen from inhaled air to the bloodstream and to exhale carbon dioxide.
The liver lies on the right side of the abdominal cavity beneath the diaphragm. Its main function is to process the contents of the blood to ensure composition remains the same. This process involves breaking down fats, producing urea, filtering harmful substances and maintaining a proper level of glucose in the blood.
The bladder is a muscular organ located in the pelvic cavity. It stretches to store urine and contracts to release urine.
The kidneys are two bean-shaped organs located at the back of the abdominal cavity, one on each side of the spinal column. Their function is to maintain the body’s chemical balance by excreting waste products and excess fluid in the form of urine.
The heart is a hollow, muscular organ that pumps blood through the blood vessels by repeated, rhythmic contractions.
The stomach is a muscular, elastic, pear-shaped bag, lying crosswise in the abdominal cavity beneath the diaphragm. Its main purpose is digestion of food through production of gastric juices which break down, mix and churn the food into a thin liquid.
The intestines are located between the stomach and the anus and are divided into two major sections: the small intestine and the large intestine. The function of the small intestine is to absorb most ingested food. The large intestine is responsible for absorption of water and excretion of solid waste material.
Links to Organ Systems