Key Biological Systems and Health Concepts Explained

Understanding Key Biological Systems and Health Concepts

Intestines

The intestines are a long, continuous tube running from the stomach to the anus. Most absorption of nutrients and water happens in the intestines. The intestines include the small intestine, large intestine, and rectum.

Excretory System

The excretory system is a passive biological system that removes excess, unnecessary materials from the body fluids of an organism.

Liver

The liver's main job is to filter the blood coming from the digestive tract before passing it to the rest of the body. The liver also detoxifies chemicals and metabolizes drugs.

Double Circulation

Double circulation describes the process where blood is first pumped into the lungs, where it becomes oxygenated, and is then pumped back into the heart, before it is finally pumped into the rest of the body.

Second Line of Defense

This line of defense involves non-specific immune responses:

• White blood cells: Surround pathogens, kill them, and release chemicals to help other white blood cells.
• Inflammation: Moves white blood cells to the affected area to stop infection from spreading.

Third Line of Defense

This line of defense involves specific immune responses:

• Specialized white blood cells: Target specific pathogens. If the same pathogen enters the body again, these cells act quickly, preventing us from getting sick from the same pathogen.

Disease Outbreak

An outbreak is the occurrence of disease in a limited geographic area.

Epidemic

An epidemic is the occurrence of disease cases that are above the normal amount expected for a population in a defined area.

Social Impact of Disease

Diseases can have significant social consequences. For example, HIV has killed more than 25 million people since 1984, profoundly affecting communities and societies worldwide.

Economic Impact of Disease

Diseases can also have severe economic impacts. For instance, livestock animals can pass on diseases to people. In 2015, bird flu forced farmers to kill 50 million chickens, resulting in millions of dollars in losses.

Nature-Sourced Medicine

Nature-sourced medicine involves using chemicals or resources derived from nature to treat illnesses and conditions.

Antibiotics

Antibiotics are substances that kill or inhibit the growth of bacteria. They are crucial in treating bacterial infections, though some bacteria can develop resistance to them.

Vaccines

A vaccine is a substance given to people to protect against certain diseases by stimulating the body's immune system to produce antibodies.

Right Atrium

The right atrium brings deoxygenated blood from the body to the heart.

Left Atrium

The left atrium brings oxygenated blood from the lungs into the heart.

Right Ventricle

The right ventricle pumps deoxygenated blood from the heart to the lungs.

Left Ventricle

The left ventricle pumps oxygenated blood from the heart to the rest of the body.

Herd Immunity

Herd immunity is the resistance to the spread of a contagious disease if a high number of people in a population are vaccinated or have developed immunity.