Biology (school) · Part 03
The human body
How organs and systems feed, move and control the body.
Last updated
- Organ systemA group of organs that work together to do a big job. Cells form tissues, tissues form organs and organs form systems.
- Digestive systemThe organs that break food into small molecules the blood can carry around the body.
- VilliTiny finger-like folds lining the small intestine. They give a huge surface area to absorb digested food.
- AlveoliTiny air sacs in the lungs where oxygen enters the blood and carbon dioxide leaves it.
- Double circulationBlood passes through the heart twice on each full trip: once to the lungs and once to the body.
- BloodA liquid tissue that carries oxygen, food, waste and heat. It has red cells, white cells, platelets and plasma.
- Coronary heart diseaseA disease where the heart's own blood vessels get clogged with fatty deposits, so the heart muscle gets too little oxygen.
- Reflex arcA fast, automatic response to a stimulus that does not need conscious thought.
- HormoneA chemical messenger made in a gland and carried by the blood to a target organ.
- HomeostasisKeeping conditions inside the body steady, such as temperature and blood sugar.
- Negative feedbackA control system where a change triggers a response that reverses the change and brings the body back to normal.