Page 8 - 02 Cells Biology Notes

#16 Tissues, Organs and organ Systems

Cells are organized to form tissue, organs, and organ
systems. In a healthy organism, all the systems work
together.

SPECIALIZED CELLS

• A specialized cell is designed to do a particular job.
• Nerve cells have long fibres to carry massages.
• Muscle cells can contract and relax.
• White blood cells attack bacteria.
• Platelets help clotting.

TISSUES

• Large numbers of specialized cells make up tissue.
• Muscles, blood and nerves are all tissues.
• Blood tissue contains red cells for carrying oxygen, white cells for
destroying harmful bacteria, and platelets to cause clotting in cuts

ORGANS

• Various tissues together make up an organ.
• Each organ has its own specific job.
• The heart, the stomach and the brain are all organs.
• The heart has to pump blood around the body. It is made up
of muscle tissue, blood vessels and nerves.
• Arteries and veins are usually thought of as organ as they consist of
several tissue layers.

ORGAN SYSTEMS

Various organs together make up an organ system. E.g. the circulatory
system carries blood to all parts of the body. It is made up of heart,
arteries, veins, capillaries and blood.