Biology notes

Cell

Smallest unit of life.

Tissue

Group of cells with the same function.

Organ

Tissue working together to perform a function.

System

Group of organs working together to perform a particular function.

Circulatory System

Transports blood around the body, carrying oxygen, nutrients and waste.

Digestive System

Breaks down food for nutrients and removes waste from the body.

Excretory System

Removes waste from the body.

Musculoskeletal System

Gives the body structure and allows it to move.

Nervous System

Sends messages around the body so it can move and respond.

Reproductive System

For reproduction.

Respiratory System

Supplies the body with oxygen.

Heart

A muscular double-pump that moves blood throughout the body.

Blood Vessels

Tubes that allow the movement of blood throughout the body.

Blood

A liquid organ that carries oxygen, nutrients, and water to cells and removes carbon dioxide and waste from them.

Atria

The top two chambers of the heart, where blood enters.

Ventricles

The bottom two chambers of the heart, where blood is pumped out.

Valves

Structures in the heart that stop blood from flowing backwards.

Pulmonary Artery

Sends deoxygenated blood to the lungs.

Pulmonary Vein

Receives oxygenated blood from the lungs.

Aorta

Sends oxygenated blood to the body.

Superior and Inferior Vena Cava

Receives deoxygenated blood from the body.

Oxygenated Blood

Blood that is rich in oxygen, delivered to the body.

Deoxygenated Blood

Blood that is low in oxygen, returning to the heart.

Arteries

Blood vessels that carry blood away from the heart.

Veins

Blood vessels that carry blood back to the heart.

Capillaries

Smallest blood vessels that allow exchange of oxygen, nutrients, and wastes.

Red Blood Cells

Cells that carry oxygen around the body, containing hemoglobin.

White Blood Cells

Cells that help fight disease and infection.

Platelets

Cell fragments that help blood clot and prevent excessive bleeding.

Plasma

Clear liquid component of blood that carries water, nutrients, and waste.

Haemoglobin

Chemical in red blood cells that carries oxygen.

Factors affecting circulation

Includes exercise, which increases heart rate and blood flow.