The Heart – 5th Class

The heart is a muscle

Location

Just to the left of the middle of the chest.

Size

Size of your fist – approximately

Function

Pumps oxygenated blood around the body, and brings waste and deoxygenated blood back to the lungs.

How it Beats

Before each beat, your heart fills with blood. The muscle then contracts (tenses) to squirt the blood along.

Parts of the Beat

4 Chambers –

Two at top, right and left atrium (atria)
Two at bottom, right and left ventricles

Septum

Muscle that separates the two sides

Valves

Keep blood flowing in correct direction.

Veins and Arteries

Feed in and out of Heart

1. Deoxygenated blood comes in to heart through superior and
   inferior vena cava into the right ventricle.
2. Passes through tricuspid valve.
3. Into right atrium.
4. Passes pulmonary valve into the pulmonary artery.
5. Blood is sent to both lungs – it collects oxygen (o2) and gets rid of waste (co2).
6. Oxygenated blood comes back into heart through aorta.
7. Through mitral valve.
8. Into left ventricle and out through aorta around the body.

Arteries carry oxygen rich blood FROM the heart.
Veins carry deoxygenated blood TO the heart.

Click here for Edible Hearts and How Valves Work