LAB INVESTIGATIONExamination of a

Mammalian Heart

BLOOD PUMP 4 Chambers left/right upper/lower

VENA CAVA

AORTA

PULMONARY ARTERY

CORONARY VESSELS

VALVES

Flap-like structures that prevent backflow of blood

LA

LVRV

RA

DOB

OB

The Heart

Pulmonary Vein

AortaPulmonary Artery

Vena Cava

Left Atrium

Left VentricleRight Ventricle

Right Atrium

GUIDE QUESTIONS:1. You will also find tiny blood vessels along the surface of the heart. These are the

coronary arteries and veins. Why do you think these blood vessels are very important?

2. The purpose of the valves is to prevent the blood from flowing backward. Using a dissecting needle (or the tip of a forceps), puncture a valve and try to lift the heart. 2- What do you observe? Explain.

3. Observe carefully and compare the thickness of the ventricle walls to the atria walls. Which are thicker? Explain (relate this to the two structures’ behavior).

4. Notice that the left ventricle is thicker than the right ventricle. Can you give a reason why?

5. Why do you think the aorta is designed to be smooth and large?

PEER ASSESSMENT

Coronary vessels provide blood supply within the heart.

Valves are designed to be tough to resist high blood pressure within heart. Damage to valve leads to backflow.

Main ideas

Left ventricle is tougher since it requires more force (blood pressure) to pump blood out to different body cells; right ventricle pumps blood only to the lungs.

Atria collects blood while ventricles pump blood requiring a tougher and muscular wall to create more force .

Aorta is main pathway of oxygenated blood so it needs continuous and steady flow.

The Heart

Pulmonary Vein

AortaPulmonary Artery

Vena Cava

Left Atrium

Left VentricleRight Ventricle

Right Atrium

BLOOD FLOW

DOB from body vena cava RA valves RV pulmonary artery LUNGS pulmonary vein LA valves LV aorta OB to body

• Not a “idealized” drawing

•Labels parallel

•Narrow, clear pencil lines

• No color/ shading

• Arrows show blood flow within the heart