The Circulatory System

An organ that pumps blood around the body in a double circulatory system.

The right atrium.

The right ventricle.

The left ventricle.

It has to pump blood around the whole body, so it needs more force.

Oxygenated blood from the left ventricle to the body.

Deoxygenated blood from the right ventricle to the lungs.

Oxygenated blood from the lungs to the left atrium.

They supply the heart muscle with oxygenated blood.

Blood goes through the heart twice on each complete trip round the body.

It loses pressure in the lung capillaries, so the heart gives it a new push to the body.

In a group of cells in the right atrium.

It sends electrical pulses to the heart to correct an irregular heartbeat.

Multiply the count by 4 to get beats per minute.

No. They are not required.

Name the vessel marked X and say what it carries.

The aorta. It carries oxygenated blood from the left ventricle to the body.

Name the chamber marked X and say where it pumps blood.

The right ventricle. It pumps deoxygenated blood to the lungs along the pulmonary artery.

Label every part of the heart.

Right atrium, right ventricle, left atrium, left ventricle, vena cava, aorta, pulmonary artery, pulmonary vein and coronary artery.

A vessel that carries blood away from the heart.

A vessel that carries blood back to the heart.

A tiny vessel with a wall one cell thick, where exchange happens.

The blood is at high pressure, so the walls must be strong and able to stretch and recoil.

Muscle and elastic fibres.

To stop the low-pressure blood flowing backwards.

It gives less resistance to the flow of low-pressure blood.

It gives a short diffusion path for exchanging substances.

They give a large surface area for exchange with the cells.

No. The pulmonary artery carries deoxygenated blood to the lungs.

No. The pulmonary vein carries oxygenated blood from the lungs.

Rate = volume of blood ÷ time.

600 ÷ 2 = 300 cm³ per minute.

An artery.

It gives more time for substances to diffuse.

Name the vessel marked X and say how its structure suits its job.

A valve in a vein. It closes to stop blood flowing backwards, because the blood is at low pressure.

Label the three blood vessels and their features.

Artery: thick muscular wall, elastic fibres, narrow lumen. Vein: thin wall, wide lumen, valve. Capillary: wall one cell thick.

The trachea.

Two bronchi, one for each lung.

Alveoli.

Tiny air sacs where gas exchange takes place.

A network of capillaries.

Oxygen.

Carbon dioxide.

By diffusion, down their concentration gradients.

To give a very large surface area for gas exchange.

To give a short diffusion path.

It carries oxygen away and brings carbon dioxide, so the concentration gradients stay steep.

It ventilates the alveoli, which keeps the concentration gradients steep.

Their walls break down, so the surface area for gas exchange is reduced.

Volume per breath × number of breaths per minute.

No. It has less oxygen and more carbon dioxide.

Name the part marked X and say what happens there.

The alveoli. Oxygen diffuses into the blood and carbon dioxide diffuses out here.

Label the airways and the structures of the lungs.

Trachea, bronchus, bronchioles, lung, alveoli and capillary network.

Plasma, red blood cells, white blood cells and platelets.

The pale yellow liquid part of the blood that carries dissolved substances.

Carbon dioxide, soluble food molecules such as glucose, and urea (also hormones and heat).

They carry oxygen from the lungs to the body cells.

The red pigment in red blood cells that binds to oxygen.

The shape gives a large surface area for oxygen to diffuse in and out quickly.

There is more room for haemoglobin, so they can carry more oxygen.

They help to defend the body against pathogens.

Yes.

Small fragments of cells that help the blood to clot.

They cause the blood to clot, forming a scab that stops bleeding and keeps microorganisms out.

The white blood cell is larger and has a stained nucleus. The red blood cell has no nucleus.

The plasma.

Infection from the donor blood, a mismatched blood group or an allergic reaction.

The plasma.

Name the blood component marked X and say what it does.

A platelet. It is a small fragment of a cell that helps the blood to clot at a wound.

Label every component of the blood.

Plasma, red blood cell (biconcave, no nucleus), white blood cell (has a nucleus) and platelets.

A disease in which layers of fatty material build up inside the coronary arteries and narrow them.

It is not caused by a pathogen, so it cannot be passed from one person to another.

Less blood reaches the heart muscle, so it gets too little oxygen.

A wire mesh tube put in a narrowed artery to hold it open.

A drug that lowers blood cholesterol, which slows down the build-up of fatty deposits.

It keeps the artery open straight away, so blood flows freely again.

It needs surgery, and the artery can narrow again.

They must be taken for a long time and can have side effects.

It may not open fully, or it may leak.

A biological valve or a mechanical valve.

It lasts a long time.

The patient needs drugs to stop the blood clotting.

In heart failure, to replace the diseased heart with a donor heart (or heart and lungs).

There are not enough donors, and the patient must take drugs for life to prevent rejection.

To keep a patient alive while they wait for a transplant, or to let the heart rest while it recovers.

Name the structure marked X in this treated artery and say what it does.

A stent. It is a mesh tube that holds the narrowed artery open so that blood can flow to the heart muscle.

Label the three arteries and the features that matter.

Healthy artery with a wide lumen. Artery wall with fatty deposit and narrow lumen. Artery with a stent holding the lumen open. Blood flow is restored.