Circulatory System Flashcards

All 17 cards in this deck

Give three ways a red blood cell is adapted to carrying oxygen.

Biconcave shape for a large surface area; no nucleus so there is more room inside; packed with haemoglobin, which binds oxygen.

What is the function of a phagocyte?

Engulfs and digests pathogens. Its flexible membrane lets it surround the pathogen.

Which component of the blood makes the blood clot at a wound?

Platelets. They are cell fragments that clump together to form a clot, sealing the wound.

Why do arteries have thick walls containing muscle and elastic fibres?

Blood in them is at high pressure — the thick wall withstands it and the elastic fibres stretch and recoil to keep blood flowing.

Give two features of a vein that help blood return to the heart, and say what each does.

Valves, which prevent the backflow of blood (keep it flowing one way); a large lumen, to maximise blood flow.

True or false? All arteries carry oxygenated blood.

False. The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.

What is the advantage of a double circulatory system?

Blood returns to the heart after the lungs and is pumped again, so it reaches the body at high pressure and flows faster, delivering oxygen and glucose more quickly.

Why is the wall of the left ventricle thicker than the wall of the right ventricle?

The left ventricle pumps blood all the way round the body at high pressure; the right ventricle only pumps blood to the lungs.

What is the function of the valves in the heart?

They prevent the backflow of blood, keeping it flowing in one direction.

What is the equation for cardiac output?

cardiac output (cm³ per minute) = stroke volume (cm³) × heart rate (beats per minute)
Stroke volume is the volume of blood pumped out of the left ventricle per beat.

True or false? Capillary walls are one cell thick.

True. This gives a short diffusion distance so substances pass quickly between the blood and the cells.

Give two reasons why cardiac output needs to increase during exercise.

To deliver more oxygen and more glucose to the muscles (also to remove more carbon dioxide), so more aerobic respiration releases more energy.

What is the function of a lymphocyte?

Produces antibodies against pathogens.

What does blood plasma transport?

Blood cells and platelets, plus dissolved substances such as carbon dioxide, glucose, urea and hormones (and heat).

Which type of blood vessel carries blood away from the heart, and which carries blood back to it?

Arteries carry blood away from the heart; veins carry blood back to the heart.

Which blood vessel brings deoxygenated blood from the body back to the heart, and which chamber does it enter?

The vena cava. It empties into the right atrium.

Which blood vessel carries oxygenated blood from the heart to the rest of the body, and which chamber pumps blood into it?

The aorta. Blood is pumped into it by the left ventricle.