Circulatory System Flashcards

All 14 cards in this deck

How is a red blood cell (erythrocyte) adapted to transport oxygen?

Biconcave shape gives a large surface area for absorbing oxygen; no nucleus leaves more room for haemoglobin, which binds oxygen.

What are the roles of phagocytes and lymphocytes?

Phagocytes engulf and digest pathogens (flexible cytoplasm and a lobed nucleus let them change shape); lymphocytes produce antibodies.

What does blood plasma transport?

Blood cells and platelets, carbon dioxide, digested food (e.g. glucose, amino acids), urea, hormones and heat.

True or false? White blood cells start the clotting process when the skin is cut.

False. Platelets start the clotting process, forming a clot that seals the wound and keeps pathogens out.

How do the wall, lumen and valves of an artery, a vein and a capillary compare?

Artery: thick muscular and elastic wall, narrow lumen, no valves. Vein: thin wall, wide lumen, valves to stop backflow. Capillary: wall one cell thick, very narrow lumen, no valves.

What are the steps in the path of blood through the heart?
e.g. starting at the vena cava

1. Vena cava → right atrium → through the valve into the right ventricle
2. Right ventricle → pulmonary artery → lungs
3. Pulmonary vein → left atrium → left ventricle → aorta → body

What is meant by a double circulatory system?

Blood passes through the heart twice in one complete circuit: one circuit carries blood to the lungs, the other to the rest of the body.

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

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

What are the steps to calculate heart rate from cardiac output and stroke volume?
e.g. cardiac output $4.9$ litres per minute, stroke volume $70$ ml

1. Rearrange: heart rate = cardiac output ÷ stroke volume
2. Make units match: $4.9$ litres = $4900$ ml
3. $4900 \div 70 = 70$ beats per minute

What are the steps to calculate the percentage change in blood flow to an organ?
e.g. flow to the muscles rises from $1000$ to $4000$ cm³ per minute

1. Change $= 4000 - 1000 = 3000$
2. Divide by the value at rest: $3000 \div 1000 = 3$
3. Multiply by 100: a $300\%$ increase

True or false? All arteries carry oxygenated blood.

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

Why does cardiac output increase during exercise?

Heart rate and stroke volume increase, so more oxygenated blood is delivered to the muscles for respiration.

True or false? During exercise the blood flow through the digestive system decreases while the blood flow through the muscles increases.

True. Blood is redirected to the muscles to supply oxygen and glucose for respiration and to remove carbon dioxide.

Which property of an artery is being tested when a ring of artery tissue is stretched with masses and then allowed to return to its original length?

Its elasticity — elastic fibres in the thick wall let the artery stretch and recoil as blood surges through at high pressure.