Circulatory System Flashcards
All 17 cards in this deck
How is a red blood cell adapted to carry oxygen?
Biconcave disc shape (large surface area for absorbing oxygen), no nucleus (more room for haemoglobin) and packed with haemoglobin, which binds oxygen.
What is the function of a phagocyte?
It engulfs and digests pathogens.
What is the function of platelets?
They make the blood clot at a wound, sealing it to stop blood loss and keep pathogens out.
Why is the wall of an artery thicker and more muscular than the wall of a vein?
Because the blood pressure in an artery is higher — the thick, muscular wall prevents the artery bursting and maintains blood pressure.
Why do veins have valves?
To stop backflow of blood and keep it flowing in one direction towards the heart, because the blood pressure in veins is low.
What feature of a capillary wall allows substances to pass quickly between the blood and the cells?
Its wall is only one cell thick, giving a short diffusion distance.
Name the artery that transports oxygenated blood from the heart to the body.
The aorta.
It leaves the left ventricle.Which blood vessel carries deoxygenated blood from the heart to the lungs?
The pulmonary artery.
It leaves the right ventricle.What is the route of oxygenated blood through the heart?
Pulmonary vein → left atrium → left ventricle → aorta.
Why is the wall of the left ventricle thicker than the wall of the right ventricle?
The left ventricle pumps blood at high pressure around the whole body, while the right ventricle only pumps blood to the nearby lungs, so the left ventricle needs more muscle.
What is the function of the valves in the heart?
To prevent backflow, keeping blood flowing in one direction through the heart.
What is the equation for cardiac output?
cardiac output = stroke volume × heart rate
e.g. in per minute, with stroke volume in and heart rate in beats per minute.What is the function of a lymphocyte?
It produces antibodies that destroy pathogens.
Name four substances transported in blood plasma.
Carbon dioxide, urea, hormones and dissolved food molecules (e.g. glucose).
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.
What is stroke volume?
The volume of blood pumped out of one ventricle each time the heart beats (contracts), e.g. in cm³.
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.