Human physiology worksheet with answers

Which cells secrete antibodies?

1. AMacrophages
2. BNeutrophils
3. CHelper T cells
4. DPlasma cells

Which blood vessels have valves that prevent blood flowing backwards?

1. AVeins
2. BArteries
3. CArterioles
4. DCapillaries

Exchange of gases and nutrients between blood and tissues happens mainly across the walls of:

1. ACapillaries
2. BArterioles
3. CVeins
4. DArteries

What is the main stimulus for breathing in a healthy person?

1. AA rise in arterial CO₂
2. BA fall in arterial O₂
3. CA rise in blood glucose
4. DA fall in blood pH caused by lactate only

What does the QRS complex on an ECG represent?

1. AAtrial depolarisation
2. BAtrial repolarisation
3. CVentricular repolarisation
4. DVentricular depolarisation

During which phase of the cardiac cycle are all four heart valves closed while ventricular pressure rises?

1. ARapid ejection
2. BRapid filling
3. CIsovolumetric contraction
4. DAtrial systole

A healthy person stands up quickly after lying down. Which reflex response prevents fainting?

1. AThe chemoreceptor reflex raises breathing rate and arterial oxygen levels
2. BThe baroreceptor reflex raises heart rate and vasoconstriction
3. CADH release immediately doubles blood volume
4. DThe Bainbridge reflex lowers heart rate

In pernicious anaemia, autoimmune destruction of gastric parietal cells leads to anaemia because:

1. AGastrin is lost, so the bone marrow is no longer stimulated
2. BIntrinsic factor is lost, so vitamin B12 is not absorbed
3. CPepsin is lost, so haemoglobin cannot be made
4. DAcid is lost, so iron is never absorbed in any form