Human physiology worksheet with answers

Which ion triggers contraction by binding to troponin in skeletal muscle?

1. AChloride
2. BPotassium
3. CCalcium
4. DSodium

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

1. AArterioles
2. BVeins
3. CArteries
4. DCapillaries

Which hormone raises blood calcium levels?

1. ACalcitonin
2. BParathyroid hormone
3. CInsulin
4. DThyroxine

What is the main function of pulmonary surfactant?

1. ATo trap dust in the bronchi
2. BTo reduce surface tension in the alveoli
3. CTo carry oxygen across the alveolar wall
4. DTo kill bacteria in the airways

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

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

Why do myelinated axons conduct action potentials faster than unmyelinated ones?

1. AMyelin contains more sodium channels
2. BMyelin releases neurotransmitter along the axon
3. CMyelin makes the axon thinner
4. DThe impulse jumps between nodes of Ranvier

Why is severe hyperkalaemia dangerous for the heart?

1. AIt speeds up the SA node until tachycardia causes fainting
2. BIt blocks the binding of calcium to troponin
3. CIt depolarises cardiac cells, inactivating sodium channels and causing arrhythmias
4. DIt hyperpolarises cardiac cells, so they can never fire

Why does left ventricular failure cause pulmonary oedema?

1. APlasma oncotic pressure in the lungs rises sharply
2. BRaised left atrial pressure increases pulmonary capillary hydrostatic pressure
3. CThe right ventricle pumps less blood into the lungs
4. DThe bronchial arteries become blocked