1.Human anatomyMedium
Which cranial nerve controls most of the muscles of facial expression?
- ATrigeminal nerve (V)
- BOculomotor nerve (III)
- CHypoglossal nerve (XII)
- DFacial nerve (VII)
Anatomy and Physiology: cram pack
Formula sheets, the key method steps for every topic and 4 practice problems, with full solutions at the back.
1Practice problems
2.Human anatomyHard
A lesion of the left optic tract causes which visual field defect?
- ALeft homonymous hemianopia
- BBlindness in the left eye only
- CBitemporal hemianopia
- DRight homonymous hemianopia
3.Human physiologyMedium
What is the main effect of aldosterone on the kidney?
- ASodium reabsorption and potassium secretion in the distal nephron
- BGlucose reabsorption in the proximal tubule
- CWater reabsorption by inserting aquaporins only
- DIncreased filtration in the glomerulus
4.Human physiologyHard
Why is severe hyperkalaemia dangerous for the heart?
- AIt blocks the binding of calcium to troponin
- BIt depolarises cardiac cells, inactivating sodium channels and causing arrhythmias
- CIt hyperpolarises cardiac cells, so they can never fire
- DIt speeds up the SA node until tachycardia causes fainting
2Solutions
1.Human anatomy
Answer: D · Facial nerve (VII)
Why this is the answer
The facial nerve (cranial nerve VII) supplies the muscles of facial expression. Damage causes facial palsy, as in Bell's palsy.
Answer
D · Facial nerve (VII)
2.Human anatomy
Answer: D · Right homonymous hemianopia
Why this is the answer
The left optic tract carries fibres from the left half of each retina, which see the right visual field. Its lesion causes loss of the right half of the field in both eyes.
Answer
D · Right homonymous hemianopia
3.Human physiology
Answer: A · Sodium reabsorption and potassium secretion in the distal nephron
Why this is the answer
Aldosterone acts on the distal tubule and collecting duct to increase Na⁺ reabsorption and K⁺ secretion. Water follows the sodium, raising blood volume.
Answer
A · Sodium reabsorption and potassium secretion in the distal nephron
4.Human physiology
Answer: B · It depolarises cardiac cells, inactivating sodium channels and causing arrhythmias
Why this is the answer
High extracellular potassium makes the resting potential less negative. Many fast sodium channels then become inactivated, slowing conduction and risking fatal arrhythmias.
Answer
B · It depolarises cardiac cells, inactivating sodium channels and causing arrhythmias
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