1.Human anatomyMedium
Which cranial nerve controls most of the muscles of facial expression?
- AOculomotor nerve (III)
- BFacial nerve (VII)
- CHypoglossal nerve (XII)
- DTrigeminal nerve (V)
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 stab wound cuts the left half of the spinal cord at T10. Which pattern of loss is expected below the lesion?
- ALeft-sided weakness and loss of proprioception, right-sided loss of pain and temperature
- BLoss of pain and temperature on both sides only
- CLoss of all sensation and movement on the left only
- DRight-sided weakness and loss of proprioception, left-sided loss of pain and temperature
3.Human physiologyMedium
What is the main function of pulmonary surfactant?
- ATo reduce surface tension in the alveoli
- BTo kill bacteria in the airways
- CTo carry oxygen across the alveolar wall
- DTo trap dust in the bronchi
4.Human physiologyHard
Why is severe hyperkalaemia dangerous for the heart?
- AIt blocks the binding of calcium to troponin
- BIt speeds up the SA node until tachycardia causes fainting
- CIt depolarises cardiac cells, inactivating sodium channels and causing arrhythmias
- DIt hyperpolarises cardiac cells, so they can never fire
2Solutions
1.Human anatomy
Answer: B · 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
B · Facial nerve (VII)
2.Human anatomy
Answer: A · Left-sided weakness and loss of proprioception, right-sided loss of pain and temperature
Why this is the answer
In Brown-Séquard syndrome the corticospinal tract and dorsal columns are lost on the same side, while the spinothalamic tract, which crosses near entry, causes contralateral pain and temperature loss.
Answer
A · Left-sided weakness and loss of proprioception, right-sided loss of pain and temperature
3.Human physiology
Answer: A · To reduce surface tension in the alveoli
Why this is the answer
Surfactant, made by type II alveolar cells, lowers surface tension so alveoli do not collapse and the lungs are easier to inflate.
Answer
A · To reduce surface tension in the alveoli
4.Human physiology
Answer: C · 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
C · It depolarises cardiac cells, inactivating sodium channels and causing arrhythmias
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