1.Human anatomyMedium
Which structure produces most of the cerebrospinal fluid?
- APineal gland
- BArachnoid granulations
- CChoroid plexus
- DPia mater
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 stroke affecting the left middle cerebral artery in a right-handed person most likely causes:
- AIsolated loss of balance
- BRight-sided weakness and left visual neglect
- CRight-sided weakness and aphasia
- DLeft-sided weakness and aphasia
3.Human physiologyMedium
The hormone secretin is released when acid enters the duodenum. What is its main effect?
- ABicarbonate secretion from the pancreas
- BInsulin release from the endocrine pancreas
- CAcid secretion from the stomach
- DContraction of the gallbladder
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 hyperpolarises cardiac cells, so they can never fire
- DIt depolarises cardiac cells, inactivating sodium channels and causing arrhythmias
2Solutions
1.Human anatomy
Answer: C · Choroid plexus
Why this is the answer
The choroid plexus in the ventricles secretes most CSF. CSF is reabsorbed into venous blood through the arachnoid granulations.
Answer
C · Choroid plexus
2.Human anatomy
Answer: C · Right-sided weakness and aphasia
Why this is the answer
The left MCA supplies the left motor cortex (face and arm of the right side) and Broca's and Wernicke's areas, so right hemiparesis with aphasia is typical.
Answer
C · Right-sided weakness and aphasia
3.Human physiology
Answer: A · Bicarbonate secretion from the pancreas
Why this is the answer
Secretin stimulates pancreatic duct cells to secrete bicarbonate-rich fluid, which neutralises acidic chyme so intestinal enzymes can work.
Answer
A · Bicarbonate secretion from the pancreas
4.Human physiology
Answer: D · 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
D · It depolarises cardiac cells, inactivating sodium channels and causing arrhythmias
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