1.Human anatomyMedium
Which spinal nerve roots form the brachial plexus?
- AC1 to C4
- BT1 to T5
- CC3 to C7
- DC5 to T1
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?
- ALoss of all sensation and movement on the left only
- BLeft-sided weakness and loss of proprioception, right-sided loss of pain and temperature
- CLoss of pain and temperature on both sides only
- DRight-sided weakness and loss of proprioception, left-sided loss of pain and temperature
3.Human physiologyMedium
Which receptors respond mainly to a fall in arterial oxygen levels?
- AStretch receptors in the lungs
- BPeripheral chemoreceptors in the carotid and aortic bodies
- CBaroreceptors in the carotid sinus
- DCentral chemoreceptors in the medulla
4.Human physiologyHard
In Otto Loewi's classic experiment, fluid from a vagus-stimulated frog heart slowed a second heart. What did this show?
- AThe heart beats without any nerve supply
- BThe vagus nerve speeds up the heart
- CNerve impulses spread through the fluid directly as electricity
- DNerves pass signals to their targets by releasing a chemical
2Solutions
1.Human anatomy
Answer: D · C5 to T1
Why this is the answer
The brachial plexus is formed by the ventral rami of C5, C6, C7, C8 and T1. It gives rise to the main nerves of the arm.
Answer
D · C5 to T1
2.Human anatomy
Answer: B · 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
B · Left-sided weakness and loss of proprioception, right-sided loss of pain and temperature
3.Human physiology
Answer: B · Peripheral chemoreceptors in the carotid and aortic bodies
Why this is the answer
The carotid and aortic bodies detect low PaO₂ (and also high CO₂ and H⁺). The central chemoreceptors respond to CO₂ but not directly to oxygen.
Answer
B · Peripheral chemoreceptors in the carotid and aortic bodies
4.Human physiology
Answer: D · Nerves pass signals to their targets by releasing a chemical
Why this is the answer
The fluid carried "Vagusstoff", later identified as acetylcholine. This was the first clear evidence for chemical neurotransmission.
Answer
D · Nerves pass signals to their targets by releasing a chemical
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