1.Human anatomyMedium
In which part of the nephron does most reabsorption of water and sodium take place?
- ALoop of Henle
- BProximal convoluted tubule
- CDistal convoluted tubule
- DCollecting duct
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:
- ARight-sided weakness and aphasia
- BIsolated loss of balance
- CLeft-sided weakness and aphasia
- DRight-sided weakness and left visual neglect
3.Human physiologyMedium
Why do myelinated axons conduct action potentials faster than unmyelinated ones?
- AThe impulse jumps between nodes of Ranvier
- BMyelin makes the axon thinner
- CMyelin contains more sodium channels
- DMyelin releases neurotransmitter along the axon
4.Human physiologyHard
A healthy person stands up quickly after lying down. Which reflex response prevents fainting?
- AThe chemoreceptor reflex raises breathing rate and arterial oxygen levels
- BADH release immediately doubles blood volume
- CThe Bainbridge reflex lowers heart rate
- DThe baroreceptor reflex raises heart rate and vasoconstriction
2Solutions
1.Human anatomy
Answer: B · Proximal convoluted tubule
Why this is the answer
The proximal convoluted tubule reabsorbs about two thirds of the filtered sodium and water, plus nearly all glucose and amino acids.
Answer
B · Proximal convoluted tubule
2.Human anatomy
Answer: A · 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
A · Right-sided weakness and aphasia
3.Human physiology
Answer: A · The impulse jumps between nodes of Ranvier
Why this is the answer
Myelin insulates the axon, so action potentials are only generated at the nodes of Ranvier. This saltatory conduction is much faster.
Answer
A · The impulse jumps between nodes of Ranvier
4.Human physiology
Answer: D · The baroreceptor reflex raises heart rate and vasoconstriction
Why this is the answer
Blood pools in the legs and pressure falls; baroreceptors fire less, which increases sympathetic and decreases vagal activity within seconds, raising heart rate and vascular tone.
Answer
D · The baroreceptor reflex raises heart rate and vasoconstriction
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