1.Human anatomyMedium
The hepatic portal vein is formed by the union of which two veins?
- AHepatic vein and splenic vein
- BInferior vena cava and renal vein
- CSuperior mesenteric vein and left renal vein
- DSuperior mesenteric vein and splenic vein
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
Which muscle is the main flexor of the hip joint?
- AGluteus maximus
- BIliopsoas
- CBiceps femoris
- DAdductor magnus
3.Human physiologyMedium
According to Poiseuille's law, if the radius of an arteriole halves, its resistance to flow:
- AHalves
- BDoubles
- CIncreases 4-fold
- DIncreases about 16-fold
4.Human physiologyHard
A pulmonary embolus blocks blood flow to a well-ventilated region of lung. How does the ventilation–perfusion (V/Q) ratio of that region change?
- AIt stays normal because ventilation falls too
- BIt becomes zero, acting as a shunt
- CIt becomes very high, acting as dead space
- DIt becomes low, like in pneumonia
2Solutions
1.Human anatomy
Answer: D · Superior mesenteric vein and splenic vein
Why this is the answer
The portal vein forms behind the neck of the pancreas from the superior mesenteric and splenic veins. It carries nutrient-rich blood to the liver.
Answer
D · Superior mesenteric vein and splenic vein
2.Human anatomy
Answer: B · Iliopsoas
Why this is the answer
Iliopsoas (psoas major and iliacus) is the strongest hip flexor. Gluteus maximus extends the hip.
Answer
B · Iliopsoas
3.Human physiology
Answer: D · Increases about 16-fold
Why this is the answer
Resistance is proportional to 1/r⁴, so halving the radius raises resistance by 2⁴ = 16. This is why small changes in arteriole diameter control blood flow so strongly.
Answer
D · Increases about 16-fold
4.Human physiology
Answer: C · It becomes very high, acting as dead space
Why this is the answer
Ventilation without perfusion gives a very high V/Q ratio (dead space). A shunt, such as in pneumonia, is the opposite: perfusion without ventilation.
Answer
C · It becomes very high, acting as dead space
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