Which number represents the medulla oblongata? (Figure 3)

Correct Answer: D

Rationale: The number 8 represents the medulla oblongata because it is the lower part of the brainstem that controls vital autonomic functions such as heart rate, breathing, and blood pressure. The medulla oblongata is essential for maintaining life and ensuring the proper functioning of the cardiovascular and respiratory systems.

Correct Answer: B

Rationale: Carry out an imagined act is the correct answer because apraxia is a motor disorder characterized by the inability to perform purposeful movements, despite having the physical ability and desire to do so. This condition results from damage to the parietal lobe or other areas involved in motor planning.

Correct Answer: D

Rationale: Cerebral cortex is the correct answer because the autonomic nervous system (ANS) primarily consists of the hypothalamus, brainstem, and peripheral nerves, which regulate involuntary bodily functions. The cerebral cortex, however, is involved in higher cognitive functions and voluntary motor control, and is not part of the ANS.

Correct Answer: B

Rationale: The conduction velocity is calculated as the distance traveled divided by the time taken. Here, the distance between the anode and cathode is 6 cm + 4.5 cm = 10.5 cm (0.105 m). The time taken is the latent period of 1.5 ms (0.0015 s). Thus, conduction velocity = 0.105 m / 0.0015 s = 70 m/s. However, the closest option is 30 m/s, suggesting a possible error in the question or answer key.

Correct Answer: B

Rationale: ADH is synthesized in the hypothalamus and released by the posterior pituitary via neurosecretion. Its secretion is increased by high plasma osmolarity or low blood volume. ADH increases water reabsorption in the distal convoluted tubule and collecting ducts by increasing their permeability to water.