As part of a student project, Sheela surgically made a full cut in the hypothalamo - hypophyseal tract in pregnant rabbits and studied the physiological effects on different tissues/organs. Which of the following should be expected ?
(i) Formation of large volume of dilute urine
(ii) Increased blood sugar levels
(iii) increased heart rate
(iv) Difficulty in parturition

Options

A. (i) and (ii)
B. (ii) and (iii)
C. (iii) and (iv)
D. (i) and (iv)

Answer

To solve the question about the physiological effects observed in pregnant rabbits after a full cut in the hypothalamo-hypophyseal tract, we need to analyze the functions of the hormones that are affected by this surgical intervention.

### Step-by-Step Solution:

1. **Understanding the Hypothalamo-Hypophyseal Tract**:
- The hypothalamo-hypophyseal tract connects the hypothalamus to the posterior pituitary gland. This connection is crucial for the release of certain hormones into the bloodstream.

2. **Identifying the Hormones Affected**:
- The posterior pituitary primarily releases two hormones: Antidiuretic Hormone (ADH) and Oxytocin.
- ADH is responsible for regulating water balance in the body by concentrating urine.
- Oxytocin plays a significant role in childbirth by stimulating uterine contractions.

3. **Analyzing Each Option**:
- **(i) Formation of large volume of dilute urine**:
- Since ADH is not released due to the cut in the tract, the kidneys will not reabsorb water effectively, leading to the production of large volumes of dilute urine (polyuria). **This option is expected.**

- **(ii) Increased blood sugar levels**:
- Blood sugar levels are regulated by insulin and glucagon, which are secreted by the pancreas. The hypothalamo-hypophyseal tract does not directly influence these hormones, so blood sugar levels should remain unchanged. **This option is not expected.**

- **(iii) Increased heart rate**:
- The heart rate is influenced by adrenaline (epinephrine), which is secreted by the adrenal medulla. The secretion of adrenaline is regulated by the anterior pituitary through ACTH, which is not affected by the cut in the hypothalamo-hypophyseal tract. Therefore, heart rate should remain unchanged. **This option is not expected.**

- **(iv) Difficulty in parturition**:
- Oxytocin, which is crucial for uterine contractions during childbirth, will not be released due to the cut in the tract. This will lead to difficulties in parturition. **This option is expected.**

4. **Conclusion**:
- The expected physiological effects after the cut in the hypothalamo-hypophyseal tract in pregnant rabbits are:
- (i) Formation of large volume of dilute urine
- (iv) Difficulty in parturition

### Final Answer:
The expected physiological effects are (i) Formation of large volume of dilute urine and (iv) Difficulty in parturition.

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