UPSC-CMS 2010 — Physiology

Q: In pregnancy, there is a physiological increase of the

cardiac output. ***cardiac output*** - **Cardiac output** increases significantly in pregnancy, by approximately 30-50%, to meet the increased metabolic demands of the growing fetus and maternal tissues. - This increase is primarily due to increases in both **heart rate** and **stroke volume**. *blood viscosity* - **Blood viscosity** actually decreases in pregnancy due to a greater increase in **plasma volume** compared to the increase in red blood cell mass, leading to hemodilution. - This reduction in viscosity can contribute to a lower peripheral vascular resistance. *peripheral resistance of the blood vessels* - **Peripheral resistance** typically decreases in pregnancy due to the vasodilatory effects of hormones like **progesterone** and the establishment of the low-resistance uteroplacental circulation. - This vasodilation helps accommodate the increased blood volume and cardiac output without a significant rise in blood pressure. *blood pressure in the third trimester* - **Blood pressure** usually decreases or remains stable in the first and second trimesters, with a slight rise towards pre-pregnancy levels in the third trimester. - A significant increase in blood pressure, especially in the third trimester, is *not* physiological and can indicate complications like **gestational hypertension** or **preeclampsia**. [Practice more Physiology PYQs on OnCourse]

Q: With reference to the role of fibre in diet, consider the following statements: 1. It inhibits faecal mutagen synthesis. 2. It reduces post-prandial glucose. 3. It decreases the transit time of food in the bowel. Which of the above represent(s) the role of fibre in our diet?

1, 2 and 3. ***1, 2 and 3*** - Dietary fiber aids in reducing the formation of **faecal mutagens** by diluting their concentration and promoting their excretion, thereby lowering the risk of colorectal cancer. - Fiber, especially **soluble fiber**, slows down the absorption of glucose from the digestive tract, which helps in reducing **post-prandial glucose** spikes and improving glycemic control. - It increases stool bulk and softness, which **decreases the transit time** of food through the bowel, preventing constipation and reducing exposure to potential toxins. *1 only* - This option is incomplete as it only includes the benefit of inhibiting faecal mutagen synthesis and ignores other established physiological roles of dietary fiber. - While fiber does inhibit faecal mutagen synthesis, it also has significant impacts on glucose metabolism and gut motility. *2 only* - This option is also incomplete, focusing solely on the reduction of post-prandial glucose. - It overlooks the crucial roles of fiber in gut health, such as inhibiting mutagen synthesis and regulating bowel transit time. *1 and 2 only* - This option recognizes the role of fiber in both **faecal mutagen synthesis** and **post-prandial glucose** control but fails to acknowledge its critical function in maintaining regular bowel movements. - Dietary fiber is well-known for its laxative effect and its ability to **decrease transit time**, which is a fundamental benefit for digestive health. [Practice more Physiology PYQs on OnCourse]

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In pregnancy, there is a physiological increase of the

With reference to the role of fibre in diet, consider the following statements: 1. It inhibits faecal mutagen synthesis. 2. It reduces post-prandial glucose. 3. It decreases the transit time of food in the bowel. Which of the above represent(s) the role of fibre in our diet?

UPSC-CMS 2010 - Physiology UPSC-CMS Practice Questions and MCQs

Question 1: In pregnancy, there is a physiological increase of the

A. cardiac output (Correct Answer)
B. blood viscosity
C. peripheral resistance of the blood vessels
D. blood pressure in the third trimester

Explanation: ***cardiac output*** - **Cardiac output** increases significantly in pregnancy, by approximately 30-50%, to meet the increased metabolic demands of the growing fetus and maternal tissues. - This increase is primarily due to increases in both **heart rate** and **stroke volume**. *blood viscosity* - **Blood viscosity** actually decreases in pregnancy due to a greater increase in **plasma volume** compared to the increase in red blood cell mass, leading to hemodilution. - This reduction in viscosity can contribute to a lower peripheral vascular resistance. *peripheral resistance of the blood vessels* - **Peripheral resistance** typically decreases in pregnancy due to the vasodilatory effects of hormones like **progesterone** and the establishment of the low-resistance uteroplacental circulation. - This vasodilation helps accommodate the increased blood volume and cardiac output without a significant rise in blood pressure. *blood pressure in the third trimester* - **Blood pressure** usually decreases or remains stable in the first and second trimesters, with a slight rise towards pre-pregnancy levels in the third trimester. - A significant increase in blood pressure, especially in the third trimester, is *not* physiological and can indicate complications like **gestational hypertension** or **preeclampsia**.

Question 2: With reference to the role of fibre in diet, consider the following statements: 1. It inhibits faecal mutagen synthesis. 2. It reduces post-prandial glucose. 3. It decreases the transit time of food in the bowel. Which of the above represent(s) the role of fibre in our diet?

A. 1 only
B. 2 only
C. 1 and 2 only
D. 1, 2 and 3 (Correct Answer)

Explanation: ***1, 2 and 3*** - Dietary fiber aids in reducing the formation of **faecal mutagens** by diluting their concentration and promoting their excretion, thereby lowering the risk of colorectal cancer. - Fiber, especially **soluble fiber**, slows down the absorption of glucose from the digestive tract, which helps in reducing **post-prandial glucose** spikes and improving glycemic control. - It increases stool bulk and softness, which **decreases the transit time** of food through the bowel, preventing constipation and reducing exposure to potential toxins. *1 only* - This option is incomplete as it only includes the benefit of inhibiting faecal mutagen synthesis and ignores other established physiological roles of dietary fiber. - While fiber does inhibit faecal mutagen synthesis, it also has significant impacts on glucose metabolism and gut motility. *2 only* - This option is also incomplete, focusing solely on the reduction of post-prandial glucose. - It overlooks the crucial roles of fiber in gut health, such as inhibiting mutagen synthesis and regulating bowel transit time. *1 and 2 only* - This option recognizes the role of fiber in both **faecal mutagen synthesis** and **post-prandial glucose** control but fails to acknowledge its critical function in maintaining regular bowel movements. - Dietary fiber is well-known for its laxative effect and its ability to **decrease transit time**, which is a fundamental benefit for digestive health.