Following are events taking place for blood glucose regulation -
(i) increase in blood glucose
(ii) increase in circulating from glucagon
(iii) release of glucose from glycogen
(iv) decrease in blood glucose level
Select the option depicting the correct sequence of these events.

Options

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

Answer

To determine the correct sequence of events for blood glucose regulation, we need to analyze the roles of glucagon and insulin in response to blood glucose levels. Here’s the step-by-step solution:

### Step-by-Step Solution:

1. **Decrease in Blood Glucose Level**:
- When blood glucose levels drop, the body needs to restore them to normal levels. This is the initial trigger for the subsequent events.

2. **Increase in Circulating Glucagon**:
- In response to low blood glucose levels, the pancreas releases glucagon from the alpha cells. Glucagon is a hormone that signals the liver to release stored glucose.

3. **Release of Glucose from Glycogen**:
- Glucagon acts on the liver to convert glycogen (the stored form of glucose) back into glucose. This process is known as glycogenolysis.

4. **Increase in Blood Glucose Level**:
- As glucose is released into the bloodstream, the blood glucose levels begin to rise back to normal.

### Correct Sequence:
The correct sequence of events is:
1. Decrease in blood glucose level (iv)
2. Increase in circulating glucagon (ii)
3. Release of glucose from glycogen (iii)
4. Increase in blood glucose level (i)

Thus, the correct order is: **iv → ii → iii → i**.