Problem 9 - Biology

Question

Arrange the following events into an appropriate sequence. 1\. blood glucose concentration increases 2 . alpha cells in islets stimulated 3. homeostasis 4. low blood glucose concentration 5\. glucagon secretion increases (a) 1,2,3,5,4 (b) 5,4,2,1,3 (c) 1,2,5,4,3 (d) 4,2,5,1,3 (e) 4,5,1,2,3

Step-by-Step Solution

Answer

The correct sequence is (d) 4,2,5,1,3.

Step 1: Identify the Initial Event

The sequence begins with low blood glucose concentration, as this is the condition that triggers a physiological response. Therefore, Event 4 (low blood glucose concentration) should be first.

Step 2: Determine the Immediate Response

Once blood glucose concentration is low, alpha cells in islets are stimulated, leading to Event 2.

Step 3: Understand the Consequent Action

The stimulation of alpha cells causes glucagon secretion to increase. Thus, Event 5 follows Event 2.

Step 4: Analyze the Effect of the Response

The increased glucagon secretion then causes the blood glucose concentration to rise, corresponding to Event 1.

Step 5: Return to Homeostasis

Finally, once the blood glucose concentration is normalized, the system returns to homeostasis, marked by Event 3.

Key Concepts

Glucagon

Glucagon is a vital hormone produced by the pancreas. It plays a key role in regulating blood glucose levels, especially when they drop too low. When your body detects that there is not enough sugar in your bloodstream, glucagon secretion is triggered from the alpha cells within the pancreas.

The job of glucagon is to prompt the liver to convert stored glycogen into glucose, which is then released into the bloodstream. This action helps increase the blood sugar level back to normal.

• Produced by the pancreas
• Regulates blood glucose levels
• Prompts liver to release glucose

Understanding glucagon's role is crucial in managing conditions like hypoglycemia, where blood glucose levels can drop dangerously low.

Alpha Cells

Alpha cells are specialized cells located in the pancreas, specifically in islets of Langerhans. These cells are responsible for producing and releasing glucagon.

When blood glucose levels dip, alpha cells become active. They detect this drop and start releasing glucagon into the bloodstream. This process is an essential part of the body's mechanism to ensure that blood sugar levels remain within a safe range.

• Located in the pancreas
• Activated by low blood sugar
• Release glucagon to increase glucose levels

Alpha cells work closely with beta cells, which produce insulin, to maintain a balance in blood glucose levels.

Homeostasis

Homeostasis refers to the body's ability to maintain a stable internal environment amidst external changes. In terms of blood sugar regulation, homeostasis is achieved when the blood glucose levels are balanced - neither too high nor too low.

The process begins with receptors detecting a change, like a drop in blood glucose. In response, alpha cells release glucagon to raise glucose levels, as explained earlier. Once the levels are balanced, the system restores homeostasis.

• Keeps internal environment stable
• Balances blood glucose levels
• Utilizes glucagon and insulin for regulation

Maintaining homeostasis is crucial for overall health, as consistent imbalances can lead to conditions like diabetes.