Question

Explain how insulin and glucagon maintain blood glucose homeostasis. What are the two types of diabetes mellitus, and what are the major symptoms? (pages \(341-44\) )

Short answer

Insulin and glucagon are hormones produced by the pancreas that help maintain blood glucose homeostasis. Insulin lowers blood sugar levels by promoting glucose uptake into cells and stimulating the storage of glucose as glycogen. Glucagon raises blood sugar levels by promoting the breakdown of glycogen into glucose. There are two types of diabetes mellitus: Type 1, where the immune system destroys insulin-producing beta cells, and Type 2, where the body resists the effects of insulin or doesn't produce enough. Major symptoms include frequent urination, excessive thirst, unintended weight loss, fatigue, blurry vision, and slow-healing sores.

Step-by-step solution

1. Introduction to Insulin and Glucagon

Insulin and glucagon are two hormones produced by the pancreas. Insulin is produced by the beta cells, while glucagon is produced by the alpha cells. These hormones play crucial roles in maintaining the proper blood glucose (sugar) concentration.

2. Maintaining Blood Glucose Homeostasis

The main function of insulin and glucagon is to keep the blood sugar level within an appropriate range, known as glucose homeostasis. Insulin and glucagon work together to achieve this. - Insulin helps lower blood sugar levels when they are too high, which usually occurs after a meal. It does this by promoting the uptake of glucose into the cells and stimulating the liver and muscles to store glucose as glycogen. - Glucagon increases blood sugar levels when they are too low, such as when the body needs more glucose for energy during fasting or intensive physical activity. It promotes the breakdown of glycogen stored in the liver and muscles into glucose, thus raising blood glucose levels. Through this continuous interaction, insulin and glucagon maintain a stable blood glucose level.

3. Diabetes Mellitus: Types and Symptoms

Diabetes mellitus is a chronic disease characterized by high blood sugar levels due to insufficient insulin production or resistance to its action. There are mainly two types of diabetes: 1. Type 1 Diabetes Mellitus: This type occurs when the body's immune system destroys the beta cells responsible for producing insulin. As a result, those affected have little or no insulin production. Type 1 diabetes is typically diagnosed during childhood or adolescence, but it can also occur later in life. 2. Type 2 Diabetes Mellitus: In this type, the body either resists the effects of insulin or does not produce enough insulin to maintain normal glucose levels. Type 2 diabetes is more common and often associated with lifestyle factors like obesity, physical inactivity, and aging. Major symptoms of diabetes mellitus include: - Frequent urination (polyuria) - Excessive thirst (polydipsia) - Unintended weight loss - Fatigue - Blurry vision - Slow-healing sores In conclusion, insulin and glucagon work together to maintain blood glucose homeostasis, which ensures that our body functions properly. Diabetes occurs when this balance is disrupted, leading to either insufficient insulin production or resistance to insulin's actions.

Key concepts

Insulin

Insulin is a vital hormone produced by the beta cells of the pancreas. Its primary role is to lower blood glucose levels in the body. After eating, the blood glucose level increases as carbohydrates are digested. Insulin helps to shift this glucose from the blood into the cells of the body, where it can be used for energy.
Another critical function of insulin is to stimulate the liver and muscles to store glucose in the form of glycogen, which can be utilized later when glucose levels in the blood drop. By performing these functions, insulin helps maintain glucose homeostasis, ensuring stable blood sugar levels.

Glucagon

Glucagon is another crucial hormone for blood glucose regulation, and it is produced by the alpha cells of the pancreas. While insulin lowers blood sugar levels, glucagon does the opposite by raising them when necessary. It is particularly active during times when the body needs more energy, such as fasting or intense physical activity.
The hormone works by promoting the conversion of glycogen back into glucose in the liver—a process known as glycogenolysis—thereby increasing blood glucose levels. Through this process, glucagon ensures that the body has enough glucose available for energy production.

Diabetes Mellitus

Diabetes Mellitus is a chronic condition characterized by elevated blood sugar levels due to issues with insulin. There are two major types: Type 1 and Type 2, both resulting in hyperglycemia, but due to different mechanisms.
It is crucial to manage diabetes since consistent high blood sugar levels can lead to severe complications affecting the heart, kidneys, vision, and nerve function.

• In Type 1, the body's immune system attacks and destroys insulin-producing beta cells.
• In Type 2, the body becomes resistant to insulin or does not produce enough insulin.

Proper management typically involves blood sugar monitoring, lifestyle changes, and potentially medication or insulin therapy.

Type 1 Diabetes

Type 1 Diabetes Mellitus is an autoimmune condition where the immune system mistakenly destroys the beta cells of the pancreas. These cells are responsible for producing insulin. With little to no insulin production, glucose remains in the bloodstream, causing high blood sugar levels.
It often presents during childhood or adolescence, hence the name juvenile diabetes, although it can also develop in adults. Common symptoms include thirst, frequent urination, increased hunger, unintended weight loss, fatigue, and blurred vision. Management of Type 1 diabetes requires regular blood glucose monitoring and lifelong insulin therapy.

Type 2 Diabetes

Type 2 Diabetes Mellitus is characterized by the body's inefficient use of insulin, often due to insulin resistance. Unlike Type 1, the pancreas does produce insulin, but it is not utilized effectively, leading to elevated blood sugar levels.
This type is more common in adults and is often linked to lifestyle factors such as obesity, sedentary behavior, and poor diet, although genetics also plays a role. Symptoms are similar to those of Type 1, including excessive thirst and urination, fatigue, and blurred vision. Management strategies include lifestyle modifications such as diet and exercise, oral medications, and in some cases, insulin therapy.