Individuals with type-I diabetes

Options

A. Lack `beta`-cells in the islets of Langerhans
B. Produce enough insulin bat lack functional receptors on their cells
C. Can control their diabetes with with diet and exercise
D. All of these are correct

Answer

### Step-by-Step Solution:

1. **Understanding Type 1 Diabetes**:
- Type 1 diabetes, also known as insulin-dependent diabetes mellitus, primarily affects younger individuals, often developing in childhood or adolescence.

2. **Mechanism of Type 1 Diabetes**:
- In Type 1 diabetes, there is an autoimmune destruction of the beta cells located in the islets of Langerhans in the pancreas. These beta cells are responsible for producing insulin.

3. **Consequences of Beta Cell Destruction**:
- The destruction of beta cells leads to a significant reduction or complete absence of insulin production. Insulin is crucial for regulating blood glucose levels.

4. **Management of Type 1 Diabetes**:
- Unlike Type 2 diabetes, which can often be managed through lifestyle changes such as diet and exercise, Type 1 diabetes cannot be controlled by these methods alone. Individuals with Type 1 diabetes require insulin therapy to manage their blood glucose levels effectively.

5. **Physical Characteristics**:
- Individuals with Type 1 diabetes are often lean or thin, as their bodies cannot utilize glucose effectively for energy due to the lack of insulin. This is in contrast to Type 2 diabetes, where individuals may be overweight or obese.

6. **Conclusion**:
- The primary issue in Type 1 diabetes is the lack of beta cells in the islets of Langerhans, leading to insufficient insulin production and the need for external insulin administration for blood glucose control.