Which of the following can be included under heterocrine glands?

Options

A. Thyroid and parathyroid
B. Pineal gland
C. Gonads and pancreas
D. Thymus

Answer

To determine which of the following can be included under heterocrine glands, we need to understand what heterocrine glands are. Heterocrine glands are those that function as both endocrine and exocrine glands. This means they release hormones (endocrine function) and also secrete substances like enzymes (exocrine function).

### Step-by-Step Solution:

1. **Definition of Heterocrine Glands**:
- Heterocrine glands are glands that have both endocrine and exocrine functions. They secrete hormones into the bloodstream and also release digestive enzymes or other substances through ducts.

2. **Analysis of Each Option**:
- **Thyroid and Parathyroid Glands**:
- The thyroid gland primarily secretes hormones such as T3 (triiodothyronine) and T4 (thyroxine). The parathyroid gland secretes parathyroid hormone (PTH). Both of these glands do not have exocrine functions, so they are not heterocrine.

- **Pineal Gland**:
- The pineal gland secretes the hormone melatonin and does not have any exocrine function. Therefore, it is not a heterocrine gland.

- **Thymus**:
- The thymus gland secretes thymosine, which is involved in the development of T-cells (a type of white blood cell). It does not have exocrine functions, so it is not classified as a heterocrine gland.

- **Pancreas**:
- The pancreas has both endocrine and exocrine functions. It secretes digestive enzymes (like amylase and trypsin) into the digestive tract (exocrine function) and hormones (like insulin and glucagon) into the bloodstream (endocrine function). Thus, the pancreas is a heterocrine gland.

- **Gonads**:
- Gonads (ovaries in females and testes in males) also have both functions. They produce sex cells (ova and sperm) and secrete sex hormones (like estrogen and testosterone). Therefore, gonads are classified as heterocrine glands.

3. **Conclusion**:
- The glands that can be included under heterocrine glands from the given options are **pancreas and gonads**.

### Final Answer:
The correct options that can be included under heterocrine glands are **pancreas and gonads**.