Which one is incorrect statement ?

Options

A. Hypothalamic neuron originating hormone release into posterior pituitary by help of action potential.
B. GH shows indirect effect on bones of body by acting with IGF
C. GH show prominent diurnal rythms with peak secretion occurring in the early morning.
D. Thymosin of thymus influences metabolism, pigmentation and defence capability

Answer

To determine which statement is incorrect regarding the endocrine system, we will analyze each statement based on the information provided in the video transcript.

### Step-by-Step Solution:

1. **Identify the Statements**:
- The first statement discusses hypothalamic neurons releasing hormones into the posterior pituitary via action potentials.
- The second statement refers to growth hormone (GH) showing indirect effects on bones through insulin-like growth factor (IGF).
- The third statement mentions that GH has a diurnal rhythm with peak secretion occurring in the early morning.
- The fourth statement claims that thymosin from the thymus influences metabolism, pigmentation, and defense capability.

2. **Analyze Each Statement**:
- **First Statement**: This statement is correct. Hypothalamic neurons do release hormones (like oxytocin) into the posterior pituitary through action potentials.
- **Second Statement**: This statement is also correct. Growth hormone does exert its effects indirectly on bones through IGF, particularly IGF-1.
- **Third Statement**: This statement is correct as well. Growth hormone does show a diurnal rhythm, with peak secretion occurring in the early morning.
- **Fourth Statement**: This statement is incorrect. Thymosin does not influence metabolism and pigmentation; instead, melatonin is responsible for these functions.

3. **Conclusion**:
- The incorrect statement is the fourth one: "Thymosin of thymus influences the metabolism, pigmentation, and defense capability."

### Final Answer:
The incorrect statement is: "Thymosin of thymus influences the metabolism, pigmentation, and defense capability."

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