Which of the following statements is correct about oxytocin (pitocin) ?

Options

A. It stimulates smooth muscles contraction
B. In female, it stimulates a vigorous contraction of uterus at the time of child birth
C. In female, it stimulates milk ejection from mammary gland
D. All

Answer

To determine which statement is correct about oxytocin (also known as pitocin), let's analyze the key functions and characteristics of this hormone.

### Step-by-Step Solution:

1. **Identify the Hormone**: Oxytocin, also referred to as pitocin, is a hormone produced in the hypothalamus and released by the posterior pituitary gland.

2. **Function in Uterine Contraction**: One of the primary functions of oxytocin is to regulate smooth muscle contraction. Specifically, it acts on the smooth muscle of the uterus.

3. **Role During Childbirth**: During childbirth, oxytocin stimulates vigorous contractions of the uterine wall. This is crucial for the process of labor and delivery, helping to push the baby through the birth canal.

4. **Milk Ejection Reflex**: In addition to its role in childbirth, oxytocin also plays a significant role in lactation. It stimulates the milk ejection reflex from the mammary glands, allowing breastfeeding to occur effectively.

5. **Conclusion**: Based on the above points, the correct statement about oxytocin is that it regulates smooth muscle contraction, particularly in the uterus during childbirth and also aids in milk ejection from the mammary glands.

### Final Answer:
The correct statement about oxytocin (pitocin) is that it regulates smooth muscle contraction, particularly stimulating vigorous contractions of the uterus during childbirth and aiding in milk ejection from the mammary glands.