Injury to the medulla oblongata in humans is not likely to affect:

Options

A. Gastric secretion
B. Cariac movements
C. Unconditioned reflex
D. Controlled respiration

Answer

To solve the question regarding the effects of injury to the medulla oblongata in humans, we can follow these steps:

### Step 1: Understand the Function of the Medulla Oblongata
The medulla oblongata is a vital part of the brainstem that controls several autonomic functions, including:
- Cardiac movements (heart rate and blood pressure)
- Respiratory functions (breathing rate and rhythm)
- Reflex actions (such as swallowing, coughing, and vomiting)

### Step 2: Analyze the Options Given
The question provides four options regarding what injury to the medulla oblongata is not likely to affect:
1. Cardiac movements
2. Gastric secretion
3. Unconditioned reflex
4. Controlled respiration

### Step 3: Evaluate Each Option
- **Cardiac movements**: The medulla oblongata regulates heart rate and blood pressure, so an injury here would affect cardiac movements.
- **Gastric secretion**: The medulla also plays a role in controlling gastric secretions, so this would be affected by an injury.
- **Controlled respiration**: The medulla is responsible for regulating the rhythm of breathing, so this function would also be affected.
- **Unconditioned reflex**: This refers to automatic responses that do not require conscious thought, such as reflexes that occur in response to stimuli. These are primarily controlled by the spinal cord and do not rely heavily on the medulla oblongata.

### Step 4: Identify the Correct Answer
Since the unconditioned reflexes are not primarily dependent on the medulla oblongata, injury to this area is not likely to affect them. Therefore, the correct answer is:
**Unconditioned reflex (Option 3)**.

### Conclusion
Injury to the medulla oblongata is not likely to affect unconditioned reflexes, making it the correct answer to the question.

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