Problem 150 - Objective Biology for NEET

Question

Assertion: Medulla oblongata causes reflex actions like vomiting, coughing and sneezing. Reason: It has many nerve cells which controls autonomic reflexes.

Step-by-Step Solution

Answer

The assertion and reason are both correct, and the reason accurately explains the assertion.

Step 1: Understanding the Assertion

The assertion states that the medulla oblongata causes reflex actions such as vomiting, coughing, and sneezing. This is indeed accurate, as the medulla oblongata is a part of the brain that serves as the coordinating center for autonomic reflexes, including such reactions mentioned above.

Step 2: Understanding the Reason

The reason states that it is due to the numerous nerve cells in the medulla oblongata which control these autonomic reflexes. These nerve cells, or neurons, indeed carry out the role stated. They transmit information in the form of nerve impulses from other parts of the body to the brain. Thus, any reflex actions, which are involuntary and automatic, are controlled through the transmission of these impulses.

Step 3: Tying the Assertion and Reason Together

Based on the analysis of the Assertion and Reason, we can conjoin that the Assertion is correct and the Reason not only stands correct individually but also accurately explains why the Assertion is true. This is because the medulla oblongata, with its numerous nerve cells, is indeed responsible for controlling autonomic reflexes such as vomiting, coughing, and sneezing.

Key Concepts

Autonomic Reflexes

Your body is constantly at work, performing actions that you are hardly aware of. These are known as autonomic reflexes. These reflexes happen automatically, without you having to think about them.
One part of the brain responsible for these reflexes is the medulla oblongata. It manages various essential functions for everyday life:

• Heart rate and blood pressure regulation
• Breathing control
• Reflexes such as swallowing, sneezing, and coughing

Reflexes like sneezing and coughing are protective mechanisms. They help clear your pathways and maintain a proper balance in your body, ensuring you stay healthy.

Nerve Cells

Nerve cells, or neurons, are like the messengers of your body. They transmit signals between different parts of your body and the brain. In every action you perform, neurons play a crucial role.
In the medulla oblongata, many neurons connect various parts of the body to the brain. Here's how they function:

• They receive stimuli from sensory organs.
• They interpret and analyze the information received.
• They send signals to muscles or glands to initiate a response.

The functioning of these neurons ensures that major bodily processes occur smoothly. They allow reflex processes, like the ones managed by the medulla oblongata, to be quick and efficient.

Vomiting Reflex

Vomiting isn't a pleasant experience, but it serves an important purpose. It helps your body expel harmful substances that may have been ingested. The medulla oblongata is crucial in controlling the vomiting reflex.
Let's understand how it works:

• The sensory signals, indicating the presence of a harmful substance, are sent to the medulla oblongata.
• The medulla oblongata processes these signals quickly.
• It then sends commands to muscles responsible for stomach contractions, leading to vomiting.

This reflex ensures that toxic or irritating substances are rapidly removed from your body, thus protecting your health.

Coughing and Sneezing

Coughing and sneezing are common reflexes that help keep your airway clear. Both reflexes involve complex actions coordinated by the medulla oblongata.
When it comes to coughing:

• An irritant enters the airway, stimulating sensory nerves.
• The medulla oblongata responds by sending signals to the respiratory muscles.
• This results in a sudden expulsion of air to remove the irritant.

Similarly, sneezing occurs when:

• An irritant affects the nasal passages.
• Sensory signals are sent to the medulla oblongata.
• This leads to a reflexive forceful expulsion of air through the nose.

Both coughing and sneezing are protective responses to ensure unobstructed breathing and to prevent irritants from entering the lungs.