(a) Why Is the Use of Iodized Salt Advisable? Name The Disease Caused Due to Deficiency of Iodine in Our Diet and State Its One Symptom. (b) How Do Nerve Impulses Travel in The Body? Explain.

Part A: Why Is the Use of Iodized Salt Advisable?

Iodine is an essential mineral that plays a crucial role in maintaining proper thyroid function and preventing a host of related illnesses. According to the World Health Organization, iodine deficiency is the world's most prevalent yet easily preventable cause of mental and developmental disabilities. Iodized salt is the most effective way of ensuring that our diets contain adequate amounts of this vital nutrient.

The Role of Iodine in The Body

Iodine is an essential component of thyroid hormones, which regulate various body functions, including metabolism, growth, and development. These hormones are produced by the thyroid gland, which requires iodine to function correctly. If the thyroid gland does not get enough iodine, it can become enlarged (known as a goiter), and its function can become impaired, leading to a variety of health problems.

One of the most severe consequences of iodine deficiency is hypothyroidism, a condition in which the thyroid gland produces too little thyroid hormone. This can lead to symptoms such as fatigue, weight gain, and depression, as well as a range of other health problems, including infertility, birth defects, and intellectual disability.

The Importance of Iodized Salt

Iodized salt is the most widely used method of ensuring adequate iodine intake. It is simply table salt that has had iodine added to it, usually in the form of potassium iodide. This makes it an easy and cost-effective way of ensuring that our diets contain sufficient iodine.

The benefits of iodized salt go beyond just preventing hypothyroidism. Studies have also shown that it can help prevent certain types of cancer, including breast, prostate, and endometrial cancer. It may also have a positive effect on cognitive function, particularly in children, helping to improve memory and concentration.

One of the most significant advantages of iodized salt is that it is widely available and inexpensive. This means that it is accessible to people of all income levels, and it can be easily incorporated into any diet. For this reason, it is a recommended public health measure by the World Health Organization, the United Nations Children's Fund, and other international organizations.

Symptoms of Iodine Deficiency

The most common symptom of iodine deficiency is goitre, which is the swelling of the thyroid gland. However, this symptom is not always present, particularly in mild cases of iodine deficiency. Other symptoms may include fatigue, weight gain, dry skin, hair loss, and feeling cold.

In pregnant women, iodine deficiency can have severe consequences for both the mother and the developing foetus. It can lead to miscarriage, stillbirth, premature birth, and congenital disabilities, including intellectual disability, deafness, and cretinism.

Part B: How Do Nerve Impulses Travel in The Body? Explain

Nerve impulses are the electrical signals that allow our nervous system to communicate with different parts of the body. They are responsible for controlling everything from muscle movements to thought processes, and they play a crucial role in maintaining overall health and wellbeing.

The nervous system is made up of two main types of cells: neurons and glial cells. Neurons are responsible for generating and transmitting nerve impulses, while glial cells provide support and protection for the neurons.

How Nerve Impulses Are Generated

Nerve impulses are generated when a neuron is stimulated, either by a chemical signal or a physical stimulus, such as touch or heat. This stimulus causes a change in the neuron's membrane potential, which is the difference in electrical charge between the inside and outside of the cell.

When a neuron is at rest, its membrane potential is negative, meaning that there are more negatively charged ions inside the cell than outside. However, when the neuron is stimulated, positively charged ions, such as sodium (Na+) and calcium (Ca2+), rush into the cell, causing the membrane potential to become more positive. This change in electrical charge is known as depolarization.

If the depolarization reaches a certain threshold, an action potential is triggered. An action potential is a rapid change in the membrane potential that propagates down the length of the neuron, allowing the nerve impulse to be transmitted. During an action potential, the membrane potential rapidly becomes positive, before returning to its resting state.

How Nerve Impulses Travel

Once an action potential is triggered, it travels down the length of the neuron's axon, which is a long, thin fibre that extends from the cell body. The axon is coated in a fatty substance called myelin, which helps to insulate the neuron and speed up the transmission of nerve impulses.

At the end of the axon, the nerve impulse reaches a specialized structure called a synapse. A synapse is the junction between two neurons or between a neuron and a muscle cell, and it is where the nerve impulse is transmitted from one cell to another.

When the nerve impulse reaches the end of the axon, it triggers the release of small, chemical messengers called neurotransmitters. These neurotransmitters diffuse across the synapse and bind to receptors on the membrane of the next neuron or muscle cell. This binding triggers a new depolarization, and the process repeats, allowing the nerve impulse to continue to propagate down the nervous system.

Types of Nerve Impulses

There are two main types of nerve impulses: excitatory and inhibitory. Excitatory impulses cause depolarization, while inhibitory impulses cause hyperpolarization, which makes it more difficult for an action potential to be triggered.

The balance between excitatory and inhibitory impulses is crucial for maintaining proper nervous system function. An imbalance can lead to a range of neurological disorders, including epilepsy, Parkinson's disease, and Alzheimer's disease.

Conclusion

Nerve impulses are the electrical signals that allow our nervous system to communicate with different parts of the body. They are generated by neurons and transmitted down the length of the axon to the synapse, where they are transmitted to the next neuron or muscle cell. Iodized salt is an effective and cost-efficient way of ensuring adequate iodine intake, preventing hypothyroidism, and promoting overall health and wellbeing.