Human Health and Disease

In Biology, Human Health and Disease is an important chapter that covers information related to various diseases, their agents, immunodeficiency, etc. Reading the whole chapter before the exam takes time as students have to learn other things. Therefore, the selected material in the main points of this chapter is always useful.

Types of Diseases

Human diseases fall into two categories:

Congenital: A condition that has existed since birth

Acquired: Disease that occurs during a person's lifetime

Immunity

The immune system refers to the body's ability to fight off infections by invading viruses or foreign bodies. There are two types, such as-

Innate Immunity

This protection is available from the time of birth and provides barriers to attack by any foreign agent that causes infections. In addition, there are four types; this includes -

• Physical barrier.
• Physiological barrier.
• Cellular barrier.
• Cytokine barrier.

Acquired immunity

This type of resistance is directly related to the pathogen, and a person acquires it during his or her lifetime.

Allergies

Allergies occur when the immune system reacts to certain things such as pollen, medicines, food, etc. The human immune system can distinguish between foreign molecules and bodies.

However, there are cases when the body beats its own cells. As a result, it is harmful to the body and is called autoimmune disease. An usual example of such a given effect is rheumatoid arthritis.

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AIDS

The Human Immunodeficiency Virus (HIV) is responsible for causing AIDS.

The first ever case of AIDS was reported in the year1981. In addition, HIV transmission to humans occurs mainly through the following:

Sexual intercourse with an HIV-positive person.

Sharing an infected syringe or needle.

However, it should be noted that HIV transmission does not occur through water or air, pets or insects, saliva, tears, sweat, kissing and sharing food, beverages or toilets.

Cancer

Cancer refers to the uncontrolled and abnormal replication of cells. These cells capture and kill neighboring tissues, and the continuous proliferation of cancer cells causes neoplasms or tumors. In addition, plants can be divided into two categories, such as:

Benign Tumors

These tumors remain trapped in their original position and do not spread to other parts of the human body and are considered non-cancerous.

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• NCERT book for class 11 Biology.
• NCERT book for class 12 Biology.

Malignant Tumors

Malignant tumor cells grow rapidly. Also, they travel across the surrounding tissues and enter the lymph and blood. As a result, it can reach other parts of the body. This is called metastasis, and only dangerous neoplasms are classified as cancer.

Causes of Cancer

Often, the exact cause or cause of cancer remains to be determined. But many factors may contribute to the growth of cancer cells. These elements or agents are called carcinogens.

Alcohol and Drug Abuse

Drug abuse commonly includes cannabinoids, coca alkaloids and opioids. Few medicines can be found in the fungus and especially in flowering plants. Opioid drugs also bind to the opioid receptors present in the human GI tract and the CNS (Central Nervous System).

On the other hand, cannabinoids interact with cannabinoid receptors in the brain. Examples of such drugs are hashish, marijuana, and chara.

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• NCERT solutions for class 12 Physics.
• NCERT solutions for class 12 Chemistry.
• NCERT solutions for class 12 Mathematics.
• NCERT solutions for class 12 Biology.

NCERT Exemplar Solutions Subject wise link:

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