Human Health and Disease

In Biology, Human Health and Disease is an essential chapter comprising information related to various diseases, their agents, body immunity, etc. Studying the entire chapter before an examination is time-consuming as students have to study other materials as well. So, a selective material on significant concepts of this chapter is always advantageous.

Here, you will find important notes of biology for NEET Human Health and Disease, which will assist you during the preparation of the same as well as for other examinations.

Kinds of Diseases

Human diseases fall under two categories:

• Congenital: Condition present from the time of birth

• Acquired: A disease that occurs in the course of one’s lifetime

Immunity

Immunity refers to a body’s ability to fight and protect itself from the attack of infectious microorganisms or foreign bodies. It is of two kinds, such as –

1. Innate Immunity

This immunity is available from the time of birth and provides barriers to the invasion of any external disease-causing agent. Moreover, there are four kinds of barriers present; these include – 

• Physical barrier.

• Physiological barrier.

• Cellular barrier.

• Cytokine barrier.

2. Acquired Immunity

This kind of resistance is pathogen-specific, and an individual acquires it during his/her lifespan.

The following table represents several infectious diseases that are common in human beings, along with their symptoms and effects.

Allergies

Allergy takes place when an individual’s immune system retaliates to particular substances like pollen, medicines, foodstuff, etc. A human’s immune system can differentiate between foreign and self-molecules or bodies.

However, there are specific scenarios where a body strikes its own cells. As a result, it harms the body and is termed as an auto-immune disease. An example of such an effect is rheumatoid arthritis.

Do It Yourself

Widal test is done to rule out which disease?

a) Malaria   b) Diabetes   c) AIDS   d) Typhoid

AIDS

Human Immuno Deficiency Virus (HIV) is responsible for causing AIDS. The first case of AIDS was reported in the year 1981. Moreover, the transfer of HIV in humans takes place mainly through the following:

• Sexual relationship with a person who has HIV.

• Sharing infected syringe or needle.

However, it must be noted that transmission of HIV does not occur through water or air, pets or insects, saliva, tears, sweat, kiss and sharing food, drinks or restrooms.

Cancer

Cancer refers to the uncontrollable and abnormal multiplication of cells. These cells occupy and kill the neighbouring tissues, and the continuous increase of cancer cells gives rise to neoplasms or tumours. Moreover, tumours can be divided into two categories, like:

• Benign Tumours

These tumours remain constricted to its original location and do not spread to other organs in the human body and are considered non-cancerous.

• Malignant Tumours

Cells in malignant tumours increase rapidly. Also, they move beyond the surrounding tissues and get into lymph and blood. Due to this happening, it can reach other body parts. This is referred to as metastasis, and only malignant neoplasms are counted as cancerous.

Reasons for Cancer

In general, the actual cause or reason of cancer is yet to be understood. But multiple factors may favour the growth of cancer cells. These factors or agents are termed as carcinogens.

Here is A Tabular Depiction of Carcinogens And The Affecting Organs

Alcohol and Drug Abuse

Drugs that are abused commonly include cannabinoids, coca alkaloids and opioids. Few drugs can be obtained from fungi and mostly from flowering plants. Opioid drugs tie with opioid receptors which exist in the human GI tract and CNS (Central Nervous System).

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