Human Health and Disease Test - 75

Lactobacillus promotes curdling of milk by creating an acidic environment. A vaccine is a biological preparation that provides active acquired immunity to a particular disease. It is made from weakened or killed forms of the microbe, its toxins or one of its surface proteins. Human malaria is transmitted only by females of the genus Anopheles. Dengue is spread through the bite of the female mosquito (Aedes aegypti). Kharif crops are those crops which are grown in monsoon season from the month of June to September. They need more water than rabi crops for their growth and development. Broadcasting is the method of random scattering of seeds on the surface of the seedbed. It can be done manually or mechanically.

Cretinism is caused by the underdeveloped thyroid gland and is characterized by short and stocky stature due to hypothyroidism since infancy or childhood. Addison’s disease is caused by the presence of ineffective ACTH which in turn leads to the deficiency of aldosterone and cortisol hormones of the adrenal cortex. It is characterized by bronzing of skin, disturbed glucose metabolism, loss of sodium and water and finally lower blood pressure. Excessive ACTH secretion by anterior pituitary results in hyperproduction of cortisol causing Cushing’s disease. It is characterized by deposition of subcutaneous fat, stimulated muscle protein metabolism and leading to diabetes mellitus, stimulated reabsorption of water and sodium making the blood pH basic and causing hypertension also. Oversecretion of thyroid hormones (hyperthyroidism) causes Graves’s disease which is characterized by the formation of an exophthalmic goitre. Autoimmune disorders are caused by abnormal functioning of the immune system against body’s own substances. The correct answer is D.

• Ringworm is a contagious itching skin disease occurring in small circular patches, caused by any of a number of fungi and affecting chiefly the scalp or the feet. The commonest form is the athlete's foot.
• Leukoderma is a skin disease that causes loss of melanin that leads to skin whitening. 
  
• Melanoma is a form of skin cancer that begins in the cells (melanocytes) that control the pigment in the skin.
  
• Diarrhea is characterized by loose, watery stools or a frequent need to have a bowel movement.
  

So, the correct answer is option D.

Vaccines are the suspension of killed or weakened microorganism which generates the immune response. 

Edward Jenner was an English physician and scientist who is the pioneer of smallpox vaccine, the world's first vaccine. He is often called the father of immunology. He saw that the healthy person when injected by the pus of pox of the infected person, developed immunity against it.

Nocturnal periodicity is exhibited by microfilarial larva of wuchereria bancrofti. It is a circadian rhythm with the periodicity expressed during night time. It is less active in day blood. It is highly found in the circulation at night. It is found in regions where the vector mosquito is a night-biting species. 

T-helper cells also known as CD4 cells are white blood cells which protects our body from infection. When any virus or bacteria attacks the body, these cells become active and provides immunity to the body. The HIV cells on entering the body, attack and destroy the helper T- cells. Thus the immunity of the body is reduced in HIV infected persons.