Obesity is caused due to the storage of excess of body fat in adipose tissue. It may induce hypertension, atherosclerotic heart disease and diabetes. Obesity may be genetic or due to excess intake of food, endocrine and metabolic disorders.

Marasmus and Kwashiorkor.

Carbohydrates are sugar and starch. These are the major source of cellular fuel which provides energy. The caloric value of carbohydrate is 4.1 calories per gram and its physiological fuel value is 4 Kcal per gram.

Bicarbonate neutralizes stomach acid. Trypsin and chymotrypsin digest proteins. Carboxypeptidase digests peptides. Amylase digests starch and glycogen. Lipase digests lipids. Nuclease digests nucleic acids.

The process of digestion converts the solid food into absorbable and assimilable forms. This is accomplished by mechanical and chemical processes.

(i) Gastero Eesophagus Reflex Disorder.
(ii) It occurs when cardiac sphincter fails to contract properly during the churning action of the stomach. The gastric juice with acid may flow back into esophagus and cause heart burn.

They are simple tubular intestinal glands which occur throughout small intestine between villi and secrete enzyme and mucus.

There are two kinds of fibres.
1. Soluble fibres soak up toxins and waste in the digestive system.
2. Insoluble fibre(roughage) moves bulk through the intestine to help regular-bowel movements. Thus both types of fibres support a healthy colon

1. The salivary glands present in our mouth produce saliva. Hence our mouth becomes watery.
2. The entry of food into the mouth triggers the brain cells which instructs the salivary gland to produce saliva. Saliva helps to soften the food.

There are three pairs of salivary glands in the mouth. They are the largest parotids gland in the cheeks, the sub-maxillary/sub-mandibular in the lower jaw and the sublingual beneath the tongue

The secretions of the Brunner's gland along with the secretions of the intestinal glands constitute the intestinal juice or succus entericus. The enzymes in the intestinal juice such as maltase, lactase, sucrase (invertase), dipeptidases, lipases, nucleosidases act on the breakdown products of bile and pancreatic digestion.

GERD - Gastro Oesophagus Reflex Disorder. It is commonly known as Heartburn.

A cartilaginous flap called epiglottis prevents the entry of food into the glottis (opening of trachea) during swallowing.

(i) In stomach digested food is incompletely formed so that cannot be absorbed.
(ii) Finger like projections called villi are not found in the wall of stomach.
(iii) The concentration gradient by active transport cannot be created in stomach.

(i) It occurs due to the excess consumption of fats in diet.
(ii) It also occurs due to more storage of fats in adipose tissues.
(iii) It leads to hypertension and atherosclerosis.
(iv) Degree of obesity is assessed by Body Mass Index (BMI).
(v) BMI is calculated as body weight in kg, divided by the square of body weight in meters.
Eg: a 50 kg person with a height of 160cms would have BMI as 19.5
i.e BMI = 50/1.6² = 19.5