HUMAN NUTRITION

HUMAN NUTRITION

Nutrition: Nutrition is the sum of the processes by which an organism providing or obtaining the food necessary for health and growth. WHO (World Health Organisation) defines nutrition as the intake of food, considered in relation to the body's dietary needs.

Ingestion: The intake of food through the mouth or by absorption is called ingestion.

Digestion : The process by which the complex, non-diffusible and non-absorbable food substances are converted into simple, diffusible and assimilable form.

Absorption : The process of movement of digested food material from the small intestine into the blood vessels is called absorption.

Assimilation : The metabolic conversion of nutrients into the tissue or the process of formation of the protoplasm of the cell is called assimilation.

Egestion : Removal of undigested waste material out of the body is called egestion or defecation.

Thecodont dentition: The arrangement of a tooth in human in which the tooth is fixed in a separate socket present in jawbones by gomphosis joint. is called thecodont dentition.

Diphyodont dentition: A type of dentition in which animals have two sets of teeth in their entire life is called diphyodont dentition. Humans have  two sets of teeth, milk teeth and permanent teeth.

Heterodont dentition:  A set of teeth of various shapes that may have different functions. Humans have four different types of teeth hence we are heterodont. Types of teeth are incisors (I) canines (C) premolars (PM) and molar (M).

Dentition : The study of teeth with respect to their number, arrangement, development etc is called dentition.

Enamel : The hardest substance of the body through which the crown of a tooth is covered called enamel. Enamel is made up of calcium phosphate and calcium carbonate.

Crown: Part of the tooth which projects above the gum is called a crown.

Alimentary canal: The long straight tube of varying diameter that starts from mouth and end with the anus is called an alimentary canal.

Root canal  : The extension of the pulp cavity in the root of the tooth is called the root canal.

Peristalsis: The rhythmic wave of contraction and relaxation of the oesophagus is called peristalsis. It helps in the passage of food through the oesophagus.

Cardiac sphincter: The smooth muscle present at the junction of oesophagus and stomach is called cardiac sphincter.

Pyloric sphincter: The smooth muscle present at the junction of pylorus of       stomach and duodenum of the small intestine called cardiac sphincter.

Appendix : The vestigial organ in human  and functional in herbivorous which are used for the digestion of cellulose is called appendix.

Rugae: A series of ridges produced by folding of the wall of an organ is called rugae. In the stomach, the mucosa is thrown into irregular folds called rugae.

Villi : finger-like projections made up of cells that line the entire length of the small intestine is called villi.

Crypts of Liberkuhn: The narrow and deep invaginations formed by mucosa between the bases of villi in the intestine is called crypts of liberkuhn.

Hepatic Lobules: The structural and functional units of the liver are called hepatic lobules.

Kupffer cells: The phagocytic cells present in the liver is called Kupfer cells.

Sphincter of Oddi: The smooth muscle that surrounds the end portion of the common bile duct and the pancreatic duct is called sphincter of Oddi.

Islet of Langerhans : The group of cells forming endocrine part of the pancreas is called islet of Langerhans.

Bolus : A small rounded mass of a chewed food at the moment of swallowing is called a bolus.

Chyme : The acidic mass of partially digested food which passes from the stomach to the small intestine is called chyme.

Chyle : The alkaline slurry which contains various nutrients ready for absorption is called chyle.

Micelles : The small aggregates (4-8 nm in diameter) of mixed lipids and bile acids suspended within the food are called micelles.

Chylomicrons : Small protein-coated fat globules are called chylomicrons.

Ghrelin: Ghrelin is a hormone that is produced mainly the stomach and small intestine, pancreas and brain. It is known as the 'hunger hormone' because it stimulates appetite, increases food intake and promotes fat storage.

Gross calorific value: The amount of heat liberated by the complete combustion of 1g  food in a bomb calorimeter is termed as gross calorific (gross energy) value.

Physiological value: The actual amount of energy liberated in the body from 1 g of carbohydrates, proteins and fats is called the physiological value of food.

Protein Energy Malnutrition  / PEM: Inadequate intake of proteins causes Protein Energy Malnutrition (PEM). It can be associated with inadequacy of vitamins and minerals in the diet.

Kwashiorkor : It is a protein deficiency disorder found generally in children between one to three years of age.

Marasmus : It is prolonged protein-energy malnutrition (PEM) found in infants under one year of age, in this disease protein    deficiency is coupled with lower total food caloric value.

Indigestion / Dyspepsia  : Because of Overeating, inadequate enzyme secretion, spicy food, anxiety can cause discomfort in the upper abdomen is called indigestion.

Constipation : When frequency of defecation is reduced to less than one per week is called constipation.

Diarrhoea : Passing of loose watery stools, more than three times a day is called diarrhoea.

Jaundice : It is a sign of abnormal bilirubin metabolism and excretion. Jaundice is associated with yellowness of conjunctiva of eyes and skin and whitish stool.

Vomiting: In this condition, the stomach contents are thrown out of the mouth due to reverse peristaltic movements of the gastric wall. It is controlled by non-vital vomiting centre of medulla.