Animal Nutrition IGCSE Biology Unit B6

A set of vocabulary flashcards based on the IGCSE Biology Unit B6 Animal Nutrition lecture, covering dietary requirements, nutrition deficiencies, and the human digestive system functions.

Balanced Diet

A diet containing proper proportions of carbohydrates, fats, proteins, vitamins, minerals, and water to maintain good health and metabolism.

Vitamin C

Nutrient found in cabbage and citrus fruit used for healthy gums and skin repair.

Vitamin D

Nutrient found in fish liver, egg yolk, and sunlight used for the uptake of calcium for teeth and bone formation and strength.

Calcium

Mineral found in flour and milk used for healthy bone and teeth health, muscle action, and blood clotting.

Iron

Mineral found in liver, red meat, and spinach used for the formation of haemoglobin.

Fibre (Roughage)

Found in fruit, vegetables, and nuts; it forms bulk in the intestine to give the muscles of peristalsis something to push against.

Water

A solvent for chemicals in the body used to cool the body, making up $68\,$ of body mass.

Scurvy

A deficiency of vitamin C leading to the weakening of connective tissue and blood vessels.

Rickets

A deficiency of vitamin D where $Ca^{2+}$ is not properly deposited, causing soft bones to deform under body weight.

Kwashiorkor and Marasmus

Conditions resulting from protein-energy malnutrition.

Ingestion

The first stage of the alimentary canal process involving taking food into the body.

Mechanical Digestion

The physical breakdown of food, such as the use of teeth in the mouth to process food.

Chemical Digestion

The breakdown of food using enzymes like amylase, protease, and lipase.

Absorption

The movement of small food molecules and ions through the wall of the intestine into the blood.

Assimilation

The movement of digested food molecules into the cells of the body where they are used, becoming part of the cells.

Egestion

The passing out of food that has not been digested or absorbed, as faeces, through the anus.

Amylase

An enzyme found in saliva and pancreatic juice that digests starch into simple sugars.

Mucin

A protein in saliva that makes food sticky and lubricated.

Bolus

A ball of food rolled by the tongue to be pushed back into the oesophagus.

Peristalsis

Waves of muscular contraction that push food boluses down the oesophagus and through the digestive tract.

Chyme

The name for food after it has been churned in the stomach.

Gastric Juice

A liquid secreted by the stomach containing the enzyme protease, hydrochloric acid, and rennin (in children).

Bile

A greenish-coloured alkaline fluid produced by the liver and stored in the gallbladder that neutralises acidic chyme and emulsifies fat.

Deamination

The removal of the nitrogen-containing part of excess amino acids to form a urea molecule in the liver.

Villi

Millions of microscopic finger-like projections on the folded walls of the ileum that increase surface area for absorption.

Microvilli

Minute folds on the cell membrane of the epithelial cells of the villi.

Lacteals

Special structures within villi designed to absorb fatty acids and glycerol into the lymphatic system.

Hepatic Portal Vein

The blood vessel that carries absorbed amino acids directly to the liver.

Glycogen

The form in which excess glucose is stored in the cells of the liver and muscles under the effect of insulin.

Glucagon

A hormone that, along with adrenaline, causes glycogen to be broken down into glucose when blood sugar is low.

Absorption

The movement of small food molecules and ions through the wall of the intestine into the blood.

Egestion

The passing out of food that has not been digested or absorbed, as faeces, through the anus.

Ingestion

The first stage of the alimentary canal process involving taking food into the body.

Mechanical Digestion

The physical breakdown of food, such as the use of teeth in the mouth to process food.

Chemical Digestion

The breakdown of food using enzymes like amylase, protease, and lipase.

Stomach

An organ that secretes gastric juice, which contains protease, hydrochloric acid and churns food to create chyme.

Liver

An organ that produces bile for fat emulsification, detoxifies chemicals, and converts excess glucose into glycogen.

Ileum

The final part of the small intestine where the majority of nutrient absorption occurs through villi and microvilli.

Gallbladder

An organ that stores bile produced by the liver until it is needed for fat digestion.

Pancreas

An organ that produces digestive enzymes and bicarbonate to neutralize gastric acid in the small intestine.

Mouth

The opening where ingestion begins; includes the teeth and saliva for mechanical and chemical digestion.

Esophagus

The tube connecting the throat to the stomach, through which food travels via peristalsis.

Stomach

An organ that secretes gastric juice, which contains protease, hydrochloric acid, and churns food to create chyme.

Small Intestine

The part of the digestive system where most chemical digestion and nutrient absorption occur; it is divided into three segments: duodenum, jejunum, and ileum.

Duodenum

The first segment of the small intestine where partially digested food mixes with bile and pancreatic juices.

Jejunum

The middle segment of the small intestine where absorption of nutrients continues.

Ileum

The final part of the small intestine where the majority of nutrient absorption occurs through villi and microvilli.

Large Intestine

The part of the digestive system that absorbs water and salt from indigestible food residue; it leads to the rectum.

Rectum

The final section of the large intestine where waste is stored before egestion.

Anus

The opening at the end of the digestive tract where egestion occurs.

Liver

An organ that produces bile for fat emulsification, detoxifies chemicals, and converts excess glucose into glycogen.

Gallbladder

An organ that stores bile produced by the liver until it is needed for fat digestion.

Pancreas

An organ that produces digestive enzymes and bicarbonate to neutralize gastric acid in the small intestine.