7. Animal nutrition Flashcards
Describe what is meant by a balanced diet
A diet that contains all the required nutrients, in suitable proportions and the right amount of energy.
sources of:
(a) carbohydrates
(b) fats and oils
(c) proteins
(d) vitamins- C and D
(e) mineral ions- calcium and iron
(f) fibre (roughage)
(g) water
(a) carbohydrates- bread, pasta, rice
(b) fats and oils
(c) proteins- meat, fish, eggs, nuts
(d) vitamins- C and D- orange, lime- butter, egg yolk, sunlight
(e) mineral ions- calcium and iron- dairy, bread- green veg, liver, red meat
(f) fibre- oats, wheat, barley
(g) water
importance of:
(a) carbohydrates
(b) fats and oils
(c) proteins
(d) vitamins- C and D
(e) mineral ions- calcium and iron
(f) fibre (roughage)
(g) water
(a) carbohydrates- energy
(b) fats and oils- energy, insulate, make cell membrane
(c) proteins- cell, protein
(d) vitamins- C and D- collagen, keep tissue in good repair- bone and teeth
(e) mineral ions- calcium and iron- bone and teeth, blood clotting- make haemoglobin
(f) fibre- muscle work harder- indigestible
(g) water- chemical reactions
Vit C- scurvy
Vit D- rickets
Iron- anaemia
Calcium- poor blood clotting, bones & teeth
Main organs and associated organs in digestive system with functions
(a) alimentary canal: mouth, oesophagus, stomach, small intestine (duodenum and ileum) and large intestine (colon, rectum, anus)
(b) associated organs:
salivary glands- saliva- water, mucus, amylase
pancreas- pancreatic juice- amylase, lipase, protease
liver- produces bile
gall bladder- stores bile
5 processes of digestion
(a) ingestion – the taking of substances, e.g. food and drink, into the body
(b) digestion – the breakdown of food
(c) absorption – the movement of nutrients from the intestines into the blood
(d) assimilation – uptake and use of nutrients by cells- movement of digested food molecules into cells ; food molecules become part of cells
(e) egestion – the removal of undigested food from the body as faeces
Describe physical digestion & chemical digestion
the breakdown of food into smaller pieces without chemical change to the food molecules.
role- increases the surface area of food for the action of enzymes in chemical digestion.
the break down of large insoluble molecules into small soluble molecules.
role- producing small soluble molecules that can be absorbed
Types of teeth with their functions
incisors- chiseled shape for biting and cutting
canines- pointed for tearing, holding and biting
premolars and molars- large flat surfaces with ridges at the edges for chewing and grinding food.
Structure of a teeth
enamel- harder
dentine- hard, living tissue
pulp- nerves & blood vessels- supply nutrients and oxygen to cytoplasm in dentine.
cement- holds tooth.
teeth are embedded in bone and the gums
Physical digestion
Chewing action of teeth
Churning by stomach
Bile- emulsifying fats and oils to increase the surface area for chemical digestion
functions of hydrochloric acid
in gastric juice
bile
killing harmful microorganisms in food and providing an acidic pH for optimum activity of pepsin.
an alkaline mixture that neutralises the acidic mixture of food and gastric
juices entering the duodenum from the stomach, to provide a suitable pH for enzyme action
Enzymes in digestion
(a) amylase- starch to maltose- mouth and duodenum (salivary glands and pancreas)
(b) maltase- maltose to glucose-membranes of the epithelium lining the small intestine
(a) pepsin- protein in the acidic conditions of the stomach
(b) trypsin- protein in the alkaline
conditions of the small intestine
lipase- fats and oils to fatty acids and glycerol- duodenum- pancreas
Absorption of water and nutrients
most water is absorbed from the small intestine but that some is also absorbed from the colon.
Villi
Microvilli
structure of villus
blood capillaries
lacteal
finger-like projections that line the internal surface area of SI- SA internal increase. absorption of (digested) nutrients into the blood
tiny folds on surfaces of cells of the epithelium of the villi in SI.
wall of villus one cell thick for short diffusion distance and active transport. all digested nutrients absorbed and passed into blood cap. structure- lacteal, capillaries,
epithelium, microvilli, large surface area
blood cap from all villi link up to join hepatic portal vein which takes all substances to liver.
absorbs fatty acids and glycerol.
