Animal Nutrition Flashcards
(25 cards)
Nutrition
The way in which an organism gets and uses its food.
Ingestion
Taking of food into mouth
Digestion
Physical and chemical breakdown of food. Necessary to allow small molecules to be absorbed through walls of intestine.
Absorption
When food passes from the small intestine into the blood or lymphatic system.
Egestion
Removal of unabsorbed waste from the digestive system.
Physical digestion
Breakdown of food by mechanical methods.
Types of teeth
Incisors: 8 Used to cut and slice food.
Canines: 4 Grip and tear food.
Premolars 8/ Molars 12: chew and crush
Chemical digestion
Breakdown of food using enzymes. Amylase in saliva digests starch to maltose.
Peristalsis
Wave of muscular action that pushes food through the alimentary canal.
Physical digestion stomach
Stomach churns the food turning it into a liquid: chyme. PD increases surface area of food so enzymes can digest more easily.
Chemical digestion stomach
Pepsinogen: inactive enzyme formed by glands in the lining of stomach. Activated to form pepsin by hydrochloric acid. Stomach is prevented by being digested by pepsin due to protective mucus and pepsin only becomes active when it mixes with the acid in the stomach.
Small intestine
Duodenum and Ileum.
Duodenum
First part of small intestine.
Function: Digestion
Products of liver and pancreas enter the duodenum.
Pancreas
Produces hormones (insulin) and enzymes ( amylase and lipase). Flow in duct and act in duodenum.
Liver
Gets blood from hepatic artery and hepatic portal vein.
Functions: break down old red blood cells/ forms bile/ breaks down poisons/ breaks down unwanted amino acids from urea( deamination)/ converts glucose to glycogen/ stores vitamins and minerals/ produces heat to warm the blood/forms plasma proteins such as clotting proteins.
Bile
Yellow-green liquid formed from the breakdown of red blood cells.
-Made in liver
-Composed of water, bile salts and bile pigments
-Stored in gall bladder/
-Released into duodenum through the bile duct.
Functions: emulsify fats/ neutralise acid coming from stomach/ eliminate bile pigments from body.
Enzymes
Amylase: Made in salivary glands/pancreas. Starch –> Maltose
Pepsin: Stomach. Protein –> Peptides
Lipase: Pancreas. Fat –> Fatty acids/ glycerol.
Final products of digestion
Carbohydrates: Glucose
Proteins: Amino Acids
Fats: Fatty acids and glycerol.
Ileum
Second part of small intestine.
Function: Absorption.
Has numerous infoldings called villi: increase surface area for absorption. One cell thick.
Absorption in the ileum
-Glucose and amino acids pass through villi into bloodstream by diffusion. Then carried to liver by hepatic portal vein.
-Fatty acids and glycerol enclosed and pass into lacteals(located in centre of villus). Contain lymph.
- Fatty acids and glycerol are carried by lymph vessels and pass into the bloodstream near neck. Coating removed and fats pass into body cells.
Adaptation of small intestine.
- Made of muscle.
-Duodenum produces many enzymes(improves digestion) - Very long ( increases surface area for absorption)
- Many villi which have thin walls and covered by many blood vessels( increased surface area of absorption) and contain lacteal( allows lipids to be absorbed)
Large intestine
Function: reabsorb water. Happens mainly in colon. Faeces stored in rectum and egested through anus.
Symbiotic bacteria in the intestines
Produce B group vitamins and vitamin K.
Break down small amounts of cellulose.
Balanced diet
Contains all the necessary nutrients in the correct proportions.
