Animal Nutrition Flashcards
What is a balanced diet?
A balanced diet is one that has the correct proportions of carbohydrates, proteins, fats, vitamins, minerals and Fibre(roughage)
List and explain the 5 processes involved in animal nutrition
- Ingestion- taking in insoluble food into the mouth
- Digestion- breakdown of food mechanically by chewing or chemically by enzymes
- Absorption- taking in simple soluble substances into the blood stream
- Assimilation- taking in simple soluble substances from the blood stream into cells
- Egestion- removal of undigested food from the body in the form of faeces
List the importance of food
- provide energy: come from carbohydrates and fats
- to grow and repair damaged tissue: comes from proteins
- regulation of body processes: vitamins and minerals
Name and explain the modes of nutrition
Animals are classified in 3 groups according to the food they eat
Herbivores- eat plants and plant material
Carnivores- eat othe animals
Omnivores- eat both plants and animals
Energy food chain
Producers > Primary consumers > Secondary consumers > tertiary consumers
List and explain the types of teath
- Incisors: chisel shape(biting and cutting)
- Canines: cone shape(gripping and holding)
- Pre molars: used for grinding
- Molars: uses for grinding and crushing food
Nutrition and dentition in herbivores
- Herbivores are animals that eat plants only (e.g. cows)
- They consume large amounts of food as the food they eat is low energy food
- wide sharp Incisors for cutting grass (biting)
- Molars that are used for grinding(chewing)
- do NOT have Canines
Grass is digested in a rumen(part of alimentary canal), with the aid of bacteria
Nutrition and dentition of Canivores
Carnivores are animals that only eat other animals(e.g. lions)
-food is high in protein therfore don’t have to eat alot
Carnivores have powerful jaws with teeth:
- incisors: sharp to bite off food
- canines: sharp canines to grip prey when hunting
- premolars and
- molars: have protutions=>stick out and are modified to form carnicial teeth
The digestion of proteins occurs mainly within the stomach
Nutrition and dentition of Omnivores
Animals that eat both plants and animals Have: - incisors - canines - premilars and - molars More like carnivores but not as sharp Teeth are not modified
Chemical digestion starts in the mouth and continues in the stomach and small intestine
Human dental formula
- 1.2.3 =8
- ——– - 1.2.3
I.C.P.M ¼ of jaw
Define digestion
Digestion may be defined as the step-wise breakdown of large food particles into molecules, small enough to enter the body’s cells
Overview of the mechanisms of nutrition
a) Ingestion: taking in food into the mouth(eating)
b) Secretion: cells within the walls of the alimentary canal & accessory organs, secrete water, enzymes and acids & alkalis
c) Mixing and Propulsion: alternating contraction & relaxation of smooth muscles in the walls of the alimentary canal, mixing food and secretions and pushing them along.
d) Digestion: mechanical and chemical processes involved, mix secreted fluids with ingested food and breakdown large food particles into smaller particles and molecules
e) Absorption: entry of products of digestion into the epithelial cells lining the lumen of small intestine, thereafter passing into the blood and lump. Mist drugs, alcohol are absorbed in the stomach
f) Defaecation(egestion): the elimination of undigested food and waste material from the large intestine through the anus
Define mechanical digestion
Mechanical digestion involves physical breakdown of food by teeth, the swallowing of food and the action to smooth muscles of the stomach and intestine that churn food so that it is mixed with enzymes
Define chemical digestion
Chemical digestion involves a series of catabolic reactions where enzymes and chemicals breakdown carbohydrates, lipids and proteins into smaller molecules
What is the elementary canal?
A long tubular structure that extends from the mouth to the anus. It consists of:
- mouth and mouth cavity
- pharynx
- oesophogus
- stomach
- small intestine
- large intestine
- rectum
- anus
List the Accessory organs
- tongue/teeth
- salivary glands
- pancreas
- liver
- gall bladder
Mouth?
Mechanical digestion- physical breakdown of food(teeth/tougue)
Chemical digestion: hydrolysis- enzymes + water
Define hydrolysis
The chemical breakdown of a compound due to reaction with water.
Tongue
- tastebuds
- move food side to side
- roll food into bolus(ball of food)
- helps in swallowing
- organ of taste(sweet, sour, salty, bitter)
- stimulates the Secretion of saliva to labrucate for easy swallowing
Teeth
Teach cut, tear and pulverise food into smaller particles for swallowing
- 8 incisors used for biting and snipping food
- 4 canines used for gripping and tearing food
- 8 premilars help in chewing food
- 12 molars used for chewing
2.1.2.3= 8
I.C.P.M- ½ of upper/lower jaw
32 teeth in total(adults)
Salivary Glands
- 3 pairs present in mouth
- secrete saliva which consists of water, mucin and an enzyme
Silava serves to soften and lubricate food which facilitates chewing, mixing and swallowing - produces saliva
- contains mucus- moisten food
- salivary amylase breaks down starch into maltose
- pH in mouth is basic.. only carbohydrates chemically breakdown
The pharynx
Back of mouth cavity, leading to oesophagus and trachea
- common passageway for food(swallowing) and air
- when food is swallowed the epigolttis closes so food doesn’t enter trachea(wind pipe)
The oesophagus(gullet)
Narrow muscular tube links pharynx to stomach behind trachea
- forces the bolus down into stomach by muscular wave-like motion..this is CALLED Peristalis.
- goblet cells secrete mucus- lubricating walls for smooth passage of bolus
The stomach
Muscular bag-like organ, lying in upper part of abdominal cavity just below diaphragm
The cardiac and pylori sphincters control the entry and exit of food
Three sections of the stomach?
- Fundus (top)
- Corpus (middle)
- Pylorus (bottom)
What is the rugae?
(Muscular folds)
The inner surface of the stomach is composed of many muscular folds which become fewer as the stomach distends(swells/bloats)
What does the stomach secrete?
Gastric glands secrete gastric juice which contains enzymes[pepsin: protein>peptones] and hydrochloric acid(HCl- creates acidic medium kills bacteria)
What is chyme?
Food turned into greyish liquid
Renin: curdles milk(sour)
The muscular action of the stomach mixes the food with saliva and gastric juice forming a watery mixture called chyme
The liver
The liver is the largest gkand in the body, lying in the upper portion of the abdominal cavity just below the diaphragm
Functions of the liver
- makes and secretes bile(breaks fat into tiny droplets/contains bicarbonate ions create basic medium in duodenum)
- converts glucose to glycogen&fat
- converts excess amino acid to urea
- detoxifies bloods of harmful substances (alcohol/drugs)
Stores ions and vitamins & minerals
Gall bladder
A pear-shaped pouch found in the depression on the lower surface of the liver. It stores bile
What is bile?
Bitter fluid which emulsified fats (converts fats into fatty acids)
The pancreas
The pancreas is a gland lying below the greater curvature of the stomach.
Ducts connect the pancreas to the duodenum
What is pancreatic juice?
The pancreas secretes pancreatic juice which contains a number of enzymes (chemical digestion)
What are the islets of langerhans?
Special groups of endocrine(glands) cells called islets of langerhans are found in the pancreas. They secrete the hormones insulin and glucagon, which controls blood sugar levels
Small intestine
The small intestine begins at the pyloric sphinter(duodenum) extends through the central part(jejunum) of the abdominal cavity and opens into the large intestine(illeum)
Divided into 3 regions: duodenum, jejunum and illeum
The duodenum
Involved in neutralizing the acidic chyme and digestion of carbohydrates(using carbohydrases), proteins(using proteases) and lipids(using lipases)
C-shaped (pancreas fits in gap)
pH- alkaline
The pyloric end of the stomach narriwas down to fkrm the first part of the the small intestine, the duodenum.
The liver, gall bladder and pancreas are important organs associated with the duodenum
Where are enzymes found in the small intestine?
Enzymes(pratcase) are found on the surface of the columnar epithelial cells (digest protein to all absorption of amino acids)
What is the villi?
Numerous finger-like projections of the mucosa, called villi, serve to increase the surface area for the increase of absorption of nutrients.(by diffusion and active transport)
What are peristalsis?And what cause them?
Food is forced into the stomach by wave-like muscular contractions called peristalsis.
The muscles of the small intestine cause peristalsis, which move food along towards the large intestine.
The jejunum
Mainly involved in digestion, using enzymes (carbohydrases, proteases and lipases)
Enzymes: lipase/sucrose/lactose/maltase
Intestinal juice
The illeum
Main function: absorption of nutrients into blood
Absorption of digested food takes place mainly through the villi (singular:villus)
Structure of the Villus
- single layer of epithelial cells(facilitates diffusion)
- has lacteal (to transport absorbed fats)
- capillaries for transport of absorbed nutrients
- columnar epithelial cells have many mitochondria (provides energy for active absorption of nutrients-mostly lipids)
- goblet cells secrete mucus(protects villi and aids absorption)
- Brunners glands secrete an alkaline mucus( serves as a lubricant and protects the lining of the intestine against the acidic chyme, by neutralizing it)
5 points on how the villi are adapted to perform their function of absorption of nutrients:
- they are folded to increase surface area for absorption
- they have a single laye or columnar epithelial for easy kovemome t of nutrients
- the absorptive surface is in close contact with the chyme
- good blood supply to transport nutrients to the liver
- the lacteal transports fatty acids away
Large intestine(colon)
Extends from the illeum to the anus
It is attracted to the abdominal wall. Is consists of the caecum, colon, rectum and anus.
The colon contains bacteria which breakdown undigested carbohydrates(gasses like methane and carbon dioxide are released as a result)
Colon: absorption of H²O and mineral salts
Caecum: absorbs water to for stool, stored in the rectum
Anus: egestion of stool
