Animal Nutrition

nutritionFood taken in, taken apart and taken up

Herbivores – plants/algae

Carnivores – eat other animals

Omnivores – consume animals and plants/algae

Most animals are opportunistic – they will eat anything outside their diets when normal foods are not available.

Adequate dietMust satisfy 3 nutritional needs

Chemical energy for chemical processesOrganic building blocks for macromoleculesEssential nutrients – preassembled organic

molecules and mineralsEssential fatty acidsEssential amino acidsVitaminsminerals

Malnutrition – lacking 1 or more of the essential nutrients

Food processing – 3 steps1. ingestion – act of eating or feeding

2. digestion – food broken down into molecules small enough for the body to absorb.

3. absorption – take up of small molecules such as amino acids and simple sugars

Elimination – undigested material passes out of the digestive system

DigestionDigestive enzymes (amylase) begin digestion in

mouth.

Intracellular digestion – food vacuoles, paramecium

Extracellular digestion – Gastrovascular cavity – hydraComplete digestive tract – alimentary canal,

mouth and anus

Figure 33.8

Tongue

Salivaryglands

Liver

Gall-bladder

Pancreas

SmallintestineLargeintestine

Rectum

Anus

Oral cavity

Pharynx

Esophagus

Sphincter

Sphincter

Stomach

Liver

Pancreas

Gallbladder

Duodenum ofsmall intestine

Stomach

Smallintestine

Largeintestine

RectumAnus

SalivaryglandsEsophagus

Mouth

Accessory glands of digestive system

Mouth – salivary glands (accessory)

Pancreas – endocrine gland

Liver – filters blood, produces bile

Gall bladder – stores bile, releases to S. Intestine

Peristalsis – waves of contraction/relaxation to move food throughout alimentary canal.

Sphincters – muscular rings that regulate passage to organs.

Oral cavity, pharynx and esophagus

Oral cavity – mouth, digestion beginsTongue – helps shapes digested food into a ball –

bolus

Pharynx – splits into 2 passagesTrachea – respiratoryEsophagus – leads to stomach

stomachStores food, begins digestion

Secretes components of a digestive fluid – gastric acidHCL – makes pH around 2, denatures proteinsPepsin – protein-digesting enzymeGastric acid does not affect cells lining stomach

because of mucus released by cells

Gastric ulcers – damaged areas of stomach lining

stomachDigestion occurs by churning of food (peristalsis)

about every 20 seconds.

Chyme – acidic nutrient rich broth made from food

Stomach sphincters closed during digestion

Acid reflex – chyme backflows into esophagus “heartburn”

Digestion in Small Intestine

Most digestion of macromolecules from food, higher pH than stomach, trypsin enzymes

Longest part of alimentary canal, 20 feet, 6 meters

Duodenum, first 25 cm of small intestine, chyme mixes with digestive juices from pancreas, liver and gall bladder.

Bile – product of liver, contains bile salts

Absorption in the small intestines

Most absorption occurs across folded surfaceVilli, microvilliSurface area is roughly the size of a tennis court!

Increase rate of absorption

Absorption of large intestines

Includes the: Colon – ascending, transverse, descending, recovers

water Cecum – pouch that ferments ingested material

Appendix – finger like extension of the human cecum, contains bacteria to break down material, accessory

Rectum – terminal portion, store feces until eliminated. Has two sphincters to regulate defecation

Irritation of lining of colon – diarrhea

Dental/mutualistic adaptations

Assortment of teach reflect the diet of the animal.

Mutualistic bacteria and protists live in some digestive organs of certain animals to help with digestion.Koala – to break down eukalyptusRuminant digestion – 4 chambered stomachRabbits/rodents – bacteria in L.ITermites – protists to help break down cellulose

Regulation of digestion Nervous system involved by triggering of

substances to be released (saliva, gastric juices)

Endocrine system – controls digestion with release of hormones released by stomach and duodenum.

Energy storage -