Ch 39 Nutrition, Digestion and absoption AP lecture

Recap Heterotrophic Autotrophic Catabolism Glycogen

What do animals need to live? Animals make energy using: food oxygen Animals build bodies using: food for raw materials amino acids, sugars, fats, nucleotides ATP energy for synthesis food ATP O2

Teeth Carnivore Herbivore Omnivore sharp ripping teeth “canines” wide grinding teeth molars Omnivore both kinds of teeth

Essential nutrients Can not be synthesized in the body but are absolutely required Macronutrients Required in large amounts Micronutrients Required in small amounts *amino acids*

Essential minerals Chemical element required in the diet Calcium (macronutrient), Iron (micronutrient), and potassium

Essential Vitamins Carbon compounds Water soluble Fat soluble Eliminated in the urine Fat soluble Build up in the body fat and become toxic to the liver Vitamin D Helps absorb calcium

Nutrient Deficiencies Malnutrition Lack of essential nutrients in the diet Can lead to diseases and organ failure

Digestive System Function: break down large molecules into smaller, absorbable molecules *monomers and hydrolysis* Tubular gut, two openings- one at each end

Digestive systems Everybody’s got one!

Length of digestive system Carnivores short digestive system protein easier to digest than cellulose Herbivores & omnivores long digestive system more time to digest cellulose symbiotic bacteria in gut

Overview of food flow Mouth Pharynx Esophagus Stomach Small intestine Large intestine Rectum

Mouth Digestion starts Chewing and amylase- starch digesting enzyme Bolus- ball of food Swallowing is an autonomic reflex Sphincter at the base of the esophagus Epiglottis covers the trachea to make sure food does not pass into the windpipe

Stomach Holds and breaks up food Starts protein digestion Pepsinogen is inactive so it will not harm the stomach tissue lining Pepsin is activated by HCl secreted by the stomach Helps with digestion

Stomach pH is around 1 Can cause ulcers Chyme- partly digested food, acid and enzymes Smooth muscle pushed chyme into the small intestines through a pyloric sphincter

mouth break up food moisten food digest starch kill germs stomach kills germs store food break up food digest proteins cardiac sphincter pyloric sphincter

Small intestine Digestion of carbohydrates and proteins continues Digestion of fat Absorbs nutrients Duodenum – most digestion Jejunum- absorb Ileum – absorb

* Accessory organs* Liver – makes and secretes bile which is then stored in the gall bladder (then to duodenum) blood from the stomach goes to the liver to be filtered of toxins and to build macromolecules Pancreas – endocrine and exocrine gland digestive juices, glucagon and insulin

mouth break up food moisten food digest starch kill germs stomach kills germs break up food digest proteins store food liver produces bile - stored in gall bladder break up fats small intestines breakdown all foods - proteins - starch - fats - nucleic acids absorb nutrients pancreas produces enzymes to digest proteins & starch

Large intestine (a.k.a) colon Absorbs water and builds feces *dehydration from diarrhea*