Ch 39 Nutrition, Digestion and absoption

AP lecture

Recap

• Heterotrophic

• Autotrophic

• Catabolism

• Glycogen

What do animals need to live?

O2

food

ATP

• Animals make energy using:– food– oxygen

• Animals build bodies using:– food for raw materials • amino acids, sugars,

fats, nucleotides

– ATP energy for synthesis

Teeth • Carnivore– sharp ripping teeth– “canines”

• Herbivore– 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 – 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 systemsEverybody’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

stomachkills germs store food break up fooddigest proteins

cardiacsphincter

pyloricsphincter

mouthbreak up foodmoisten food digest starchkill germs

• 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

small intestinesbreakdown all foods

- proteins- starch- fats- nucleic acids

absorb nutrients

stomachkills germs break up fooddigest proteinsstore food

pancreasproduces enzymes to digest proteins & starch

liverproduces bile

- stored in gall bladderbreak up fats

mouthbreak up foodmoisten food digest starchkill germs

• Large intestine (a.k.a) colon – Absorbs water and builds feces

*dehydration from diarrhea*