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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*