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TOPIC 6.1. Digestion. Series of events in order:. Ingestion- eat the food Digestion- series of chemical rxs to convert food to smaller molecules Absorption- small molecules are absorbed through the cells of your digestive system into blood or lymphatic vessels - PowerPoint PPT Presentation
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Digestion
Ingestion- eat the food Digestion- series of chemical
rxs to convert food to smaller molecules
Absorption- small molecules are absorbed through the cells of your digestive system into blood or lymphatic vessels
Transport- circulatory system delivers the small molecular nutrients to body cells
process of making food absorbable
it must be changed into simpler chemical compounds
nutrients can't be used by the body until they are absorbed into the cells & tissues
They can't be absorbed unless they are small & soluble
MOLECULAR FORM INGESTED
FORM AFTER DIGESTION
Protein Triglycerides poly, di and
monosaccharides
DNA and RNA
Amino acids Glycerol and
fatty acids Monosaccharid
es Nucleotides
Breaking food into smallest components
ex. albumin in egg whites
contain amino acid serine
needed in pancreas to produce insulin
You can think of the digestive system as two sets of structures
First set called the alimentary canal:
consists of organs that food passes through directly
it’s a one-way tube with two openings
accessory organs outside of but connected to the alimentary canal
these organs produce digestive enzymes
Liver, pancreas, gall bladder, salivary glands, etc.
Increase rate of rx at lower T° (37°C)
Lower energy of activationAmylase in salivary glands of mouth
Pepsin (a protease) in stomach cells
Lipase in pancreas cells
Salivary Amylase
Pepsin(a protease)
Lipase
Source Salivary glands
Stomach cells
Pancreas cells
Substrate Amylose (starch)
Proteins (polypeptide
s)
Lipids
Products Maltose & glucose
Amino acids Glycerol & fatty acids
Optimum pH Neutral (pH 7)
Acidic (pH 3) Neutral (pH 7)
Be able to draw and label!!!!!!!!!!
Mouth- amylase (in saliva) mechanical digestion of all
food (teeth chewing & grinding)
chemical digestion of carbohydrates begins
esophagus- passageway to stomachsmooth muscle- peristalsis
Gastric Juices:Pepsin – protease enzymeHCl – creates optimium pH for pepsin to be active & helps degrade and breakdown food
Mucus – lines and protects stomach from HCl
mechanical digestion of food (churning of stomach walls)
1st portion called duodenum Accessory organs secrete
juices:Bile – produced in liver, stored in gall bladder (emulsifies fats)
Trypsin (protease), lipase, amylase and bicarbonate from pancreas
absorption: small soluble nutrients (sugars, amino acids, fatty acids)
Contain capillaries and lacteals (small vessel of the lymph system)
Small molecules taken into capillaries, except fatty acids which are absorbed into lacteals
lacteal
inside are two types of vessels, capillaries & lacteal
the capillaries web around the lacteal
protein & carbohydrates (amino acids & simple sugars) are absorbed by capillaries
lipids (fatty acids & glycerol) are absorbed in the lacteal
Nutrient molecules used by cells: For energy (e.g. glucose) For buiding larger molecules (e.g.
amino acids)
Assimilation= the process of bringing nutrients to a body cell and using it to build larger molecules
2. You ingest a glucose molecule in the starch of a breakfast cereal. State as many specific locations as you can for this single glucose molecule from the time it is in your mouth to the time it enters a muscle cell of your right forearm.