Digestion, Absorption etc Flashcards
What is appetite?
Psychological desire for foods
- driven by environmental cues (senses)
- triggered by association
Hunger and satiety
- physiological function
- not food specific
- appetite can over power hunger
- regulated by the brain, esp hypothalamus
What foods keep you full longer? Shortest?
Protein and bulky = longer
Carbs and semi sold or liquids = shorter
Anatomy of the gi system
mouth, pharynx, esophagus, stomach, small intestine then large
Where does digestion start and what happen?
Mechanical = chewing Chemical = saliva mixes with food
Three salivary glands secret saliva that contain
Amylase - break down starches
Ab and enzymes - protect teeth
bicarbonate - neutralize
Digestion: mouth to esophagus
swallowing passes the food through the pharynx
once food is swallowed, becomes a bolus
swallowing causes epligottis to close trachea
Digestion: esophagus to stomach
eso has a sphincter on each end
passes through the gastrophageal sphincter to the stomach
Digestion: Stomach
- gastric acidic juices and turns bolus into chyme
- released through the pyloric sphincter into small intestine
What does the gastric juices contain
“HEMI”
- hydrochloric acid
- enzymes
- mucous: protects stomach lining
- intrinsic factor
Liver excretes what during digestion
Stored where?
Bile - helps emulsifies fats
Gallbladder stores bile
Digestion: what does the pancreas secret?
What does it do?
Sodium bicarbonate to help neutralize chyme
Digestion: lipids
What is in the stomach that degrades lipids?
Lingual lipase and gastric lipase
Digestion: lipids
What is in the small intestine that helps with digestion
(2)
- bile that emulsifies fat (brings water into suspension)
- pancreatic lipase
What are the by-product of lipids?
Monoaglyceride (glyceride +1 FA) and two individual FA units
Digestion: protein
What is in the stomach that helps with digestion?
- acid denatures proteins
- pepsin: cleaves proteins into smaller
Digestion: proteins
What are things that can degrade peptide?
Small intestine
- intestinal protease, dipeptidase, tripeptidase
What is peristalsis and segmentation
1) circular and longitudinal muscles contract to move food along
2) circular muscles contract to break up food
Active transport
Facil
active; glucose and galactose
facil; fructose
How are lipids absorbed? (ie. chylo)
- intestinal cells assemble products of digestion (choles, phospho, remade triglycerides) and transports them
- they cluster together with proteins –> chylomicron
- chylo are released into the lymphatic system
The role of micelles and enterocytes in absorption
Absorption of what macronutrient?
Lipids
- micelles collect lipids and bring them into enterocytes
- enterocytes (epithelial cells of intestines) absorb products of digestion
What products can go directly into the blood?
Short and medium fatty acid chains
Intestinal cells and absorb what proteins
Tripeptides
Dipeptides
Amoino acids
How are tri and di broken down?
Broken down by tripeptidase and dipeptidase
they are broken down into the smallest unit
