GI Tract Flashcards
Functions of digestive system
Break down food physically and chemically
Absorb water ‘excrete cholesterol
Function of mouth
Breakdown of food
Food mixed with saliva and broken down into small pieces before being pushed by the tongue
Pharynx
Food goes through pharynx from oral cavity to oesophagus through pharynx
Oesphagus
Tube that moves food from the pharynx to the stomach via peristalsis
Sph incter
Prevents back flow
Tongue
Swallowing
Salivary gland
Amylase
Stomach
Food storage reservoir for food
Chemical digestion
Waves of peristalsis churn food
Duodenum
Start of small intestine
Water enters through gut wall
Bile emulsify fats
Liver
Produces bile
Emulsify fat
Gall bladder
Store and concentrates bile
Pancreas
Stores insulin and glucagon
Jejunum
Next section after duodenum
Produces moulin to increase gastric motility
Mainly nutrient absorption
Ileum
Secrete intestinal juice
Final digestion
Nutrient re absorption
Large intestine
Final water and electrolyte absorption
Caecum
Acts as a reservoir
Rectum
Defeacation
Carbohydrates structure
Alpha glucose
Helical and compact for energy storage
Water insoluble
Hydrolyse quickly
Starch - amylose - long straight chains amylopectin branched chains
Carbs function
Every storage
Protein structure
1 no and equence of amino acids
2 hydrogen bonds form - a helix or b pleated sheet
3 ionic, disulphide and hydrogen bonds form 3d shape
4 more than one polypeptide chains form
Protein function
Acts as enzyme
Helps body repair cells
Fat structure
Trigylercides 1 glycerols and 3 fatty acid
Phospholipid glycerol hydrophilic head 2 fatty acids hydrophobic tails
Saturated no double bonds
Unsaturated double bon
Fat function
Energy source
Digestion of carbs
In mouth an small intestines
Amylas - start into maltose
Matisse - maltose into glucose
Protein digestion
Endopeptidase - hydrolyse Peptide bonds in middle
Exopeptidase - hydrolyse end bonds
dipeptidase hydroolyse peptide bonds in dipeptides
Absorption of carbs
Co transport
Na ions transported out of cell so has low conc in epitheal cell
Na diffuse in and glucose is contransported in
Glucose moves out by facilitated diffusion into bloodstream
Amino acids absorption
Specific ano acid cotransport proteins
For every na ion in a amino aid enters
By facilitated diffusion
Diffuses to capillaries
Lipid absorption
Lipids emulsify by bile into smaller droplets
Lipase breaks down trigylercides into monooglycerdes
Then packed into micelles and absorbed by mmicrovilli
Converted into triglycerides in the er as monoglyceride and glycerol recombine
Then packaged into chylomicrons and then enter bloodstream
Glycogenesis
Glucose molecules combines to make glycogen
Glycogenolysis
Break down of glycogen to glucose
Glycogeneogenesis
Generation of glucose from glycerol
Glycolysis
Glucose to pyruvate
Glucose broken down to produce energy pyruvate and atp
Insulin
Enables glucose to enter cells where they use t to produce energy
Reduces high blood sugar levels
Produced beta cells
Released into bloodstream when bloodstream when blood glucose are high and helps glucose in blood move across cell membrane into the cell
Glucagon
Breaks down glycogen into glucose
Increases low blood sugar levels
Produced by alpha cells
Released into bloodstream when blood glucose levels are low and breaks down glycogen at stored in liver into glucose
Healthy diet
Carbs
Dairy
Protein
Fats
Gastric juice
Prevent bacterial growth
Convert Pepsinogen to pepsin
Protein catabolism
When there is an excess of amino acids the amino group is removed - deamination
Creates by products co2 and ammonia
Ammmonia is converted into urea by the liver
Urea is excreted by the kidneys into urine
