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human digestive system (full) - Coggle Diagram
human digestive system (full)
digestion
definition
the process of breaking down complex food molecules into simple soluble molecules, small enough to be absorbed into the body cells
types of digestion
physical digestion
the mechanical process of food particles into smaller particles to provide large surface area to volume ratio to ensure faster rate of chemical digestion by digestive enzymes
difference
large food particle->smaller food particle
chewing, peristalsis
mechanical breakdown
chemical digestion
the breakdown of large food molecules into smaller soluble molecules catalysed by digestive enzymes through hydrolytic reactions
difference
chemical breakdown
high molecular weight->low molecular weight
hydrolytic reactions catalysed by enzymes
location-> alimentary canal
structure
small intestine
segments
jejunum
ileum
duodenum
chemical
pancreatic juice
trypsin
protein--trypsin-->polypeptides
lipase
emulsified fat--lipase-->fatty acids+glycerol
pancreatic amylase
starch--pancreatic amylase-->maltose
intestinal juice
maltase
maltose--maltase-->glucose
sucrase
sucrose--sucrase-->glucose+fructose
peptidase
polypeptides--peptidase-->amino acids
lactase
lactose--lactase-->glucose+galactose
intestinal lipase
emulsified fat--lipase-->fatty acids+glycerol
pH 9
physical adaptation possible qn
why got villi+microvilli?
to increase SA to V ratio for faster absorption of digested food substances by diffusion
why so long?
provides sufficient time for absorption to take place
epithelium is one-cell thick
to reduce the distance for digested products to diffuse into capillaries and lacteal
dense network of blood capillaries and lacteal
maintains steep concentration gradient for faster absorption
stomach
chemical+physical
churning-> chyme
produces gastric juice
HCL
kills pathogens
denatures proteins
Pepsin
proteins--pepsin-->polypeptides
optimum pH 2
up to 5kg of food
esophagus
physical
food rolled into bolus is moved along the esophagus by peristalsis
antagonistic muscles: one contracts, other relaxes
longitudinal muscles+circular muscles
large intestine
physical
absorbs water+mineral salts
mostly storage
mouth
chemical+physical
chewing: breaks down the food into smaller pieces
increases SA to V ratio, faster chemical digestion by enzyme
saliva: produced by salivary glands to soften and moisten food
salivary amylase: starch --salivary amylase--> maltose
optimum pH 6.5-7.5
associated organs
liver
produces bile
bile is not an enzyme
through the breakdown of RBC
emulsifies
breaks down big fat globule into tiny fat droplet
other functions
deamination of excess amino acids to form urea for excretion
detoxification whereby harmful substances=>harmless
break down hormones that are no longer required
[ASSIMILATION] regulation of blood glucose concentration (with pancreas darling)
store excess by converting into glycogen (insulin stimul)
break down back to glucose if needed (glucagon stimul)
protein synthesis
gallbladder
stores excess bile from the liver
releases to duodenum if more is needed
pancreas
btw theres no cure for pancreatic cancer
produces pancreatic juice
trypsin
proteins=>polypeptide
pancreatic amylase
starch=>maltose
lipase
lipds=>fatty acids+glycerol
small intestine
structure
epithelium
microvilli on epithelial cell
lacteal/lymphatic capillary
fatty acids+glycerol
diffuse into epithelial cell, form minute fat globule=>diffuse into lacteal
blood capillaries
glucose and amino acids
facilitated diffusion+active transport
answering qn take note
always include after "faster rate of digestion"-> of what to what
e.g situation "talking about bile" first make statement of function like"bile emulsifies fats"
when there is a blockage, digestion decreases, not ELIMINATED