The Human Digestive System Flashcards
(26 cards)
What are the functions of the human digestive system?
1.Breaks down complex food substances
2.Provides the very large surface area for max absorption of food.
What catalyses the breakdown of food?
enzymes
Where/How are enzymes used in the digestive system produced?
by specialised cells in the gland and in the gut lining
What are the different parts of the digestive system?
.mouth
.salivary glands
.gullet
.stomach
.liver
.gall bladder
.pancreas
.large intestine
.small intestine
.appendix
.rectum
.anus
What happens with the salivary glands?
they’re in the mouth under the tongue and produce amylase in the saliva
What is the gullet?
Oesophagus
What happens in the stomach
.pummels/churns food mechanically with its muscular walls
.produces pepsin (protease enzyme)
.Produces HCL to:
-kill bacteria
-give right pH for pepsin to work (pH 2)
What happens in the liver?
.where bile is produced
-neutralises stomach acid
-emulsifies fats
-helps digestion of lipids
.filters toxins
What happens in the gall bladder?
Where bile is stored before its released into the small intestine
-helps with digestion of lipids
What happens in the pancreas?
.produces protease, amylase and lipase enzymes
.releases the enzymes into the small intestine
What happens in the large intestine?
.Where excess water is absorbed from the undigested food to produce faeces
What happens in small intestine?
.Produces protease amylase and lipase enzymes to complete digestion
.where digested food (soluble molecules) is absorbed out of the digestive system into the blood
What happens in the rectum?
.where faeces is stored before being expelled out thru the anus (shitted out)
How do glands work in the digestive system?
salivary glands and the pancreas produce digestive juices containing enzymes which break down food
Stages of digestive system
1
Starts in the mouth, salivary glands produce saliva containing amylase to break down carbs (chemical digestion) and the teeth grind food into smaller pieces, increasing the surface area (mechanical digestion)
What does this combo of mechanical and chemical digestion do?
make digestion faster
2
The food is swallowed and travel down the Oesophagus to the stomach for the next stage of digestion
3
The stomach is a muscular, hollow, J-shaped organ. The strong muscular walls churn the food (mechanical). Proteins are also digested by protease (chemical) & small molecules (i.e.alchohols) are absorbed . The HCL in the stomach creates the optimum pH for protease and it kills bacteria in food
4
The food then passes into the duodenum in the small intestine where digestion carbs & proteins is continued & digestion of lipids begins. The bile squirted into the small intestine from the liver+gall bladder provides the optimum pH, neutralises HCL & emulsifies fats and the digestive enzymes from the pancreas help break down the food.
5
Food passes into the ileum in the small intestine. The ileum has villi around the inside which increase SA, increasing absorption (kinda like grabbing the food as it passes down). In the ileum carbs & proteins are fully digested and ALL the little molecules are absorbed into blood.
6
Anything left in the small intestine goes to the large intestine where water is absorped and undigested food is digested. Faecal matter travels through the rectum out through the anus
Villi
Which adaptions of the villi increase the SA:V?
.the wall/surface layer is only 1 cell thick which decreases the diffusion distance
.The epithelial that cover each villus themselves have projections called micro-villi which increase the SA
