The Digestive System
- Created by: abbiechapman
- Created on: 01-02-15 16:15
View mindmap
- THE DIGESTIVE SYSTEM
- Digestion breaks down large molecules into smaller molecules.
- Many of the molecules in our food are polymers.
- Large complex molecules composed of long chains of monomers (small basic molecular units).
- In proteins the monomers are called amino acids, they contain hydrogen, oxygen and nitrogen.
- In carbohydrates the monomers are called monosaccharides, they contain carbon, hydrogen and oxygen.
- Insoluble - they cannot be directly absorbed into our bloodstream and assimilated in to new products.
- Polymers have to be hydrolysed into smaller, more soluble molecules by adding water.
- This process happens during digestion.
- Hydrolysis is catalysed by digestive enzymes.
- Large complex molecules composed of long chains of monomers (small basic molecular units).
- Many of the molecules in our food are polymers.
- Functions
- (2) The Stomach
- A small sac with lots of folds that allow it to expand = can hold up to 4 litres of food and liquid.
- The entrance and exit are controlled by sphincter muscles.
- The walls of the stomach produce gastric juice to help break down the food.
- Gastric juice = HCl, pepsin (an enzyme) and mucus.
- Pepsin hydrolyses proteins into smaller polypeptide chains - only works in acidic conditions provided by HCl.
- Gastric juice = HCl, pepsin (an enzyme) and mucus.
- Peristalsis of the stomach turns food into an acidic fluid called chyme.
- (1) Oesophagus
- The tube that takes food from the mouth to the stomach using waves of muscle contractions = peristalsis.
- Mucus is secreted from tissues in the walls to lubricate the foods passage downwards.
- (3) The Small Intestine
- Two main parts: the duodenum and ileum.
- Chyme is moved along the small intestine by peristalsis in the duodenum.
- In the ileum, the small, soluble molecules are absorbed through structures called villi that line the gut wall.
- Molecules are absorbed by diffusion, facilitated diffusion and active transport.
- Two main parts: the duodenum and ileum.
- (4) Large Intestine
- Absorbs water,salts and minerals.
- Has a folded wall = large surface area for absorption.
- Bacteria that decompose some of the undigested nutrients are found in the large intestine.
- (5) Rectum
- Faeces are stored in the rectum and then pass through the sphincter muscles at the anus during defecation.
- (2) The Stomach
- Glands
- The Salivary Glands
- There are three main pairs of salivary glands in the mouth.
- They secrete saliva that consists of mucus, mineral salts and salivary amylase.
- Salivary Amylase breaks down starch into maltose, a disaccharide.
- It helps to lubricate food, making it easier to swallow.
- They secrete saliva that consists of mucus, mineral salts and salivary amylase.
- There are three main pairs of salivary glands in the mouth.
- The Pancreas
- Releases pancreatic juice into the duodenum through the pancreatic duct.
- Pancreatic juice contains amylase, trypsin, chymotrypsin and lipase.
- Also contains sodium hydrogencarbonate, which neutralises the acidity of the hydrochloric acid from the stomach.
- Pancreatic juice contains amylase, trypsin, chymotrypsin and lipase.
- Releases pancreatic juice into the duodenum through the pancreatic duct.
- The Salivary Glands
- Enzymes
- Location:
- Salivary glands
- Enzyme:
- Pancreas: Amylase Trypsin Chymotryspin Carboxypepti-dase Lipase
- Stomach: Pepsin
- Salivary glands: Amylase
- Class
- Pancreas: Amylase Trypsin Chymotryspin Carboxypepti-dase Lipase
- Stomach: Pepsin
- Ileum: Maltase = Carbohydrase Sucrase = Carbohydrase Lactase = Carbohydrase Peptidase = Protease
- Stomach: Pepsin = Protease
- Salivary glands: Amylase = Carbohydras-e
- Pancreas: Amylase = Starch Trypsin = Protein Chymotryspin = Protein Carboxypepti-dase = Peptides Lipase = Lipids
- Hydrolyses
- Salivary glands: Amylase = Carbohydras-e
- Stomach: Pepsin = Protease
- Ileum: Maltase = Carbohydrase Sucrase = Carbohydrase Lactase = Carbohydrase Peptidase = Protease
- Stomach: Pepsin = Protein
- Salivary glands: Amylase = Starch
- Ileum: Maltase = Maltose Sucrase = Sucrose Lactase = Lactose Peptidase = Peptides
- Hydrolyses
- Class
- Enzyme:
- Stomach
- Enzyme:
- Salivary glands: Amylase
- Class
- Pancreas: Amylase = Starch Trypsin = Protein Chymotryspin = Protein Carboxypepti-dase = Peptides Lipase = Lipids
- Hydrolyses
- Stomach: Pepsin = Protein
- Salivary glands: Amylase = Starch
- Ileum: Maltase = Maltose Sucrase = Sucrose Lactase = Lactose Peptidase = Peptides
- Hydrolyses
- Pancreas: Amylase = Starch Trypsin = Protein Chymotryspin = Protein Carboxypepti-dase = Peptides Lipase = Lipids
- Class
- Salivary glands: Amylase
- Enzyme:
- Pancreas
- Iluem
- Salivary glands
- Location:
- Digestion breaks down large molecules into smaller molecules.
- Digestion breaks down large molecules into smaller molecules.
- Many of the molecules in our food are polymers.
- Large complex molecules composed of long chains of monomers (small basic molecular units).
- In proteins the monomers are called amino acids, they contain hydrogen, oxygen and nitrogen.
- In carbohydrates the monomers are called monosaccharides, they contain carbon, hydrogen and oxygen.
- Insoluble - they cannot be directly absorbed into our bloodstream and assimilated in to new products.
- Polymers have to be hydrolysed into smaller, more soluble molecules by adding water.
- This process happens during digestion.
- Hydrolysis is catalysed by digestive enzymes.
- Large complex molecules composed of long chains of monomers (small basic molecular units).
- Many of the molecules in our food are polymers.
- Mucus is secreted from tissues in the walls to lubricate the foods passage downwards.
- Into
- Pancreas: Amylase = Maltose Tryspin = Peptides Chymotryspin = Peptides Carboxypepti -dase = Amino acids Lipase = Fatty acids and glycerol
- Salivary glands: Amylase = Maltose
- Stomach: Pepsin = Peptides
- Ileum: Maltase = Glucose Sucrase = Glucose and Fructose Lactase = Glucose and Galactose Peptidase = Amino acids
- Pancreas: Amylase = Starch Trypsin = Protein Chymotryspin = Protein Carboxypepti-dase = Peptides Lipase = Lipids
- Into
- Pancreas: Amylase = Maltose Tryspin = Peptides Chymotryspin = Peptides Carboxypepti -dase = Amino acids Lipase = Fatty acids and glycerol
- Salivary glands: Amylase = Maltose
- Stomach: Pepsin = Peptides
- Ileum: Maltase = Glucose Sucrase = Glucose and Fructose Lactase = Glucose and Galactose Peptidase = Amino acids
- Into
Comments
No comments have yet been made