2 animal nutrition -_lesson2_ppt_final (2)
DESCRIPTION
2 animal nutrition -_lesson2_ppt_final (2)TRANSCRIPT
Human Digestive
System
1. Describe the functions of the stomach, duodenum, pancreas, gall bladder, liver, ileum, jejunum in relation to physical digestion, chemical digestion, absorption of nutrients and water.
2. State the function of proteases pepsin and rennin on proteins and list the end products of protein digestion in the stomach.
3. List the digestive enzymes produced by the intestinal glands and pancreas.
4. Describe the function of bile in the emulsification of fats.
Objectives
Stomach Peristalsis in the stomach wall churns and break up the food
Peristalsis also mix food with the gastric juice
Gastric gland secrete gastric juices into the stomach
Hydrochloric acid
Proteases •Pepsin •Rennin
Hydrochloric acid
•Kills most bacteria taken in with food
•Provides an acidic medium suitable for the action of gastric enzymes.
Stomach
Hydrochloric acid
Pepsinogen Pepsin (active enzyme)
Prorennin Rennin (active enzyme)
Why is pepsinogen produced instead of pepsin?
To prevent pepsin from digesting the
stomach walls
Protein Digestion
Proteins Polypeptides
Pepsin
Soluble Insoluble milk proteins milk proteins
Rennin
Insoluble Polypeptides milk proteins
Pepsin
Why is there no digestion of starch in the stomach?
The acidic environment in the stomach due to the presence of hydrochloric acid. Salivary amylase works best in alkaline pH. Thus no starch is digested in the stomach.
Question Time!
Stomach After mixing and enzyme digestion, food becomesa nutrient-rich broth : Chyme
Small IntestineDigestion of carbohydrates, proteinsand fats and absorption of digestedfood products, water and mineral salts
Liver
Pancreas
Gall bladder
Duodenumof Small intestine
DuodenumChyme from the
stomach is mix with digestive juices
produced from the intestinal gland, liver and
pancreas
Liver
Pancreas
Gall bladder
Duodenumof Small intestine
Pancreatic juice, bile and intestinal juice are
alkaline.• Neutralize the acidic
chyme• Provide a suitable
medium for the action of pancreatic and intestinal enzymes.
Secrete Intestinal juice
Maltase Sucrase
Lactase ErepsinIntestinal
lipase
Intestinal Gland
Secrete Pancreatic Juice:
• Pancreatic amylase,• Pancreatic lipase • Trypsinogen
trypsin (active enzyme)
Pancreas
enterokinase
Region of Digestion
Source Enzyme Action
MOUTH Salivary glands Salivary amylase Starch Maltose
STOMACH Gastric glandsPepsin
Rennin
Protein Polypeptide Soluble Insoluble milk proteins milk proteins
SMALL INTESTINE
Pancreas
Intestinal glands
Pancreatic Amylase
Trypsinogen trypsin
Pancreatic Lipase
Maltase
Erepsin
Lipase
Starch Maltose
Protein Polypeptides
Fats Fatty acids+ glycerol
Maltose Glucose
Polypeptides Amino acids
Fats Fatty acids+ glycerol
Liver produces bile which is an enzyme that breaks down fats
The bile salts which emulsify fats into tiny fat droplets is stored in the liver
Four friends werediscussing about the
role of the gall bladder,
liver and the function of
bile. Who do you agree
with the most? Explain why
others are not correct.
Bile which emulsify fats is produced from the liver and stored in the gall bladder
Gall bladder produces bile which breaks down fats
John
Daniel
Mary Bella
Liver cells secrete bile containing bile salts and bile pigmentBile = bile salts + bile pigment
Bile is temporarily stored in the gall bladder
Bile flows into the duodenum via the bile duct
Bile salts emulsify the fats by reducing the attractive forces between the fat molecules
Physically breaks-up the fat molecules
Bile Salts
Tiny fat droplets
Increase surface area to volume ratio – speed up digestion by lipase.
Bile salts
1. Describe the functions of the stomach, duodenum, pancreas, gall bladder, liver, ileum, jejunum in relation to physical digestion, chemical digestion, absorption of nutrients and water.
2. State the function of proteases pepsin and rennin on proteins and list the end products of protein digestion in the stomach.
3. List the digestive enzymes produced by the intestinal glands and pancreas.
4. Describe the function of bile in the emulsification of fats.
Let’s Review
Due to cancer of the stomach, the entire stomach of Patient A have being surgically removed.
As the doctor of Patient A, you are to provide information on the effect on the lifestyle and digestive function upon removing the stomach.
• Stomach is the site of initial protein digestion. Removal of stomach will cause protein digestion to be greatly affected;
• Patient A can rely only on the small intestine for protein digestion, rate of protein digestion will be lowered.
• No HCl, prone to food infection by bacteria.• Need to reduce protein intake to avoid congesting
the small intestine.