Region of digestion
|
Name of the secretion
|
Enzymes or Secretion
|
Substrate
|
Optimal pH
|
Products formed
|
Mouth:
oral digestion
Salivary glands
|
Saliva
|
Salivary amylase
|
Starch
|
6.8
|
Maltose (disaccharide
) via dextrins
|
Stomach:
Gastric digestion
(a)Gastric glands
(i) Chief cells
|
Gastric juice
(a)Pepsinogen (inactive0 +
HCI----Pepsin active
(b)Prorennin (inactive)+H—Rennin
(active
(c)Gastric lipase
|
Protein
Milk protein caseinogens
Fats/Lipids
|
|
1.5 to 2.0
|
Peptones via and metaprorins nd
proteoses “
“Curdling “ of milk
Fatty acids &monoglycerides
|
(ii)Parietal cells
(iii)Mucous
(iv)G-cells
|
(a)HCI
(b)Intrinsic factor
(c)Mucuse
(d)Gastrin (in hormone
|
Pepsinogen
|
|
|
(a)Converts peopino gen (inactive )
(b) For absorption of vitamin B₁₂
(c) Protection of
underlying layers & lubrication of food.
(d) It stimulates
paritel cells to secrete HCI
|
3.
Intestine:
Intestinal
digestion
|
|
|
|
|
|
(a)Pancreas
(Pancreatic acini in exocrine part of
pancreas)
|
1.Pancreatic juice
|
Protein splitting
(a)Trypsin
: Trysinogen (inactive)+enterokinase from duodenal
mucosa>Trypsin
(b)Chymotrypsin:
Chymotrypsinogen (inactive)+trypsin>Chymotrypsin
|
Protein
|
8.0
|
Polypeptides via metaproteins,
proteoses and peptones
|
|
|
(c)Carboxypeptidate
(d)Elastase
(e) Pancreatic amylase (amylopsin)
(f) Nucleases
(i) Deoxyribonuclease
(ii) Ribonuclease
(g) Pancreatic Lipase (Fat splitting)
|
Terminal amino acids at carboxy end
Polypeptide
Starch
(carbohydrate splitting)
DNA
RNA
Fat
|
Do
8.0
do
do
do
|
Amino acids
|
Maltose (disaccharide)
Via dextrins Maltotriose
(trisaccharide)
Nucleotides
Nucleotides
Glycerol
|
(b)Liver
|
Bile
|
No enzyme; Instead contains bile salts which activate Lipases
& emulsify fats
|
|
7.1 to 7.3
|
|
(c)Small
Intestine (Brush border cells of
intestinal glands)
|
Intestinal juice (succus entericus)
|
Protein splitting
|
Polypeptides and short peptides
|
8.0
|
Amino acids Peptide fragments
|
|
|
(a)Aminopeptidase
|
(a)Terminal aminoacids at amino end
|
|
|
|
|
(b)Dipeptidase
|
Dipeptides
|
|
|
|
|
(c)
Tripeptidase
|
Tripeptides
|
|
|
|
|
(d)Maltase
(Carbohydrate splitting)
|
Maltose
|
do
|
Glucose + glucose
|
|
|
(e) Lactase
|
Lactose
|
do
|
Glucose + galactose
|
|
|
(f)
Sucrase
|
Sucrose
|
do
|
Glucose +fructose
|
|
|
(g)
Lipase
|
Fat
|
do
|
Fatty acids+glycerol
|
|
|
(h)
Nucleosidases & Phosphatases
|
Nucleotides
|
do
|
Nitrogenous bases,pentoses &
phosphate
|
|
|
Enterokinase
|
Trysinogen
|
do
|
Trypsin
|
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