compositions of digestive enzymes and juices like saliva,gastric juice , pancreatic juice, intestinal juice, mechanism of absorption,stimulation of motor function of stomach.
4. TWO STAGE HYPOTHESIS
OF SALIVA FORMATION
Water &
electrolytes
Isotonic
primary saliva
Most proteins
Some proteins electrolytes
Na+ Cl- resorbed
K+ secreted,
Hco3
Hypotonic
final saliva
into mouth
5.
6. Factors Stimulating the
Secretion
of Hydrochloric Acid
• 1. Gastrin
• 2. Histamine
• 3. Vagal stimulation.
Factors Inhibiting the
Secretion
of Hydrochloric Acid
• 1. Secretin
• 2. Gastric inhibitory
polypeptide
• 3. Peptide YY.
According to Davenport theory, hydrochloric acid
secretion is an active process that takes place in
thecanaliculi of parietal cells in gastric glands. The energy
for this process is derived from oxidation of glucose.
12. • There are micro and macro molecules
transport. Transport by phagocytosis and
pinocytosis - endocytosis. Endocytosis-
intracellular digestion. Some substances may
be transported through intercellular spaces -
persorption. This mechanism explains the
falling into the external environment a small
number of proteins (antibodies, allergens,
enzymes) other substances (dyes) and
bacteria.
13. • Passive transport : diffusion (for the gradient of
concentration) osmosis ( for osmotic gradient )
and filtration ( for electrochemical gradient) .
Water, cations, anions, salts, fatty acids, water-
soluble , liposoluble vitamins , fructose and folic
acid are absorbed by passive transport
• Active transport (against to the gradient of
concentration, osmotic and electrochemical
gradients) . By help of protein and energy. Active
transport need energy of ATP. Amino acids,
monosaccharides are absorbed by active
transport.
14.
15. Defecation is a reflex act.
irritation of mechano receptor
↓
afferent fibers of n.pelvicus
↓
defecation center(sacral segment of spinal cord)
↓
efferent fibers of n.pelvicus
↓
smooth myocyts of
internal anal sphinchter
↓
external anal sphinchter
(center---cortex)
