The document summarizes key information about gastric juice, including its components and functions. About 2 liters of gastric juice are secreted daily by glands in the stomach mucosa. It contains water, hydrochloric acid, pepsinogens, and intrinsic factor. Hydrochloric acid acidifies food and kills microbes. Pepsins are activated by hydrochloric acid to digest proteins. Intrinsic factor enables vitamin B12 absorption. Gastric juice is secreted in three phases: cephalic, gastric, and intestinal. Secretion is stimulated by foods, hormones like gastrin, and vagus nerve signals. The stomach's functions include temporary food storage, chemical and mechanical digestion, limited absorption, and protection against micro

1. GASTRIC JUICE
Group members: Shafqat Mukhtar, Anum, Aiza

2. Gastric juice:
About 2 liters of gastric juice are secreted daily by specialized secretory glands in the
mucosa, it consist of:

4. FUNCTIONS OF GASTRIC JUICE
Water further liquefies the food
swallowed.
• Hydrochloric acid (hcl) -
(1)Acidifies the food and stops the
action of salivary amylase.
(2)Kills ingested microbes.
(3)Provide the acid environment
needed f or the action of pepsins.
• Pepsinogens are activated to pepsins
by HCL and by pepsin already
present in the

5. o Intrinsic factor (a protein) is
necessary for the absorption of
Vitamin 812 f rom the ileum.
• JCUS prevents mechanical injury
to the stomach wall by lubricating
the contents prevents chemical
injury by acting as a barrier b/w
the stomach wall and the
corrosive gastric juice (HCL and
Pepsins).

6. Secretion of gastric juice
® 3 phases of secretion
of gastric juice
1) Cephalic phase - flow of
juice occur before f
ood reaches the stomach
and is due to reflex
stimulation of the vagus
(parasymP.athetic) nerves
initiated by the sight'
smell or taste of food.
Sympathetic stimulation
e.g. during emotional stress,
also inhibits gastric activity.

7. Gastric phase
• When food enters the stomach(causing
distension of stomach) is called gastric
phase.
• Presence of food in stomach stimulates
enteroendocrine cells in the pylorus and
duodenum secrete the hormone gastrin
whi.ch passes directly into the circulating
blood.
• Circulating gastrin is supplied to the
stomach and stimulates the gastric glands.
to produce more gastric Juice, pepsin and
hcl.

8. Functions of the stomach
• These includes:
 T
emporary storage allowing time for the digestive enzymes, pepsins,to act.
 Chemical digestion-pepsins break proteins into polypeptides.
 Mechanical breakdown.
 Limited absorption.
 Non specific defense against m icrobes.
 Preparation of iron for absorption.
 Production and secretion of intrinsic factors needed for absorption of vit.B12
 Regu lation of the passage of gastric contents into the duodenum .

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