Seminar
On

• Stomach is a hollow muscular organ consisting of following parts
1. Fundus
2. Body
3. Pyloric part
Body

Physiologically stomach is devided into two parts
1. Orad portion
2. Caudad portion
Orad
Caudad

• In the empty state the stomach is contracted and its mucosa and submucosa are thrown up into distinct folds called rugae

• Storage of food
• Mixing of food with gastric secretion
• Slow empting of stomach

1. Food enter in stomach and form concentric circle of food in orad portion of stomach
2. Newest food lying closest to the oesophageal opening
3. Oldest food lying nearest the outer wall of the stomach

• This reflex also known as receptive relaxation
• Reflex start from stomach to the brain stem and then back to the stomach this is vagovagal reflex
• This reflex reduces tone in muscular wall of the body of stomach
• Normal capacity of relaxed stomach is 0.8-
1.5 liter

-40 mV
Mixing of food with gastric
• Basic electrical secretion rhythm
• It is electrical slow wave
• It Initiate peristaltic constrictor wave in gut wall
-80 mV
00 5 10 15 20
Time (sec)
25 30 35 40 45

Weak peristaltic constrictor wave
• It is mixing wave
• Start in mid to upper portion of stomach wall and move towards antrum in every 15 - 20 sec.
• constrictor wave process from body of stomach in to antrum
• It become extreemly intense and provide powerful peristaltic action potential.
Relaxation
Grinding

• A wave of contraction closes the distal antrum thus as the caudad stomach contracts. Food is propelled back into the stomach to mixed
• It is an important mixing movement mechanism in the stomach

• After food in the stomach has become thoroughly mixed with the stomach reaction the resulting, murky semifluid mixture called chyme

• Stomach emptying promoted by intense peristaltic contraction or pyloric pump
• Emptying of stomach opposed by resistance to passage of chyme at the pylorus

Pyloric pump or
Intense Peristaltic Contraction
• Intense peristaltic wave force up to several ml of chyme into duodenum
• This wave causing mixing in the stomach also provide pumping action called pyloric pump

Role of Pylorus in controlling stomach emptying
• Distal opening of stomach is pylorus there is a circular muscle called pyloric sphincter
• Pylorus usually open enough for water and other fluid to empty from stomach into duodenum
• Constriction usually prevent passage of food particles until they have become mixed in the Chyme

• Stomach empties is regulated by signal from both stomach and duodenum controlling the emptying of chyme into duodenum at a rate no greater than the rate at which the chyme can be digested an absorbed in the small intestine

• Gastrin hormone
• Gastric food volume

• GIP
• CCK
• Secretin
• H+ ion in duodenum

• Vomiting is a forceful expulsion of contents of the stomach and often the small intestine