fUNCTIONAL organization of the gastrointestinal tract

1. FUNCTIONAL
ORGANIZATION OF
GIT
DR HYDER YAHYA

5. LEARNING OBJECTIVES
• Digestive system
• Sequences
• Overview
• Basic digestive processes
• Parts of digestive system
• Food stuffs
• Function of digestive system

6. DIGESTIVE SYSTEM
• Performs the MECHANICAL and CHEMICAL
processes of digestion, absorption of nutrients and
elimination of wastes.

8. DEFINED AS
• The process by which food is broken down into
simple chemical substances that can be absorbed
and used as nutrients by the body

9. SEQUENCES
• The sequences of nutrient acquisition is
• INGESTION
• DIGESTION
• ABSORPTION
• DISTRIBUTION
• USAGE

11. OVERVIEW
• The gastrointestinal system is a complex tube bounded by the
mouth at one end and the anus at the other
• Food enters the MOUTH: travel through the ESOPHAGUS,
STOMACH, SMALL INTESTINE ( duodenum, jejunum and
ileum), LARGE INTESTINE ( ascending, transverse and
descending colon) and RECTUM and then exits via the ANUS

13. BASIC DIGESTIVE PROCESSES
• FOUR BASIC DIGESTIVE
PROCESSES ARE
• Motility
• Secretion
• Digestion
• Absorption

14. MOTILITY
• Refers to the muscular contraction that mix and move forward the
contents of the digestive tract
• NOTE
Smooth muscle in the walls of digestive tract is phasic smooth
muscle that displays ACTION POTENTIAL induced bursts of contraction
It also maintains a constant low level of contraction known as TONE

15. PHASIC DIGESTIVE MOTILITY
• Two basic types of phasic digestive motility are superimposed
on this ongoing tonic activity
• Propulsive movements
• Mixing movements

17. SECRETION
• A number of digestive juices are secreted into the
digestive tract lumen by EXOCRINE GLANDS
along the route, each with its own specific
secretory products

18. DIFFERENCE
• EXOCRINE GLANDS Exocrine glands are glands that secrete substances on to
an epithelial surface by way of a duct. Examples of exocrine glands include sweat,
salivary, mammary, ceruminous, lacrimal, sebaceous, prostate and mucous
• ENDOCRINE GLANDS hormones released by internal glands of an organism
directly into the circulatory system, regulating distant target organs Important
endocrine glands include the pituitary, thyroid, parathyroid, thymus, and adrenal
glands. There are other glands that contain endocrine tissue and secrete hormones,
including the pancreas, ovaries, and testes

20. DIGESTION
• Human consumes three different biochemical categories
of energy rich food stuffs
• Carbohydrates
• Proteins
• Fats

21. WHAT IS DIGESTION
• Biochemical breakdown of structurally complex
foodstuffs of the diet into smaller, absorbable units by
the enzymes produced within the digestive system
• This all down by hydrolysis
• HYDROLYSIS = BREAKDOWN BY WATR (H2O)

22. ABSORPTION
• In the small intestine, digestion is completed and most
absorption occurs
• Through the process of absorption, the small
absorbable units that result from digestion, along with
water, vitamins, and electrolytes, are transferred from the
digestive tract lumen into the blood or lymph.

23. DIGESTIVE SYSTEM
• The digestive system consists of digestive tract (Gastrointestinal) tract
Mouth
Pharynx
Esophagus
Stomach
Small intestine
Large intestine.

24. ACCESSORY DIGESTIVE ORGANS
• Accessory digestive organs are those which help primary digestive organs in the
process of digestion.
• Accessory digestive organs are:
Teeth
Tongue
Salivary glands
Exocrine part of pancreas
Liver
Gallbladder

25. FOODSTUFFS
• Foodstuffs are complex foreign particles that would be attacked
by the immune system if they were in contact with the body
proper
• However, the foodstuffs are digested within the lumen into
absorbable units such as glucose, amino acids and fatty acids that
are indistinguishable from there simple energy rich molecules
already present in the body

26. FUNCTIONS OF DIGESTIVE SYSTEM
• Ingestion and consumption of food substances
• Breaking them into small particles
• Transport of small particles to different areas of the digestive tract
• Secretion of necessary enzymes and other substances for digestion
• Digestion of food particles
• Absorption of digestive products (nutrients)
• Removal of unwanted substances from the body

28. Summary
• WE STUDIED
• The digestive system act as mechanical and chemical processes of digestion
• It is define as process by which food is broken down into simple chemical
substances
• Sequences of nutrient acquisition which include ingestion, digestion,
absorption, distribution and usage
• The overview of GI tract from mouth to anus

29. Continued
• The basic digestive processes which includes motility, secretion, digestion
and absorption
• Motility has two movements propulsive and mixing
• Secretion is down by its own specific secretory products
• Digestion is done on carbohydrates, proteins and fats
• Absorption is done in small intestine

30. Continued
• Digestive system consists of digestive tract and accessory digestive organs
• Food stuffs are complex foreign particles that would be digested within the
lumen into absorbable units
• Function of digestive system.