- •2. Cell
- •3. Tissue
- •4. Epidermis
- •5. Dermis
- •6. Cutaneous appendages
- •7. Matter
- •8. Skeletal system
- •9. Muskular system
- •10. Skeleton
- •11. Muscles
- •12. Bones
- •13. Bones. Chemical structure
- •14. Skull
- •15. Neck. Cervical vertebrae, cartilages, triangels
- •16. Neck. Root, fascies of the neck
- •17. Thoracic wall
- •18. Blood. Formed elements of the blood. Erythrocytes and platelets
- •19. Blood. Formed elements of the blood. Leukocytes
- •20. Plasma
- •21. Hematopoietic tissue. Erythropoiesis
- •22. Hematopoietic tissue
- •23. Arteries
- •24. Capillaries
- •25. Veins
- •26. Heart
- •27. Lungs
- •28. Respiratory system
- •29. Lung volumes and capacities
- •30. Ventilation
- •31. Air flow
- •32. Mechanics of breathing
- •33. Surface tension forces
- •34. The nose
- •35. Nasopharynx and larynx
- •36. Trachea
- •37. Respiratory bronchioles
- •38. Pleura
- •39. Nasal cavities
- •40. Pharynx and related areas
- •41. Oral cavity
- •42. Oral glands
- •43. The digestive tract structure
- •44. The digestion
- •45. The digestive system: the function
- •46. The digestive system: liver and stomach. Sources of energy
- •47. The urinary system: embriogenesis
- •48. The urinary system: kidneys
- •49. The urinary system: kidney vascular sypply
- •50. The urinary system: ureters, uretra
- •51. The kidney's function
- •52. Acute renal failure
- •53. Iron in the body
- •54. Atherosclerotic mechanisms
- •55. Advances in blood component separation and plasma treatment for therapeutics
- •56. Artificial oxygen carries
43. The digestive tract structure
The gastrointestinal tract and associated organs are collectively called the digestive system. This system is responsible for receiving food and breaking it down by using enzymes from the glands and by the movement of the various parts of the intestinal tract; for absorption of these components into the blood; and for eliminating undigested food and certain metabolic wastes from the body. The alimentary canal extends from the mouth to the anus. It is a long tube varying in size and shape depending on what function the particular part performs. The tract has a very good blood sup ply, because food, once it is broken down, has to be absorbed into the bloodstream. The mouth contains the tongue and the teeth and communicates with the salivary glands situated round it. Behind the nose and mouth is the pharynx. Leading from the pharynx is a mus cular tube called the esophagus which passes down the thoracic cavity to the stomach. The stomach lies below the diaphragm in the upper left side, of the abdominal cavity. The opening into the small intestine is called the pylorus and is closed by the pyloric sphincter. The small intestine is a muscular tube coiled up in the abdominal ca vity. It is divided into three parts; the duodenum, the jejunum, and the ilium. The large intestine, also a muscular tube but with wider lumen than the small intestine, is often called the colon. It is divided into several different parts: the, cecum, the ascending colon, the transverse colon, the descending colon, the rectum and the anal canal. The glands belonging to the digestive system are the salivary glands, the liver and the pancreas.
Stomach is probably the most distensible of any in the human body. The proximal portion is the cardiac portion; the portion above the entrance of the esophagus is the fundus; the distal portion is the pyloric part; and the body is between the fundus and the pyloric part.
The coats of the stomach are four: an outer, peritoneal or serous coat; a muscular coat, made up of longitudinal, oblique, and circular fibres; a submucous coat; and tine mucous coat or membrane forming the inner lining.
Gastric glands, which are in mucous coat, secrete gastric juice containing hydrochloric acid and other digestive enzymes into the cavity of the stomach. The glands of the fundus and body moot important in the secretion of gastric juice.
The shape of the stomach varies from individual to individual and from time to time in the same individual depending upon the degree of digestion, degree of contraction, and the age and the body–built of the individual. Frequently in more J–shaped than U–shaped so that its greater curvature can even lie in the greater pelvis. Cardia and fundus are relatively fixed and, hence, tend to move only with the respiratory excursions of the diaphragm.
New words
gastrointestinal tract – желудочно–кишечный тракт
food – пища (еда)
enzymes – ферменты
intestinal tract – кишечный тракт
anus – задний проход
esophagus – пищевод
diaphragm – диафрагма
abdominal – брюшной
pyloric sphincter – пилорический сфинктер