The GI tract Flashcards
Draw a diagram showing the location of the 9 abdominal regions.
R Hypochondrium Epigastrium L Hyochondrium
R Lumbar Umbilical L Lumbar
R Illiac Hypogastrium/superpubic L Illiac
Describe the arrangement of the peritoneum.
Peritoneum - Double layered serous membrane that covers the abdominal and pelvic cavities
Parietal peritoneum - Lines the body wall
Visceral peritoneum - Covers the organs
Intraperitoneal organs - fully covered by peritoneum
Retroperitoneal organs - pushed up against posterior abdominal wall and partially covered by peritoneum
Draw a labelled diagram showing the position of the organs of the digestive tract.
.
Describe the structure and function of each organ of the digestive tract.
OESPHAGUS - Pharynx -> stomach. Lined by stratified squamous epithelium
STOMACH - Stores, mechanically and chemically digests food, protects the body from bacteria via HCL, absorbs aspirin and alcohol. Funds, body, antrum and pyloric canal. Has extra layers of muscle and rugae (folds). Parietal cells - HCL and chief cells - pepsinogen
PANCREAS - secretes digestive enzymes (acini cells), water and sodium bicarbonate (duct cells)
LIVER - Bile production
GALL BLADDER - Stores and concentrates bile
SMALL INTESTINE - Duodenum (digestion), jejunum (absorption), ileum (absorb vit B12). Many features to inc SA.
LARGE INTESTINE - Caecum and colon
Describe the general histological arrangement of the gastrointestinal tract and state how this arrangement is modified in the different organs according to function.
Contains lots of microvilli and folds in order to increase surface area. Also contains lots of smooth muscle in order for peristaltic contractions to occur.
4 basic layers - Mucosa, Submucosa, Muscular externa and Serosa/Adventia
Explain how the contents of the digestive tract are mixed and moved (Chewing, swallowing, peristalsis, segmentation, haustral churning, mass movement and defecation).
Chewing - teeth cut and grind the food with the tongue helping in compaction of the bolus. Temporomandibular joint and muscles of mastication facilitate action of teeth.
Churning - Further breaks down the bolus
Segmentation - Breaks down the bolus and mixes it with gastric juices
Haustral churning - haustra are pouches that help the intestines to contract
Mass movement - Occurs in the large intestine. Powerful peristaltic contractions.
Explain the neural and hormonal control of the digestive tract.
PNS increases the activity of the GI tract and the SNS decreases it
CCK - released from pancreatic acinal cells. Causes release of bile from gall bladder. Stimulates digestion.
SECRETIN - Regulates water homeostasis. Regulates secretions from s. intestine. Stimulates bicarbonate secretion and bile production. Slows gastric juice secretions and gastric motility
GASTRIN - Increases production of gastric juices. Increases gastric motility and relaxation of the pyloric sphincter.
Describe the blood supply and the venous drainage of the digestive tract.
Has a very rich blood supply to deliver the digested products to the body and to provide all the muscles with oxygen so they can preform peristalsis.
List the secretions of each digestive organ and explain how these secretions aid digestion.
.
Explain how and where proteins, carbohydrates and fats are digested and absorbed.
.
Describe the role of fibre in the diet.
.
