GI Anatomy Flashcards
upper GI anatomy includes
- oral cavity
- salivary glands
- pharynx
- oesophagus
- stomach
- liver, pancreas and gall bladder
lower GI anatomy
small and large intestine
structure of the GI Tract
comprised of 4 layers of tissue
- serosa
- muscle layer
- sub mucosa
- mucosa
serosa
- the outer most layer
- thorax - loose covering of fibrous tissues
- Abdo/pelvis - peritoneum
muscle layer
- 2 layers - contains blood and lymph vessels and nerves
- involved in rhythmic contractions- peristalsis
- sphincters- thickened rings of muscle allow entry and prevent backflow
sub mucosa
- binds the muscle layer to the mucosa - contains blood and lymph vessels
mucosa
lining of the tract , mucous mebrane is columnar epithelium
- 3 functions - protect secrete and absorb
peritoneum - double layer
parietal and visceral peritoneum
parietal peritoneum
lines the anterior abdominal wall
visceral peritoneum
- covers the abdominal organs with loops and folds
- anchors abdominal organs to the abdominal wall
organs that are covered almost entirely by the visceral peritoneum are called?
intraperitoneal
- gall bladder
- liver
- stomach
- transverse colon
- jejunum
- caecum
- ileum
rgans that are only covered on their
anterior surface are referred to as?.
retroperitoneal.
Rectum, duodenum, ascending colon,
descending colon, adrenals, kidneys, bladder
3 parts of the pharynx
- nasopharynx - respiratory
- oropharynx - respirative and digestive
- laryngopharynx - respirative and digestive
oesophagus
- 25cm long, 2cm diameter
- centrally located
- has 2 sphincters - upper and lower
- joins the stomach inferiorly
- sharp upwards curve to reduce regurgitation of stomach contents
the stomach
- ‘J -shaped’
- continuous with the oesophagus at the lower oesophageal sphincter
- continuous with the duodenum at the pyloric sphincter
- located under the left hemidiaphragm
- divided into 3 regions -fundus, body, pylorus
stomach internal mucosa
- has longitudinal folds (rugae) - allows the stomach to stretch according to volume of contents
gross anatomy of liver
- largest gland in the body
- divided into 2 main lobes by the falciform ligament
- ## 2 smaller lobes: caudate and quadrate lobe
anatomical position of liver
mostly RUQ
covers most of the RT hypochondriac region, extends across the epigastric region and into the LT hypochondriac region
anatomic associations
- sup and ant - diaphragm and anterior abdominal wall
- inf - stomach, bile ducts, duodenum, hepatic flecure colon, rt kidney and adrenal gland
- post oesophagus, IVC, gallbladder, diaphragm and spine
- lat - lower ribs
Liver portal vein
- ## blood from stomach, spleen, pancreas, small and large intestine
liver Hepatic artery
carries arterial blood from the abdominal aorta
liver Hepatic ducts
- carrying bile from the liver the gallbladder for storage
liver lymphatic vessels
draining to the abdominal and thoracic nodes
liver hepatic veins
venous return to the IVC
liver function carbohydrate metabolism
- maintaining plasma glucose levels
- conversion of glucose to glycogen when levels are high
liver function fat metabolism
- stored fats can be converted to a form which can be used as energy
liver function protein metabolism
dea,ination of amino acids
removes the nitrogenous portion of AA making urea which is secreted as urine
liver function synthesis of plasma proteins
- plasma proteins are produced by the liver
liver function red blood cell break down
- break down of red blood cells - phagocytic hepatuc macrophages
liver function detoxification
toxic substances which arrive at the liver in the blood are deactivated
liver function secretion of bile
- assists with fat digestion
- making cholesterol and fatty acids more water soluble
liver function - heat production
- high metablic rate produces more heat
- large organ
pancreas gross anatomy
- 12-15cm long
- divided into broad head, body and tail sections
pancreas anatomical position
- transverses the RT and LT upper quadrants
pancreas anatomical associations
- head - curve of the duodenum
- body - posterior to the stomach
- tail - anterior to the spleen
endocrine function of the pancreas
- releases hormones from internal glands into the circulatory system to act to act on and regulate distant organs
exocrine function of pancreas
secretes it products into ducts for transport
pancreatic juice is produced, containing enzymes to digest carbohydrates, proteins and fats
just before entering the duodenum, the pancreatic duct….
joins with the common bile duct to form the hepatopancreatic ampulla- which opens in to the duodenum via hepatopancreatic sphincter
just before entering the duodenum, the pancreatic duct….
joins with the common bile duct to form the hepatopancreatic ampulla- which opens in to the duodenum via hepatopancreatic sphincter
small intestine comprises of
- duodenum
- jejunum
- ilieum
duodenum
- secretions from the gallbladder and pancreas enter the duodenum
- 25cm long
- 1st part of the small bowel
jejunum
- 2nd part of the small intestine
- extends from the duodenum to ileum
- 2.5m in length
ileum
- final part of the small intestine
- 3.5m in lenth
microscopic anatomy of small intestine
villi
villi
- 1mm high
- velvety texture
- longest in the duodenum
microscopic anatomy of small intestine
microvilli
- brush border appearance
- contain enzymes to help compete carbohydrate digestion
microscopic anatomy of small intestine
permanent circular folds
increased SA = increased absorption of nutrients and products of digestion
permanent circular folds (valvulae conniventes)
deep folds in the mucosa and submucosa - 1cm in depth
increases time available for absorption
when small intestine is distended - they are ruggae like
large intestine
- located peripherally to the small intesine which it surrounds within the abdominal cavity
- 6.5cm diameter
- 1.5m in length
large intestine is comprised of
- caecum
- colon
- rectum
large intestine - caecum
- start of the large intestine
- continuous with ascending colon
- appendix - fine closed tube, 8-9cm
- contains lymphoid tissue
4 parts of the colon
ascending colon, transverse colon, descending colon, sigmoid colon
ascending colon
- passes up from the caecum to the liver then curves acutely to the left to become transverse colon
transverse colon
extends across the abdominal cavity in front of the duodenum and stomach to the location of the spleen.
curves acutely downwards (splenic flexure) to become the descending colon
descending colon
passes down the left side of the abdominal cavity
at the level of the iliac crest, it becomes the sigmoid colon
sigmoid colon
s-shaped curve that continues in the pelvic cavity to become the rectum
rectum
13cm in length
slightly dialated
anal canal
- 4cm long
- passage from the rectum to the anus
- 2 muscular sphincters - internal - smooth muscle - autonomic nervous system
external sphincter - skeletal muscle - voluntary control
large intestine imaging
- barium enema
- CT abdomen with contrast
- transit time study
- CT colonography
