1. Human Structure and Development 212
Abdomen 1
Abdomen – 1
Human Structure and Development 212
Week 6 – 2005
Avinash Bharadwaj
212-Wk5 L1 - avb 2005

2. Regions of Abdomen Descriptive convenience Landmarks used
Midclavicular lines (planes)
Transpyloric and transtubercular planes
Variation in descriptions
Epigastrium, umbilical, hypogastrium
Two each – hypochondrium, lumbar, iliac

3. Peritoneum Highly complex cavity, especially in the upper abdomen.
Essential concepts
Visceral and parietal layers
Mesenteries (The mesentery, mesogastrium, mesocolon etc)
Retroperitoneal structures
Greater and lesser sacs

4. Peritoneum Lesser sac Greater sac Greater omentum Lesser omentum
The mesentery –Small intestine
Mesocolon – Transverse + sigmoid

5. Retroperitoneal Structures
Organs which lose their mesentery
Secondarily retroperitoneal
Duodenum, pancreas, ascending colon, descending colon
Organs which develop posterior to the cavity
Primarily retroperitoneal
Kidneys, adrenals

6. GI Tract – General Plan Four layers Submucosa Muscularis externa
Lining epithelium + Lamina propria
Muscle layer – muscularis mucosae
Submucosa
Main connective tissue layer
Major network of blood vessels
Network of nerves
Muscularis externa
Smooth muscle
Inner circular
Outer longitudinal
Serosa or adventitia

7. Stomach Curvatures – variability in shape Parts
Fundus, body, pyloric antrum and canal
Functional divisions more important!
Interior – rugae (Folds)
Sphincters : “gate mechanisms”
Functional
Anatomical – thickening of circular muscle
What type are the sphincters of the stomach?

8. Small Intestine Absorptive function Duodenum Jejunum and ileum
Large surface area
Circular folds of mucosa
Villi – projections of epithelium
Duodenum
Largely retroperitoneal, C-shaped
Openings of bile and pancreatic ducts
Jejunum and ileum
Long, with mesentery
Gradual transition
Thinner wall, smaller folds and villi, pattern of blood vessels

9. Colon General features Caecum + appendix
Haustration
Taeniae coli – three bands of longitudinal muscle
Caecum + appendix
Vermiform appendix
Importance and positions
Ascending, transverse and descending parts
Location, peritoneal covering
Flexures – hepatic and splenic
Variability

11. Pattern of Blood Vessels
Three major arteries
Coeliac
Superior mesenteric
Inferior mesenteric
Branches and anastomoses
Long channels parallel to gut tube
Short straight vessels
Submucosa – rich network

12. Liver Largest gland in the body Functions Anatomical perspective
Production of bile
Metabolic functions – carbohydrates, amino acids
Protein synthesis
Breakdown of haemoglobin
And many others…!
Anatomical perspective

13. Liver Receives venous blood from abdominal GIT
Portal vein
Arterial blood supply – hepatic artery
Hepatic veins – venous drainage to IVC
Porta hepatis – the gateway
Hepatic artery, portal vein, bile ducts
One each from right and left ‘lobes’
Functional lobes more important!
Anatomical lobes by landmarks

14. Liver Peritoneal connections Diaphragmatic surface
Falciform ligament
Lesser omentum
Diaphragmatic surface
“Visceral” surface Details of relations not necessary
Ligamentum teres
Obliterated umbilical vein
Umbilical vein – blood from the placenta
Ligamentum venosum
Obliterated ductus venosus
Ductus venosus – shunt between portal vein and IVC

15. Portal Vein IMV  Splenic SMV + Splenic  Portal vein
Joined by smaller veins from stomach etc

16. Portasystemic anastomoses
Junctional regions
Oesophagus  systemic veins to thorax, stomach  portal vein
Anal canal (terminal part  systemic)
Other regions
“Bare area” of liver
Around the umbilicus
Around retroperitoneal organs
Liver disease especially “cirrhosis”
Portal hypertension  “varicosity”.