Abdomen/GIT Flashcards
What muscle is the most superficial muscular layer and in which direction do its fibres fun?
External oblique and its fibres run inferiorly from lateral to medial
All the muscular layers of the abdominal wall form apopneuroses across the medial part of the abdominal anterior wall - what do they form?
The linea alba (white line)
What muscle lies beneath external oblique and in what direction do its fibres run?
Internal oblique and at 90 degrees to external oblique fibres
What is the deepest muscular layer in the abdomen? What direction does its fibres run?
Transverse abdominus - fibres run transversely
What muscle forms the “six pack”? What is it enveloped by?
Rectus abdominus rectus sheath (the apopneuroses)
What blood vessel supplies the inferior abdominal wall?
Inferior epigastric artery, deep circumflex iliac arteries - branches of the external iliac artery
What blood vessel supplies the superior abdominal wall?
Superior epigastric artery
What is the venous drainage of the inferior part of the abdominal wall?
3 inguinal veins (superficial) drain into the greater saphenous vein
What is the venous drainage of the superior part of the abdominal wall?
Superficial epigastric vein
What is peritoneum?
Thin single celled layer of mesothelium
What is parietal peritoneum?
The mesothelium that covers the internal surfaces of the abdominal wall
What is visceral peritoneum?
The mesothelium that envelops the abdominal viscera
What is mesentery?
A double layered flap of peritoneum connects viscera to abdominal wall - contains blood vessels, nerves and lymphatics and fat stores
What is an omentum and what are the two omentums?
Double layered peritoneum that connects stomach to other organs: greater and lesser
Where does the greater omentum run?
Starts from greater curvature of the stomach and proximal part of duodenum –> hangs like an apron and passes back up to the transverse colon
Where does the lesser omentum run?
Between the liver and the lesser curve of the stomach
What does the inguinal canal connect and why is it clinically significant?
Connects the abdomen to the scrotum and is significant as it is a weak spot prone to herniation
What are the four main layers of the GIT moving from the lumen outwards?
Mucosa, sub-mucosa, Muscularis and Serosa
Briefly describe the mucosal layer of the GIT
Epithelial layer, underneath which is a connective tissue layer called the lamina propria - contains GALT, the innermost layer is the muscularis mucosa and is the innermost layer of smooth muscle.
Describe the submucosa of the GIT
Layer of dense connective tissue, contains nervous plexuses as well as main blood and lymph vessels
Describe the muscularis layer of the GIT
Two layers of smooth muscle: inner circular and outer longitudinal layer
Describe the serosa of the GIT
Loose connective tissue, adipose tissue and blood and lymph vessels surrounded by mesothelium
What type of epithelium lines the oesophagus?
Non-keratinised squamous epithelium
Describe the epithelium of the stomach
Single layered columnar epithelium with main invaginations that extend into the lamina propria (gastric pits)
What is the name for the folds in the stomach area and what is their function?
Rugae - to increase SA
What are the 4 sections of the stomach?
The cardia, fundus, body and pylorus
What are pilae circularis and where in the GIT are they most prominent?
Permanent folds in the mucosa - prominent in jejenum
What is the defining feature of the apical brush border?
Densely packed microvilli
What are Peyers patches?
Aggregates of lymphoid material - containing APC’s
What are Paneth cells?
Exocrine cells that secrete lysozomes - antimicrobial
What are Brunners glands? What are they a defining feature of?
Deep coiled glands that secrete alkaline mucus Duodenum
What artery supplies the upper third (cervical) section of the oesophagus?
Inferior thyroid artery
Which artery supplies the middle third (thoracic) section of the oesophagus?
Oesophageal brances from aorta and bronchial arteries
Which artery supplies the lower third (abdominal) oesophagus?
Branches from left inferior phrenic and left gastric artery
At what vertebral level does the duodenum start?
About L1
What gives the sympathetic innervation of the stomach?
The coeliac plexus (T6-T9)
What is the parasympathetic innervation of the stomach?
Vagus nerve
What are the 3 parts of the small intestine in order?
Duodenum, jejenum and ileum
What is the blood supply to the foregut?
Coeliax axis
What is the blood suppy to the midgut?
superior mesenteric axis
What divides the left and right lobes of the liver?
The falciform ligament
What duct connects the gallbladder and the common hepatic duct?
The cystic duct
Where do the pancreatic duct and common bile duct meet?
In the second part of the duodenum at the ampulla of vater
What are the intrinsic muscles of the tongue?
superior and inferior: longitudinal, transverse and vertical
What are the extrinsic muscles of the tongue?
geniglossus, hypoglossus, palatoglossus and styloglossus
What are the three extrinsic salivary glands that lie outside of the oral mucosa?
Parotid, submandibular and sublingal
What are the two layers of the peritoneum?
Parietal and visceral
What is the most fixed part of the small intestine?
Duodenum
How does the pancreas lie within the abdomen?
Retroperitoneally
Why is the ascending colon retroperitoneal?
As only its front and sides are covered with peritoneum
What does the inguinal canal “follow” in men and women?
In men: spermatic cord
Women: round ligament of the uterus
What is the inguinal canal?
An oblique passage through the lower anterior abdominal wall - not a true canal but a series of non overlapping holes in the musculo fascial layers
What is the body’s largest lymphatic organ?
The spleen
What connects the spleem to the upper part of the greater curvature of the stomach
The gastro-splenic ligament
What connects the spleen to the left kidney?
The lineo-renal ligament
What are the three major openings in the diaphragm?
The aortic, oesophageal and vena caval openings
What are the single branches of the abdominal aorta?
Coeliac artery and superior and inferior mesenteric
What artery supplies the stomach and lower end of the oesophagus?
The left gastric artery
What is the main artery that provides branches to the pancreas and fundus of the stomach?
Splenic artery
What artery supplies the gall bladder and what is it a branch of?
Cystic artery - right branch of the hepatic artery
What are the branches of the hepatic artery?
Cystic artery, gastroduodenal artery and right gastric artery
What artery supplies the midgut? (2nd part of duodenum –> half way along the transverse colon)
The superior mesenteric artery
What does the inferior mesenteric artery supply?
Hind gut: middle of transcerse colon to superior part of the anal canal
What forms the inferior vena cava?
The two common iliac veins
What does the alimentary tract and its derivatives drain via?
The hepatic portal system
What does the external iliac artery become?
The femoral artery
What are the 4 narrowings of the oesophagus?
Where pharynx becomes continuous with proximal oesophagus
Where aortic arch crosses
Where it is compressed by left main bronchus
Where it passes through the diaphragm
