Anatomy Topic 4 Case 2 Flashcards
What is the peritoneum?
- Membrane that lines the abdominal cavity and covers much of the viscera
Identify the two layers of peritoneum
- Parietal peritoneum lines the walls of the abdominal cavity
- Visceral peritoneum covers the organs
How are abdominal viscera suspended in the peritoneal cavity?
- Mesenteries
What is the difference between intraperitoneal and extraperitoneal organs?
- Intraperitoneal organs are located within the peritoneal cavity
- Retroperitoneal organs are located outside of the peritoneum with only one surface in contact with the peritoneum
What is the greater sac and where does it extent between?
- Largest space in peritoneal cavity, deep to parietal peritoneum
- Beginning superiorly at the diaphragm and continuing inferiorly into the pelvic cavity
What is the omental bursa and where is it located?
- Smaller subdivision of the peritoneal cavity
- Located posterior to the stomach and liver
How is the omental bursa continuous with the greater sac?
- Through the omental foramen
Identify the structures surrounding the omental foramen
- Portal vein and hepatic artery proper
- Bile duct anteriorly
- Inferior vena cave posteriorly
- Caudate lobe of the liver superiorly
- First part of the duodenum inferiorly
What is the purpose of peritoneal fluid in the peritoneal cavity?
- Lubricates movement of the viscera suspended in the abdominal cavity
Identify an advantage and a disadvantage of the large surface area of the peritoneal cavity
- Can be used for administering certain types of treatments and a number of procedures e.g. ventriculoperitoneal shunts for obstructive hydrocephalus.
- Facilitates the spread of disease through the peritoneal cavity and over the bowel and visceral surfaces.
Identify three types of peritoneal folds
- Omenta
- Mesenteries
- Ligaments
Identify two roles of peritoneal folds
- Contain nerves and vessels
- Maintain proper positioning of viscera
What is the embryological origin of the greater omentum?
- Dorsal mesentery
What are the attachments of the greater omentum?
- Greater curvature of the stomach and first part of the duodenum.
- After descending it turns posteriorly and ascends
- Where it becomes adherent to superior surface of transverse colon
Which vessels are positioned between the two layers of the greater omentum?
- Right and left gastro-omental vessels
What does thickening of the greater omentum indicate?
- Metastasis
What is the embryological origin of the lesser omentum?
- Ventral mesentery
What are the attachments of the lesser omentum?
- Lesser curvature of stomach
- First part of duodenum,
- inferior surface of liver
Identify the two ligaments of the lesser omentum
- Hepatogastric ligament between liver and stomach
- Hepatoduodenal ligament between liver and duodenum
What is the anatomical significance of the hepatoduodenal ligament?
- Ends laterally as a free margin
- Which serves as the anterior border of the omental foramen
What is enclosed within the free edge of the hepatoduodenal ligament?
- Hepatic artery proper
- Bile duct
- Portal vein
What are mesenteries?
- Peritoneal folds that attach viscera to the posterior abdominal wall
- That allow some movement and provide a conduit of vessels, nerves and lymphatics
Identify the embryological origin of the mesenteries?
- Dorsal mesentery
What is the mesentery?
- Large, fan shaped, double-layered fold of peritoneum
- That connects the jejunum and ileum to posterior abdominal wall
What is are the superior and inferior attachments of the mesentery?
- Superior: duodenojejunal junction
- Inferior: Ileocecal junction
What is the transverse mesocolon?
- Double layered fold of peritoneum that connects the transverse colon to the posterior abdominal wall
What is the anterior layer of the transverse mesocolon adherent to?
- Posterior layer of greater omentum
What is the sigmoid mesocolon?
- V-shaped peritoneal fold
- That attaches the sigmoid colon to the abdominal wall
- Wit the apex of the V near the left common iliac artery
- Left limb along the medial border of the left psoas muscle
- Right limb descending into pelvis at level L3
What are ligaments?
- Two layers of peritoneum that connect two organs to each other or an organ to the body wall
Identify the four parts of the stomach
- Cardia
- Fundus
- Body
- Pyloric part
Identify the different parts of the pyloric part of the stomach
- Pyloric antrum
- Pyloric canal
- Pylorus
Identify the different parts of the pylorus
- Pyloric constriction
- Pyloric sphincter
- Pyloric orifice
At which vertebral level is the pylroic orifice located?
- Lower border of L1 (transpyloric plane)
Identify which artery the left gastric artery arises from and the part of the stomach that it supplies
- Branches from coeliac trunk
- Lower third of oesophagus + upper right part of stomach
Identify which artery the right gastric artery arises from and the part of the stomach that it supplies
- Hepatic artery proper
- Lower right part of stomach
Identify which artery the short gastric arteries arises from and the part of the stomach that it supplies
- Splenic artery
- Fundus
Identify which artery the left gastro-omental artery arises from and the part of the stomach that it supplies
- Splenic artery
- Upper part of greater curvature
Identify which artery the right gastro-omental artery arises from and the part of the stomach that it supplies
- Gastroduodenal branch of hepatic artery proper
- Lower part of greater curvature
Which vessel do the left and right gastric veins drain into?
- Directly into portal vein
Which vessel do the short gastric veins drain into?
- Splenic vein
Which vessel do the left-gastro-omental veins drain into?
- Splenic vein
Which vessel do the right-gastro-omental veins drain into?
- Superior mesenteric vein
Outline the lymphatic drainage of the stomach
- Left and right gastric nodes
- Left and right gastro-omental nodes
- Short gastric nodes
- Into coeliac nodes around the root of the coeliac artery on the posterior abdominal wall
Outline the parasympathetic nerve supply to the stomach
- Anterior and posterior vagal trunks
- Anterior vagal trunk gives off a large pyloric branch
- Posterior vagal trunk passes to coeliac and superior mesenteric plexuses
Outline the sympathetic nerve supply to the stomach
- Preganglionic fibre from T6
- Passes through white ramus communicans into sympathetic trunk
- Synapses with coeliac ganglion
- Gives off postganglionic neuron which accompanies branches of coeliac trunk to supply stomach
Identify the histological layers of the stomach
- Mucosa composed of gastric pits
- Muscularis mucosae
- Submucosa
- Inner oblique muscle layer
- Inner circular layer
- Outer longitudinal layer
Identify five types of cells of gastric glands and their function
- Neck mucus cells, secrete mucus
- Parietal cells, secrete gastric acid and intrinsic factor
- Chief cells, secrete pepsinogen
- Stem cells, replace old cells
- Neuroendocrine cells, secrete hormones (e.g. G cells that secrete gastrin)
Identify the structure of a gastric parietal cell
- Plasma membrane forms canaliculi that extent throughout the cytoplasm
- Which consists of membrane bound vesicles which include a proton pump
Identify the mucosal transition at the pyloric sphincter
- From glandular secretory type
- To villous absorptive type
What are Brunner’s glands?
- Mucus-secreting glands
- Located exclusively in submucosa of duodenum
- Secrete a thin, alkaline mucus
Identify the three anterior branches of the abdominal aorta and the region of the primitive gut tube that each supplies
- Coeliac trunk (foregut)
- Superior mesenteric artery (midgut)
- Inferior mesenteric artery (hindgut)
Identify the contents of the foregut
- Abdominal oesophagus
- Stomach
- Spleen
- Duodenum
- Liver
- Gallbladder
Identify the contents of the midgut
- Jejunum
- Ileum
- Cecum
- Appendix
- Ascending colon
- Right 2/3 of transverse colon
Identify the contents of the hindgut
- Left 1/3 of transverse colon
- Descending colon
- Sigmoid colon
- Rectum
- Upper part of anal canal
Identify the three branches of the coeliac trunk
- Left gastric artery
- Splenic artery
- Common hepatic artery
Outline the course taken by the left gastric artery and identify its branches
- Ascends to the cardioesophageal junction
- Sends oesophageal branches to the abdominal oesophagus which anastomose with oesophageal branches of thoracic aorta
- Turns right and descends along lesser curvature to anastomose with right gastric artery
Outline the course taken by the splenic artery and identify its branches
- Travels along superior border of pancreas
- Gives off branches to supply neck, body and tail of pancreas
- Passes in splenorenal ligament and enters hilum of spleen
- Gives off short gastric artery and left gastro-omental artery which anastomoses with right gastro-omental artery
Outline the course taken by the common hepatic artery and identify its branches
- Runs to the right and divides into hepatic artery proper and gastroduodenal artery
Outline the course of the hepatic artery proper and identify its branches
- Ascends toward liver in free edge of lesser omentum
- Runs to left of bile duct and anterior to portal vein
- Divides into right and left hepatic artery
- Right hepatic artery gives of cystic artery
Outline the course of the gastroduodenal artery and identify its branches
- Gives off supraduodenal artery and posterior superior pancreaticoduodenal artery
- Descends posterior to superior part of duodenum
- Gives off its terminal branches, right gastro-omental and anterior superior pancreaticoduodenal artery
Which veins unite to form the portal vein? At which vertebral level does this occur?
- Splenic vein and superior mesenteric vein
- L2
Outline the course of the portal vein
- Ascends towards liver
- Enters the right margin of the lesser omentum
- Divides into right and left branches which enter liver parenchyma
Identify three tributaries of the portal vein and what they drain
- Right and left gastric veins (draining lesser curvature and abdominal oesophagus)
- Cystic veins (draining gallbladder)
- Para-umbilical vein (anterior abdominal wall)
Outline the course of the splenic vein
- Leaves hilum of spleen
- Passes right through splenorenal ligament
- Passes over pan
- Joins superior mesenteric vein to form portal vein
Identify four tributaries of the splenic vein and what they drain
- Short gastric veins (fundus)
- Left gastro-omental vein (greater curvature)
- Pancreatic veins (body and tail of pancreas)
- Inferior mesenteric vein
What do the coeliac nodes drain into?
- Cisterna chyli
What are the sympathetic trunks
- Two parallel nerve cords that descend on either side of the vertebral column
Describe the positioning of the sympathetic trunks as they descend through the thorax and abdomen
- Posterior to carotid sheath
- Anterior to neck of ribs in upper thorax
- Lateral aspect of vertebral bodies in lower thorax
- Anterolateral to lumbar bodies continuing into pelvis
How many of the each of the different types of ganglia are there in the sympathetic trunks?
- 3 cervical
- 11 thoracic
- 4 lumbar
- 4 sacral
- Ganglion impar anterior to coccyx
How are the ganglia and trunk connected to adjacent spinal nerves?
- Grey rami communicantes
How are the ganglia and trunk connected in the region of T1-L2?
- White rami communicantes
What are splanchnic nerves?
- Pass from sympathetic trunk
- To sympathetic ganglia
Identify the three types of thoracic splanchnic nerve, from where they arise and to which ganglion they travel to
- Greater: 5-9th thoracic ganglia to coeliac ganglion
- Lesser: 10-11th thoracic ganglia to aorticorenal ganglion
- Least: 12th thoracic ganglia to renal plexus
To which nerve plexus do lumbar splanchnic nerves pass to?
- Prevertebral plexus
To which nerve plexus do pelvic splanchnic nerves pass to?
- Inferior hypogastric plexus (extension of prevertebral plexus in pelvis)
Why are pelvic splanchnic nerves unique?
- They carry parasympathetic fibres
- Meaning they do not originate from sympathetic trunk
- Rather, they arise from anterior rami of S2 to S4
What do the pelvic splanchnic nerves innervate?
- Distal 1/3 of transverse colon
- Descending colon
- Sigmoid colon
What is the abdominal prevertebral plexus?
- Collection of nerve fibres that surrounds the abdominal aorta
Identify the three major divisions of the abdominal prevertebral plexus
- Coeliac plexus
- Aortic plexus
- Superior hypogastric plexus
Identify the ganglia associated with the coeliac plexus
- Two coeliac ganglia
- One superior mesenteric ganglion
- Two aorticorenal ganglia
Identify the ganglia associated with the aortic plexus
- Inferior mesenteric ganglion
Identify the ganglia associated with the superior hypogastric plexus
- Numerous small ganglia
Identify fibres to the abdominal prevertebral plexus
- Preganglionic parasympathetic fibres from vagus nerve
- Preganglionic sympathetic fibres from splanchnic nerves
Identify two sources of parasympathetic innervation to the abdominal viscera
- Vagus nerves which give off vagal trunks which give off branches containing preganglionic parasympathetic fibres to prevertebral plexus
- Pelvic splanchnic nerves, carrying preganglionic parasympathetic fibres from S2-S4 to hypogastric plexus
Identify two two plexuses of the enteric nervous system, where they are located and what they control
- Myenteric plexus between outer longitudinal and inner muscular layers, controlling GI movements
- Submucosal plexus in submucosa controlling GI secretions and local blood flow
Which regions of the abdomen is the stomach located in?
- Left hypochdonrium
- Epigastric region
- Umbilical region
