UNIT 2: Foregut Flashcards
What structures does the pharynx connect with?
Connects to the nasal cavity by the nasopharynx
Connects to the oral cavity through the oropharynx
Continues inferiorly as the laryngopharynx which will then split into two as the oesophagus and the trachea.
What are the different sections of the large intestine?
The cecum
The ascending colon
The right colic flexure
The transverse colon
The left colic or splenic flexure
the descending colon
The sigmoid colon
How is the excretion of food through the anus controlled?
Through an internal and external sphincter
What are the accessory organs of digestion?
Salivary gland
Liver
Pancreas
Gall bladder
Name the different types of slivary glands.
Parotid gland
Submandibular gland
Sublingual gland.
Give an overview of bile in digestion?
Produced/secreted in the liver and stored in the gall bladder.
Key role in the digestion of fats
How does accessory organs of digestion link up with the small intestine?
Glands from the liver, gall bladder and pancreas connect with the small intestine.
What does the pancreas do?
Produces a basic mixture to neutralise acid content entering the small intestine from the stomach. Also secretes digestive enzymes.
What is the reasoning behind where the duodenum and the pancreas connect?
Pancreas connects to the lower corner like appearance of the duodenum.
This acts as a pool for digesting content to sit in and be covered by secretions from the pancreas and gall bladder before entering the jejunum
Give a basic description of the peritoneum. As if to a five year old.
A basic sheet like structure that covers and folds around certain abdominal structures.
What is the difference between intraperitoneal and retroperitoneal?
Intraperitoneal are entirely covered on all surfaces by the peritoneum.
Retroperitoneal organs are being pushed posteriorly by the peritoneum so are only covered on their anterior side.
What structures are intraperitoneal?
The stomach, the ileum and the jejunum.
What is the difference between visceral and parietal?
visceral peritoneum surrounds the organs surface
Parietal is any other part of the membrane excluding the mesentry.
What is meant as mesentry?
The section of the peritoneum or any pleural membrane which is being ‘pinched off’ from an organ.
How does the peritoneal membrane affect movement?
Retroperitoneal structures are effectively strapped to a location such as the abdominal wall so have very little movement.
A mesentery in the peritoneal allows a greater range of movement of these structures.
What is the greater omentum?
A folding of the peritoneum, it extends downwards from the greater curvate of the stomach, reaches level with the end of the descending colon (roughly), then fold back up on itself.
Foldes around the posterior section of the transverse colon then pinches off to make contact with the posterior abdominal wall.
Is a sheet like structure.
What is the lesser omentum?
An extension of the peritoneum.
Extends from the lesser curvature of the stomach.
Made of the hepatogastric ligament which connects the liver to the stomach.
Also made of the hepatoduodenal ligament from the liver to the duodenum.
What allows for extension of the stomach?
Rugae - folds in the lining of the stomach, they are most numerous when the stomach is at rest.
What is the name of the collections of the longitudinally arranged smooth muscle along the wall of the large intestine?
Teniae coli
What are the different sections of the aorta?
Asceding aorta when it first leaves the heart.
Branching aorta (vessels to supply the head and neck)
At level T4 becomes the descending aorta, divided into the thoracic and abdominal aorta by the diaphragm.
What is the diameter of the aorta like?
very thick but is still highly elastic.
What are the three unpaired vessels of the aorta?
The celiac trunk - supplies foregut.
The superior mesentric artery - large parts of the abdomen derived from the midgut.
The inferior mesenteric artery - inferior sections, of the gut
What are the subdivision of the celiac trunk?
What areas of the body to they supply with blood?
The splenic artery - supplies the spleen and the body/tail of the pancreas
Common hepatic artery - live, gallbladder, head of pancreas, parts of duodenum and the greater curvature of the stomach
Left gastric artery - lesser curvature of the stomach
what areas of the body does the superior meseteric artery supply with blood?
Supplies to parts of the duodenum and the pancreas.
2/3 of the proximal large intestine (all ascending and parts of transverse).
All of the jejunum and the ileum
The midgut.
What areas of the body does the inferior meseteric artery supply with blood?
Last third of the transverse colon
Descening colon
Sigmoid colon
Superior third of the rectum.
Where do sympathetic nerves arise from?
The central parts of the spinal cord.
Where do parasympathetic nerves arise from?
The inferior sections of the spinal cord.
Or within the brain stem.
What is the parasympathetic nerve supply for the foregut?
Originates solely from the brainstem as the vagus nerve.
Travels through the diaphragm.
Connects as a bundle of nerves called the coeliac ganglion
Travel along the branches of the abdominal aorta, end in synpases.
Where is the coelic ganglion located?
Near where the celiac branches originate from the abdominal aorta.
Explain the first part of the sympathetic nerve structure?
Branches out of vertebrae.
At each level has a sympathetic chain ganglion which are connected by the sympathetic trunk.
Explain how the sympathetic nerves in the foregut originate from the chain of sympathetic ganglions??
Pass through the sympathetic chain but do not synapse in the sympathetic chain ganglion.
Branch off into thoracic splanchic nerves.
Grouped as greater, lesser and least splanchnic nerves.
Greater travels towards the celiac ganglion nerves, here it synapses and the postsynaptic axon continue along the blood supply to supply organs.
What is contained within the foregut?
The oesophagus, the stomach, parts of the small intestine, (from which the liver and pancreas develop)
What is considered within the hindgut?
Distal third of the transverse colon to the pectinate line in the anal canal
What is contained within the midgut?
Where the major duodenal papila enters the duodenum to the second third of the transverse colon (second third included in midgut)
Where does the coeliac trunk orginate and what does it split into?
Orignates from the abdominal aorta at T12 levels.
Splits into:
Common hepatic artery
Splenic Artery
Left Gastric artery.
What direction does the common hepatic artery travel and what does it supply?
First travels in a antereolateral direction to supply the pancreas.
Then it travels to supply the first part of the duodenum and become the right gastric artery.
Travels anterosuperiorly to become the hepatic artery proper and the gastroduodenal artery supplying the liver and the pylorus of the stomach/head of duodenum/head of pancreas.
What direction does the left gastric artery travel in and what structures does it supply?
Travels superiorly to supply the oesophagus.
Curves backwards on itself to travel more inferiorly and anteriorly to supply the lesser curvature of the stomach.
What direction does the splenic artery travel and what structures does it supply?
Travels anteroinferior to the pancreas, then passes anteriorly to the left kidney and adrenal gland (does not supply these) to enter the spleen as the splenic branches and the splenic artery.
Also branches into the short gastric artery to supply the posterior and superior surface of the stomach.
And the left gastroomental artery to supply the left greater curvature if the stomach
Which of the branches of the celiac artery is the smallest?
Left gastric artery
What one of the branches of the celiac artery is described as torus and what does this mean?
The splenic artery.
Ranges in length from 8 to 32 cm.
This means the artery twists often to form donut shaped loops.
What two sections does the common hepatic artery split into?
A hepatic componenet made of the proper hepatic artery.
The GI tract component made of the right gastric artery and the gastroduodenal artery.
What is the relationship between the splenic artery and the pancreas?
The splenic artery travels anetrioinferiorly to then travel just superiorly to the body and tail of the pancreas.
What is the basic structure of the oesophagus?
A fibrosis cular tube, approximately 25cm in length that transports food from the pharynx to the stomach.
It originates at the cricoid artery at C6 and extends to the cardiac orifice of the stomach
What is the anatomical course of the oesophagus?
Begins at C6 level and is continuous with the laryngeal pharynx superiorly.
Travels down the mediastinum between the trachea and the. vertebrae.
At T10 it enters the abdomen at the oesophagus hiatus.
Then terminates by joining with the cardiac orifice at T11.
What is peristalsis?
Rhythmic contraction of muscle is the oesophagus to transport food.
Explain how the foregut develops.
It starts as a long cylindrical tube, then as it grows it rotates on its axis and lengthens along a double curve.
This continues to form a double curvature and widens to become the stomach and the proximal part of the duodenuem.
How does the peritoneum of the foregut differ from the rest of the digestive system in embryonic development?
Attahces to the peritoneum is two places, posteriorly and anteriorly.
These are called the dorsal and ventral mesogastrum.
Other structures of the gut only attach along the dorsal end.
How does the location of the dorsal and ventral mesogastrum change as the gut develops?
As the gut develops and rotates the mesogastrum also rotate from their solely anterior and posterior location.
They become more curved.
The ventral mesogastrum swings round to the right and ends up running along the lesser curvature of the stomach and the top proximal duodenum.
The dorsal mesogastrum swings round to the left and runs along the greater curvature of the stomach and the underside of the duodenum.
What structures develop in the mesogastrum?
The liver develops inside the ventral mesogastrum.
The spleen develops in the dorsal mesogastrum.
The liver grows rapidly in size pressing against the body walls, this creates a pocket called the lesser sack that is posterior to the stomach and
What are the greater and lesser omentum?
The lesser omentum attaches the stomach to the liver and the duodenum, marks the boundary of the lesser sack.
The greater omentum attaches the stomach to the transverse colon, also marks the boundary of the lesser sack.
How are the greater omentum and the greater sack linked?
The greater omentum grows down to become the greater sack.
The greater omentum grows inferiorly, anteriorly over the transverse colon, it fuses with the transverse mesacolon