Flashcards in GI Deck (142):
What makes up the upper GI?
Oral cavity, pharynx, oesophagus, stomach and small intestine.
What does the TMJ stand for and what is its job?
Opening and closing of the jaw.
What is the collective name of the muscles that control the TMJ?
The muscles of mastication.
Name the muscles of mastication?
Which muscles are responsible for opening and closing the mouth?
Only the the lateral pterygoid is responsible for opening (gravity helps).
and medial pterygoid closer the mouth.
What cranial nerve controls the muscles of mastication?
The mandibular division of the trigeminal nerve.
Where are the palatine tonsils?
The arches of the soft palate, either side of the uvula.
Usually the tonsils that are removed.
What cranial nerves supply the teeth?
Maxillary teeth are supplied by CN V2, mandibular teeth are supplied by CN V3.
Cell composition of the oral cavity?
The oral cavity is made up of layers of mucosa composed of stratified squamous epithelium.
Arrangement of teeth?
There are 32 teeth, divided into four quadrants, each containing 8 teeth. All should have erupted by age 18 and the shape of each tooth is determined by its function.
The tongue is what type of muscle?
Name the 4 types of papilla on the dorsum of the tongue?
Which papillae contain taste buds?
Vallate, foliate and fungiform papillae contain taste receptors in the taste buds.
(NOTE* not filiform**)
Why does the tongue move?
mastication, speech and swallowing.
What cranial nerves supply the tongue?
The vagus (CN X) and majority by the hypoglossal (CN XII) nerves.
What is the purpose of the anterior 2/3rds of the tongue and what is it supplied by?
Touch and temperature.
Supplied by the lingual nerve, branch of CN V3
Which nerve supplies the sensory part of the gag reflex?
Which nerve supplies the motor part of the gag reflex?
mainly by CN X
What does touching the posterior wall of the oropharynx do?
Constrict the pharynx to prevent entry.
Name the 3 salivary glands?
What is the role of saliva?
Act as a lubricant to aid swallowing and speech.
Also a buffer for acid and contains amylase to begin carbohydrate digestion.
Route of the parotid duct?
The parotid duct crosses the face and secretes into the mouth at the upper second molar. It is supplied by parasympathetic secretomotor from CN IX.
Route of the submandibular duct?
The submandibular duct enters the floor of the mouth and secretes via the lingual caruncle. It is supplied by CN VII.
Route of the sublingual gland?
The sublingual gland lies in the floor of the mouth and secretes via several ducts superiorly. It is also supplied by CN VII.
Which bones and organ form the abdominal cavity?
the ribs, spine, diaphragm and pelvis
What is the peritoneum?
The peritoneum is a continuous serous membrane that secretes lubricating fluid into the peritoneal cavity. It lines the abdominal cavity.
Name the two layers of peritoneum?
Visceral and parietal
Name the intraperitoneal organs?
Parts of the small intestine and large intestine.
Name the retroperitoneal organs?
Parts of the small intestine and large intestine.
Name the pouch caused by the peritoneum in males?
Name the pouches caused by the peritoneum in females?
Vesicouterine and rectouterine pouches
What does mesentery do?
The mesentery connects organs to the posterior body wall.
What is the mesentery proper?
The mesentery proper of the small intestine provides high levels of mobility
The location of the peritoneum?
The peritoneum drapes over the superior aspect of the pelvic organs.
What is the greater omentum?
The greater omentum is made up of 4 layers and hangs like an apron over the small intestine.
Purpose of the greater omentum?
It stops the spread of infection by surrounding the infection site
Location of the greater omentum?
It attaches the greater curvature of the stomach to the transverse colon
What is the lesser omentum?
The lesser omentum is double layered.
Location of the lesser omentum?
Runs between the lesser curvature of the stomach and duodenum to the liver.
What lies in the free edge of the lesser omentum?
The portal triad.
What does the omenta divide the peritoneal cavity into
A greater and lesser sac
How does the greater and lesser sac communicate?
Through the omental foramen (foramen of Winslow).
Where is the stomach found?
Between the oesophagus and small intestine.
What is the main function of the stomach?
Its chief function is acidic and mechanical digestion.
Gastric juice converts a mass of food into chime, which then passes through the pyloric sphincter to the duodenum
What are the 4 parts of the stomach?
Pyloric part (pyloric sphincter)
What is the cardia?
The cardia surrounds the cardial orifice, the trumpet shaped opening of the oesophagus into the stomach.
Name the gastric folds in the stomach?
What is the main blood supply for the stomach?
Along the lesser curvature by the right and left gastric arteries and along the greater curvature by the right and left gastro-omental artery.
What is the venous system in relation to the stomach?
Gastric veins run parallel to gastric arteries and drain to the hepatic portal venous system.
Where are the lymph nodes around the stomach?
Gastric lymph vessels drain lymph to the gastric and gastro-omental lymph nodes, located along the lesser and greater curvatures.
Parasympathetic innervation of stomach?
From the anterior and posterior vagal trunks and their branches, which enter the abdomen through the oesophageal hiatus.
Sympathetic nerve supply of the stomach?
From T6-T9 and passes to the celiac plexus via the greater splanchnic nerves.
Name the three parts of the small intestine?
What is the beginning of the small intestine?
The pyloric sphincter.
What is the end of the small intestine?
The ileocecal junction.
Name the 4 parts of the duodenum in order
The first and second parts of the duodenum are supplied by which arteries?
The gastroduodenal artery and pancreaticoduodenal artery.
Which sections of the duodenum are foregut structures?
First and Second
The third and fourth parts of the duodenum are supplied by which arteries?
The inferior pancreaticoduodenal artery, a branch of the superior mesenteric artery.
Which sections of the duodenum are midgut structures?
The third and fourth.
Where do you duodenal veins drain?
The hepatic portal vein.
Where are the jejunum and ileum found?
All 4 quadrants
Where does the jejunum begin?
The duodenojejunal flexure.
Where does the ileum end?
The ileocecal junction.
What are the differences in characteristics between the jejunum and ileum?
The jejunum is a darker red due to greater vascularity than the ileum.
The jejunum has a thicker wall.
The jejunum has less mesenteric fat than the ileum.
Jejunum has large, tall closely packed folds vs Ileum has low, sparse folds that are absent distally.
Peyer's patches are only present in the ileum.
What is the main blood supply to the jejunum and ileum?
SMA via the jejunal and ileal arteries.
How arcades are different in the jejunum from the ileum?
Jejunum - arteries have fewer and larger arcades with long vasa rectae.
Ileum- arteries have more arcades that are smaller and shorter vasa rectae.
What are vasa rectae?
When arcades form (in loops) they give rise to straight arteries called vasa rectae.
How does venous blood drain from the jejunum and ileum?
The jejunal and ileal veins to the SMV and into the hepatic portal vein.
Where does most absorption occur?
In the small intestine. Then drained by the portal venous system to be taken to the liver.
What does the large intestine consist of?
Colon, rectum, anal canal and anus.
What are the functions of the large intestine?
Its functions include defence, absorption of water and salts and the excretion of formed stool.
What are the features specific to the colon?
Teniae coli: three thickened bands of longitudinal smooth muscle fibres
Haustra: pouches between the teniae
Omental appendices: small, fatty appendices of colon
What does the colon consist of?
What is different about the transverse colon?
It is intraperitoneal and has mesentery, making it highly mobile.
Where are the caecum and appendix located?
The right iliac fossa.
Where is the appendix specifically located?
Retrocaecal position (normally but can vary).
What is the location of the sigmoid colon?
The left iliac fossa.
What is the name of the mesentery attached to the sigmoid colon?
The sigmoid mesocolon
What is sigmoid volvulus?
When the sigmoid colon twists round itself, due to the movement provided by the mesentery. Causes bowel obstruction which is at risk of bowel infarction due to twisting of vasculature in the mesentery.
When does the sigmoid colon become the rectum?
Anterior to S3.
At the rectosigmoid junction.
Where is the rectum located?
The pelvic cavity.
When does the rectum become the anal canal?
Anterior to the tip of the coccyx.
Just before it passes through the levator ani muscle into the peritoneum.
What is the levator ani?
A muscle that forms most of the pelvic diaphragm.
What does the levator ani do?
It provides continual support for the pelvic organs due to tonic contraction. It reflexively contracts further during increase in intra-abdominal pressure e.g. coughing, sneezing. It must relax to allow defaecation to occur.
Which nerve supplies the levator ani?
Branch of sacral plexus and pudendal S2, 3 and 4.
What are the muscles that make up the levator ani?
Iliococcygeus, pubococcygeus and puborectalis.
Why is the puborectalis important?
Important in maintaining faecal continence and is slung around the rectum.
What does contraction of the puborectalis do?
Contraction decreases the anorectal angle which creates a kink and acts as a sphincter.
What is the relationship between the rectal ampulla and the puborectalis?
When the rectal ampulla is relaxed and full of faeces, voluntary contraction of the puborectalis helps to maintain continence.
What are the names of the 2 anal sphincters?
Internal (involuntary) and external (voluntary).
What causes the internal anal sphincter to contract?
Stimulation by sympathetics from T12- L2.
What inhibits the contraction of the internal anal sphincter?
Parasympathetic stimulation from S2-4
Memory aid - S2, 3 and 4 keep your shit off the floor.
Where do the ischioanal fossae lie?
Each side of the anal canal.
What is an infection within the ischioanal fossa called?
An ischioanal abscess.
What does the SMA supply?
Which branch of the SMA supplies the transverse colon?
Middle colic artery.
Which branch of the SMA supplies the ascending colon?
Right colic artery.
Which branch of the SMA supplies the caecum and the appendix?
What does the IMA supply?
Which branch of the IMA supplies the descending colon?
Left colic artery
Which branch of the IMA supplies the sigmoid colon?
Which branch of the IMA supplies the rectum?
Superior rectal arteries.
What does anastamoses between the SMA and IMA help stop?
It helps prevent intestinal ischaemia by providing collateral circulation. This is called the marginal artery of Drummond.
What does the inferior mesenteric vein and to where?
Drains blood from hindgut structures to the splenic vein.
Where does the internal iliac vein drain?
Below the pectinate line (end of the GI tract) to the IVC.
What are the functions of the liver?
Its functions include glycogen storage, bile secretion and other metabolic processes.
Where is the liver located?
Right upper quadrant.
Protected by ribs 7 - 11
How does breathing affects the location of the liver?
It descends on inspiration as it is pushed down by the diaphragm.
What are the anatomical relations to the liver?
The gallbladder lies posterior and inferior, the hepatic flexure is inferior, the right kidney, right adrenal gland, IVC and abdominal aorta lie posterior and the stomach is posterior and to the left.
Name the 4 anatomical lobes of the liver?
Caudate (looks like a tail, it is superior)
What runs between the right and left lobe of the liver?
The falciform ligament
What does each of the 8 functional segments of the liver have?
A branch of the hepatic artery
A branch of the hepatic portal vein
Why is it useful for the liver to have 8 functional segments?
It allows for segmentectomy.
Why does damage to the liver affect right atrial pressure?
Because the IVC and hepatic veins lack valves, the liver can be damages by increased pressure in the RA.
What does the portal triad include?
The hepatic portal vein
The hepatic artery proper
Where does the hepatic triad run?
Within the hepatoduodenal ligament (part of the lesser omentum).
What is peritonitis?
A collection of pus either in the hepatorenal recess (posteriorly) and subphrenic recess (anteriorly) both lie within the greater sac, which leads to abscess formation.
What is the lowest part of the peritoneal cavity when the patient is supine?
The hepatorenal recess.
This is important if the patient is bedridden.
What is the arterial blood supply to the liver?
The right and left hepatic arteries (branches of the hepatic artery proper).
Where does the majority of the blood supply to the liver come from?
The hepatic portal vein
The IVC is retroperitoneal?
True or false.
What vessel drains the cleaned blood from the hepatic veins to the right atrium?
Is the spleen retroperitoneal?
The spleen is intraperitoneal.
What organs is the spleen anatomically related to?
Which ribs is the spleen under?
Ribs 9 - 11
What are the functions of the spleen?
Functions include the breakdown of RBCs to produce bilirubin.
Where does the gallbladder lie?
The gall bladder lies on the posterior aspect of the liver and anterior to the duodenum.
What are the functions of the gallbladder?
It stores and concentrates bile in between meals.
Where does bile flow too and from the gallbladder?
Bile flows in and out of the gallbladder through the cystic duct (spiral).
Which arteries supply the gallbladder?
The cystic arteries.
Where do you find the cystic arteries?
The triangle of callot.
Where do visceral afferents from the gallbladder enter the spinal cord
T6 - T9
How does pain from the gallbladder usually present?
Pain usually presents in the epigastric region and can radiate to the back.
Is the pacreas retroperitoneal?
Name the parts of the pancreas?
The pancreas has a head (with ucinate process), neck, body and tail
Main functions of the pancreas?
Endocrine (secretes hormones such as insulin or glucagon into the blood) and exocrine functions (secretes pancreatic digestive enzymes into the main pancreatic duct).
Where is pain from the pancreas often felt?
Pain from the pancreas can be felt in the epigastric or umbilical region and can radiate to the back.
What is the biliary tree?
A number of ducts that transport bile
Which 2 ducts join to form the common hepatic duct?
The right and left hepatic ducts.
Which 2 ducts join to form the common bile duct?
Common hepatic duct and cystic duct