Gastrointestinal Flashcards
What is the course of the trigeminal nerve (CNV)
Comes off the CNS at the pons
Passes through the foramen ovale of the sphenoid bone
How many divisions of the trigeminal nerve are there?
3
What is the course of the facial nerve (CNVII)?
Comes off the CNS between the pons and the medulla
Leaves through the internal acoustic meatus of the temporal bone
Emerges externally through the stylomastoid foramen
What are some of the innervations of the facial nerve?
Supplies muscles of facial expression
It branches in to the chorda tympani which innervates the anterior 2/3rds of the tongue and is involved in taste and sensation
It supplies the sublingual salivary glands with parasympathetic axons.
What branch of CNV supplies what part of the oral cavity?
CNV2 supplies the superior oral cavity
CNV3 supplies the inferior oral cavity
What is the course of CNV2?
maxillary division of the trigeminal nerve
Comes off the CNS at the pons
Exits through the foramen rotundum in the sphenoid bone
What is the course of the glossopharyngeal nerve (CNIX) ?
It leaves the CNS at the medulla
Exits through the jugular foramen which is between the temporal and occipital bones
What is the course of the hypoglossal nerve (CNXII) ?
Connected to the CNS via many rootlets that attach to the medulla oblongata
Leaves through the hypoglossal canal in the occipital bone
What are the 4 pairs of muscles of mastication?
Temporalis
Masseter
Medial pterygoid
Lateral pterygoid
Which three cranial nerves supply sensation to the tongue?
CNVII (facial nerve)
CNV3 (trigeminal)
CNIX (glossopharyngeal)
What effect do autonomic nerves have on peristalsis?
Parasympathetics speed up peristalsis
Sympathetics slow down peristalsis
At what level does the laryngopharynx become the oesophagus?
C6
What is the name of the anatomical upper sphincter of the oesophagus?
Cricopharyngeus
The lower oesophageal sphincter is physiological not anatomical. What two things produce its physiological effect?
Contraction of the diaphragm
Higher intra-abdominal pressure than intra-gastric pressure
What 3 regions does the stomach lie in?
Left hypochondrium, epigastric, umbilical
On the lesser curvature side of the stomach, what is the indent called?
Incisura Angularis
Talk logically through the nine regions of the abdomen
Right hypochondrium, epigastric, left hypochondrium
Right lumbar, umbilical, Left lumbar,
Right inguinal, pubic, left inguinal
What are the two ligaments of the liver?
Falciform ligament
Round ligament
Which liver ligament attaches the liver to the body wall?
The falciform ligament
What are the three parts of the small intestine?
Duodenum, Jejunum, Ileum
What are the parts of the large intestine?
Appendix caecum Ascending colon Hepatic flexure Transverse colon Splenic flexure Descending colon Sigmoid colon Rectum Anal canal Anus
Explain the musculature of the anterolateral abdominal wall
The rectus abdominus are the ‘ab muscles’ at the front
There are three layers of muscles at the side;
The external oblique
The internal oblique
The transverses abdominus
If blood/pus or faeces enter the peritoneal cavity, what will this cause?
Peritonitis
What is mesentery?
A double layer of peritoneum that comes together and wraps behind the organ
Name 3 retroperitoneal organs and 3 intraperitoneal organs
RETROPERITONEAL; Kidneys Adrenal Glands Pancreas INTRAPERITONEAL; Stomach Spleen Liver
What is omentum?
A double layer of peritoneum that passes from the stomach
How many layers does the greater momentum have and what are its attachments?
4 Layers
It hangs over many structures
Attached to the greater curvature of the stomach and the transverse colon
How many layers does the lesser momentum have and what are its attachments?
2 (double-layered)
Attached to the lesser curvature of the stomach and the liver. It has a right ‘free’ edge.
Peritoneum forms pouches at its inferior aspect. What are these pouches called in males and females?
There is 1 pouch in males - called the ‘rectovesical pouch’
There are 2 pouches in females - called the ‘vesicle-uterine pouch’ and ‘recto-uterine pouch (a.k.a pouch of douglas) in females.
What is ascites, what is its most common cause and how is it managed?
Ascites is a collection of fluid in the peritoneal cavity
it is most commonly caused by liver disease.
It is managed by paracentesis in which a needle is used to drain the fluid.
What nerves supply the abdominal organs and what nerves supply the abdominal wall?
ORGANS Visceral afferents ENS Parasympathetics and sympathetics WALL Somatic sensory and motor Sympathetics
At what level do sympathetic nerves leave the spinal cord and where do they synapse? what is the exception to this rule?
T5 - L2
Synapse at pre vertebral ganglia
*Sympathetics for the adrenal gland leave at T10-L1
Synapse directly onto the cells
What is the outflow of parasympathetic nerves?
CRANIAL-SACRAL OUTFLOW;
CNX (vagus)
Pelvic splanchnic nerves (S2,3 &4)
At what levels do visceral afferents from the different areas of the gut enter the spinal cord?
FOREGUT - T6 - T9
MIDGUT - T8 -T12
HINDGUT - T10 - L2
What are the common areas that the gut refers pain to?
FOREGUT - Epigastric
MIDGUT - Umbilical
HINDGUT - Pubic
Explain how appendicitis presents in terms of pain
Initially, the pain from appendicitis can be described as dull, and localised to the umbilical region.
As the condition worsens however the pain become sharp and ‘pin-pointed’ to the right iliac fossa.
The pain can be described as having changed from visceral to somatic.
What causes jaundice and how can it be detected?
- An increase in the blood levels of bilirubin (a normal break-down product of red blood cells)
- can be detected by;
- Yellowing of sclera
- Yellowing of the skin
- Itchiness of the skin
What is the role of the gall bladder?
Storage and concentration of bile
What is the role of bile?
It is important for the normal absorption of fats from the small intestine!
State 3 functions of the liver
Glycogen storage
Bile secretion
Metabolic functions
Describe the location of the liver and its anatomical relations
The liver is mainly located in the RUQ and is protected by ribs 7-11
Its location is affected by breathing
- Inferior to the diaphragm
- Anterior to the gallbladder
- Superior to the hepatic flexure
- Anterior to the kidney, IVC and abdominal aorta
- Anterior to the stomach
What are the 4 anatomical lobes of the liver?
Right lobe
Left Lobe
Caudate lobe
Quadrate lobe
What are the ligaments of the liver?
The falciform ligament (attaches to the body wall)
The round ligament (embryological remnant of the umbilical vein)
The triangular ligaments
The coronary ligaments
Where is the bare area on the liver?
The bare area is the area of the liver where there is no peritoneum as this is the attachment to the diaphragm
What is the porta hepatis?
The site of entrance of the portal triad structures
What specific vasculature do each of the 8 functional lobes of the liver all have? List 4
Branch of a hepatic artery
Branch of a hepatic portal vein
Bile drainage to the bile duct
Venous drainage to the IVC
Which two vessels associated with the liver lack valves?
IVC
Hepatic veins
(thus an increase in central venous pressure is directed to the liver)
What 3 structures make up the portal triad? And which ligament do these structures run within?
Hepatic portal vein
Hepatic artery proper
Bile duct
*Run within the hepatoduodenal ligament
The coeliac trunk is one of the first 3 midline branches of the aorta.
At what level does it leave the aorta?
T12
What 3 branches does the coeliac trunk branch into?
Splenic artery
Left gastric artery
Common hepatic artery
What does the common hepatic artery branch into?
Gastroduodenal
Hepatic artery proper, then Right gastric
Describe the location of the spleen and its anatomical relations
Left hypochondrium, protected by ribs 9-11
Medial to the left kidney
Posterior to the stomach
Superior to the splenic flexure
Describe the anastomoses of the vessels supplying the stomach
Right gastric artery anastomoses with the left gastric artery at the junction of the lesser curvature and the lesser omentum
Right gastro-omental artery anastomoses with the left gastro-omental at the greater curvature and the greater omentum
What kind of blood supply does the liver have? What are the vessels called?
DUAL blood supply
- Right and left hepatic arteries
- Hepatic artery proper
- Hepatic portal vein
What structures do liver lobules contain?
Central vein
Interlobular portal triad
What is the function of the hepatic portal vein?
It is formed from the splenic veins and the superior mesenteric vein which drain the foregut and midgut respectively. The vein then transports this blood to the liver.
Where does the inferior mesenteric vein drain blood from?
It drains blood from the hindgut to the splenic vein, which then becomes the hepatic portal vein, and drains back to the liver
Name the two recesses around the liver in the peritoneal cavity within the greater sac
Subphrenic recess
Hepatorenal recess
What are the lowest parts of the peritoneal cavity when the patient is supine?
Hepatorenal recess
Rectovesical/ recto-uterine pouch
Describe the location of the gall bladder
It lies on the posterior aspect of the liver, anterior to the duodenum
Explain the blood supply to the gall bladder
The cystic artery (a branch of the right hepatic artery) - it branches within the triangle of clot before entering the gall bladder
Explain how gall bladder pain may be felt
The gall bladder is a foregut organ and so visceral afferents enter the spinal cord between T6-T9 - early pain is felt in the epigastric region
Pain can later present in the hyperchondrium, with or with out referral to the right shoulder/neck
What is the term used to describe surgical removal of the gall bladder
Cholecystectomy
Describe the relationship of the duodenum with the peritoneum
The 1st part is intraperitoneal
2nd, 3rd and 4th parts are retroperitoneal
Which two peptide hormones does the duodenum secrete?
Gastrin
CCK
What does the head of the pancreas have?
An uncinate process
Which cells make up the exocrine pancreas and are responsible for secreting enzymes?
Acinar cells
Which cells make up the endocrine pancreas and are responsible for secreting hormones?
Islets of Langerhan
Explain the nerve supply to the pancreas
abdomino pelvic splanchnic nerves - SYMPATHETIC
Vagus nerve - PARASYMPATHETIC
VISCERAL AFFERENTS
The bile duct joins with the main pancreatic duct to form what structure?
The hepatopancreatic ampulla (of Vater)
Where does the hepatopancreatic ampulla drain into?
The 2nd part of the duodenum
How many sphincters are involved in the drainage of the biliary system and what are they called?
3
- Bile duct sphincter
- Pancreatic duct sphincter
- Sphincter of Oddi
What two things can obstruct the biliary tree, causing jaundice?
- Gallstones
- Carcinoma at the head of the pancreas (blocks sphincters)
- These things cause flow of bile back up to the liver and overspill of bile and bilirubin into the blood.
Which two vessels anastomose at the pancreas?
Superior pancreaticduodenal artery
Inferior pancreaticduodenal artery
Where can pancreatic pain radiate to?
The back
What two signs can vascular haemorrhage presents with as a consequence of acute pancreatitis?
Grey-turner’s sign
(huge deep purple bruises on the flanks)
Cullen’s sign
(deep purple around the umbilicus)
What are the main groups of abdominal lymph nodes?
Celiac
Superior mesenteric
Inferior mesenteric
Lumbar
Where do the left and right venous angles drain into?
Left - thoracic duct
Right - right lymphatic duct
Where are paracolic gutters found and what can accumulate here?
Greater sac in the peritoneal cavity - between the ascending/ descending colon and the abdominal wall
(pus can accumulate here)
What are the omental appendices on the colon?
Small fatty projections
What are teniae coli?
The 3 distinct bands of longitudinal muscle on the colon
What are haustra?
The pouches which give the colon its segmental appearance
What are the two orifices on the caecum?
The appendiceal orifice (at McBurney’s point)
The ileocaecal orifice
At what level do the three branches of the abdominal aorta come off?
Celiac trunk - T12
Superior Mesenteric artery - L1
Inferior Mesenteric artery - L3
What are the branches of the SMA? (6)
Inferior pancreaticduodenal artery Middle colic artery Right colic artery Ileocolic artery Jejunal and Ileal arteries
Describe the differences between the jejunal and ileal arteries in terms of vasa rectae and arcades
JEJUNUM - Longer vasa rectae - Less complex arcades ILEUM - Shorter vasa rectae - more complex arcades
What are the branches of the IMA? (3)
Left colic artery
Sigmoid arteries
Superior rectal artery
The Marginal Artery of Drummond involves the anastomosis of which 2 vessels?
Superior and Inferior mesenteric arteries
There are two venous systems in the body - where do these drain to?
Hepatic Portal Venous System - drains to the liver
Systemic Venous System - drains to the IVC
What are the three important sites of venous anastomosis between the portal and systemic circulations?
Distal end of the oesophagus
Skin around the umbilicus
Rectum/ anal canal
How can portal hypertension present clinically?
Oesophageal varices
Caput medusa
Rectal varices
What muscle makes up the pelvic floor?
Levator Ani Muscle
At what vertebrae level does the sigmoid colon become the rectum and what is this junction called?
S3
Rectosigmoid junction
What pouch is formed in males between the bladder and the rectum?
Rectovesical pouch
what pouch is formed in females between the uterus and the rectum?
Rectouterine pouch
What 3 smaller muscles make up the levator ani muscle?
iliococcygeus
pubococcygeus
Puborectalis
What is the nervous supply of the levator ani muscle?
A branch of the sacral plexus involving S2, 3 & 4
Which smaller muscle within the levator ani muscle has a crucial role in maintaining faecal continence?
Puborectalis
Which nerve fibres stimulate contraction of the internal anal sphincter and which stimulate contraction of the external anal sphincter?
Sympathetics - Internal
Pudendal - external
Which kind of muscle is the internal and external anal sphincter made up of? Which is voluntary and which is involuntary?
Internal anal sphincter - smooth muscle, involuntary
External anal sphincter - skeletal muscle, voluntary
Which area of the spinal cord do sympathetic fibres come from which cause contraction of the internal anal sphincter and cause inhibition of peristalsis?
T12 - L2
Which area of the spinal cord do; - somatic motor (pudendal) - parasympathetic fibres - visceral afferents come from?
S2 - S4
Which nerves do parasympathetic fibres run alongside?
Pelvic splanchnic nerves
Which foramen does the pudendal nerve pass through?
Greater sciatic foramen - exits the pelvis
Lesser sciatic foramen - enters the perineum
What does the pectinate line mark the junction between?
The part of the embryo which formed the GI tract (endoderm) and the part which formed the skin (ectoderm)
Is above the pectinate line endoderm or ectoderm derived?
Above the line - endoderm
Below the line - ectoderm
What is a rectal varice and why does it form?
A dilation of collateral veins between the portal and the systemic venous system which forms due to portal hypertension
Why do haemorrhoids form?
Haemorrhoids form due to raised pressure. E.g coughing and constipation
What is the name of the fossae which lie either side of the anal canal?
Ischioanal fossae
Describe the location of the parotid gland and how its secretions enter the mouth
Anterior to the ear, Inferior to the zygomatic arch
- The duct of stensen enters the mouth opposite second maxillary molar teeth
Describe the location of the submandibular gland and how its secretions enter the mouth
Medial to the body of the mandible on the floor of the mouth
- The duct of wharton enters the mouth under the tongue by lingual frenulum via sublingual caracula
Describe the location of the sublingual gland and how its secretions enter the mouth
Medial to the submandibular glands
- The duct of rivinus and common bartholin connect with wharton’s at the sublingual caruncular
Describe he anatomy of the inguinal canal in terms of the walls and the floor and roof
Posterior wall = transversals fascia
Anterior wall = aponeurosis of external oblique, internal oblique
Floor =
Inguinal ligament and the lacunar ligament
Roof =
Transversalis fascia
Internal oblique
Transversus abdominus
At what level do the iliohypogastric and the ilioninguinal nerves branch off the intercostal nerves?
At the level of L1
