Gastroenterology Flashcards
What is the peritoneal cavity?
A potential space between the parietal and visceral peritoneum
It normally contains only a thin film of peritoneal fluid, which consists of water, electrolytes, leukocytes and antibodies. This fluid acts as a lubricant, enabling free movement of the abdominal viscera, and the antibodies in the fluid fight infection.
What is a subphrenic abscess
An accumulation of pus in the left or right subphrenic space
They are more common on the right side due to the increased frequency of appendicitis and ruptured duodenal ulcers
Lowest point of male peritoneal cavity?
rectovesical pouch, peritoneum is closed
Lowest point of female peritoneal cavity?
two lowest points = rectouterine pouch of douglas and vesicouterine pouch
Clinical significance lowest point of peritoneum and male vs female
Lowest point = fluid will collect there due to gravity
Female = peritoneum is open (the uterine tubes open into the peritoneal cavity), providing a potential pathway between the female genital tract and the abdominal cavity.
Clinically, this means that infections of the vagina, uterus, or uterine tubes may result in infection and inflammation of the peritoneum (peritonitis).
Define ascites
Ascites refers to an accumulation of excess fluid within the peritoneal cavity
typical cause ascites
other causes
portal hypertension (secondary to liver cirrhosis)
malignancy of the GI tract, malnutrition, heart failure, and mechanical injuries which result in internal bleeding
features ascites
abdominal distension, abdominal discomfort, nausea, and dyspnoea due to pressure on the lungs from the enlarged abdominal cavity.
What is the parietal peritoneum
lines the internal surface of the abdominopelvic wall = somatic mesoderm = sensations well localised to region of abdominal wall that it lines
What is the visceral peritoneum?
lines organs - sensations not well localised = Pain from the visceral peritoneum is referred to areas of skin (dermatomes)
What are peritoneal adhesions? causes?
Damage as a result of infection, surgery or injury –> inflammation and repair –> formation of fibrous scar tissue –> abnormal attachments between the visceral peritoneum of adjacent organs or between visceral and parietal peritoneum –>
Such adhesions can result in pain and complications such as volvulus, when the intestine becomes twisted around an adhesion resulting in a bowel obstruction.
What are the two types of inguinal hernia? who gets them?
Indirect inguinal hernia – where the peritoneal sac enters the inguinal canal through the deep inguinal ring. (can be congenital)
Direct inguinal hernia – where the peritoneal sac enters the inguinal canal through the posterior wall of the inguinal canal. (acquired due to weakening of musculature)
What are the muscular layers of the anterior abdominal wall?
SSS EXITT
Skin
Subcutaneous fat
Superficial fascia
Ex external oblique
Internal oblique
Transverse abdominis
Transversalis fascia
Their aponeuroses connect to form rectus abdominis medially
What is the rectus sheath
the rectus sheath covers the rectus abdominis muscle
at the lowest part of the abdomen, the rectus sheath only covers the rectus abdominis anteriorally
What is the transpyloric plane?
located halfway between the suprasternal notch of the manibrium and the upper border of the symphysis pubis.
What structures lie along the transpyloric plane?
Please Feed Him Some Love
P = pylorus of stomach
F = fundus of gall bladder
H = hilum of both kidneys
S = origin of the superior mesenteric artery
L = lower end of spinal cord (L1)
kocher scar
open cholecystectomy
mercedes benz scar
liver transplant
midline laparotomy
intra-abdominal access
paramedian scar
intra-abdominal access
transverse scar
stoma closure/formation
rutherford-morrison scar
kidney transplant
gridiron scar
open appendiectomy
lanz scar
open appendiectomy
pfannenstiel scar
gynaecological, obstetric scar
pathophysiology of varices
- cirrhosis of the liver causes a significant increase in the resistance to blood flow through the liver
- the increased resistance to blood flow through the liver cause sthe pressure in the hepatic portal venous system to rise (portal hypertension)
- gastroesophageal varices form (expanded blood vessels) in an attempt to decompress the rising pressure in the hepatic portal venous system. These can rupture causing massive bleeding
What lines divide the abdomen into the 9 sections
midclavicular lines
transpyloric plane
intertubecular plane
What is a hiatus hernia
part of the stomach protrudes into the chest through the oesophageal hiatus in the diaphragm
Why is appendicitis pain initially felt centrally
The sympathetic afferent fibres of the appendix arise from T10 of the spinal cord – thus explaining why the visceral pain of early appendicitis is felt centrally within the abdomen.
most common position for appendix to be in
retrocaecal
where is mcburneys point?
2/3 of the way from umbillicus to anterior superior iliac spine
What comprises of the foregut?
major arterial supply?
Parasympathetic supply?
oesophagus –> duodenum + liver, pancreas, bile ducts
arterial supply: celiac trunk
parasympathetic: vagus nerve
What comprises of the midgut?
major arterial supply?
Parasympathetic supply?
distal duodenum –> proximal 2/3 of transverse colon
arterial supply: superior mesenteric artery
Parasympathetic: vagus nerve
what comprises of the hindgut?
major arterial supply?
Parasympathetic supply?
distal 1/3 of transverse colon –> rectum
aretrial supply : inferior mesenteric artery
Parasympathetic: pelvic splanchnic nerve
Blood supply of liver
- hepatic artery proper (25% of blood) derived from coeliac trunk
- hepatic portal vein (75% of blood) carrying nutrients absorbed from the small intestine
Components and path of biliary tree
left and right hepatic ducts carry bile from liver –> join to become common hepatic duct –> joins cystic duct and common bile duct. cystic duct allows flow of bile to and from gall bladder. common bile duct carries bile towards intestine. the pancreatic duct also joins the common bile duct at the ampulla vater where they then all drain into the duodenum
define cholelithiasis
uncomplicated gallstones
define biliary colic
typically right upper quadrant pain following a fatty meal as gallstones obstruct the cystic duct during contraction of the gallbladder. Not associated with systemic upset
define cholecystitis
inflammation of the gallbladder. Pain is often associated with nausea, vomiting or fever
define choledocholithiasis
gallstone within the common bile duct. Often causes deranged liver function tests.
Define cholangitis
infection of the common bile duct often secondary to choledocholithiasis. Typically presents with right upper quadrant pain, fever and jaundice (Charcot’s Triad)
anatomical position of the pancreas
positioned at the level of the transpyloric plane (L1)
it is a retroperitoneal organ, located deep within the upper abdomen in the epigastrium and left hypochondrium regions.
complication of splenic rupture
profuse bleeding into peritoneal cavity –> requires splennectomy if this is the case
what does cortex of adrenal glands do?
secretes two cholesterol derived hormones – corticosteroids and androgens
Layers of adrenal cortex and what they secrete?
From superficial to deep: acronym GFR
Zona glomerulosa – produces and secretes mineralocorticoids such as aldosterone.
Zona fasciculata – produces and secretes corticosteroids such as cortisol. It also secretes a small amount of androgens.
Zona reticularis – produces and secretes androgens such as dehydroepiandrosterone (DHES). It also secretes a small amount of corticosteroids.
What does the adrenal medulla do?
It contains chromaffin cells, which secrete catecholamines (such as adrenaline) into the bloodstream in response to stress.
what is a pheochromocytoma
A tumour of the adrenal medulla or preganglionic sympathetic neurones. It secretes adrenaline and noradrenaline uncontrollably, causing blood pressure to greatly increase. Patients may present with palpitations, headaches and diaphoresis (profuse sweating).
At what spinal level does the aorta terminate and into what?
It terminates at the level of L4 by bifurcating into the left and right common iliac arteries
Branches of the aortic arch?
1) left and right aortic sinuses –> coronoary arteries
2) branchiocephalic trunk –> right common carotid and right subclavian arteries
3) left common carotid (supplies left side of head and neck)
4) left subclavian artery (supplies left upper limb)
which are the retroperitoneal organs?
SAD PUCKER
Suprarenal (adrenal glands)
Aorta and inferior vena cava
Duodenum (2nd and 3rd segments)
Pancreas
Ureters
Colon (ascending and decending)
Kidneys
Esophagus
Rectum
