Basic science Flashcards
Histology, anatomy, embriology
what are the three major salivary glands?
sublingual
submandibular
parotid
where do the liver and pancreas develop?
as an outgrowth of the gut tube
which epithelium is the parenchyma of the liver and the pancreas composed of?
glandular epithelial cells
list some functions of the liver (9)
oxidise triglycerides to produce energy
synthesize plasma lipoproteins
synthesize cholesterol
convert carbohydrates and proteins to fatty acids.
regulate blood glucose
synthesize plasma proteins
detoxification of metabolic waste products
storage of glycogen, vitamins and iron
synthesis and secretion of bile
where does venous blood in the liver drain into and where does that drain to?
hepatic veins which drain to the IVC
what is the liver covered by and describe this?
collagenous connective tissue capsule (which is covered by mesothelial cells = simple squamous epithelium)
describe the structure of the liver.
made of lobules
each lobule is hexagonal, has a branch of the hepatic vein (central vein) at the centre and portal triads at the corners (each triad contains bile duct, portal vein and hepatic artery)
CT connects the lobules
what is a portal tract (in the liver) composed of?
hepatic portal vein
hepatic artery
bile ductule
(tracts also typically include lymphatic vessels)
what is the bile ductule (of the portal tract) lined by?
simple cuboidal cells = cholangiocytes
what are the main cells of the liver?
hepatocytes
what are the blood channels in the liver between the sheets of hepatocytes called?
sinusoids
what direction does blood travel in in the liver?
from the portal triads at the corners of the lobule, towards a hepatic vein at the middle of a lobule
what is the space of Disse and what is projected into that space?
the space between the lining epithelial cells of the sinusoids and the hepatocytes.
Microvilli of the hepatocytes project into that space
how is the epithelium of the sinusoids organised and why?
it is fenstrated so the liquid component of the blood has free access to the hepatocytes but the blood cells do not
what type of collagen is found in the space of Disse?
type I
where is type III collagen found in the liver?
in the parenchyma
What are hepatic stellate cells and where are they found?
modified fibrobasts
found scattered in space of Disse
what do hepatic stellate cells do?
make CT and store Vit A within fat droplets in their cytoplasm.
in cirrhosis they transform into myofibroblasts and produce scar tissue
what are Kupffer cells and where are they found?
resident macrophages found scattered within the sinusoids of the liver.
what do Kupffer cells do?
remove particulate matter from the blood and help remove worn out RBCs
what is bile?
an alkaline soultion containing water, ions, phospholipids, bilirubin and bile salts.
what is bilirubin in bile?
a pigment made from the breakdown of haemoglobin in the spleen (responsible for the brown colour of faeces)
why are bile salts necessary?
emulsification of fats in the digestive tract
which cells line the biliary tree?
cholangiocytes
How does bile flow through the lobules in the liver (remember all hepatocytes produce bile)
via bile canaliculi towards the bile ducts in the portal tracts
what are bile canaliculi (in the liver)?
small channels formed by tight junctions between cell membranes of adjacent hepatocytes
what is the gall bladder and what does it do?
a muscular sac which removes bile from the liver and stores and modifies it
what is the gall bladder lined with?
simple columnar epithelium with brush border backed by a lamina propria of loose CT rich in blood and lymphatic vessels. A coat of smooth muscle and an outer collagenous layer of adventitia
how does the gall bladder remove bile from the liver?
actively pumping Na and Cl ions from the bile into the spaces between adjacent epithelial cells (water follows and is carried away in lymphatic vessels in the lamina propria)
where does the gall bladder deliver bile to?
the duodenum
what stimulates the release of bile from the gall bladder into the duodenum?
nervous control, mainly vagal due to the release of cholecystokinin by endocrine cells of duodenum, secreted when fatty food enters it
what is cholecystitis?
inflammation of the gall bladder
how is the pancreas a dual functioning organ?
it is both endo and exocrine gland (mostly exo)
what does the exocrine pancreas do?
produces digestive juices containing proteases, lipases, nucleases and amylase.
what is the pancreatic duct for?
transferring exocrine pancreas juices into the duodenum
what does the endocrine pancreas consist of?
Islets of Langerhans (small scattered islands of tissue)
what do the Islets of Langerhans in the pancreas do?
produce a number of hormones (like insulin and glucagon)
how are enzymes produced by the exocrine pancreas activated?
by arriving at the duodenum where an enteropeptidase converts the inactive trypsinogen into the active form of trypsin, beginning a cascade of activating further enzymes
what is the pancreas covered by?
thin CT capsule that is continuous with CT septa that divides the glands into lobules
why do the acinar glands in the pancreas differ from in other glands?
the duct system goes straight into the core of the acinus whereas in salivary glands the duct joins its edge.
what is the hepatopancreatic ampulla?
an opening into the duodenum on a papillae composed of the pancreatic and common bile duct
what is the large intestine made up of?
colon (caecum, appendix, ascending transverse and descending colon, sigmoid colon)
Rectum, anal canal and anus
what is the small intestine made up of?
duodenum, jejunum, ileum
what are the three embryological catagorizations of the abdominal organs?
foregut
midgut
hindgut
where does the foregut begin and end and what accessory organs are within this?
oesophagus to mid-duodenum
liver, gallbladder, spleen and 1/2 of pancreas
where does the midgut begin and end and what accessory organs does it contain?
mid-duodenum to proximal 2/3rds of transverse colon
other half of pancreas
where does the hindgut begin and end?
distal 1/3rd of transverse colon to proximal 1/2 of the anal canal
what are all organs in each part of the fore, mid and hindgut supplied by (generally speaking)
arterial blood
venous drainage
lymphatic drainage
nerve supply
all via common route
what are the 9 clinical regions of the abdomen?
right/left hypochrondrium epigastric right/left lumbar/flank umbilical right/left inguinal/iliac fossa pubic/suprapubic/hypogastric
what lines divide the abdomen into its 9 clinical segments?
midclavicular
subcostal
trans-tubercular
how can the abdomen be split into quadrants (what lines)?
median and trans-umbilical planes
what organs are located in the RUQ? (generally)
liver, right kidney, right adrenal gland, transverse colon, part of small intestine
what organs are in the LUQ? (generally)
stomach, part of liver, other part of transverse colon, part of small intestine, left kidney and adrenal gland
what organs are in the RLQ? (generally)
appendix, ascending colon, small intestine
what organs are in the LLQ? (generally)
small intestine, descending colon, sigmoidal colon
which muscles are present in the abdominal muscle wall?
anteriorly = rectus abdominis
laterally = external and internal oblique, transversus abdominus
what is the peritoneal cavity, where is it and what does it do?
thin, transparent, semi-permeable serous membrane between the visceral and parietal layers.
lines walls of abdominopelvic cavity and organs.
secretes a small amount of lubricating fluid
what causes peritonitis and what is it?
severe and painful inflammation of the peritoneum.
due to blood, pus or faeces in peritoneal cavity
how can organs be classed in relation to the peritoneum and give an example?
intraperitoneal (liver)
retroperitoneal (kidney)
with a mesentery (intestines)
describe the motility of organs depending on their relationship to the peritineum.
intra = minimally mobile retro = minimally mobile mesentery = very mobile
what is a mesentery?
a double layer of visceral peritoneum surrounding an organ attaching it either to other organs of the body wall
what is the 4 layered flap that covers the abdomen anteriorly known as?
the greater and lesser omentum
what is the omental foramen?
where the greater and lesser omenta meet
where does the portal triad lie in relation to the omentum?
at the free edge of the lesser omentum
what are the pouches creates by the peritoneum called in males and females?
males = one pouch = rectovesical
females = two pouches: vesico-uterine pouch and recto-uterine pouch/pouch of Douglas
where is excess fluid in the abdominal cavity of a woman most likely to collect and why?
Pouch of Douglas/recto-uterine pouch as it is the most inferior part
what is ascites?
pathological collection of fluid in the peritoneal cavity
what is the procedure to treat ascites called?
paracentesis/abdominocentesis
where is the needle inserted in paracentesis and why?
lateral to the rectus sheath so to avoid the inferior epigastric artery
where does the inferior epigastric artery lie and where does it arise from?
anterior abdominal wall deep to the rectus abdominis
arises from external iliac, medial to the deep inguinal ring
how would visceral pain be localised and what character would it have?
not localised, dull, achy, nauseating
what are the four main questions you ask about abdominal pain?
location
character
timing
pain referral pattern