Anatomy Flashcards
what is the outer connective tissue called in the digestive tract wall?
serosa
what is the circular muscle layer called?
muscularis externa
what else is in the muscularis externa apart from muscle?
myentetric plexus (neurone network)
what is found in the submucosa?
connective tissue, larger blood and lympth vessels, glands and submucous plexus (neurone network)
what is found in the mucosa?
mucous membrane, lamina propria (capillaries, enteric neurons, gut-associated lympthoid tissue), muscularis mucosae
What are the functions of the upper GI tract?
- mastication (chewing)
- taste
- deglutition (swallowing)
- salivation
how many teeth do adults have?
32
which joint articulates between the temporal bone and mandible?
temporomandibular joint
what are the muscles of mastication supplied by?
mandibular division of trigeminal nerve - CN V3
what does the temporalis m. do?
coronoid process of mandible to temporal fossa
what does masseter m. do?
angle of mandible to zygomatic arch
how many muscles control mastication?
4
how many muscles responsible for jaw opening/closing?
3 closing and 1 opening
What is the course of the mandibular division of trigeminal nerve (CNV3)?
Comes from pons, through foramen ovale to muscles of mastication and sensory area
what does the lateral pterygoid do?
pulls condyle of mandible to pterygoid plates of sphenoid bone
what does medial pterygoid do?
pulls angle of mandible to pterygoid plates of phenoid bone
what re the two cavities in the temporomandibular joint divided by?
articular disc
what is the superior cavity in temporomandibular joint for?
translocation
what is the inferior cavity in temporomandibular joint for?
rotation
what is aspiration?
inhalation of liquid or solid matter into lungs
what nerve is the posterior 1/3rd of the tongue supplied by?
CNIX -
what nerve is the 2/3rd of the tongue supplied by?
CNV3 (mandibular division of trigeminal nerve ) and CNVII (facial nerve)
what is the course of the facial nerve?
- from pontomedullary junction
- travel through temporal bone via internal acoustic meatus then stylomastoid foramen
- to supply taste ant. 2/3rd tongue, muscles of facial expression and glands in floor of mouth.
what does the chorda tympani nerve supply?
taste to anterior 2/3rd of tongue and parasympathetics to glands
what is the lingual nerve a branch of?
CN V3
what nerve supplies the gingiva or oral cavity and palate?
CN V2
What is the purpose of the gag reflex?
protects foreign bodies from entering the pharynx or larynx
what nerve carries the sensory part of the gag reflex?
CN IX
what nerves carry the motor part of the gag reflex?
CN IX and CN X
what will spraying a local anaesthetic do?
block sensory action potentials in CN V2, CN V3, CN VII and CN IX
what is the course of the CN V2?
from pons, through foramen rotundum to sensory area
what is the course of CN IX?
from medulla, through jugular foramen to posterior wall of oropharynx, parotid gland and post 1/3rd tongue.
where does parotid gland secrete saliva?
by upper 2nd molar tooth
what does the submandibular gland do?
enters floor of mouth and secretes via lingual caruncle
what does the sublingual gland do?
lays in floor of mouth secretes via several ducts superiorly
what can duct clogging/blockage cause?
swelling, due to back up of secretions
what do extrinsic muscles of the tongue do?
function to change the position of the tongue during mastication, swallowing and speech
what do intrinsic muscles of the tongue do?
modify the shape of the tongue during function
what are all tongue muscles innervated by? what is the exception?
CNXII except palatoglossus
what are the 4 skeletal muscles of the tongue?
palatoglossus
styloglossus
genioglossus
hyoglossus
what is the course of the CN XII?
from medulla, through hypoglossal canal to extrinsic and intrinsic muscle of tongue.
what is the name for CN XII?
hypoglossal nerve
what is the pharynx innervated by?
CN X (vagus)
what is the muscle of the pharynx called?
stylopharyngeus
what nerves is the pharynx supplied by?
CN X and CN IX
what is the pharynx made of?
3x longitudinal muscle
where does the osophagus start?
begins at inferior edge of cricopharyngeus muscle (vertebral level C6)
What does parasympathetic stimulation do to peristalsis?
speeds it up
What does sympathetic stimulation do to peristalsis?
slows it down
what factors produce the lower oesophageal sphincter?
- contraction of diaghram
- intrabdominal pressure slightly higher than intragastric pressure
- oblique angle at which oesophagus anters the cardia of stomach
what does the lower oesophageal sphincter do?
helps reduce occurrence of reflux
what might a hiatus hernia do to the lower oesophageal sphincter do?
reduce effectiveness and lead to symptoms of reflux
what are the four different parts of the colon?
ascending, transverse, descending and sigmoid
what organs are in the foregut?
- oesophagus to mid-duodenum
- liver and gall bladder
- spleen
- 1/2 of pancreas
what organs are in the midgut?
- mid duodenum to proximal 2/3rds of transverse colon
- 1/2 pancreas
what organs are in the hindgut?
distal 1/3rd of transverse colon to proximal 1/2 of anal canal
what are the nine regions of the abdomen (from top right to bottom left)?
- right hypochondrium
- epigastric
- left hypochondrium
- right lumbar
- umbilical
- left lumbar
- right linguinal
- pubic
- left linguinal
which organs contract to ‘guard’ abdominal organs from injury?
- rectus abdominis
- external oblique
- internal oblique
- transversus abdominis
- parietal peritoneum
apart from injury what other medical condition does guarding also occur in?
peritonitis
what is the peritoneum?
a thin, transparent, semi-permeable, serous membrane which lines the walls of the abdominopelvic cavity and organs
which layer of the peritoneum lines the body wall?
parietal
which layer of the peritoneum lines the organs?
visceral
what is the peritoneal cavity?
cavity between the visceral and parietal layer
what is peritonitis?
when blood, pus or feaces in the peritoneal cavity cause severe and painful inflammation of the peritoneum
what are intraperitoneal organs?
organs completely covered by visceral peritoneum, minimally mobile.
what are organs with a mesentery (intraperitoneal)?
organs covered in visceral peritoneum but the visceral peritoneum wraps behind the organ to form a double layer (mesentery), the mesentery suspends the organ from the posterior abdominal wall - very mobile
what are retroperitoneal organs?
only has visceral peritoneum on its anterior surface, located in the retroperitoneum
which organs are classified as intraperitoneal organs?
liver + gall bladder stomach spleen parts of small intestine transverse colon
which organs are classified as retroperitoneal organs?
kidneys adrenal gland pancreas ascending colon descending colon
what are condensations of the peritoneum?
double layers that attach organs to each other or to the abdominal wall
what are the different types of peritoneal formations?
mesentery, omentum and peritoneal ligaments
what do mesentery formations usually do?
connect organ to posterior body wall
what are omentum (greater and lesser) formations?
double layer of peritoneum that passes from stomach to adjacent organs (‘ cover of the abdominal organs’)
what do peritoneal ligaments do?
double layer of peritoneum connect organs to one another or body wall
what are mesentery formations?
have a core of connective tissue with blood and lymph vessels, nerve, lymph nodes and fat
what is the greater omentum?
four layered, hangs like apron, attaches the greater curvature of stomach to transverse colon
what is the lesser omentum?
double layered, runs between lesser curvature of stomach and duodenum to liver, has a free edge
what does the omenta divide the peritoneal cavity into?
a greater sac and a lesser sac
how do the two sacs in peritoneum communicate?
through the omental foramen (foramen of winslow)
where does the portal triad lie?
in the free edge of the lesser omentum
what are the two pouches in the pelvic area of the female called?
- vesico-uterine pouch
- recto-uterine pouch (pouch of douglas)
what is the pouch in the pelvic area o the male called?
recto-uterine pouch (pouch of douglas)
what are ascites?
collection of fluid in the peritoneal cavity
what are ascites most commonly caused by?
cirrhosis and portal hypertension
how can ascitic fluid be drained?
by a procedure called paracentesis
what is the character of visceral pain?
dull, achy and nauseating
what is the character of somatic pain?
sharp and stabbing
how do sympathetic nerve fibres get from the CNS to the abdominal organs?
leave spinal cord between levels T5 and L2, enter the sympathetic chains but do not synapse, leave the sympathetic chains within abdominopelvic splanchnic nerves, synapse at prevertebral ganglia which are located anterior to the aorta at the exit points of the major branches of the abdominal aorta, postsynaptic sympathetic nerve fibres pass from the prevertbral ganglia onto the surface of the arterial branches leaving the abdominal aorta, they take part in periarterial plexuses with other nerve fibres, as they hitch a ride with the arteries and their branches towards the smooth muscle and glands of organs.
at which point do sympathetic nerve fibres for the adrenal gland leave the spinal cord?
T10-L1
If the problem is in the foregut where does the pain tend to be felt?
epigastric region
If the problem is in the midgut where does the pain tend to be felt?
umbilical region
If the problem is in the hindgut where does the pain tend to be felt?
pubic region
which part of the spinal cord do foregut structure nerves enter at?
approx T6-T9
which part of the spinal cord do midgut structure nerves enter at?
approx T8-T12
which part of the spinal cord do hindgut structure nerves enter at?
approx T12-L2
what is jaundice?
yellowing of the sclera and skin caused by an increase in the blood levels of bilirubin
what is bilirubin?
normal by-product of the break down of red blood cells mainly occurring in the spleen
what is bilirubin used to form?
bile
why is bile important?
for normal absorption of fats from the small intestine
what does the gallbladder do?
stores and concentrates bile
what is the largest organ in the body?
liver
what is the function of the liver?
glycogen storage
bile secretions
other metabolic functions
what is the surface anatomy of the liver?
located mainly in RUQ, protected by ribs 7-11, location changes in breathing
what are the four anatomical lobes of the liver called?
caudate lobe
right lobe
quadrate lobe
left lobe
how many functional lobes does the liver have?
eight
what does each segment of the liver have?
- branch of hepatic artery
- branch of hepatic portal vein
- bile drainage (to bile duct)
- venous drainage (to IVC)
what does the portal triad consist of?
hepatic portal vein
hepatic artery proper
bile duct
what does the portal triad run within?
hepatoduodenal ligament
what is the first of three midline branches of the aorta called?
coeliac trunk
what vertebral level does the coeliac trunk leave the aorta?
T12
what does the coeliac trunk supply?
organs of the foregut
what does the coeliac trunk trifurcate into?
splenic artery
left gastric artery
common hepatic artery
which ribs is the spleen protected by?
9-11
what does the spleen do?
breaks down red blood cells to produce bilirubin
what are the major blood supplies to the stomach called?
right and left gastric arteries and right and left gastro-omental arteries
where does the blood supply to the liver come from?
right and left hepatic arteries and hepatic portal vein
what are the right and left hepatic arteries branches of?
hepatic artery proper
how much of the blood supply to the liver is from the hepatic arteries?
20-25%
what are the two clinically important areas of the peritoneal cavity related to the liver?
- hepatorenal recess (morrisons pouch)
- sub-phrenic recess
what does the hepatic portal vein (HPV) do?
drains blood from foregut, midgut and hindgut to the liver for first pass metabolism (cleaning)
what is the hepatic portal vein formed by?
splenic vein (drains foregut) superior mesenteric vein (midgut)
what does the inferior mesenteric vein do?
drains the blood from the hindgut to the splenic vein
what does the inferior vena cava do?
drains the cleaned blood from the hepatic veins into the right atrium
what does bile flow out/in the gallbladder via?
cystic duct
what is the blood supply to the gallbladder?
cystic artery
what is the cystic artery a branch of in most people?
right hepatic artery
where is the cystic artery located?
cystohepatic triangle (of calot)
what is gallbladder pain a result of?
inflammation of the gallbladder or cystic duct following irritation from or impaction of a gallstone
what is the name for the surgical removal of the gallbladder?
cholecystectomy
where will gallbladder pain present?
early pain in the epigastric region, can also present in the hypochondrium with or without pain referral to the right shoulder - a result of anterior diaghragmatic irritation
what does the central vein do?
collects cleaned blood and drains into the hepatic veins
what is the biliary tree made up of?
a number of ‘ducts’ which transport bile
what do the right and left hepatic ducts unite to form?
common hepatic duct
what does the common hepatic unite with?
cystic duct to form bile duct
what does the bile duct drain into?
2nd part of duodenum, along with main pancreatic duct
what are the four parts of the duodenum called?
- superior - duodenal cap (relatively mobile)
- descending
- horizontal
- ascending
where does the duodenum begin?
pyloric sphincter
where does the duodenum end?
duodenojejunal flexure
what does the duodenum secrete?
a number of peptide hormones into blood e.g. gastrin and CCK
where can pain from duodenal ulcer be felt?
epigastric region
what is the pancreas described as having?
head
neck
body
tail
what lies posteriorly to the pancreas?
right kidney and adrenal gland IVC bile duct abdominal aorta superior mesenteric vesels left kidney and adrenal gland part of the portal venous system
what lies anteriorly to the pancreas?
stomach
what surrounds the head of the pancreas?
duodenum
what lies superoposteriorly to the pancreas?
splenic vessels
what are the functions of the pancreas?
exocrine: acinar cells - pancreatic digestive enzymes into main pancreatic duct
endocrine: islets of langerhans - insulin and glucagon into bloodstream
what does the bile duct form when it joins the main pancreatic duct?
ampulla of vater/ hepatopancreatic ampulla
what are anatomical sphincters?
discrete areas where muscle completely encircles the lumen of the tract
what sphincters are located in the biliary tract?
bile duct sphincter
pancreatic duct sphincter
sphincter of oddi
what is endoscopic retrograde cholangiopncreatography (ERCP)?
investigation used to study the biliary tree and pancreas and treat some pathology associated with it
what is involved in an ERCP?
- endoscope inserted through oral cavity, oesophagus, stomach and into duodenum
- cannula placed into major duodenal papilla and radio-opaque dye injected back into biliary tree
- radiographic images taken of dye-filled biliary tree
what could cause an obstruction of the biliary tree?
gallstones
carcinoma at head of pancreas
what is inflammation of the pancreas called?
pancreatitis
what is a potential cause of pancreatitis?
blockage of ampulla by a gallstone - bile is then diverted into pancreas leading to irritation and inflammation
where would pain from the pancreas be present?
epigastric and/or umbilical region and can also radiate to back
what can happen in advanced cases of pancreatitis?
vascular haemorrhage leading to blood/fluid accumulation in the retroperitoneal space
where does the jejunum begin?
at duodenaljejunal flexure
where does the ileum end?
ileocaecal junction
what are the differences between the jejunum and ileum?
colour - jejunum is deep red, ileum is lighter pink
wall - jejunum is thicker and heavy, ileum is thinner and lighter
vascularity - jejunum is more vascular, ileum is less vascular
mesenteric fat - jejunum has less
circular folds - jejunum has large, tall and closely packed fold, ileum has low and sparse folds
lymphoid tissue - present in ileum
where does arterial blood come from to the jejunum and ileum?
from superior mesenteric artery via jejunal and ileal arteries
what is the venous drainage of the jejunum and ileum?
from jejunal and ileul veins to superior mesenteric vein to hepatic portal vein
what do vessels travel within?
the mesentery
where are proteins and carbohydrates absorbed?
from the small intestine into the portal venous system to be taken to liver
at what vertebral level do the superior mesenteric vessels leave the aorta?
L1
how is fat absorbed?
bile helps absorb fat from GI tract into intestinal cells, they are then absorbed into specialised lymphatic vessels of the small intestine called lacteals, they travel via the lymphatic system to eventually drain into the venous system at the left venous angle
what are the main groups of lymph nodes draining abdominal organs?
- celiac
- superior mesenteric
- inferior mesenteric
- lumbar
what do superficial lymph vessels drain into?
deep lymph vessels
what will lymphs either drain into?
thoracic duct
or
right lymphatic duct
where are the venous angles?
- junction between subclavian and internal jugular veins
- left venous angle - thoracic duct drainage
- right venous angle - right lymphatic duct drainage
what are the functions of the large intestine?
defence
absorption - H2O and electrolytes
excretion
Where are the paracolic gutters located?
between lateral edge of ascending and descending colon, and abdominal wall
what are the three distinguishing features of the colon?
omental appendices
teniae coli
haustra
what are teniae coli?
3 distinct longitudinal bands of thickened smooth muscle, running from caecum to distal end of sigmoid colon, come together at the appendix
what are omental appendices?
small, fatty projections
where do the caecum and appendix lie?
right illiac fossa
where does the sigmoid colon lie?
left illiac fossa
what does the sigmoid mesocolon give?
a degree of movement to the sigmoid colon
what is the negative side of a sigmoid mesocolon?
risk of twisting around itself - sigmoid volvulus - results in bowel obstruction
what are the three midline branches of the abdominal aorta?
celiac trunk
superior mesenteric artery
inferior mesenteric artery
what do the lateral branches of the abdominal aorta supply?
kidneys/adrenal gland gonads (testes/ovaries) body wall (posterolateral)
what do the abdominal aorta bifurcate into and where?
common iliacs at L4. further bifurcate to internal and extrernal iliacs
what could the arterial anastomoses between the SMA and the IMA help prevent and how?
intestinal ischaemia by providing an alternative route by which blood can travel
what vessel supplies blood to the rectum and anal canal?
superior rectal artery (branch of IMA)
what is the remainder (not rectum and anal canal) supplied by?
internal iliac artery
what are the two main venous systems in the body?
hepatic portal venous system and systemic venous system
what does the hepatic portal venous system do?
drains venous blood from absorptive parts of the GI tract and associated organs to the liver for ‘ cleaning’
what does the systemic venous system do?
drains venous blood from all other organs and tissues into the superior or inferior vena cava
what does the inferior vena cava do?
drains cleaned blood from the hepatic veins into the right atrium
what does the hepatic portal vein do?
drains blood from foregut, midgut and hindgut structures to the liver for first pass metabolism
what does the splenic vein do?
drains blood from foregut structures to hepatic portal vein
what does the superior mesenteric vein do?
drains blood from midgut structures to hepatic portal vein
what does the inferior mesenteric vein do?
drains blood from hindgut structures to splenic vein
what are the 3 clinically important sites of venous anastomosis between systemic and portal venous systems?
distal end of oesophagus
skin around umbilicus
rectum/anal canal
what does blood do in the portal-systemic anastamosis?
can go either into systemic or portal venous system, normally there is very little blood flow within these collateral veins
what does portal hypertension lead to?
reversal of blood flow, larger volume of bloof to the anastomatic (collateral) areas causes them to be varicosed
what an cause portal hypertension?
liver pathology and tumour compressing HPV
