Anatomy Flashcards
name each component of the alimentary canal and what it does…
mouth & oropharynx: processes food
oesophagus: propels food into stomach
stomach: stores & churns
small intestine: digestion & absorption
large intestine: absorbs water and stores faeces
rectum & anus: expulsion
what are accessory structures of the alimentary canal
salivary glands, pancreas, liver & gall bladder
what are the 4 functions of the alimentary canal?
motility: muscle contraction
secretion: hormones, NTS
digestion: chemical breakdown
absorption: transfer of digestive products to blood or lymph
what are the pacemaker cells of the GI tract called?
interstitial cells of Cajal (ICCs)
True/False…
ICC activity is in slow waves?
True
slow waves are…
the BER and vary in frequency
what is the force of contractions of the intestine muscle dependent upon?
the no of APs discharged
what are organs innervated with?
visceral afferents & autonomic and enteric nerves
what is the body wall innervated with?
somatic sensory, motor nerves, and ANS
parasympathetic nerves of the GI tract can be..
excitatory: inc secretions, blood flow, contraction
inhibitory: relaxation of some sphincters and stomach
how do parasympathetic nerves reach organs?
enter abdominal cavity on surface of oesophagus > reach periarterial plexuses around abdominal aorta and travel to organs
where does parasympathetic innervation reach in the GI tract?
up to transverse colon
sympathetic nerves can be…
excitatory: inc sphincter tone
inhibitory: dec motility, blood flow and secretions
how do sympathetic nerves reach organs?
leave spinal cord at T5 & L2 and enter sympathetic chain > exit via splanchnic nerve and synapse at anterior of aorta where major branches of abdominal aorta branch out> reach organs
where do visceral afferents for foregut travel back to?
T6-T9
where do visceral afferents for midgut travel back to?
T8-T12
where do visceral afferents for hindgut travel back to?
T10-L2
what do visceral afferents run along side with?
sympathetic nerves
what is the enteric nervous system?
mesh like system of neurones that governs GI tract
describe the 5 types of motility patterns in GI tract?
peristalsis: waves of relaxation & contraction
segmentation: contraction of circular muscle
colonic mass movement: sweeping contraction that pushes faeces to rectum
migrating motor complex: sweeping contraction from stomach to terminal ileum
tonic contractions: low & high pressure contractions
True/False…
low pressure contractions occur in sphincters
False..
low pressure occur in organs with storage function
high pressure occur in sphincters
how man sphincters are there in GI tract
6
what are sphincters?
acts as 1 way valves encircled by SM which contract and relax according to stimuli
what are the 3 closure muscles of the mouth
masseter, temporalis, medial pterygoid
what is the 1 open muscle of the mouth
lateral pterygoid
what are the names of the 3 salivary glands…
parotid, submandibular, sublingual
what 2 cranial nerves are responsible for the gag reflex
CN IX, CN X
what cranial nerve supplies tongue muscles
CN XII
what cranial nerve supplies pharyngeal muscles
innervated by CN X
what is the part of the body with an anatomical and physiological sphincter?
oesophagus
where does the oesophageal plexus terminate?
cardia of stomach
what is the physiological sphincter…
lower oesophageal sphincter and due to the oesophagus’s oblique entrance to cardia it creates sphincter effect
why is lower oesophageal sphincter important?
prevents reflux
what organs belong to foregut, midgut, hindgut?
Foregut : oesophagus, mid duodenum, liver, gall bladder, spleen, ½ pancreas
Midgut: mid duodenum to 2/3of transverse colon, ½ of pancreas
Hindgut: distal 1/3 of transverse colon, ½ of anal canal
what are the layers of the abdominal wall?
rectus abdominus
external & internal oblique
transverse abdominus
parietal peritoneum
what are the 2 layers of the peritoneum and its function
parietal peritoneum: body wall
visceral peritoneum (organs)
- secretes lubricant and has nerve supply
what does retroperitoneal mean?
the visceral peritoneum is on anterior surface of organs
what does in a mesentery mean?
visceral peritoneum covers organs entirely suspending them from posterior and anterior walls of abdomen
what can peritoneum form?
pouches
1-males
2-females
what is peritonitis?
inflammation of peritoneum
what does the omentum do?
divides peritoneal cavity into greater and lesser sacs
is bile alkaline or acidic?
alkaline
what does bilirubin do?
provides bile with colour
purpose of cholangiocytes?
modify 1y bile
what cells produce bile and where does it go?
hepatocytes- flows via canaliculi into bile duct
where does bilirubin originate
produced in break down of red blood cells which occurs in spleen
why is bile important?
for digestion and absorption of fats
what is the anatomical location of the spleen and what does it do?
left hypochondriac
breaks down red blood cells
what is the blood supply of the spleen
cephalic trunk (1st of 3 branches of abdominal aorta)
what does the cephalic trunk trifurcate into?
splenic, hepatic, left gastric arteries
describe the location and and action of liver…
right upper quadrant
converts bilirubin to bile and synthesises cholesterol
what are the segments of the liver?
right lobe
left lobe
caudate lobe
quadrate lobe
what is an anatomical pathology of the liver?
contains hepatorenal and subphrenic recess which can become inflamed and infected
what is the blood supply to the liver?
portal triad (hepatic artery, hepatic portal vein and common bile duct)
what is the hepatic portal vein sub-comprised of?
splenic vein: drains blood from foregut to HPV
inferior mesenteric vein: drains blood from hindgut to splenic vein
superior mesenteric vein: drains blood from midgut to HPV
where does the hepatic portal vein drain into?
Inferior vena cava where cleaned blood is returned to RA of heart
location and function of gallbladder…
posterior to liver but anterior to duodenum- foregut
stores and concentrates bile
segmentation of gall bladder
body and neck (neck narrows to form cystic duct)
what is most common pathology of gallbladder
gallstones causing cholecystitis
where does pain usually refer to?
pain often radiates to right shoulder
what is the blood supply to the gallbladder?
cystic artery (branch of right hepatic artery)
what is the bile duct made up of?
right & left hepatic ducts (common hepatic duct) & cystic duct
where does bile duct usually join onto?
main pancreatic duct which drain into duodenum
location and function of pancreas…
stomach lies anteriorly and duodenum surrounds head
- produces digestive enzymes, insulin and glucagon
segments of pancreas?
head, neck, body, tail
what is the blood supply of the pancreas?
splenic artery, gastroduodenal artery and superior mesenteric artery
what are the 3 components of the small intestine?
duodenum, jejunum, ileum
location and function of SI?
close to pancreas, starts at pyloric sphincter
- secretes peptide hormones
True/False…
duodenum is highly folded
False…
jejunum and ileum are
blood supply of SI?
superior mesenteric artery, jejunal and ileal arteries
superior mesenteric, jejunal, ileal veins
where does GI tract lymph eventually drain into?
thoracic duct or right lymphatic duct and returns to venous system at venous angle
which lymphatic drainage vessel drain into right venous angle?
right lymphatic duct
what are the 4 lymph node groups of the GI tract?
celiac
superior mesenteric
inferior mesenteric
lumbar
why do hernias typically occur?
structural weakness and inc pressure
where does gut typically push through in inguinal herniation?
Hasselbach’s triangle
True/False…
a DIRECT inguinal hernia will use pathway already created by body to gain inguinal access ie. testes pathway
False…
that is INDIRECT inguinal pathway
DIRECT inguinal pathway pushes directly through to access inguinal canal
how to identify a direct inguinal hernia?
hernia lies parallel to spermatic cord
passes medial to inferior epigastric vessels
how to identify an indirect hernia?
hernia lies within spermatic cord
passes laterally to inferior epigastric vessels to enter inguinal ring
what are the 2 inguinal ligament attachments?
Lateral= asis Medial= Pubic Tuberal
how to clinically differentiate between direct and indirect inguinal hernias?
note 2 inguinal ligament attachements- deep inguinal ring is halfway between these. if protrusion there then = direct hernia
other than Hasselbach’s triangle, what is a common area of weakness for abdominal hernias?
Myopectineal Orifice
describe the 3 abdominal muscle appearances…
external oblique: hands in pockets fibres
internal oblique: hand on chest fibres
transversus abdominus: horizontal fibres
what does the inguinal canal contain for women and men?
spermatic cord, round ligament of uterus, blood & lymph vessels, iliolinguinal nerve
