Digestive Anatomy Flashcards
what are the major sites of mechanical and chemical digestion?
mechanical - stomach - some chemical digestion with little absorption
- also occurs i mouth
chemical - small intestine - major site of chemical and H2O absorption
what do the parietal and visceral peritoneum develop from? what structures are intraperitoneal and retroperitoneal?
parietal - somatic mesoderm
visceral - splanchnic mesoderm
intraperitoneal - stomach, liver, small intestine
retroperitoneal - kidney
describe what the following mesentery connects: lesser omentum, greater omentum, mesoderm colon, mesentery proper, mesentery of sigmoid colon
lesser omentum - liver and lesser curvature of stomach
greater omentum - greater curvature of stomach down to edge of transverse colon
- forms double layer that goes back on itself
mesocolon - transverse and sigmoid colon
mesentery proper - surrounds small intestine
mesentery of sigmoid colon - attaches to sigmoid colon
describe the following mesentery: transverse mesocolon, root of the mesentery, mesentery proper what is connected to the ascending and descending colon?
transverse mesocolon - suspends transverse colon from posterior abdominal wall
root of the mesentery - attaches small intestine to the posterior abdominal wall - scrunched
- follows superior mesentery vein
mesentery proper - double layer that surrounds small intestine, 21 feet long, attaches via root of mesentery
- parietal peritoneum
ascending and descending colon are retroperitoneal
what structures pass through the hilum of the liver?
hepatic artery, hepatic portal vein, common bile duct
what structures are retroperitoneal? which are primary and which are secondary?`
pancreas, ascending and descending colon, duodenum (small intestine), kidneys
kidneys are the only primary retroperitoneal structure
- all other structures were intraperitoneal during fetal development
- reorganization before birth causes them to be retro
what are the branches of the celiac trunk? describe the branches that come off of them
L gastric - lesser curvature
- gives off R gastric artery - goes to hepatic artery
splenic - supplies spleen
- gives off short gastric arteries
- gives off L gastromental artery - greater curvature of stomach
common hepatic
- gives off gastroduodenal artery
- once gastroduodenal is given off, becomes hepatic proper
gastroduodenal - gives off R gastroomental artery - links up with L gastroomental on greater curvature of stomach
hepatic proper - joins portal vein to deliver nutrients to the liver
describe the branches of superior mesenteric branches. what does it supply? where do we see arches? what does the interior mesenteric supply>
superior mesenteric branches to small intestine via mesenteric proper
- duodenum - single arches
- ileum - multiple arches
superior mesenteric supplies all of the small intestine, ascending and transverse colon
inferior mesenteric - descending colon
- branches into superior rectal
describe the vasculature of the middle and inferior rectal arteries
common iliac - internal iliac - middle rectal
internal iliac gives off internal pudendal and inferior rectal
what is the innervation of the digestive system? how does it correlate with the vasculature system?
same portion of the digestive system that is supplies by the Celiac trunk and superior mesenteric arteries are supplied by VAGUS
pelvic splanchnic nerve (parasympathetic) - portion of digestive system supplied by inferior mesenteric and branches of internal iliac
describe the veins of the digestive system. get from the inferior mesenteric to the portal vein
splenic vein receives inferior mesenteric vein
- joins the superior mesenteric to form the portal vein
gastric veins drain straight into portal veins
describe the general GPAT layout from inside out
GPAT - general plan of the alimentary tract
mucosa - epithelium + loose irregular CT (lamina propia)
- noncornified stratified squamous or simple columnar
- muscularis mucosa - deepest layer of mucosa - found wherever muscularis externa is made of muscle
submucosa - dense irregular CT
- submucosal glands in esophagus and duodenum
- lymphatic follicles - payers patches in ileum
muscularis externa - smooth muscle - peristalsis using:
- inner circular - constricts lumen
- outer longitudinal - stretch organ
serosa - visceral peritoneum
What is the GPAT of the mouth like?
mucosa - non cornified stratified squamous with loose irregular CT
submucosa - dense irregular CT
muscularis externa - skeletal muscle
- buccinator: cheek - sucking in - facial nerve
- orbicularis Boris - sphincter muscle - facial nerve
- mylohyoid muscle
serosa - cornified stratified squamous ET
- loose irregular/dense irregular ct
what are the muscles of the mouth that contain the palatine tonsil?
palatoglossal and palatopharyngeal muscles
what are the chewing muscles
closes jaw: temporals and masseter
medial/lateral phregoid
innervated by trigeminal CN 3
what are the functions of the following tongue muscles and what innervates them: genioglossus, styloglossus, palatoglossus, hyoglossus
geniglossus - sticks tongue out
styloglossus - pulls tongue up and back when swallowing
palatoglossus - pulls tongue up
hyoglossus - depressing and stabilizing lateral movement
innervation of tongue muscles
- palatoglossus - vagus nerve
- all other muscles - hypoglossal
what are the innervations for tongue sensation and what are the sensations that they are responsible for?
anterior 2/3 - taste - facial nerve CN7
- mandibular nerve - trigeminal (CN3) - touch and temperature
posterior 1/3 - glossopharyngeal (CN 9) - special sensory
what are the frenula and where are they located
superior and inferior labial frenula - attach the lips to the gums
lingual frenula - attaches tongue to floor of mouth
describe the following papillae: circumvallate, filiform, fungiform
circumvallate - circular moat
- larger with tastebuds at bottom
- form chevron
filiform - most common, contains no tastebuds
fungiform - tastebuds near surface
- most concentrated at front 2/3 of tongue
describe the following regions of the tooth and what they contain: crown, neck and root. what is the pulp cavity?
crown - contains enamel and denton
- denton - living tissue similar to bone
neck - contains enamel that is deep to gum line
- gingiva - gum line
- contains denton
root - denton covered with cementum
- cementum - living tissue
pulp cavity - supplied nutrients and O2 to denton
what kind of ligament connects the gums to the tooth?
perioseteol ligaments - fibrous CT
- connwcra cementum and alveolar process
Gomphosis - cannot move
- fibrous, synartthrotic
what happens when you get a cavity to the denton? to the pulp cavity?
denton - filling
pulp cavity - root canal
what are the teeth in primary dentition? how many teeth in total?
central incisor, lateral incisor, cuspid (canine), 1st molar, 2nd molar
20 teeth total in kids
what are the teeth in secondary dentition? bold the ones that are not present in primary. ow many teeth in total?
central incisor, lateral incisor, cuspid (canine), 1ST BICUSPID (premolar), 2ND BICUSPID (premolar), 1st molar, 2nd molar, 3RD MOLAR (wisdom tooth)
32 teeth total
describe the serous and mucous cells of the salivary glands
serous - basic stain, balls of cells
- basophilic - lots of proteins for digestion
- nuclei at base - lots of room for Golgi and ER
- secrete into center to go into ducts
mucous cells - frothy
- ET making mucous for channel/duct
- function to bind food together
describe the following salivary glands: parotid, sublingual, submandibular
parotid - most common, glossopharyngeal CN9
- opens to mouth surface opposite of 2nd molar
- serous only
sublingual - multiple ducts that empty in front
- gleeking
- mixed - mucous with some serous
submandibular - makes J shape around jaw
- empties into side of flow of mouth
- serous with some mucous
describe the following salivary glands: parotid, sublingual, submandibular
parotid - most common, glossopharyngeal CN9
- opens to mouth surface opposite of 2nd molar
- serous only
sublingual - multiple ducts that empty in front
- gleeking arm and retroperitoneal
- mixed - mucous with some serous
submandibular - makes J shape around jaw
- empties into side of flow of mouth
- serous with some mucous
what are the stages of swallowing
- buccal phase - bolus moves from mouth past soft palate
- pharyngeal phase - tongue presses p against roof of mouth
- esophageal phase - peristalsis moves bolus down esophagus
- bolus enters stomach
no digestion in esophagus
what are the two sphincters in the stomach? what nerve controls the stomach?
top - cardiac sphincter
bottom - pyloric sphincter
vagus nerve - uncharge of stomach peristalsis, secretion of enzymes and HCl
Describe the GMAP of the stomach
mucosa - simple columnar without microvilli or goblet cells
- mucous/neck mucous cells - not goblet
- chief cells - makes enzymes and HCl
- parietal cells - release HCl
- G cells - bottom of gastric pit - secrete gastrin
submucosa - dense irregular CT
muscularis externa - smooth muscle - 3 layers - mechanical dig
- innermost oblique
- inner circular
- outer longitudinal
serosa - visceral peritoneum
- simple squamous and loose irregular CT
what are the approximate lengths of the three regions of the small intestine?
duodenum - 10 inches
jejunum - 8-9 feet
ileum - 10-11 feet
what are Brunner’s glands and where are they located?
submucosal glands located in the duodenum
- protects duodenum from the pH of stomach chyme
increased pH in jejunum is also due HCO3- from pancreas
what are Peyer’s patches and where are they located?
lymphatic follicles that are located primarily in the submucosa of the ileum
- also contains diffuse lymphatic tissue in the mucosa and submucosa
what is a lacteal and where is it located?
lymphatic vessel located in the small intestine that absorbs fat
describe the GPAT of the small intestine
mucosa - simple columnar with microvilli
- first location with microvilli
- contains goblet cells
- CT - loose irregular CT
- muscularis mucosa
submucosa - dense irregular CT
- duodenum - Brunner’s grlands
- ileum - Peyers patches
- submucosal plexus - enteric NS
muscularis externa
- inner circular
- myenteric reflex - ct between the two
- outer longitudinal
serosa - visceral peritoneum
- loose irregular CT and simple squamous
what are enteroendocrine cells and where are they located?
in base of columnar cells small intestine - clear looking cells that secrete 3 hormones
what are paneth cells? and where are they located? what are their functions>?
pink staining granules in the base of the columnar cells of SI
- non specific immunity - 2nd wall of defense protecting epithelia
- help ID the organ as small intestine
what are the three orders of folding in the small intestine?
- microvilli - folds of plasma membrane
- nonmotile, contain actin - villus - fold of loose irregular CT of mucosa
- place circulars - fold of submucosa
- think of a scrunched up sleeve
- wrinkles in wall of SI
all increase SA for increased absorption
what is the cecum? what sphincter does it contain?
first part of the large intestine that connects it to the small intestine
contains the ileocecal valve - sphincter
what is haustra? what is the teniae coli?
haustra - pouches formed by tone/contraction of the outer longitudinal (muscularis externa) muscle of the colon
teniae coli - three evenly distributed bands of smooth muscle that create haustra
- does not completely surround colon
describe the GPAT of the large intestine
mucosa - nothing on surface - smooth
- simple columnar with microvilli
- MANY goblet cells, only 25% but loos like 100%
- secrete mucous to lubricate feca mater
- muscularis mucosa
thick submucosa - dense irregular CT
muscularis externa
- internal circular
- external longitudinal - 3 bands forming teniae coli
what parts of the colon are intraperitoneal and retroperitoneal? what innervates each part of the colon? what are the blood supply?
ascending colon
- retroperitoneal
- vagus innervation
- superior mesenteric
transverse colon
- intraperitoneal
- vagus innervation
- superior mesenteric
descending colon
- retroperitoneal
- pelvic splanchnic innervation (PS)
- inferior mesenteric
sigmoid colon
- intraperitoneal
- pelvic splanchnic innervation (PS)
- inferior mesenteric
describe the GPAT for rectum
same as GPAT for large intestine
- more goblet cells
- valves help move fecal matter
last 2.5 inches is anal canal
- thickens to become external anal sphincter - innervated by pudental
what are the veins of the rectum?
middle rectal veins - branches off the internal iliac vein
- formed internal hemorrhoids
internal rectal veins - branches of the internal pudendal vein
- forms external hemorrhoids
describe the GPAT of the anal canal. what does the inner circular layer form?
mucosa - non cornified stratified squamous
- muscularis mucosa
muscularis externa
- inner circular layer forms internal anal sphincter
- autonomic NS - parasympathetic stimulation causes it to relax
describe the defecation reflex
- stretching of the sigmoid colon and rectum by feces triggers afferent signals to spinal cord
- efferent signals return to the rectum via parasympathetic pelvic splanchnic nerves to stimulate peristalsis of the rectum and relaxation of internal anal sphincter
- lower motor neuron fibers to the external anal sphincter cause it to relax
describe the livers lobes. what splits the two lobes and what does it contain?
Right and L lobes
split by the falciform ligament - mesentery
- contains the ligamentum teres - collapsed umbilical vein
on the posterior view of the liver, what are the two other lobes? what is the porta hepatis and where is it located?
caudate lobe - L side of inferior vena cava
- superior lobe
quadrate lobe - found between ligamentum teres and gallbladder
- inferior of the two
porta hepatis - in between the caudate and quadrate
- contains the hepatic portal vein, hepatic artery and bile duct
what is the largest gland in the body> describe its functions
liver - largest gland in the body
- hepatocyte - hepatic epithelial cell
functions:
- synthesizes proteins
- stores glucose as glycogen
- recycles RBC
- synthesizes bile salts for emulsification of lipids
- detoxification - smooth ER breaks down drugs/alcohol
what are the protein that the liver synthesizes and what are their functions?
albumin - maintains osmotic P
transport proteins: transferrin, LDL, HDL, VLDL, lipids
clotting factors
complement
what cells of the liver are important for RBC recycling?
Kupffer cells - macrophages in the liver sinusoids (blood)
- contain bilirubin - bile waste
caput Medusae - caused by cirrhosis
describe how simple sugars, aa’s and lipids get to the liver
simple sugar/AA’s
- absorbed in small intestine: 1st cap bed villi
- travel to hepatic portal vein and to the liver
lipids - absorbed by lacteals in vili
- go to thoracic duct, brachiocephalic duct, heart
- enter the liver via the HEPATIC ARTERY
what is a hepatic lobule? what is the hepatic portal triad and where is it located?
hepatic lobule - made of 6 borders of CT
hepatic triad - located at corners of louyles
- contains branches of the portal vein, hepatic artery, bile duct
portal vein and hepatic artery run parallel toward center, bile duct opposite
what is a hepatic lobule? what is the hepatic portal triad and where is it located?
hepatic lobule - made of 6 borders of CT
- arranges to that they are never more than 2 cells thick
hepatic triad (6) - located at corners of louyles
- contains branches of the portal vein, hepatic artery, bile duct
portal vein and hepatic artery run parallel toward central vein (1), bile duct opposite to edge
what is the second capillary bed in the liver? where does the fluid flow? what are the macrophages called
sinusoids - large diameter muscle free channels, simple squamous
- similar to capillaries - have fenestra
- no basement membrane/tight junctions - allows for easy addition of proteins, removal of AA/sugars
- always in contact with hepatocytes
flows toward central vein
- central veins flow together to form hepatic vein and go into the inferior vena cava
contain Kupffer macrophages
what is the second capillary bed in the liver? where does the fluid flow? what are the macrophages called
sinusoids - large diameter muscle free channels, simple squamous
- similar to capillaries - have fenestra
- no basement membrane/tight junctions - allows for easy addition of proteins, removal of AA/sugars
- always in contact with hepatocytes
flows toward central vein
- central veins flow together to form hepatic vein and go into the inferior vena cava
contain Kupffer macrophages
describe the bile canaliculi of the liver. which direction does it flow?
no plasma membrane of cell beside the plasma membrane of hepatocyte
- all flow toward bile duct - toward the hepatic triad
what are the hepatic portal vein, hepatic artery, and bile duct lined with?
hepatic portal and hepatic artery - simple squamous
bile duct - simple columnar
what is the space of disé in the liver and what is its function?
space between hepatocyte and sinusoid that allows food, glucose, AA to move out of blood sinusoids via fenestra
- this allows the hepatocyte to uptake them
describe the biliary tree. what does it empty into?
R and L hepatic duct come together to form common hepatic duct
- received input from the gallbladder via cystic duct - becomes common bile duct
common bile duct meets the main pancreatic duct at the duodenum
describe the structure of the gall bladder. what is its function? describe the cystic duct
gall bladder - stores bile
- contains thin wall of smooth muscle
- lined with simple columnar ET
sensitive to vagus and hormones
cystic duct - connects gall bladder to common hepatic duct to form common bile duct
- bile can flow in both directions depending on pressure
describe gallstones and how they form
predicate of bile salts, typically formed in the gall bladder
- asymptomatic in gall bladder, symptomatic in ducts
- RUQ pain and shoulder pain
fat, 40, fecund (has children)
hormones in pregnant women can cause bile salts to form precipitates
describe the sphincter of odi. what are the papilla surrounding it? what feeds into it? what happens if its blocked?
sphincter where hepatopancreatic ampulla enters duodenum
- received input from common bile duct and main pancreatic duct
- surrounded by major duodenal papilla
accessory pancreatic duct enters duodenum superiorly, surrounded by minor duodenal papilla
odi blocked - enzymes backed up and digest pancreas - pancreatitis
