2.3 Digestive System Liver, Pancreas Gallbladder Flashcards
Parakeritinsed epithelium?
Hard palate/masticatory mucosa.
Superficial cells not pyknotic nuclei.
What is pyknotic ? Irreversible condensation of chromatin.
9 main areas of digestive system and function?
Oral cavity - ingestion and initial fragmentation
Tongue and pharynx
names for parotid and submandibular gland ducts?
Stensens and whartons duct
4 types of tongue papillae?
Filiform, fungiform, circumvallate, foliate
How to differentiate between oesophagus and ureter?
Muscularis externa - oesophagus inner circular outer longitudinal. Ureter - opposite
Organs of GI tract and accessory organ
Mouth, isthmus of fauces, oesophagus, stomach, si, li, cecum, rectum
Teeth, tongue, salivary glands, liver, gallbladder, pancreas
Glands of GI tract?
Intraepithelial - goblet cells
Mural
Intra - tunica : mucosa, submucosa
Extra - major salivary glands, liver, pancreas
Functions of digestive system? (6)
Ingestion, swallowing H+ secretion, digestive enzymes Mixing and propulsion Absorption Reabsorption of water and undigested mat Elimination of digested material - defecation
Oral cavity consists of?
What is the isthmus of fauces?
Cheeks, hard and soft palate, tongue
Space extends from gums + teeth
Fauces - opening between oral cavity + pharynx
Salivary glands (3)
Moist and clean oral cavity
Secretion of mucus increase - chemical digestion
3 pairs of glands
Frenulums - teeth?
Decidous - baby teeth, 6months, 20 by 2 years, fall out by 2-6 years
Permanent - 32 total, 3rd set of molars by end of adolecense (Widom teeth)
Tongue structure, extra (2)
Mostly muscular -
grip + reposition food
Swallowing
Speech
Taste buds - circumvallate, foliate, fungiform, filiform papillae
Lingual tonsils
What is the isthmus of fauces?
.
Pharynx (3)
Naso - respiratory
Oral - digestive and respiratory
Laryngo - digestive and respiratory
Opening of laryngopharynx regulated by
Epiglottis -> elastic cartilage - 9th cartilage of larynx
What are the different phases of swallowing?
.
Structure of pharynx ?
Muscular and adventitia
Pseudostratified ciliated
Oro+laryngopharnx -> ssnk
Striated skeletal muscle
Adventitia external to muscle
What are the pharyngeal aponeurosis?
Fibroelastic ct -> muscle insertion
Muscle of pharynx(3)
Innervation
Constrictor muscles
Sup, mid, inf
Squeeze bolus -> into esophagus
Vagus nerve
Esophagus (5)
Food swallow -> folding longitudinal of lumen
C6-T10
25cm length
Behind trachea
Passes thru oesophageal hiatus (diaphragm) -> enter abdomen
4 constrictions of esophagus?
4 parts and length?
Cricoid, aortic, bronchial, diaphragmatic
Cervical 4-5, mediastinic 16, diaphagmatic 1-2, abdominal 3
GI Tract - general structure 4
Describe first 2 and how increase SA of first?
Mucosa, submucosa, muscularis externa, serosa
Mucosa - epithelium, lamina propria (MALT LCT with capillaries)
Muscularis mucosa - thin layer of sm cells - local movements
Submucosa - CT - minor blood+lymph vessels , nerves - elastic fibres - regain shape
Plicae, microvilli, villi, glands/crypts
Last 2 layers of GI tract?
And innervation of muscularis externa
Muscularis externa - 2 layers of SM - peristalsis, segmentation
Inner circular - squeezes, formation of sphincters
Outer longitudinal - shortens gut
Myenteric plexus between ME.
Submucosal plexus of gi tract?
Meissner plexus -> control gland, sensory function, contraction of MM
Structure of esophagus?
Mucosa - ss non keratinised, lp, mm
Submucosa – seromucous glands
Muscularis externa - inner and outer
In thirds : sup - skeletal. Mid - sm and skeletal. Inf - only sm
Adventitia - CT, no serosa
Esophagus - seromucous glands?
Secrete thin layer of mucus - lubrication
Esophageal cardiac glands - tubular - only LP - terminal part of oesophagus - neutral mucous
Muscosa and submucosa form?
Longitudinal folds -> stellate aspect of lumen disappears when swallowing. Reappears -> elastic recoil
Muscularis mucosa where evident in esophagus?
Submucosa contain.,
2nd and 3rd part
Elastic fibres, venous plexuses, drain into venous + hepatic portal circulation
Gastro-oesophageal junction (3)
Z line
Abrupt transition
Ss - epithelium - secretory mucosa (simple columnar)
2 sphincters of eosophagus?
UES - sup - cricopharyngeal sphincter - mech of swallowing + prevent air entrance
LES - inf - prevent reflux of acid into esophagus
What is reflux esophagitis?
Ulceration, difficulty swallowing (caudal stratified - replaced by columnar - lose resistance
Development defect of diaphram?
Hernia hiatus - herniation of abdominal portion of oesophagus
Abdomen surgical ares?
Left and right:
Hypochrondium
Lumber
Iliac fossa
In the centre : epigastric, umbilical, hypogastric
Example of retroperitoneal and extra peritoneal organs!
Pancreas, kidney
Duodenum and post abdominal wall?
Not completely surround by peritoneum
Abdominal aorta splits into
Celiac ( gastric, common hepatic, gastrodudenal )
sup - (ascending and transverse colon 2/3)
inf mesenteric artery - 1/3 transverse, descending, sigmoid
Renal - 20% of cardiac output
Adrenal
Infra and supra mesocolic space ?
.
Does retroperitoneal have a mesentery?
Lesser omentum is surrounded by?
Greater omentum?
No
Surrouded by peritoneum
Formation of other cavities
Stomach ?
Pyloric sphincter function
1.5L, EPIGASTRIC REGION - hypogastric
Greater and lesser curvature - ligaments attached - stomach and liver (lesser omentum)
Angular incisor, cardiac notch, fundus, body, pyloric antrum and canal
Regulation mat from stomach to duodenum
crypts of lieberkaun?
Found in SI
Brunenrs gland found in duodenum (submucosa)
Ileum - peyers patched
You need to learn about the stomach?
Posture, wispdth, position of other vicera, extent of filling effect, shape of stomach
Stomach position?
Inferior to diaphram, under liver
What forms the lesser omentum!
Hepatogastirc and hepatoduodenal ligament-
Bv reach liver
Portal vein
Hepatic artery
Extra hepatic billiary duct inserted onto ligament
Quick fact about greater omentum?
Behind - adipose tissue
Muscularis externa of stomach?
3 layers - oblique, circular, longitudinal.
Mechanical contraction - muscles contract
Mixing of digestive enzymes and proteolytic enzymes
Stomach mucosa epithelium?
Simple columnar, surface mucous cells.
Produce mucous -> protect stomach from acidic content
No absorption - except h2o, salts, lipids, drugs, alcohol
Effect of drugs and alcohol on stomach?
Damage mucosa of stomach,
Prostaglandins released
Loss protective function of mucosa
What level are the greater and lessor curvatures of the stomach located?
Level of the body
What angle antrum and body of stomach?
Pylorus and duodenum connected via?
What is at the surface of the internal wall of stomach? Where/when is this less prominent
90
Pyloric sphincter
Rugae, less prominent middle area + when stomach fills
Vascularisation of stomach?
Celiac trunk - l-r gastric artery; l-r gastro-omental artery
Veins parallel to artery, drained into hepatic portal vein
What supplies the fundus and body of stomach? Vascular
Upper gastric arteries
Gastric folds?
Longitudinal - distensibility
What are mammiliated areas in stomach?
Aeroles - delimited by permanent sulca
Where are glands of stomach located? What type? Name? Secretion? Cells in glands? Purpose?
Lamina propria,
Tubular, single, branched
body, fundus, cardiac, pylorus,
Mucous secretion -> protection against high acid level of stomach
How to differentiate between stomach and colon?
Lamina propria - stomach glands
Colon - mucous secreting cells + intercalated between are enterocytes
Submucosa, muscularis, serosa of stomach?
Submucosa - little
Muscularis externa - internal :oblique, circ, longi
Serosa - peritoneum
Defensive forces in the stomach? (6)
Surface mucosa, bicarbonate, mucosal blood flow, membrane transport, epithelium regenerative capacity, elaboration of prostaglandins
Injury of stomach leads to?
Ischemia, shock, delayed gastric emptying
3 types of stomach glands and where found?
Cardiac - simple compound tubular, mucous secreting - cardiac region, surround esophageal orifice
Pyloric - tubular branched coiled mucous + gastric secretion - pyloric antrum
Gastric/fundic - simple tubular branched at base - thruout stomach except above areas. Long lifespan of cells - Pariental cells 200days
Gastric mucosa - gastric glands. Cells, tubularvesicular system
Pariental(150-200days) - hcl and intrinsic factor (b12 vit absorption -> rbc production) -> tubulovesicular system -> proton pump, maintain acidic ph of stomach. Large no. Of mito.
Chief (60-90days) - pepsinogen (zymogen granules) + hcl -> pepsin
Neuroendocrine cells -gastrin
Surface/neck mucous cells
Pariental cells - larger - bud from lining epithelium, darker well stained compared to chief cells
Stomach glands -> Fundic mucosa, -3 levels and what cells located within
Surface neck cells - mucous cloudy production - level of lining epithelium + gastric pit
Neck cells - soluble clear secretion
Gastric pit(surface mucous cells) - isthmus (stem cells located, pariental, mucous neck) - fundus (chief and enteroendocrine cells)
Enteroendocrine cells (g cells)
Hcl
Gastric motility
Growth of epithelial cells
Open (chemoreceptors) and closed.
Gastrin, ghrelin, cck, secretin, gip, motilin. Where synthesised, stim and inhibit what?
Gastrin - g cells stomach - gastric acid - nothing
Ghrelin-cells in stomach-gh secretion-lipid met+fat usage in adipose
Cck - i cells duo+jujenum- gallbladder contraction,same as secretin-gastric emptying
Secretin - s cells duodenum - pancreatic enzyme, bicarbonate, growth- inhibit gastric acid secretion
Gip - k cells duo + jujenum - insulin released - gastric acid secretion
Motilin - m cells duodenum + jujenum - gastric+intestinal motility - nothing
Zollinger ellison syndrome?
Gastrinomas -> gastric + duodenal ulcers - damage of mucosa
2 types of neuroendocrine cells?
Open - cytoplasmic prolongement exposed to lumen - chemoreceptors
Closed - not reach lumen
Gastric serosa continuous with?
Parietal peritoneum of abdominal cavity via greater omentum
Visceral peritoneum of liver - lesser omentum
Small intestine - mesenteric arteries
Jej and ileum
Duodenum length and 2 extras
25cm - different structure and relationship to peritoneum
Si Function of enterocytes ->
Enterokinase - trypsinogen -> trypsin
Trypsin : pancreatic zymogens (inactive proenzymes) ->active enzymes
Eg pro:elastase, carboxypeptidase, phospholipase -> without pro.
Chymotrypsinogen -> trypsinogen
SI (4)
Continues digestive process started in stomach
Absorbs food and water
Food exiting stomach : chyme -> chymus
Chymus exposed to pancreatic and biliary secretion -> chyle
Pancrease and duodenum.
Wall of intestine?
Exocrine pancreas secrete into duodenum
Wall of intestine - lacteal + bv
SI Macroscopic and microscopic devices
Plicae, villi, crypts and glands, microvilli
Si where are plicae most numerous?
And plicae points
Distal - duo
Beginning of jej
Perm tranverse folds - cont core of submucosa
Biochemical devices of si digestion
Luminal - pancreatic enzymes and bile
Membrane - enzymes of microvilli (glycocalyx)
Mechanical devices of si?
Contraction and relax of intestinal wall (muscularis externa - cl)
Duodenum?
25cm, first, shirtest and widest part.
Bulbis duodenalis, descending, horizontal, ascending portion
C shaped.
Retroperitoneal except bulbos duodenalis
Sup mesenteric artery and veins drain into?
Portal vein
SI Explain bile, pancreatic enzymes, major-minor papillary duct?
Bile - emulsify lipids
Pancreatic enzymes - proteases, amylases, lipases, nucleases
Minor pap - accessory pancreatic duct
Major pap - main pancreatic duct + coleducus -> sphincter of oddi.
What stimulates opening/closing of the sphincter of oddi?
CCK
Si mesenterial part
Jej(2.5m) ileum(3.5m) - surrounded by peritoneum.
Root of mesentary
Length 15cm
Aterial arcade - longer in jej, shorter in ileum
Vasa recta - jej few large loops, ileum greater no. Of loops
Nerves
And bv from sup mesenteric artery
Structure of SI summary
Mucosa - simple cuboidal epi, villi, tubular glands/crypts, muscularis mucosa(2layers), lamina propria (galt)
Submucosa - duo(brunner glands) - acidic secretion - compound tubular
Muscularis externa - CL
Serosa
si villi cross-section
Lamina propria - lacteal, vascular, immune cells
Sm cells extending from muscularis mucosa into core of villus
Loost ct, cappillaries, lymphatic vessels (lipid absorption)
Si - crypts of lieberkaun
Paneth cells - defensins + lysozymes. Basally located
5 cells types found in intestinal mucosal epithelium
Enterocytes - primary function - absorption Goblet cells - mucous secretion Paneth cells - defensins and lysozomes Enteroendocrine cells - paracrine and endocrine hormones M cells (microfold cells) - modified enterocytes cover lymph nodules in lamina propria
Si- Enterocytes ?
Simple columnar - line mucosa
glycocalyx - important enzymes - digestion
Digestion of sugars(di+oligo-saccharides-> mono), proteins (peptidases + brush border)
What is the first enzyme involved in digestion
.
Pepsin
Si - bile
Convert lipids - smaller molecules -> into lacteal vessels
Si - stem cells for renewal -
3/5 days - enterocytes+ mucous cells
4 weeks - paneth+enteroendocrine cells
Ileum (4)
Peyers patches - galt (higher no. In ileum) - mucosa lamina propria / sometimes submucosa
Dome b cells
Germinal centre (b and t cells, apc)
Follicle associated epithelium (m cells(dendritic cells) - take up antigen)
However galt/lymphoid tissue found thruout digestive system
Lamina propria of villus of illeum
Plasma cells, eosinophils, macrophages, mast cells
Sm, bv,lv
What does sm do? Connects villus to muscularis mucosae
What is inflammatory bowel disese
Crypts knvaded by inflammatory cells - chronic granulomas -> destroy musuclaris mucosae -> fibrosis - replaced by CT (collagen)
Distinguish duodenum, jej, ileum
Duo - submucosa - brunner glands. Leaf life villi.
Ileum - peyers patches
D->I increase in goblet cells
2 types of motility?
Segmentation - non-coordinate sm contraction
Peristalsis - co-ordinated
Brunenr glands?
Mixed tubular submucosal, duodenum,
Zymogen + mucus secreting.
Alkaline -> protect proximal si from stomach acid
Si, epithelial cell renewal?
Stem cells from base of intestinal gland
LI length, portions and relaitons to peritoneum, function, structures
1.5-1.8m. Cecum + vermiform appendix 1 Ascending 15cm 2 Transverse 50cm 3 Descending 25cm 4 Sigmoid Rectum Anal canal 1-3 not covered by peritoneum 2-4 connect to post wall of abdominal wall by mesenteries -> visceral peritoneum - form double layer
Three distinct features of LI?
Teniae coli - 3 narrow bands outer longitudinal layer of externa. Absent in rectum, anal canal, vermiform appendix
Haustra coli - sacculatiojs between external surface of cecum and colon
Omental appendices - fatty projections of serosa on outer surface
Function of LI
Reabsorption of electrolytes and water,
Elimination of undigested food and waste - propulsion - rectum
Columnar to goblet cell ratio in LI.
TOWARDS RECTum the ratio is?
4: 1
1: 1 goblet cell increases
LI epithelial cell turnover
Similar to SI
Vascularisation of LI
Sup, inf mesenteric arteries
Splenic and sup mesenteric vein -> form hepatic portal vein - drain mesentery of sigmoid colon (intra peritoneal) - connected to post wall of abdomen .
Inner wall of LI (3)
Sulci - semilunar plicae
Due to tonic contraction of ext longitudinal layer
No plicae or villi
Structure of LI
Mucosa - no villi, plicae. Smooth surface, crypts of lieberkaun(straight tubular) extend thruout. Simple columnar.
Lamina propria - collagen table(collagen and proteoglycans between basal lamina and epithelial cells), pericryptal fibroblast sheath(may differentiate into macrophage), galt, lymphatic vessels(muscularis mucosae)
Submucosa - similar to rest of gi tract
Muscularis - CL
Serosa - peritoneum
Goblet cells more numerous in LI than SI
How to distinguish stomach and colon?
Lining epithelium - stomach only mucous secreting cells form mucous membrane. Whereas LI other cells present
Hirshsprings disease
Congential megacolon - dilation - consitpation
Neural crest cell migration failure - abnormal innervation of bowel
Aooendix contain?
Lymphatic follicles in mucosa. Extend into submucosa.
Thick circular layer. Thin outer longi layer.
Serosa continuous with mesentery of appendix
Rectum length and extra point!
Anal canal length and 4
15cm - lacks haustra
Anal canal - tenai dilated in ampulla of anal canal - communicates with anus by sphincter system - 3 zones,
Anal canal 3 zones and what glands
Colorectal - simple columnar
Anal transitional - ss epi. Also stratified columnar between transition of colorectal to ATZ
Squamous - ss epi
Anal glands - extend into submucosa + muscularis externa. Branches tubular straight mucous. Ducts lined with stratified columnar epi.
Also skin surrounding anl orifice!
Large apocrine glands - circumanal glands.
Maybe sexual attractant.
Hair follicles and sebacous glands found at this site
Internal and external sphincter?
Int - sm - involuntary
Ext - skeletal - voluntary contraction
Anal folds, valves and sinuses
8-10 longitudinal folds
Valves - small horizontal plicae at base of folds
Anal sinuses - behind valves - where glands open
Pectinate line - determined by valves
Deep to anal columns there are?
Protrusions int and ext
Av anastomoses. If vascular plexa protrude - int/ext -> int/ext hemmoroids - bleeding
Major salivary glands
Extra mural glands
Parotid - tubuloacinar - duct of steno - into upper cavity of molar teeth
Sublingual - mixed tubuloacinar
Submandibular - mixed tubuloacinar
Liver exocrine and endocrine function?
Exo - Bile secretion - emulsify fatty acid -> droplets -> absorbed in SI
Endo - synthesis of proteins - albumins, globulins etc
Liver 6 main functions
Fat met - ox of troglycerides. Synthesis of plasma lipoproteins. Synthesis of cholesterol
Carb met - convert carbs and proteins into fatty acids + triglycerides. Regulation of blood glucose conc (glycogenesis, glycogenolysis, gluconeogenesis)
Protein met - syn plasma proteins, non essential aa, detox of waste products (deamination of urine)
Glycogen storage
Detox of drugs and toxins - eg alcohol
Secretion of bile
Liver protein met -> plasma proteins examples
albumins, globulins, clotting factors
Liver where is visceral peritoneum not present?
Bare area where liver adhere/connects to other organs
Lesser omentum and liver?
Connects stomach, duodenum and liver
Post margin of liver?
Veins draining into vena cava
Liver: shape, weight, lobes, ligaments
Kidney shaped. 1.5kg. 4 lobes - left right caudate quadrate.
Falciform, coronary, triangular, round ligament
Falciform ligament
Connects diaphragmatic face of liver to diaphram -> only see ligaments and 2 lobes
Ligament venosu , round ligament
Residue of embryonic blood vessels,
Emrbyonic development of liver?
Endodermal evagination wall of foregut
Hepatic diverticulum - proliferates - hepatocytes (cords)
Original stalk of diverticulum -> common bile duct.
Outgrowth from common bile duct - gallbladder and cystic duct
H zone of liver
2 longitudinal and 1 transverse sulci - specific structures
2 extra lobes seen - only seen inferiorly.
Post face of liver
Hepatic veins -> inf vena cava
Triangular ligament -> obtained by fusion of 2 peritoneum layers (bare area of liver)
Corinary ligament surround bare area
How many segments in liver?
8 based on distribution of bile ducts and hepatic vessels
Liver vascularisation
Proper hepatic
Inf mesenteric vein -> splenic vein + sup mesenteric -> hepatic portal vein
Liver structure
Glisson capsule - parenchymal organ. Sinusoids, hepatic lobules. Central vein
Portal triad : at corner of hexagonal lobules. (Bile duct, art, portal vein.)
Portal triad
Art, vein, bile duct. Canal of herring,
Cholangiocytes (undifferentiated) - epithelial cells, line biliary tree. Primary cilium - detect luminal flow. Initially cuboidal. Increase in duct diameter -> columnar
Bile flow in opposite direction to blood flow (to central vein)
Classic lobule venous
Central vein (terminal hepatic venule) -> sublobular vein-> hepatic portal vein -> inf vena cav
Liver - portal triad - small ducts
Fuse form large duct - common hepatic duct - ultimately empty major papillae in duodenum
Liver - cappilaries
Mixed blood from liver and blood from digestive system
Liver - Different faces of classic lobule
Biliary face - adjacent to neighbouring hepatocyte - small depression on pm - canaliculi - bile produced - released
Vascular face - faces wall of capillary - sinusoid.
Liver - space between sinusoid and hepatocyte
Space of disse (0.2-0.5um)
Cells of ito (hepatic stellate cells/fat storing)
Store vit A.
Pathological condition - aSMA expressed - fibroblast prolongement - release collagen- fibrosis - myofibroblast - express specific marker
Wall of sinusoid - kupffer cell
Liver regen
Aged liver
Cells quintescent. Remove liver portion, cells activated - mitosis proliferation
Aged liver - regen - able to be donor
Stroma of liver contain?
Reticular fibres - t3 collagen
Portal lobules
Triangular
Biliary ductule
Corners of triangle with central vein.
Central part of triangle - portal triad
Liver acinus
3 zones
Rappaporta - diamond shape. 2 opposite corner = central vein. Other 2 = portal triad
Zone :
1 most oxygenated - sensitive to bile duct occlusion
2 mediate oxy
3 least oxy - sensitive to necrosis and oxygen deprivation
Increase in o2 increase in met activity
Damage to liver - zone 3 most vulnerable and involved
Mod of kidney
Accumulation of collagen.
Renal fibrosis
Which stain for collagen?
Sirus red
Biliary tree intra and extra hepatic bile duct
Monitored flow of bile and content regulation by cholangiocytes
Canal of herring lined by hepatocytes and cholangiocytes (liver progenitor cells).
Difference between space of mall and canal of herring?
Not location.
Whether lined entirely by cholangiocytes or partially
Space of mall duct lined entirely by above
Intra/exta-hepatic bile duct
Intra - ductules to interlobular bile duct to L/R hepatic duct - common hepatic duct
Extra - bile to gallbladder and duodenum.
Ducts contain - tall columnar epithelium, layers similar to alimentary canal except no Musuclaris mucosa
Gallbladder structure and basic info
10cm. 40-60ml. Cystic duct. Concentration of bile. Mucosa with folds.
Attached to visceral surface of liver. Remove 90% of water from bile.
Simple columnar epithelium.
Gallbladder mucosa characteristic features 4
Numerous short apical microvilli
Junctional complexes between adjacent cells
Apical and basal cytoplasm - conc mito
Complex lateral plications
Mucous secreting glands present lamina propria near neck of organ.
Wall of gallbladder?
What are the deep invaginations of mucosa extending into epm.externa?
No submucosa and muscularis mucosa
Rokitansky-ashoff sinuses
Pancreas quick points!
L1 and l2 level
Retroperitoneal
2 ducts - main pancreatic duct and accessory pancreatic duct
What are sphinctors on ducts made of?
Smooth muscle
Function of exocrine pancreas?
Tubuloacinar compound serous
Function - synthesis+ secretion if lytic enzymes (zymogens) activated by trypsin
