GI A&P Lecture Powerpoint Flashcards
Recall the 9 regions of the abdomen
Hypochondriac (L/R), epigastric, lumbar (L/R), umbilical, iliac (L/R), hypogastric
Nearly all nutrients (carb protein fat electrolytes vitamins and water) are absorbed/chemically digested in the ___ section of the GI tract
Small intestine
4 layers of the entire alimentary canal
- Mucosa (epithelium with mucus, lamina propria and muscularis mucosa)
- submucosa (connective tissue and meisner’s plexus)
- muscularis externa (inner circular, outer longitudinal, aurbach’s plexus)
- serosa/adventitia (Provide lubrication)
Intraperitoneal organs are surrounded by ___, the retroperitoneal are by ____
serosa, adventitia
Ascites occurs in what organ structure of the body?
Peritoneal cavity
Mesentary
Double layer of visceral peritoenaum, attaches intestines to posterior abdominal wall and holds it in place like an apron to keep intestines from falling into pelvis
Mesenteric adenitis
Inflammation of lymph nodes of the mesentery caused by infection, inflammatory conditions, and cancer, if a patient has abdominal pain out of proportion to physical exam findings***
Intrinsic vs extrinsic tongue muscles
Intrinsic does not attach to bone and allows shape change for speech and swallow, extrinsic extends from bone to support tongue to support it and allow its movements
3 phases of swallowing
buccal phase - tongue pushing backward to throat
pharyngeal - pharyngeal constrictors
Esophageal phase - drops down heading toward stomach
Lower esophageal sphincter
Physiologic sphincter that acts as valve along with muscular diaphragm to help keep sphincter closed unless food is being swallowed
Stomach muscular layers
2 layers of smooth muscle + a 3rd oblique layer for crushing, collapses on itself forming gastric folds called rugae when empty
Stomach absorbs nearly nothing except 3 things
- alcohol
- aspirin
- nsaids
4 cells and their secretions of the gastric glands
Mucus cells - maintain mucus layer
parietal cell - secrete HCL and intrinsic factor
Chief cells - secrete pepsinogen (activated by HCL)
enteroendocrine cells - gastrin (regulates gastric acid secretion and motility)
3 Phases of gastric secretion
1) Cephalic - triggered by aroma or sight get ready for digestion relayingfrom hypothalamus to stimulate secretory activity of gastrin
2) Gastric - stimulated by distension of the stomach presence of food as well as rise in pH causing release of gastrin which then stimulates HCL
3) intestinal - excitatory release when food enters the duodenum to stimulate release of gastrin and HCL, followed by inhibitory where as intestines distend with chyme the enterogastric reflex is activated inhibiting secretory activity to slow gastric emptying to prevent intestine from becoming too acidic
Veins of the esophagus and esophageal varicies
The lower 1/3rd of the esophagus is drained by gastric veins and drains into the portal system so in the case of portal hypertension from cirrhosis of the liver can see esophageal varicies that are at risk of rupture (hematemesis)
Caput medusae
A sign seen in patients with portal hypertension describing appearance of distended and engorged paraumbilical veins seen radiating from the umbilicus across abdomen
Lymphatic drainage system of the body right and left
Right side only drains right arm, right side of head and chest, left side (thoracic duct) clears the rest of the body, both ultimately empty into the subclavian veins and then into the superior vena cava
Ligament of treitz
A thickened part of the small intestine separating duodenum and jejunum
Small intestine released hormones (4)
Secretin - found in duodenum and stimulates bicarb release from pancreas and bile ducts
Cholecystokinin - found in duodenum and stimulates release of digestive enzymes of pancreas and bile ducts
Gastric inhibitory peptide - produced in duodenum, decreases stomach motility to slow emptying of stomach and decrease acid production
Motilin - released from duodenum and stimulates contraction of smooth muscle
Carbohydrate/lipid/protein digestive enzymes
- Amylase
- lipase
- HCL and pepsin
Small intestine villi/microvilli and crypts of lieberkuhn
- finger like projections exclusive to the small intestine that increase nutrient absorption by 30 fold
- cells for immune defense, stem cells that replenish the epithelial cells
Brunner’s glands
Submucosal glands found in duodenum, roduce alkaline bicarb to protect duodenum from acidic content
Peyer’s patches
Lymphoid nodules locaed in the ileum that help with immune surveillance of the intestinal lumen
Segmentation
Random ringlike constrictions of the small intestine that churn contents of the duodenum
Peristalsis
Wave like movements that move chyme thru the intestines toward the rectum and anus
Tenae coli and haustra
Large bands of smooth muscle that contract forming haustra pouches giving the colon its trademark segmented appearance
Blood supply of the small intestine
- Gastroduodenal artery supplies upper duodenum and upper pancreas
- Superior mesenteric artery supplies the majority** including distal duodenum, jejunum, ileum, and cecum
Large intestine reabsorbs these 2 things
water
electrolytes
Hemorrhoids
Permanently distended veins often from straining to have a bowel movement either interior (superior to the denticulate line) which are painless or external which are painful
Internal anal sphincter vs external anal sphincter
- Internal works thru an intrinsic defacation reflex via the myenteric plexus that causes it to drop into the lower rectum/anus
- external works thru parasympathetic reflex involving the spinal cord where stretching of rectum sends sensory signals to spinal cord and splanchnic nerve returns signals intesnifying peristalsis and removal (must relax and override to allow this reflex to occur)
4 lobes of the liver
Right
Left
Caudate (most posterior
quadrate (inferior to left lobe)
Liver functional lobes
Liver has 8 completely independent segments that each have their own vascular in and outflow/biliary drainage allowing for easy resection if necessary without compromising function
Hepatic blood supply
Portal vein (75% of the blood supply, 50% of the oxygen) derived from the intestinal tract Hepatic artery (25% of blood supply, 50% of oxygen) derived from the celiac complex
Biliary canuliculi
“space of disse” between stacks of hepatocytes that form a pseudoduct collecting bile excreted by hepatocytes
Bilirubin
Breakdown product of RBC degredation as a breakdown product of heme
Gallbladder duct system
Gallbladder has the common cystic duct which merges from the common hepatic duct from the liver to form the common bile duct, then the pancreatic duct merges with it within the pancreas before emptying into the spincter of oddi into the duodenum
Portal triad
Revers to each lobule of the liver receiving a branch of the hepatic artery (oxygen) branch of hepatic portal vein (nutrients), and biliary duct (bile secretion)
Hepatocytes and its 9 big functions***
Most versatile and multifunctional cell in the body with thousands of enzymes assisting in
- glycogen storage
- decomposition of RBC
- plasma protein synthesis
- production of non essential amino acids
- gluconeogenesis
- hormone production
- detox
- bile production
- urea production
Kupffer cells
Liver macrophages that line the sinusoids that perform multiple immune based functions
Unconjugated (indirect) bilirubin vs conjugated (direct) bilirubin
- Indirect is bound to albumin, water insoluble/fat soluble and typically calculated from total - direct and reabsorbed in small bowel
- direct is measured result, water soluble, in the hepatocyte, not reabsorbed, direct + indirect = total
3 categories of jaundice
Prehepatic - excess hemolysis of RBC
Intrahepatic - disorders that affect ability of liver to remove bilirubin from blood or conjugate it so it can be eliminated in bile
Posthepatic - bile flow obstruction between liver and intestine
Somatostatin
Released by delta cell of pancreas that inhibits insulin and glucagon release
Pancreatic polypeptide
Hormone released by the pancreatic polypeptide cell and plays a role in facilitating appetite
Bile production mech of action and excretion
- made up of bile acids, cholesterol, and bile pigments such as bilirubin
- bilirubin is from when the spleen breaks down hemoglobin into heme+ globin from RBC lysis
- globin is recycled
- heme is split into iron (used for storage as ferritin) and bilirubin
- Bile is secreted into duodenum
- most unconjugated is reabsorbed into small bowel, conjugated is not
- in large bowel, bacteria metabolize direct bilirubin into urobilinogen
- some is reabsorbed and excreted in urine (yellow color), most exit colon after conversion to urobilin and stereobilin (brown)
Bilirubin of __ or higher will manifest as jaundice or icterus on physical exam
4mg/dL
