Abdominal Organs Flashcards
Esophagus
- Circular and longitudinal muscles
A. Striated (sup 1/3) -> smooth (inf 1/3)- Middle 1/3 = combo
- Passes thru esophageal hiatus of diaphragm (T10)
A. Phrenico-esophageal lig - attaches esophageal hiatus- Allows independent movement from diaphragm
Stomach
- Chyme = gastric juice + food
- Intraperitoneal
- Upper left quadrant
- Parts
A. Cardia- where esophagus meets stomach
B. Fundus - part sup to cardia
C. Body
D. Pyloric part- Antrum
- Canal
- Sphincter
- Mucosal layer
A. Rugae- folds that allow temp stretching
Small intestine
- Primary absorption site
- Duodenum
A. C-shaped from pylorus-> duodenojejunal flexure (L2)
B. Sup. Part- mesentery and mobile, rest = fixed and secondarily retroperitoneal
C. 4 parts- Sup (1st) - attached to hepatoduodenal lig (lesser omentum) sup and greater omentum inf
- Descending (2nd) - curves around head of pancreas (contains minor and major duodenal papillae
- Inferior (3rd) - crossed by SMA and root of mesentery (aorta posterior)
- Ascending (4th) - attaches jejunum, supported by suspensory lig (of Treitz) (muscular)
A. Muscle contraction -> duodenojejunal flexure angle widens -> contents pass thru
D. Major duodenal papilla receives bile duct - Marks transition foregut -> midgut
- Sup. Pancreaticoduodenal and inf. Pancreaticoduodenal a. Anastamose there
- Prox supplied celiac trunk branches
- Distal supplied SMA branches
- Jejunum
- Ileum
Pancreas
- Secondarily retroperitoneal
- Post stomach
- Oblique from duodenum -> spleen
- Parts
A. Head - attacked w/in “C” of duodenum- Uncinate process from inf border -> post SMA
B. Neck - overlies SMV
C. Body
D. Tail - relatively mobile, near splenic hilum
- Uncinate process from inf border -> post SMA
- Main pancreatic duct: tail -> head -> joins bile duct -> dilated hepatopancreatic ampulla at major duodenal papilla
A. Sphincter muscles control digestive secretion flow direction - Accessory pancreatic duct
A. Sometimes -> minor duodenal papilla
B. Usually joins main pancreatic duct
Liver
- Produces bile
A. Leaves via left and right hepatic ducts -> common hepatic duct + cystic duct (gallbladder) -> bile duct
B. Bile duct + main pancreatic duct at hepatopancreatic ampulla -> joins major duodenal papilla - Upper right quadrant, partially protected by ribs
- Surfaces sep inf by inf border that follows right costal margin
A. Diaphragmatic - covered by visceral peritoneum (except bare area)
B. Visceral - concave, H-shaped fissures, and many fossa for organs- right sagittal- longitudinal on right lobe (impression for IVC and gallbladder)
- Umbilical (left) - longitudinal, sep left and right lobes
A. Impression for ligamentum venosum and round lig - Porta hepatic - transverse, connects left and right fissures
A. Contains portal triad (portal vein, hepatic a., and hepatic duct), hepatic n. Plexus, and lymphatic vessels
- Peritoneal reflections
A. Coronary lig. - ant and post layers of peritoneum, demarcates bare area
B. Triangular lig - layers of coronary lig that meet on right and left aspects of liver
C. Falciform lig - connects diaphragmatic surface to ant abd wall and diaphragm- Boundary between left and right lobes
- Divides sup -> ant layer coronary lig
- Inf margin contains round lig
D. Lesser omentum
- Anatomical lobes: superficially divided
A. Right and left anatomical lobes
B. Right lobe -> 2 accessory lobes- Quadrate- ant and inf
- Caudate- post and sup
- Functional subdivision (8) - segments that can be respected w/o damaging others
Gallbladder
1. Parts A. Fundus- blunt, rounded end at level of right 9th costal cartilage B. Body C. Neck - continuous w/ cystic duct 2. Stores and concentrates bile
Spleen
- Not gut derived, but supplied by branch celiac trunk
- Superolateral left upper quadrant
- Gastrosplenic lig - connects stomach
- Spenorenal lig - connects left kidney
- Largest lymphatic organ
- Blood reservoir
Foregut
Supplied by celiac trunk
- Esophagus
- Stomach
- Prox 1/2 duodenum
- Pancreas
- Liver
- Gallbladder
- Spleen (not gut derivative)
Midgut
Supplied by superior mesenteric artery (SMA)
- Distal 1/2 duodenum
- Jejunum
- Ileum
- Ascending colon
- Prox 2/3 transverse colon
Hindgut
Supplied by inferior mesenteric artery (IMA)
- Distal 1/3 transverse colon
- Descending colon
- Sigmoid colon
- Rectum
- Sup. Anal canal
Peritoneum
Serous membrane that lines abdominopelvic cavity and viscera
1. Parietal: lines inner abdominopelvic wall
2. Visceral: lines surface of organs
3. Folds: from dorsal and ventral mesenteries in developing area
A. Omenta
B. Mesenteries
C. Ligaments
Intraperitoneal organs
Develop in peritoneal space
- Invaginate in closed sac (not in cavity)
- Surface almost completely covered by visceral peritoneum (except bare area)
- Stomach
- Small intestine (jejunum, ileum, sup duodenum)
- Spleen
- Liver
- Gallbladder
- Cecum
- Transverse and sigmoid colon
- Uterus
- Ovaries
- Uterine tubes
Extraperitoneal
Outside peritoneal space
- Partially covered w/ peritoneum
- Retroperitoneum
- Subperitoneum
- Secondary retroperitoneal
Primarily retroperitoneal organs
Develop posterior to peritoneum
- Kidneys
- Ureters
- Suprarenal glands
- Uterine cervix
Secondarily retroperitoneal organs
Develop intraperitoneal -> pushed out and posterior
- Duodenum (except sup. Part)
- Pancreas
- Ascending and descending colon and cecum
- Rectum (upper 2/3)
Subperitoneal organs
Inferior to peritoneum
- Urinary bladder
- Distal ureters
- Prostate
- Seminal vesicle
- Uterine cervix
- Vagina
- Rectum (lower 1/3)
Mesentery
Fused visceral and parietal peritoneum
- Connects organs to posterior wall
- Allows neurovascular communication between organs and wall
Mesentery proper
Suspends jejunum and ileum
Transverse mesocyclone
Suspend transverse mesocolon
Sigmoid mesocolon
Suspend sigmoid
Mesogastrium
Suspends stomach
Meso-appendix
Suspends appendix
Meso-esophagus
Suspends esophagus
Greater omentum
Large, apron-like fatty peritoneal fold
1. Greater curvature stomach and proximal duodenum -> transverse colon and small bowel -> anterior transverse colon and mesentery
Lesser omentum
Smaller fatty peritoneal fold 1. Lesser curvature stomach and proximal duodenum -> inferior surface liver 2. Two ligaments A. Hepatogastric B. Hepatoduodenal
Hepatogastric ligament
Thin, membranous portion between stomach and liver
Hepatoduodenal ligament
Thicker portion of lesser omentum between duodenum and liver
1. Conducts hepatic triad
A. Portal vein
B. Hepatic artery
C. Bile duct
2. Epiploic (Winslow) foramen - opening into lesser sac
Peritoneal ligaments
- Root of mesentery
- Suspensory (of Trietz) - suspensory lig of duodenum
- Falciform
- Gastrophrenic
- Gastrosplenic
- Gastocolic
Falciform ligament
Separates lobes of liver
1. Remnant of ventral mesentery
Round ligament of liver
Ligamentum teres hapatis
1. Remnant of umbilical vein
Supracolic compartment
- Stomach
- Liver
- Spleen
Infracolic compartment
Posterior to greater omentum, divided -> right and left mesentery proper
- Small intestine
- Ascending colon
- Descending colon
Paracolic gutters
Allow free communication between compartments of the peritoneum
Celiac trunk
- Arises T12 level posterior stomach and omental bursa
- Branches
A. Splenic artery- Left gastro-omental (gastro-epiploic) a. - left asset of greater curvature of stomach
- Pancreatic branches
- Short gastric a. - fundus and sup body of stomach
- Terminal splenic - spleen
B. Left gastric a. - Esophageal br. - lower esophagus
- Terminal brs. - left aspect lesser curvature of stomach
C. Common hepatic a. - Hepatic proper
A. Divides left and right lobes liver (rt-> cystic a. -> gallbladder) - Right gastric a. -> right aspect lesser curvature stomach
- Gastroduodenal a.
A. Right gastric-omental (gastro-epiploic) -> right aspect greater curvature stomach
B. Superior pancreaticoduodenal a. -> ant and post branches -> prox duodenum and pancreas head
Innervation of foregut
- Sympathetic
A. Pre-synaptic fibers T5-T9 -> sympathetic chain (don’t synapse)
B. Exit chain greater splanchnic n. -> synapse w/ celiac ganglion
C. Post-synaptic -> organs via plexuses surrounding arterial branches - Parasympathetic
Jejunum
- Larger diameter, thicker walls
- Longer vasa recta
- Few large arcades
- Less fatty mesentery
- More plicae circulares
- Few lymphoid nodules
Ileum
- Smaller diameter, thinner walls
- Shorter vasa recta
- Many short arcades
- Encroaching, fatty mesentery
- Fewer plicae circulares
- Many lymphoid nodules (Peyer’s patch)
Small bowel mesentery
- Root mesentery from duodenojejunal junction-> iliocolic junction
- Sup mesenteric vessels, lymph nodes, autonomic n. And fat between 2 layers
- SMA supplies jejunum and ileum (L1)
A. 15-18 branches form arterial arcades -> vasa recta - SMV drains jejunum and ileum
A. Ends posterior neck pancreas
B. Joins splenic vein -> hepatic portal vein
Large intestine
- H2O reabsorption, feces production
- Omental appendices: small, fatty omentum-like projections -> attach omental teniae
- Teniae coli: 3 thickened longitudinal bands smooth muscle from base appendix -> merge at rectosigmoidal junction -> around rectum
A. Mesocolic teniae: transverse and sigmoid mesocolons attach
B. Omental teniae: where greater omentum attaches
C. Free teniae: neither mesocolons or omental appendices attached - Haustra: sacculations of wall of colon between teniae
Cecum
- Large intestine
- Right lower quadrant
- Enveloped by peritoneum, no mesentery -> freely moveable
- Papilla acts as flap in ileal orifice, no sphincter
- Iliocecal a.
Appendix
- Diverticulum posteromedial to ileocecal junction
- Contains lymphoid tissue
- Meso-appendix: short, triangular mesentery
A. From mesentery proper - Vessels
A. Appendicular artery
B. Ileocolic v. - Lymphatics: meso-appendix -> ileocecal lymph nodes
Ascending colon
- Secondarily retroperitoneal
- Right paracolic gutter
- Arteries:
A. Ileocolic and right colic anastomose-> arcades -> left colic and sigmoid -> marginal - Veins:
A. Ileocolic
B. Right colic
Transverse colon
- Most mobile
- Intraperitoneal
- Transverse mesocolon
- Arteries:
A. Middle colic
B. Left colic
Descending colon
- Secondarily retroperitoneal
2. Left paracolic gutter
Sigmoid colon
- S-shaped loop
- End teniae coli and omental appendices = rectosigmoid junction
- Freely moveable
- Sigmoid mesocolon
Rectum
Fixed terminal portion
1. Continuous w/ anal canal
Superior mesenteric artery (SMA)
- Arises from abdominal aorta below celiac trunk (L1)
- Crossed anteriorly by splenic vein and head of pancreas
- Branches
A. Inf pancreaticoduodenal a. (Ant and post) -> distal duodenum and head/uncinate process pancreas
B. Jujunal and ilial branches -> jejunum and ileum
C. Middle colic -> transverse colon
D. Right colic (ascending and descending)
E. Ileocolic a. (Sup and inf) -> distal ileum, cecum, inf ascending colon, appendix- Inf branch divides
A. Colic
B. Cecal
C. Appendicular
D. Ileal
- Inf branch divides
Inferior mesenteric artery (IMA)
- Descends left from abdominal aorta (L3)
- Branches
A. Left colic a. (Ascending and descending) -> left 1/3 transverse colon and sup descending colon
B. Sigmoid a. = 2-4 branches -> inf descending and sigmoid
C. Sup rectal a. = terminal branch -> sup rectum
Arterial anastomoses in abdomen
- Pancreaticoduodenal a. = celiac trunk and SMA -> midgut and foregut
- Marginal a. = SMA and IMA -> arcade -> midgut and hindgut
- Rectal a. = IMA and internal iliac a. -> hindgut and systemic circulation
Midgut innervation
- Sympathetics
A. Pre-synaptic (T10-T12) -> sympathetic chain - don’t synapse
B. Exit chain -> lesser (T10-11) and least (T12) splanchnic n. -> synapse w/ sup mesenteric ganglia
C. Post-synaptic -> organs via plexuses around arterial supply - Parasympathetic: vagus n. (CN X)
Hindgut innervation
- Sympathetics
A. Pre-synaptic (L1-L2) -> sympathetic chain ->- Distal 1/3 transverse colon -> sup rectum
A. Don’t synapse -> exit chain -> lumbar splanchnic n. (L1-L2) -> synapse w/ inf mesenteric ganglie
B. Post-synaptic -> organs via plexuses - Inferior rectum (above pectinate line)
A. Synapse w/ chain
B. Post-synaptic -> exit lumbar splanchnic n. (3-5 lumbar ganglia) -> middle and inferior rectum
- Distal 1/3 transverse colon -> sup rectum
- Parasympathetic: pelvic splanchnic n. (S2-S4)