Exam 4: Abdominal Cavity Flashcards
Proctodeum / Stomodeum
Lining of anus / mouth. Derived from Ectoderm.
What are the boundaries of the foregut? Arterial supply? Gives rise to what embryological structures?
stomodeum (mouth) thru the first 1/3 of the duodenum. Arterial supply: celiac trunk. Grives rise to pharyngeal pouches, lower respiratory system, liver, pancreas, gallbladder.
What are the boundaries of the midgut? Arterial supply? Gives rise to what embryological structures?
Last 2/3 of duodenum thru the proximal 2/3 of colon. Arterial supply: SMA. Gives rise to yolk stalk.
What are the boundaries of the hindgut? Arterial supply? Gives rise to what embryological structures?
Last 1/3 of colon to proctodeum (anus). Arterial supply: IMA. Gives rise to allantois (embryological waste sac), urinary bladder, most of urethra.
What does recanalization refer to during embryological development?
Hollowing out of primitive gut tube.
Atresia vs Stenosis
Recanalization failures.
Atresia = blockage
Stenosis = narrowing of lumen
Vacuoles
Compartmentalized pockets of air that trigger the formation of a hollow tube. No/few vacuoles will cause a atresia/stenosis.
Mesenteries. What are the two types?
Double layer of peritoneum formed by splanchnic mesoderm which connects organs to the body wall. Two types: Parietal (lines body wall) and Visceral (lines organs)
Three remnants of the ventral mesentery
Falciform ligament (from liver to ventral body wall) Coronary ligament (from liver to diaphragm) Lesser Omentum: sheet of mesentery that goes from liver to stomach to duodenum. Not attached to body wall.
Dorsal mesentery
provides mesentery for most abdominal organs
Intraperitoneal Organs
abdominal esophagus, stomach, proximal 1/3 of duodenum, liver, gall bladder, bile duct, spleen, transverse colon, jejunum, ilium, cecum, appendix, sigmoid colon
Primarily retroperitoneal organs
thoracic esophagus, rectum, anal canal, kidneys
Secondairly Retroperitoneal
Suprarenal glands, aorta, vena cava, distal 2/3 of duodenum, pancreas, ureters, ascending and descending colon
Annular Pancreas
Bilobed ventral pancreatic buds during development wrap around gut tube and cause stenosis/atresia.
What germ layer is the spleen derived from?
NOT endodermal derivative like most other abdominal organs, but its an outpocketing of MESODERM in the dorsal mesentery.
Cloaca
Urorectal septum
Urorectal membrane
Anal membrane
Cloaca = ‘common sewer’ caudal hindgut forms from cloaca. Urorectal septum divides allantois and yolk stalk and seperates cloaca into the urogenital membrane and anal membrane (separates caudal hindgut from proctodeum)
Pectinate Line
ABOVE: Endoderm, drainage and innervation from hindgut, pressure and stretch receptors, no pain receptors.
BELOW: ectoderm, drainage and innervation from abdominal wall, lots of pain receptors
Non-perforate anus
Anoperineal fistula
Rectrourethral fistula
Rectovaginal fstula
Anal canal malformations
Anoperineal fistula - abnormal anatomical passage that connects anal canal and perineum
Rectourethral fistula - passage that connects anal canal and urethra
Rectovaginal fistula - passage that connects anal canal and vagina
What border of the stomach grows faster?
Dorsal border
Produces greater and lesser curvatures
Lesser curvature (ventral border) of stomach moves to the
right
Greater curvature moves to the left
Right Vagus nerve turns onto what surface of the stomach?
Dorsal surface
left vagus nerve on the ventral surface
Characteristics of Large intestine
taenia coli, haustra, and epiploic appendages
Cecum
blind intestinal pouch
Has vermiform appendix
Intraperitoneal
Ascending colon
between cecum and right colic flexure
Secondarily retroperitoneal
Transverse colon
between right and left colic flexures
Fuses with greater omentum
Intraperitoneal
Descending Colon
forms left paracolic gutter
Secondarily retroperitoneal
Sigmoid colon
S-shaped free portion of large intestine
Intraperitoneal
Rectum
Pelvic, fixed portion of large intestine
Primarily retroperitoneal
Arteries of the foregut are supplied by
the celiac trunk
Left gastric a.
branch of celiac trunk
goes to proximal portion of lesser curvature of stomach
Anastomoses with r. gastric a.
Splenic a.
branch of celiac trunk
Serves spleen
Common hepatic a.
branch of celiac trunk
Goes towards liver
Pancreatic a.
From Splenic a.
goes to neck, body, and tail of pancreas
Short gastric a.
from Spenic a.
goes to stomach closest to spleen
Left gastro-omental a.
from Splenic a.
Goes to left side of greater curvature of stomach
Anastomoses with r. gastro-omental a.
Gastroduodenal a.
branch of common hepatic a.
gives rise to R. gastro-omental a., superior pancreaticoduodenal a., and supraduodenal a.
Right gastro-omenal a.
from Gastroduodenal a.
Goes to right side of greater curvature of stomach
Anastomoses with left gastro-omental a.
Superior pancreaticduodenal a.
branch of gastroduodenal a.
Goes to stomach, pancreas, and head of duodenum
Anastomoses with inferior pancreaticoduodenal a.
Supraduodenal a.
branch of gastroduodenal a.
Goes to superior duodenum
Sometimes absent
Right gastric a.
branch of common hepatic a.
Goes to right lesser curvature of stomach
Anastomoses with L. gastric a.
Proper hepatic a.
branch of common hepatic a.
Goes to liver, Branches include Right hepatic a. and Left hepatic a.
Cystic a.
branch of right hepatic a.
Goes to gall bladder
Midgut is oxygenated by the
Superior mesenteric a. (SMA)
Inferior pancreaticoduodenal a.
Branch of SMA
goes to the head of the pancreas and the duodenum
Anastomoeses with superior pancreaticoduodenal a. and jejunal a.s
Intestinal a.s
from SMA
goes to jejunum and ileum
Ileocolic a.
from SMA
goes to the distal ileum and cecum
R. colic a.
from SMA
goes to the ascending colon
Middle colic a.
from SMA
goes to the transverse colon
Marginal a.
circles the colon
formed by branches of the SMA: ileocolic, r. colic, middle colic, and l. colic (IMA)
Gives rise to vasae rectae (straight vessels)
Hindgut is oxygenated by the
inferior mesenteric artery (IMA)
Left colic a.
from IMA
goes to descending colon
contributes to Marginal a.
Sigmoid a.
from IMA
goes to sigmoid colon
Superior rectal a.
from IMA
goes to proximal rectum
Anastomoses with middle and inferior rectal a.s
Main branches of hepatic portal system
Splenic vein, Superior mesenteric ein (SMV), and Inferior mesenteric vein (IMV)
Portal hypertension
raised blood pressure due to resistance of diseased liver
Therefore, blood will find alternate routes around the hepatic portal vein (portal-caval anastomoses)
Esophageal, Rectal, Umbilical, and Colic anastomosis
In the gut, sympathetics generally act to
innervate blood vessels and inhibit parasympathetics
In the gut, parasympathetics generally act to
promote peristalsis and some secretions
The foregut is innervated by
the celiac plexus
Foregut sympathetics
arise from T5-T9, pass through the sympathetic chain and greater splanchnic nerve
Synapse in celiac ganglia and postsynaptics follow branches of celiac trunk to organs
Foregut parasympathetics
Pass through Vagus nerve, through the celiac plexus, follow brnaches of celiac trunk and synapse in ganglia of gut plexuses
Postsynaptics reach target via short fibers
Midgut is innervated by
superior mesenteric plexus
Midgut sympathethics
arise from T10-T12
Pass through lesser splanchnic or least splanchnic nerves
Synapse in superior mesenteric ganglion & follow SMA to organs
Midgut parasympathetics
Vagus nerve
Pass through sumperior mesenteric plexus and follow branches of SMA to targets
Synapse in ganglia in gut plexus
Hindgut innervated by
inferior mesenteric plexus and hyposastric plexus
Hindgut Sympathetics
Arise from L1-L2 spinal nerves
Pass through lumbar splanchnic nerves (L1-L2)
Synapse in the inferior mesenteric ganglion
Postsynaptics follow branches of IMA to organs
Hindgut parasympathetics
Arise from S2-S4 spinal nerve levels
Pass through sacral spinal nerves and pelvic splanchnic nerves
Branches to colon pass cranially through hypogastric plexus and inferior mesenteric plexus
Follow branches of IMA to targets
Synapse in ganglia in gut plexuses
Greater peritoneal sac
potential space surrounding the stomach and spleen
Lesser peritoneal sac (omental bursa)
Space behind stomach; between the posterior body wall and the stomach
Provides mobility for stomach
Greater omentum
fatty apron
Composed of Gastrocolic ligament, gastrolinenal ligament, and gastrophrenic ligament
Gastrocolic ligament
connects stomach to transverse colon
Gastrolienal ligament
connect spleen to greater curvature of stomach
Gastrophrenic ligament
connects stomach to diaphragm
Less omentum
Composed to hepatoduodenal ligament and hepatogastric ligament
Hepatoduodenal ligament
connects liver to the duodenum
Hepatogastric ligament
connects liver to stomach
Dorsal mesointestine
frilly skirt mesentery that supports ileum and jejunum
Dorsal mesocolon
supports cecum
Mesoappendix
supports appendix
Transverse mesocolon
divides abdominal cavity into supracolic compartment and infracolic compartment
Supracolic compartment
contains stomach, liver, and spleen
Infracolic compartment
contains small intestine, ascending and descending colon
Sigmoid mesocolon
supports sigmoid colon
Lienorenal ligament
from left kidney to spleen
Coronary ligaments
peritoneal reflections around bare area of liver
Hepatorenal ligament
coronary ligament running between peritoneum above right kidney and liver
Falciform ligament
remnant of ventral mesentery connecting liver to anterior body wall
Ligamentum teres (round ligament)
part of falciform ligament
Remnant of fetal umbilical vein
Esophagus function
movement of food from mouth to stomach via peristalsis
Stomach function
mechanical breakdown of food via muscular churning, aided by stomach acid and pepsin
Rugae
folds on inside of stomach - allow for stomach streatching
Small intestine function
Absorption of nutrients, electrolytes, and water
Chemical digestion of chyme
Duodenum function
neutralize acid
break down fats - bile
Insulin and other pancreatic juices secreted
Jejunum features
Deep red, 2-4 cm, thick and heavy wall, greater vascularity, long vasas recta, few large arcade loops, less fat, large and numerous plicae circulares
Ileum features
Pinkish, thin and light wall, less vascular, short vasas recta, many short arcade loops, more fat in mesentery, low and sparse plicae circulares
Large intestine functions
absorb water and remaining salts, commensal bacteria synthesize some vitamins
Liver is innervated by
the celiac plexus
Liver function
Protein synthesis, bile secretion, metabolism, detoxification
Liver lobes
Right - large
Left - small
Caudate - upper tongue
Quadrate - lower, separated from right by gallbladder
Porta hepatis
transverse fissure in liver where major vessels pass through
Glisson’s capsule
thin capsule of dense connective tissue in liver, thickest at hilum
Portal vein
carries oxygen poor, nutrient rich blood from gut to liver
Blood is detoxified before it drains into central vein, then goes back to heart via hepatic vein
Hepatic artery
Oxygenated blood to liver
Gallbladder innervated by
celiac plexus and some phrenic nerve
Gallbladder functions
store and concentrates bile
Gallbladder blood supply
cystic a., r. hepatic a.
Pancreas is innervated by
celiac plexus and superior mesenteric plexus
Pancreas functions
principal enzyme producing accessory gland of digestive system, endocrine functions (insulin synthesis)
Spleen innervated by
celiac plexus
Spleen functions
secondary lymphoid organ, proliferation of mature lymphocytes, antibody secretion, destruction of old RBC, recycling of chemicals from destroyed RBC
Blood supply to spleen
Splenic artery (and vein)
Kidney function
remove excess water, salts, and wastes of protein metabolism from blood, return nutrients to blood, regulate blood pressure and production of RBC
Blood supply to kidney
Renal a., segmental a., interlobar a., arcuate a.
Kidney innervation
Sympathetic (T10-L1)
Parasympathetic (Vagus and S2-S4)
Suprarenal (adrenal) glands function
produce corticosteroids and androgens (cortex), produce norepinephrine and epinephrine (medulla)
Blood supply to suprarenal glands
Superior suprarenal a., Middle suprarenal a., inferior suprarenal a.
Superior suprarenal a.
from inferior phrenic a. to suprarenal gland
Middle suprarenal a.
from aorta to suprarenal gland
Inferior suprarenal a.
from renal a. to suprarenal gland
Suprarenal gland innervated by
Presynaptic sympathetics to medulla (synapse on chromaffin cells)
Autonomic fibers with blood cells in cortex
Diaphragm innervation
phrenic nerve (C3-5) - motor and sensory Intercostal nerves - sensory to periphery
Diaphragm blood supply
Superior phrenic from thoracic aorta & inferior phrenic from abdominal aorta
Psoas major m.
O: transverse processes of lumbar vertebrae; sides of vertebral bodies of T12-S1
I: lesser trochanter of femur
N: lumbar plexus via anterior branches of L2-L4
A: flexes thigh, flexes vertebral column laterally to balance trunk, flex trunk when sitting
Iliacus m.
O: superior2/3 of iliac fossa, ala sacrum and anterior sacro-iliac ligaments
I: lesser trochanter of femur and shaft
N: femoral n. (L2-4)
A: flex thigh and stabilize hip joint
Quadratus lumborum
O: medial half of inferior border of 12th rib and tips of lumbar transverse processes
I: iliolumbar ligament and internal lip of iliac crest
N: anterior branch of T12 and L1-L4
A: extend and laterally flex vertebral column, fixes 12th rib during inspiration
Subcostal nerves
from ventral rami of T12 to external oblique m. and skin of anterolateral abdominal wall
Lumbar spinal nerves
From L1-L5 to deep back muscles, skin of back, sink and muscles of most inferior trunk and lower limb
Ilioinguinal and iliohypogastric n.
From L1 to abdominal m. and skin of inguinal and pubic regions
Ilioinguinal in inguinal canal
Genitofemoral n.
From L1-L2 to skin below inguinal ligament
Divides into genital and femoral branches
Lateral femoral cutaneous n.
from L2-L3 to anterolateral skin of thigh
Femoral n.
L2-L4 to iliacus, hip flexor, knee extensor
Obturator n.
L2-L4 to medial thigh and adductors
Goes through obturator foramen
Accessory obturator n.
From L3-L4 to pectineus, hip joint
Lumbosacral trunk
From L4-L5 to join sacral plexus
Subcostal a.
from thoracic aorta to posterior body wall inferior to the 12th rib
Inferior phrenic a.
from abdominal aorta to inferior surface of diaphragm and suprarenal glands
Renal a.
from abdominal aorta to kidneys
Gonadal a. (testicular or ovarian)
from abdominal aorta to testes or ovaries
Lumbar a.
from abdominal aorta to posterior abdominal wall
Median sacral a.
from abdominal aorta to sacrum and coccyx
unpaired
Abdominal aorta splits into
right and left common iliac a. at L4
Common iliac a. divide into
internal and external iliac a.
Inferior vena cava
drains blood from lower limbs, most of back, abdominal wall, and abdominopelvic viscera back to heart for oxygenation
Blood from gut passes through hepatic portal system first
R, L, and middle hepatic veins
drain from liver to IVC
R & L inferior phrenic veins
drain from inferior side of diaphragm to IVC
R suprarenal vein
drain from Right suprarenal gland to IVC
Left suprarenal vein
drain from left suprarenal gland to left renal vein
Lumbar veins
drain from posterior body wall to IVC
Right gonadal veins
drain from right testicle or ovary to IVC
Left gonadal veins
drain from left testicle or ovary to left renal vein
Which veins do not drain into the IVC?
Left suprarenal vein and left gonadal vein - drain into left renal vein
Blood can bypass the IVC and return to heart if there is blockage via
Superior and inferior epigastric veins, thoracoepigastric veins, epidural venous plexus (lumbar veins of caval system & azygous)
Origin of thoracic duct
anterior to L1 & L2 (between right crus and aorta) - ends at junction of Left subclavian and internal jugular vein