Abdomen/Pelvis Flashcards
Abdomen
Abdomen is located between thoracic cavity and
pelvic cavity
Bulges into thoracic cage
Continuous with pelvic cavity
Partially covered by rib cage
Support of viscera by bony pelvis
Diaphragm
A skeletal muscle.
Attaches to inferior
borders of the rib cage, the xiphoid process, the
lumbar vertebrae, and the posterior wall of the
abdominal cavity.
Separates the thoracic and abdominal cavities
from each other.
Diaphragm limits abdomen superiorly
Three openings in the diaphragm:
- Caval opening (T8)
- Esophageal hiatus (T10) *vagus also travels with
- Aortic hiatus between right and left crura (T12)
Pelvic Floor
Supports the abdominal and pelvic viscera.
Has hiatuses for for rectum, urethra, and vagina, as
well as other small openings.
Posterior Abdominal Wall Musculature
Three layers of anterior abdominal wall muscles
Quadratus lumborum muscle
Psoas muscle
Iliacus muscle
Psoas muscle + iliacus muscle = iliopsoas muscle
Function: support all the organs in the abdomen cavity
and keep them in place, Also to compress the
abdomen during breathing, coughing, empty bladder and rectum and parturition. Some of them actually move the trunk.
Upper Right Quadrant
Liver Gall bladder with biliary tree Duodenum Head of pancreas Hepatic flexure of colon
Upper Left Quadrant
Stomach Spleen Left lobe of liver Body of pancreas Left kidney and adrenal gland Splenic flexure of colon Parts of transverse and descending colon
Greater Omentum
First thing when you cut open in the abdominal cavity and slice open that sac and move the peritoneal sac aside – what you are going to see is this sheet of fat called the greater omentum,
– has many functions :
collects fat
functions in immune system, so if you have an infection in the abdomen it will migrate to that area and
isolate it
Underneath is see the large intestine,
small intestine and cecum.
Esophagus
Conveys food from pharynx to stomach
Begins at the inferior pharynx, continuous with the cricopharyngeus muscle
Terminates at cardiac orifice of stomach
Esophagus enters abdomen through right crus (leg) of
diaphragm, which acts as a physiological constrictor
(T10) and a level of T11, switches from esophageal
mucosa to gastric mucosa: Zigzag (Z) line
Stomach
Primary function is enzymatic digestion
Two curvatures
- Greater curvature
- Lesser curvature
4 main subdivisions - Cardiac part - Fundus - Body - Pyloris > Antrum (the beginning of it) >Pyloric canal >Pyloric sphincter: that controls the passage of food out of the stomach and opens into the duodenum.
Note
Z-line = junction of gastric and esophageal mucosa
Rugae = folds in stomach wall for increase surface area
Pyloric orifice = controls passage of food
Small Intestine
Extends from pyloric orifice of stomach to the ileocecal junction (where it joins the large intestine)
mesentery which is this sheet of peritoneum that attaches the intestines to the back wall of the abdomen and allows for passage of blood vessels
and nerves and lymph to get to and from the intestines.
Three subdivisions:
1) Duodenum (primary function is digestion)
2) Jejunum (primary function is nutrient absorption)
3) Ileum (primary function is water absorption)
Duodenum
Begins at pyloric orifice ends at duodeno- jejunal junction
C-shaped path around head of pancreas
Much about digestion of ingested food
Four subdivisions
1) Superior: 1st part
2) Descending (receives bile and pancreatic ducts: 2nd part)
3) Horizontal: 3rd part
4) Ascending (joins jejunum at duodenojejunal junction): 4th part
Jejunum & Ileum
From duodenojejunal junction to ileocecal junction
Jejunum is primarily for nutrient absorption
Ileum is primarily for water absorption
Plicae circulares (circular folds/valves of Kerking) more frequent in jejunum
Simpler arterial arcades in jejunum
Pyers patches in ileum
More encroaching fat in ileum
End of the ileum and here is what we call the ileocecal junction (joining of the ileum to the the
cecum - the very beginning of the large intestine)
Large Intestine
The colon = large intestine
- Cecum is a blind pouch
- Appendix
- Ascending colon
ileocecal junction to hepatic flexure (right colic
flexure)
water absorption - Transverse colon
hepatic flexure to splenic flexure (left colic flexure)
(because they are located in close proximity to the liver and and spleen)
water absorption (more absorption here)
- Descending colon splenic flexure to left iliac fossa fecal transport - Sigmoid colon iliac fossa to S3 fecal storage - Rectum storage and evacuation - Anal canal evacuation
Large vs. Small Intestine
Large intestine is very large (thick in diameter), it has these extra muscles called
- TENIAE COLI = look like stripes along the surface of the colon.
- It has these things that hang of that are like little droplets of fatty tissue they are call EPIPOLIC (mental) appendages
- It has these HAUSTRA which are just these balloon shaped structures
- the caliber of the lumen is much thicker than that of the small intestine.
Accessory Organs of the GI Tract
Liver
Gall Bladder
Pancreas
Liver
Metabolism Processing of drugs and hormones Storage of glycogen, vitamins and minerals Excretion of bilirubin Synthesis of bile salts (made in the liver and stored in the gall bladder) Phagocytosis Activation of vitamin D
Falciform ligament: peritoneum coming out of the liver to the front wall of the abdomen)
Ligamentum teres
(remnant of umbilical vein)
Porta hepatis (passageway into liver)
1) Portal vein
2) Hepatic ducts
3) Hepatic artery
Note that Inferior vena cava run posterior to liver,
partly surrounded by it.
Four lobes
1) Left
2) Caudate
3) Right
4) Quadrate
Portal Triad
Found in the hepatoduodenal ligament (free margin of lesser omentum)
Structures:
1) Proper hepatic artery -supplying the liver with oxygenated blood
2) Portal vein
3) Bile duct - which is bringing bile out of the liver
Biliary Ducts
Right and left hepatic ducts join to form the
COMMON HEPACTIC duct
The cystic duct joins the common hepatic duct to
form the BILE DUCT (common bile duct)
The bile duct joins pancreatic duct and enters duodenum at the major duodenal papilla
Pancreas
Runs transversely between duodenum and spleen.
Accessory digestive gland:
- Endocrine secretion into vascular system (e.g. insulin). - Exocrine secretion via main pancreatic duct and accessory pancreatic duct (pancreatic juices).
Main pancreatic duct joins the common bile
duct.
The head of the pancreas is tucked in between the C of the duodenum and the tail of the pancreas is at the spleen.
Spleen
Largest lymphatic organ in the body
“Rests” on left colic flexure (also called
the splenic flexure), under the diaphragm
Foregut
Stomach
1⁄2 of descending duodenum
Liver & gallbladder
Pancreas
Blood Supply: Celiac trunk to foregut derivative
Parasympathetics: Vagus X (from dorsal motor nucleus) and synapses at target structue
Sympathetics: Greater splanchnic nerve (synapses at Celiac ganglion) and post ganglionic sympathetics travel along branches of Celiac artery
Midgut
From lower 1⁄2 of descending duodenum onwards Jejunum & ileum Cecum & appendix Ascending colon 2/3 of transverse colon
Blood Supply: Superior mesenteric
Parasympathetics: Vagus (X) nerve (from dorsal motor nucleus) and synapses at target structue
Sympathetics: Lesser splanchnic nerve (synapsed at Superior mesenteric ganglion) and post ganglionics travel along branches of superior mesenteric a.
Hindgut
1/3 of transverse colon Descending colon Sigmoid colon Rectum Anal canal (part of)
Blood Supply:
Inferior mesenteric
Parasympathetics: Spinal cords S2-S4 - Pelvic Splanchnic nerves synapsing at target organ
Sympathetics: Lumbar splanchnic nerve (synapsed at Inferior mesenteric ganglion) and post ganglionics travel along branches of inferior mesenteric a.
Vascular Supply of GI Tract
Three large unpaired branches from the aorta:
1) Celiac trunk/artery
2) Superior mesenteric artery
3) Inferior mesenteric artery
**Note that the aorta splits into common iliac arteries