Digestive system
System of the body concerned with the breakdown of food and absorption of nutrients
Peritoneum
Large, highly folded, serous membrane located in the abdomen.
Parietal peritoneum
Portion of peritoneum that lines the inner surface of the abdominal wall
Visceral peritoneum
The portion of the peritoneum that is located on the surface of the organs of the abdomen
Peritoneal cavity
Cavity between these two layers; potential space filled with a thin film of fluid
Greater sac of peritoneal cavity
Main portion of the peritoneal cavity; extends from the diaphragm to the pelvic floor and from the anterior abdominal wall to the posterior abdominal wall
Lesser sac (omental bursa)
Smaller portion of the peritoneal cavity located posterior to the stomach and extending upward behind the liver and downward into the greater omentum
Epiploic foramen (of Winslow)
Only opening between the greater and lesser sacs - bound by the portal vein, hepatic artery proper, bile duct, duodenum, inferior vena cava, liver
Peritoneal folds and membranes
Reflections of visceral peritoneum
Falciform ligament
Extends from the liver to the anterior abdominal wall
Round ligament of the liver
AKA obliterated umbilical vein
In the free edge of the falciform ligament
Greater omentum
Extends from the greater curvature of the stomach to the transverse colon, forming a fatty apron over the small intestines
Lesser omentum
Extends from the lesser curvature of the stomach to the liver and contains in its right free edge the bile duct, portal vein, and hepatic artery proper
Mesentery
Supports and suspends the jejunum and ileum from the posterior abdominal wall
Transverse mesocolon
Suspends the transverse colon from the posterior abdominal wall
Sigmoid mesocolon
Suspends the sigmoid colon from the posterior abdominal wall
Retroperitoneal structures
Duodenum
Ascending colon
Descending colon
Pancreas
Kidney and ureter
Aorta and inferior vena cava
Oral cavity
AKA mouth
Contains tongue, teeth, openings for the salivary glands
Tongue
Skeletal muscular organ that functions in the sense of taste, mastication and the movement of food
Teeth
Adult has 32 teeth; four types: incisors, canines, premolars and molars
Salivary glands
Endocrine glands (drained by a duct); empty saliva into oral cavity
Parotid gland
Located just below the ear and drained by the parotid duct (Stensen's duct)
Submandibular gland
Located just below the mandible and is drained by the submandibular duct
Sublinguinal gland
Located just below the tongue and drainged by the sublingual ducts (of Bartholin and Rivinus)
Pharynx
Composed of skeletal muscle, functions in swallowing
Three divisions of the pharynx
Nasopharynx
Oropharynx
Laryngopharynx (continuous with the esophagus - aka hypopharynx)
Esophagus
Muscular tube extending 25 cm from the lower end of the pharynx (CV6) to the cardiac opening of the stomach TV11 inferiorly
Cervical part of esophagus
In the neck, lies posterior to the trachea
Thoracic part of the esophagus
In the thorax, lies posterior to the trachea in the upper half and posterior tot he heart in the lower half
Abdominal part of the esophagus
Pierces the diaphragm and enters the abdomen
Arterial supply of the esophagus
Esophageal and bronchial branches (aorta); superiorly from the inferior thyroid (thyrocervical trunk, subclavian artery and inferiorly from the esophageal branches of the left gastric (celiac trunk)
Stomach
Digestive organ responsible for the storage of food
Fundus
Part of stomach above the level of the esophagus
Body
Located between the fundus and the pyloric part of the stomach. Compromises the main mass of the stomach
Pyloric
Extends toward the right from the lower part of the body of the stomach; ends at pyloric opening between the stomach and the first part of the duodenum
Pyloric sphincter
Pyloric opening surrounded by circular smooth muscle
Greater curvature of stomach
Margin of stomach that courses over the fundus and inferiority on the left side of the stomach to the inferior side of the pyloris
Lesser curvature of stomach
Name given to the margin that is located on the right side of the stomach, its curvature concave
Cardiac opening of stomach
Between the cavity of the esophagus and the cavity of the stomach; located at the junction of the greater and lesser curvatures
Pyloric opening
Between the stomach and the first part of the duodenum; surrounded by smooth muscle termed the pyloric sphincter.
Rugae
Internal surface folds of the stomach
Arterial supply of the stomach
Right and left gastic, short gastric, and right and left gastroepiploic arteries.
Small intestine
Part of intestine between the pyloric sphincter (where its connected to the stomach) and the ileocecal junction (where it joins the large intestine)
Length of small intestine
7 m
Duodenum
First part of small intestine, which extends from the pyloric sphincter to where it joins the jejunum. C-shaped organ with its concave medial border receiving the openings of ducts draining the liver, gallbladder and pancreas.
Four parts of duodenum
First/superior, second/descending (receives bile and pancreatic juices), third/horizontal, fourth/ascending (courses upward to the suspensory ligament of the duodenum (suspensory ligament of Treitz) where it leads to duodenojejunal flexure)
Arterial supply to the duodenum
Pancreaticoduodenal arteries (arising from gastroduodenal and superior mesenteric artery (SMA)
Jejunum
Proximal two-fifths of the remainder of the small intestine, supplied by the jejunal branches of the small intestine
Ileum
Distal three-fifths of the remainder of the small intestine. Ileal branches of the ileocolic artery from the SMA supply it.
Mesentary
Connective tissue structure that surround and suspends the ileum and jejunum
Ileocecal junction
Junction of the ileum portion of the small intestine and the cecum of the large intestine
Ileocecal opening
Opening between the lumen of the ileum and the lumen of the cecum (guarded by the iliocecal valve)
Large intestine or colon
Part of the intestine extending from the ileocecal junction to the anus.
Cecum
Part of the large intestine that lies at and below the level of entrance of the ileum
Vermiform appendix
Lymphatic organ attached to the posteromedial surface of the cecum
Ascending colon
Portion of the large intestine that extends superiorly from the right side of the posterior abdominal wall to the liver
Right colic flexure (hepatic flexure)
Where the ascending colon bends because it cannot course above the liver.
Transverse colon
Portion of the large intestine that extends from the right colic flexure on the right side of the abdomen to the spleen on the left side
Left colic flexure (splenic flexure)
Where the transverse colon bends and courses inferiorly at the spleen
Descending colon
Portion of the large intestine that extends from the left colic flexure inferiorly along the left side of the posterior abdominal wall
Sigmoid colon
Part of the large intestine that extends from the descending colon to the pelvis, where it is continuous with the rectum (forms a loop, shape and position depend on degree of filling)
Arterial supply of proximal portion of colon to splenic flexure
Branches of the SMA (ileocolic artery to cecum, appendix, ascending colon, right colic to ascending and transverse colon, transverse colon is also supplied by middle colic artery and left colic artery from IMA)
Arterial supply of the distal portion of the colon
Branches from the IMA - left colic artery (descending colon), sigmoid arteries (sigmoid colon), superior rectal artery (supplies rectum)
R and L paracolic gutters
Lie lateral to the ascending and descending colon, respectively.
Rectum
Portion of digestive system between sigmoid colon and anus narrowing inferiorly to form the anal canal
Anal verge
Boundary between external environment and the internal environment at the anus
Pectinate/dentate line
Boundary between the internal mucosa and the external epithelium - division between internal hemorrhoids above and extrnal hemorrhoids below as well as greater sensitivity below and lesser sensitivity above the dentate line.
Anus
Sphinteric muscle located at the termination of the anal canal which functions in the retention of feces
Arterial supply to the rectum and anus
Superior rectal artery, middle rectal artery, and inferior rectal artery
Vasculature of the abdomen
Branches from the aorta - inferior phrenic arteries, celiac trunk, superior mesenteric artery, suprarenal arteries, renal arteries, gonadal arteries, inferior mesenteric artery, common iliac arteries
Celiac trunk
Arises from aorta immediately below the aortic opening of the diaphragm
Celiac plexus
Dense meshwork of nerves
Left gastric artery
Small branch of celiac trunk that courses toward the left then along the lesser curvature of the stomach (also gives off the esophageal arteries)
Splenic artery
Large branch of the trunk that has a tortuous course along the upper margin of the pancreas as it courses to the spleen
Left gastroepiploic
Branches off splenic artery. Courses along greater curvature of the stomach.
Short gastric arteries
Supply the fundus of the stomach
Common hepatic artery
Courses toward R and divides into the hepatic artery proper and gastroduodenal artery
Right gastric artery
To the lesser curvature of the stomach then divides into right hepatic artery and left hepatic artery
Cystic artery
Branch off the right hepatic artery, supplies gallbladder.
Right gastroepiploic
To the greater curvature of the stomach
Superior mesenteric artery
Arises from aorta just below celiac trunk
SMA gives off:
Jejunal and ileal branches to the small intestine and the ileocolic, right colic, and middle colic to the large intestine.
Inferior mesenteric artery
Arises from aorta a few centimeters above its bifurcation; courses large intestine, branching into left colic, sigmoid, and superior rectal arteries.
Marginal artery of Drummond
Formed by the extensive anastomosis of ascending and descending branches of the various arteries that supply the large intestine
Portal vein
Contains nutrient-rich blood from the digestive system. Formed by its two tributaries, the splenic vein and the superior mesenteric vein. Drains into the liver.
Lymph fluid travels:
from the organ then along vessels toward celiac nodes from celiac nodes, lymph drains into the cisterna chyli and then into the thoracic duct
Liver
Largest gland in the body (exocrine gland); produces bile
Diaphragmatic surface of liver
Related to the right dome of the diaphragm
Visceral surface of liver
Adjacent to the abdominal visceram (this surface presents the four lobes: right, left, quadrate, caudate)
Porta hepatis
Structures that enter and exit the liver (R and L hepatic arteries, portal vein, R and L hepatic ducts) do so here (junction of 4 lobes)
Gall bladder
Located on the visceral surface of the liver between the right lobe and quadrate lobe, bile is stored and concentrated here, supplied by cystic artery.
Pancreas
Both exocrine gland (digestive enzymes) and endocrine gland (insulin production)
Parts of the pancreas
Head, body, and tail
Blood supply to the pancreas
Pancreaticoduodenal branches from the gastroduodenal and superior mesenteric arteries (primarily to the head), splenic artery (body and tail)
Right hepatic duct
Drains right side of liver
Left hepatic duct
Drains left side of liver
Common hepatic duct
Joining of right and left hepatic ducts
Cystic duct
Drains gallbladder
Common bile duct
Cystic duct + common hepatic duct
Main pancreatic duct
Drains most of pancreas (sometimes also has an accessory pancreatic duct) - drains into the minor duodenal papilla, which lies superior to the major duodenal papilla
Hepatopancreatic ampulla of Vater
Bile duct + pancreatic duct
Sphincter of Oddi
Opens into the duodenum at the major duodenal papilla
Spleen
Acts like large lymph node, located in LUQ of abdomen, lies to left of pancreatic tail, under the diaphragm and deep to the lower left ribs. Splenic artery supplies it.