Peritoneum, Peritoneal Cavity, and Mesenteries Lecture (Test 1) Flashcards
Organization of GI Tract
1) Foregut
2) Midgut
3) Hindgut
Foregut
Organs:
1) Stomach
2) Liver
3) Gallbladder
4) Pancreas
5) Spleen
6) First half of Duodenum
Arteries:
1) Celiac Trunk
- Ileocolic
- Right Colic
- Middle Colic
Motor Nerve Supply:
- Vagus Nerve
Midgut
Organs:
1) 2nd Half of Duodenum
2) Jejunum and Ileum
3) Cecum
4) Ascending Colon
5) 2/3 Transverse Colon
Arteries:
1) Superior Mesenteric Artery
- Ileocolic
- Right Colic
- Middle Colic
Motor Nerve Supply:
- Vagus Nerve
Hindgut
Organs:
1) Left 1/3 of Transverse Colon
2) Descending Colon
3) Sigmoid Colon
4) Rectum
Arteries:
1) Inferior Mesenteric Artery
- Left Colic
- Sigmoid Branches
- Superior Rectal
Motor Nerve Supply:
- Pelvic Splanchnic Nerves
Peritoneum (General)
- A Serous Membrane
Subdivisions (Think Pleura or Pericardium)
1) Parietal Layer:
- Lines the Body Wall
- Has abundant PAIN FIBERS via nerves from the Body Wall
2) Visceral Layers (Serosa)
- Covers Viscera
- LACKS pain fibers
Nerve Supply to the Parietal Peritoneum
A) Nerves from the adjacent body wall supply Parietal Peritoneum
B) Supply PAIN and VASOMOTOR FIBERS
C) Conduct Sharp, Stabbing pain
- Rigid Abdomen
- Abdominal Rigidity is a stiffness of your stomach muscles that occur when the abdomen is touched
- This is an Involuntary response to prevent pain caused by pressure on your abdomen
- Another term for this protective mechanism is “guarding”
Visceral Peritoneum
- Invests Viscera/ Organs
- Same Blood Supply Lymphatic Vasculature and Visceral Nerve Supply as the Organs it covers
- Insensitive to Touch, Heat, Cold, Laceration
- Sensitive to Stretching and Chemical Irritation
- Pain from Visceral Peritoneum is POORLY LOCALIZED, ex Referred Pain
a) Unmyelinated C-fibers
b) Crampy, Colicky pain
General Relations of Viscera to Peritoneum
A) Intraperitoneal Organs
- Covered on most sides by Visceral Peritoneum
- Suspended by MESENTERY from the Body Wall
B) Retroperitoneal Organs
- Lie deep to the Parietal Peritoneum
- Covered by Parietal Peritoneum on ONE SIDE ONLY!!
Intraperitoneal Organs
- Stomach
- Small Intestine (Jeujenum, Ileum, some of the Superior part of the Duodenum)
- Spleen
- Liver
- Gallbladder
- Cecum with Vermiform Appendix (Portions of Variable size may be RETROPERITONEAL)
- Large Intestine (Transverse and Sigmoid Colon)
Retroperitoneal Organs
PRIMARILY (Never had a Mesentery):
- Kidneys
- Suprarenal Glands
- Uterine Cervix
SECONDARILY (Lost the Mesentery):
- Duodenum (Descending, Horizontal, and Ascending)
- Pancreas
- Ascending and Descending Colon
- Rectum (Upper 2/3)
Peritoneal Reflections (Adult)
- Mesenteries
- 2 layers fold of the Peritoneum
The Mesentery:
- Attaches the “Free” Small Intestine to the POSTERIOR BODY WALL
- Jejunum
- Ileum
Developmentally for the Mesentery
- Dorsal Mesentery
- Ventral Mesentery
a) Mesentery attached to the Stomach = MESOGASTRIUM - DORSAL AORTA and its 3 Branches run through the Dorsal Mesentery
- VENTRAL MESENTERY only Extends from the Respiratory Diaphragm to the Duodenum
Peritoneal Reflections (Adult)
Subdivisions of Mesentery:
1) TRANSVERSE MESOCOLON:
- Mesentery of the Transverse Colon
- Holds the Transverse Colon to the Posterior Body Wall
- Fuses with he Posterior Layer of the Greater Omentum
2) SIGMOID MESOCOLON:
- Mesentery of the Sigmoid Colon
- Holds the Sigmoid Colon to the Posterior Body Wall
3) MESOAPPENDIX
- Mesentery of the Vermiform Appendix
Note: The Mesenteries of the Duodenum, Ascending Colon, Descending Colon and Cecum are usually lost during development. Since they are no longer suspended by a Mesentery, these Organs are SECONDARILY RETROPERITONEAL
Peritoneal Ligaments
- May be Subdivisions of a Larger Structure
- Usually transmit Nerves ad Vessels
- Usually lack Connective Tissue and are NOT the same as Ligaments that Join Bones
1) GASTROSPLENIC Ligament
2) SPLENORENAL (Ileorenal) Ligament
Peritoneal Reflections (Adult)
- Omentum (Epiploon)
- Borad, 2-layered sheet of Peritoneum that attaches the Stomach to other Viscera
- Lesser Omentum (Connects liver to Stomach and Duodenum)
a) Develops from VENTRAL MESOGASTRIUM (Mesentery)
b) Subdivided into parts
1) HEPATOGASTRIC Ligament (Stomach to Liver)
2) HEPATODUODENAL Ligament (Liver to Duodenum)