Peritoneum and Peritoneal Structures Flashcards
where is the pelvic cavity?
- smallest cavity at caudal end
what is the peritoneum?
serous membrane lines abdominal, cranial part of pelvic, and scrotal cavities, reflects out and around organs within it
largest and longest membrane in body
what are the functions of peritoneum?
- friction reduction
- free movement of mesentery
- fixation as by ligaments
- fat storage as in omentum
what is a retroperitoneal organ?
- outside the cavity
- examples: kidneys, ureters (most of length), adrenal glands, aorta, Cd VC, lumbar lymph nodes
what is a peritoneal organ?
- surrounded by peritoneum
what gastrulation layer does the peritoneum come from?
- mesoderm
what is the coleum?
peritoneal cavity
what is clinically important about retroperitoneal organs?
- kidneys are covered by peritoneum on ventral surface only, trauma to kidney blood or urine may accumulate in space, fluids retained in this area cannot be diagnosed by palpation or abdominocentesis so can be harder and delayed in diagnosis
what is clinically important to peritoneal cavity?
- if no serous fluid, peritonitis or rough handling may cause adhesions where layers stick and impair movement of organs thus impairing function
- peritoneal cavity has 2 openings in female for uterine tubes so peritonitis is more common
what are the connecting peritoneums?
- dorsal mesentary
- ventral mesentary
what is mesentary?
- a type of connecting peritoneum - wide and double layered
- connects: intestinal and reproductive tracts with abdominal wall
- contains blood vessels, lymphatics, and nerves
how are the different lengths of mesentery formed?
- herniation –> rotation –> retraction of gut tube
- to begin gut tube growth exceeds that of body cavity and herniates through incomplete wall –> two rotations of gut loops –> body cavity enlarges –> return of gut
- return or retraction: begins at cranial and caudal most ends of tube (stomach, duodenum, colon) are first, then jejunum is last
what is fixed viscera?
- early viscera packed tightly against body wall by the portions of gut that enter later, so mesenteries are partially fused with dorsal body wall
- stomach and duodenum cranially
- ileum, cecum, and all three parts colon caudally
what is mobile viscera?
- regions of gut retracted late, mainly jejunum not crowded and retain long mesentery
why is length of mesentery important?
- determines ease of access during surgery
- jejunum easily accessed - small incision
- stomach or colon would require larger incision
what are the landmark mesenteries of fixed viscera?
- broad ligaments of uterus (right and left) - lateral most mesenteries and can be used to easily located uterine horns
what are the short mesentary?
- descending duodenum (right)
- descending colon (left)
where does the liver develop?
- ventral mesentery: lesser omentum and peritoneal ligaments of liver (falciform, coronary, triangular ligg.
what is the root of mesentery?
- @ L2
- narrow attachment of long mesojejunum and mesoileum to dorsal body wall
- thick: contains cranial mesenteric a., intestinal lymphatics, autonomic n. plexus
is ruminant mesentery short or long?
- short
is horse mesentery long or short?
- long: common to have strangulation
what is the omentum?
- passes from stomach to other organs or to abdominal wall
- lesser and greater (greater curve of stomach)
what is lesser omentum?
- extends from liver to lesser curvature of stomach (hepatogastric lig.) and initial duodenum
- single sheet (2 layers) remnant of ventral mesogastrium
- covers papillary process of caudate lobe
what is greater omentum?
- remnant of dorsal mesogastrium
- unattached at caudal border (can be lifted)
- has deep sheet and superficial sheet (each sheet has 2 layers)
where is the superficial sheet of greater omentum and what is in it?
- next to ventral body wall
- encloses spleen
what is the deep sheet of greater omentum and what is in it?
- continues from bladder cranially, adjacent to abdominal organs, enclosed left lobe pancreas
what is the omental bursa?
a subdivision of peritoneal cavity enclosed by greater and lesser omentum
a potential space - collapsed in real life
what is the epiploic foramen?
short passage between omental bursa and main peritoneal cavity
found at base of caudate lobe of liver in all domestic animals
what are the boundaries of epiploic foramen?
dorsally: caudal vena cava
ventrally: portal vein
caudally: hepatic a. in mesoduodenum
what are the species differences of greater omentum?
carnivores: well-developed, peritoneum should be included in sutured layer
ruminants: well-developed
equine: poorly developed
why is greater omentum clinically important?
- very mobile - surgeons tack bits on site of opened viscera
- very vascular: used by surgeons to aid in re-vascularization
- policeman of abdomen: limits spread of infection, has milky spots (macrophages) and omental adhesions (tissues stick)
- can be removed, does not regenerate
what are the remnants of ventral mesentary?
- ventral peritoneal folds carried umbilical arteries and vein in fetus
- the falciform ligament: begins at umbilicus and passes to liver, attached to linea alba, in fetus carries umbilical vein (round ligament of liver in adult)
- median ligament of bladder
- lateral ligaments of bladder
what is in the falciform ligament?
- adipose tissue that contains high conc of stem cells
- attaches liver to ventral wall (linea alba)
what is median ligament of bladder?
- attached ventral midline of bladder to abdomen caudal to umbilicus
what are the lateral ligaments of bladder?
- lateral bladder to lateral abdominal walls
what are ligaments?
- type of connection peritoneum, narrow and double layered
- pass from wall to organ or form organ to organ
- serves to fix organs more than as channels of vessels and nerves
what is a fold?
- connecting peritoneum
- less or no blood vessels
- between 2 visceral organs
- ex: cecocolic fold
what nervous system supplies parietal peritoneum?
- somatic nn (because it covers walls of abdomen)
- sensory innervation is by segmental spinal nn. (lumbar and thoracic nn.)
- peritoneum on diaphragm receives sensory from phrenic n.
- sensitive to irritation and cause localized pain
what nervous system supplies visceral peritoneum?
- autonomic nn. (covers viscera)
- sensory innervation of mesenteries, omenta, and ligaments proceeds from stretch not ordinary pain, temp, touch receptors
- if excessive stretch or pressure avoided, viscera can be incised and sx manipulated without pain to animal
what is vaginal process?
- blind ended portion of peritoneum protrudes through the inguinal canal and sits SQ
- vaginal tunic (male) and vaginal process (female) - not in female cat
