Ch. 86 Peritoneum

Question 1

What mesoderm gives rise to the peritoneal cavity?

Answer 1

the somatic (parietal) and the splanchnic (visceral) mesoderms

Question 2

What is the coelom?

Answer 2

this is the space that is enclosed by the somatic and splanchnic mesoderm - party will be enclosed as the body cavity and the rest is transient but in the embryo, it is all continuous

Question 3

what is an omphalocele

Answer 3

embryonic herniation of abdominal contents through the umbilicus into the umbilical stalk
an umbilical hernia results from a defect in development of the muscular wall around the umbilicus

Question 4

What are the nine regions of the abdominal cavity and how is it divided?

Answer 4

Divided by two transverse and two sagittal planes
right and left hypochondriac regions, epigastric or xiphoid region, umbilical region, left and right lateral regions (includes flanks and paralumbar fossae), right and left inguinal regions, and pubic region

Question 5

Where do the sympathetic and splanchnic nerves enter the abdominal cavity?

Answer 5

through paired slit like openings dorsal to the diaphragm and ventral to the psoas muscles

Question 6

What passes through the inguinal canal

Answer 6

vaginal process with the spermatic cord or round ligament in the female
external pudendal vessels
genital nerve

Question 7

What passes through the vascular lacunae?

Answer 7

in the caudal abdomen, the vascular lacunae contains the femoral artery and vein, lymphatics, and saphenous nerve

Question 8

what is a cullen sign

Answer 8

a ring of subcutaneous hemorrhage around the umbilicus may appear in cases of a hemoperitoneum or septic abdomen if there is a direct extension from the abdominal cavity into the subcutis - this would be from an incomplete mesodermal lining at the level of the umbilicus

Question 9

what is the peritoneal cavity?

Answer 9

a potential space between the visceral and parietal peritoneum and contans no organs except at the time of ovulation when the egg ruptures from the ovary

Question 10

what are the three portions of greater omentum?

Answer 10

bursal, splenic, veil

Question 11

what is the bursal portion of the greater omentum

Answer 11

the omental bursa is a potential space between the paries superficiales and paries profundus layers
opens at the epiploic foramen when is bounded dorsally by the caudal vena cava and ventrally by the portal vein
The bursal portion is what is used for omentalization

Question 12

what are the boundaries of the epiploic foramen

Answer 12

dorsally: caudal vena cava
ventrally: portal vein

Question 13

what is the splenic portion of the greater omentum

Answer 13

extends to the hilus of the spleen to form the gastrosplenic ligament

Question 14

what is the veil portion of the greater omentum

Answer 14

the smallest portion of the greater omentum

contains the left limb of the pancreas

Question 15

what are the boundaries of the lesser omentum

Answer 15

lies between the lesser curvature of the stomach and porta hepatis and becomes continuous with the mesoduodenum
some of the lesser omentum will give rise to the hepatoduodenal ligament and the hepatogastric ligament

Question 16

what are milky spots?

Answer 16

aggregations of cells within the omentum which contain neutrophils, macrophages, and lymphocytes

Question 17

Describe the peritoneum on a microscopic level

Answer 17

a single layer of squamous cells of mesothelial origin
covered in microvilli
the squamous cells are supported by connective tissue layer
the peritoneum on the visceral surface of the diaphragm has fenestrations, or stomata, of varying size - 4-16 um in dogs and cats
The stomata and the lymph vessels (called lacunae) aid in clearance of fluid from the cavity

Question 18

what is the colloid osmotic pressure of normal peritoneal fluid? what is the normal protein concentration? what is the normal number of cells?

Answer 18

normal colloid osmotic pressure is 28 mmHg
normal protein is 3 g/dL
normal cells <300

Question 19

what is the protein and cell count for a transudate

Answer 19

protein <2.5 g/dL

cells <1500 cells/uL

Question 20

what is the protein and cell count in a modified transudate

Answer 20

protein 2.5-7.5 g/dL

cells 1000-7000 cells/uL

Question 21

what is the protein and cell count for an exudate

Answer 21

protein >3 g/dL

cells >5000 cells/uL

Question 22

How quickly does the abdominal lymph system drain

Answer 22

The primary route of drainage of particles was through the diaphragmatic lymphatics to the mediastinal lymph node and finally by way of the thoracic duct into the systemic circulation
For small particles less than 10 um, within about 10-90 minutes for a dog and 3 minutes for a cat if injected intraperitoneally

Question 23

What causes lymph to flow from the peritoneal cavity

Answer 23

Passive stretching of the diaphragm moves fluid from the cavity to the diaphragmatic lacunae. Diaphragmatic muscle contraction and decreased intrathoracic pressure during exhalation moves fluid through the lymphatics into efferent ducts along a pressure gradient

Question 24

Which side of the body has a higher distribution of lymphatics?

Answer 24

the right side - no idea why

Question 25

How quickly can the peritoneal cavity absorb fluid

Answer 25

3-8% of body weight per hour

Question 26

what is the normal range for intrabdominal pressure in a dog

Answer 26

2.0-7.5 cm H20 | mean 4.5 cm H20

Question 27

How do you convert mm Hg to cm H20?

Answer 27

multiple mm Hg by 1.36 to get cm H20

Question 28

What does altered abdominal compliance result in?

Answer 28

increased intrabdominal pressure

Question 29

At what pressure, in pigs, will abdominal insufflation cause increased HR, increased MAP, increased systemic vascular resistance, decreased cardiac output, decreased mesenteric arterial blood flow, decreased intestinal mucosal blood flow, increased bacterial translocation?

Answer 29

greater than 20.4 cm H20

Question 30

what is acute abdominal compartment syndrome

Answer 30

a marked increase in intraabdominal pressure and is associated with MODS because of compressive atelectasis with increased peak inspiratory pressure --> impaired gas exchange, increased pleural and pericardial pressures, decreased venous return, intestinal ischemia, renal failure

Question 31

how do you diagnose acute abdominal compartment syndrome

Answer 31

high peak inspiratory pressure with oliguria and an apparently tight abdomen usually the urinary bladder pressure would be greater than 20-25 cm H20

Question 32

What must the environment be for adhesions to form

Answer 32

inflammatory cells and fibrin come in and in the absence of ischemia, fibrinolysis occurs if there is vascular damage though, fibrin is infiltrated by fibroblasts making collagen and then fibrinous adhesions form

Question 33

what is the mainstay of peritoneal fluid's innate defense system

Answer 33

release of C3a and C5a, which will stimulate neutrophil chemotaxis and degranulation of basophils and mast cells

Question 34

What cytokines are dominant in a gram negative peritonitis

Answer 34

TNF alpha and IL 6

Question 35

What happens to the peritoneal fibrinolytic system during inflammation

Answer 35

the system is inactivated lack of fibrin clearance leads to fibrin clumps fibrin clumps will occlude peritoneal stomata and impede clearance of fluid and particles the fibrin then sequesters microorganisms from normal host defenses

Question 36

how does gastrin mucin polysaccharide act as a peritonitis adjuvant

Answer 36

has a heparin like anticomplement effect that inhibits phagocytosis

Question 37

how do bile salts act as a peritonitis adjuvant

Answer 37

lowers surface tension and lyses RBCs which release hemoglobin hemoglobin interferes with phagocytic cell chemotaxis and intracellular killing may also provide iron to microorganisms inhibits bacterial clearance from the peritoneal cavity by interfering with lymphatic clearance mechanisms

Question 38

how does peritonitis cause ileus?

Answer 38

sympathoadrenergic reflex inhibition | the reflexes completely block myenteric cholinergic neurons

Question 39

what is the role of reflex rigidity in peritonitis

Answer 39

diaphragmatic rigidity impedes respiratory movements which then reduces intraperitoneal circulation and decreases the lymphatic clearance of fluid through the diaphragm

Question 40

what is primary peritonitis

Answer 40

spontaneous inflammation in the abscence of an evident intraabdominal source of infection or penetrating injury usually monobacterial and may be called spontaneous bacterial peritonitis best example would be feline coronavirus causing FIP

Question 41

what is secondary peritonitis

Answer 41

secondary generalized septic peritonitis is the most common form of peritonitis in dogs basically, there is a source for the peritonitis that is clearly evident

Question 42

examples of causes of aseptic peritonitis

Answer 42

``` chemical (like pancreatitis or barium) bile (usually aseptic) uroperitoneum (usually aseptic) peritoneal FB starch granulomatous peritonitis mechanical peritonitis sclerosing encapsulating peritonitis ```

Question 43

examples of causes of septic peritonitis

Answer 43

``` leakage of GI contents penetrating abdominal wounds blunt abdominal trauma ischemic intestinal injury pancreatitis rupture pyometra uterine torsion ruptured prostatic abscess liver abscess or hepatitis splenic abscess or splenitis splenic torsion msenteric lymph node abscess ruptured gallblader or bile duct with bacterbilia ruptured bladder with cystitis umbilical abscess surgical contamination peritoneal dialysis ```

Question 44

how would a gosspiboma appear on ultrasound

Answer 44

likely would have a hypoechoic mass with an irregular hyperechoic center

Question 45

how can starch induced peritonitis be diagnosed

Answer 45

iodine staining or polarized light microscopic exam of peritoneal fluid treat with steroids

Question 46

what is the most common source of septic peritonitis?

Answer 46

intraabdominal bacterial contamination and GI leakage in 60-63% of septic peritonitis cases in dogs and 47% of septic peritonitis cases in cats