Understanding the peritoneal cavity Flashcards
what is the peritoneal cavity’s origin
Origin of the gut
The embryo – gastrula – the stage following the blastula, embryo develops 3 layers ecto, endo and mesoderm
what forms the peritoneal cavity
Endoderm – majority of the gut, including most of epithelium and glands of digestive tract
Mesoderm – muscular layers
Ectoderm – epithelium at extremities of tract (cranial and caudal)
how is the primitive gut formed
Formed as a result of two folds
Cranial-caudal (head to tail) and lateral (side to side)
At 4 weeks the cranial and caudal ends still closed by membranes, bucco-pharyngeal (cranial) and cloacal (caudal)
what are gut divisions and what do they become
Foregut – oesophagus, stomach, proximal half duodenum, liver, pancreas
Midgut- distal half duodenum, jejunum, ileum, cecum, ascending and ¾ transverse colon
Hindgut – ¼ transverse, descending and sigmoid colon and rectum
what are mesenteries
hold primitive gut in place
of mesodermal origin
formed by double layer of peritoneum, dorsal or ventral according to relative position in respect to gut (visceral and parietal peritoneum attached by mesenteries)
what do mesenteries do
suspends intestines
pathway for blood, innervation, lymphatics to reach gut
ventral mesentery degenerates during development, except foregut
what happens to the gut in development
folds
what can result from incorrect folding
cause unclear Format – duodenum constriction Midgut volvulus, leading to ischaemia, necrosis or possibly death Common symptoms Vomiting, pain, abdominal distension
what is the dorsal mesentery
Attaches gut organs to posterior abdominal wall
Gives rise to gastrophrenic ligament, lienorenal ligament, greater omentum, mesentery of small and large intestine
what is the ventral mesentery
At foregut region only, gives rise to ligaments around liver, falciform ligament, lesser omentum
Lesser omentum – attaches lesser curvature stomach to back of liver and has a free edge
where is the abdomen located
Below diaphragm
Abdominal cavity occasionally called abdominopelvic (abdomen proper + greater pelvis)
Greater pelvis continuous with lesser pelvis
what is the inguinal ligament
attach ASIS to pubic tubercle on iliac bone (pelvis)
what muscles make up the abdominal wall
Flat abdominal muscles
Lumbar vertebral column
what are the muscles of the anterior abdominal wall
external and internal oblique
transverse abdominis
rectus abdominis
where is the external oblique
from outer surface of lower 8 ribs to linea alba, iliac crest and public tubercle
where is the internal oblique
from lateral 1/3 inguinal ligament, anterior 2/3 of iliac crest to linea alba, costal margin, crest of pubic bone
where is the transverse abdominis
from lateral 1/3 inguinal ligament, internal surface of lower 6 ribs, iliac crest to linea alba and crest of pubic bone
where is the rectus abdominis
from public symphysis and crest to xiphoid process, 5th-7th costal cartilages
what is the blood supply and innervation of the muscles of the anterior abdominal wall
Arteries – sup and inf epigastric, intercostal, circumflex iliac
Veins – thoracoepigastric (between lat thoracic and sup epigastric)
Innervation
Thoracoabdominal nerves (also thoracic and subcostal nerves for rectus abdominis)
what is the function of the muscles of the muscles of the anterior abdominal wall
Ext oblique work with int oblique for torsional movement of trunk
Int oblique – flex and rotate trunk, compress viscera
Transverse abdominus – compress and support viscera
Rectus abdominis – flex trunk, compress viscera
what are the greater and lesser sacs
Formed as a result of organ rotation
Lesser sac behind stomach
Rest of peritoneal cavity – greater sac
Communicate via epiphonic foramen (of winslow)
what does the inguinal canal do
Serves as a passageway for the spermatic cord to reach scrotum of male and the round ligament of the uterus to reach labia majora in the female
Limited by the superficial and deep inguinal rings
what also runs in the inguinal canal cavity
For both genders the genital nerve (a branch from the genitofemoral) and other blood and lymphatic vessels also travel through this canal
The inguinal canal is considerably larger in males, compared to females
what does the spermatic cord consist of
vas deferens, gonadal vessels, nerves, lymphatics, cremaster muscle
what happens to the spermatic cord as it passes through the abdominal wall
it takes a sleeve or covering from each of the 3 layers
Transversalis fascia – contributes the innermost covering of the spermatic cord – internal spermatic fascia
Internal oblique – contributes the middle covering layer – the cremasteric fascia
External oblique – the outer covering – the external spermatic fascia
