Understanding the peritoneal cavity Flashcards
Endoderm forms
Majority of gut, including most of epithelium and glands of digestive tract
Mesoderm forms
Muscular layers
Ectoderm forms
Epithelium at extremities of tract (cranial and caudal)
The primitive gut
Formed as a result of two folds:
- cranial- caudal
- lateral- back to from
At 4 weeks the cranial and caudal ends are still closed by membranes:
- bucco- pharyngeal
- cloacal
Gut divisions
Foregut
Midgut
Hindgut
Foregut fate
Oesophagus
Stomach
Proximal hald duodenum
Liver
Pancreas
Midgut fate
Distal hald duodenum
Jejunum
Ileum
Cecum
Asc. + 3/4 transv colon
Hindgut fate
1/4 transv + desc + sigmoid colon and rectum
Peritoneum and mesentery
Mesentery formed by a double layer of peritoneum
Dorsal or ventral according to its relative position with respect to gut tube
Mesentery
Suspends gut organs
Pathway for blood, innervation, lymphatics etc to reach the gut
Ventral mesentery degenerates during development, except for foregut
Dorsal mesentery
Attaches gut organs to posterior abdominal wall
Gives rise to
- gastrosplenic ligament
- lienorenal ligament
- greater omentum
- mesentery of small and large intestine
Ventral mesentery
At foregut region only, it gives rise to
- ligaments around the liver
- falciform ligament
- lesser omentum
Lesser omentum
Attaches lesser curvature stomach to back of liver
Has a free edge
Abdomen
Trunk below diaphragm
Abdominal cavity occasionally called abdominopelvic
Greater pelvis is continuous with less pelvis
Abdomen wall (external)
Flat abdominal muscles
Lumbar vertebral column
External oblique
From: outer surface of lower eight ribs
To: linea alba, iliac crest, pubic tubercle
Internal oblique
From: lat 1/3 inguinal ligament and ant 2/3 of iliac crest
To: linea alba, costal margin, crest of pubic bone
Transverse abdominus
From: lat 1/3 inguinal ligaments, int surface lower 6 ribs, iliac crest
To: linea alba, crest of pubic bone
Rectus abdominis
From: pubic symphysis and crest
To: xiphoid process, 5th-7th costal cartilages
Blood supply/ drainage of muscle ant abd wall
Arteries: sup and inf epigastric, intercostal, circumflex iliac
Veins: thoracoepigastric
Innervation of muscles ant abd wall
Thoracoabdominal nerves
also thoracic and subcostal nerves for rectus abdominis
Function of external obliques
Work with int obl for torsional movement of trunk
Function of internal obliques
Flex and rotate trunk
Compress viscera
Function of transverse abdominals
Compress and support viscera
Function of rectus abdominals
Flexes trunk
Compress viscera
Lesser/ greater sacs
Formed as a result of organ rotation
Lesser sac behind stomach
Rest of peritoneal cavity- greater sac
Communicate via the epiploic foramen
Inguinal canal
Serves as passageway for the
- spermatic cord to reach the scrotum in male
- the round ligament of the uterus to reach the labia majora in female
Limited by the superficial and deep inguinal rings
For both genders the genital nerve and other blood and lymphatic vessels also travel through this canal
Considerably larger in males
Spermatic cord consists of
- vas deferens
- gonadal vessels
- nerves
- lymphatics
- the cremaster muscle
3 layers of the sleeve/ covering the spermatic cord takes as it passes through the abdominal wall
- transversalis fascia
- internal oblique
- external oblique
Transversalis fascia
Contributes the innermost covering of the spermatic cord
The internal spermatic fascia
Internal oblique
Contributes the middle covering layer to the cord
The cremasteric fascia
External oblique
Contributes the outer covering of the cord
The external spermatic fascia
