Theme 1 - Lecture 2 Peritoneal cavity Flashcards
Endoderm
Majority of gut, including most of epithelium and glands of digestive tract
Mesoderm
Muscular layers
Ectoderm
Epithelium at extremities of tract(cranial and caudal)
What is the primitive gut formed as a result of?
- Cranial-caudal
- Lateral
Which membranes close the cranial and caudal ends at 4 weeks
- Bucco-pharyngeal
- Cloacal
What does the foregut contain?
- Oesophagus
- Stomach
- Proximal half duodenum
- Liver
- Pancreas
What does the midgut contain?
- Distal half duodenum
- Jejunum
- Ileum
- Cecum
- Asc +3/4 transv.colon
What does the hindgut contain?
- 1/4 transv + desc + sigmoid colon and rectum
What is a mesentery?
Formed by a double layer of peritoneum
Purpose of mesentery?
- Suspends gut organs
- Pathway for blood, innervation, lymphatics etc to reach the gut
- Ventral mesentery degenerates during development, except for foregut
What does the dorsal mesentery give rise to?
- Gastrosplenic ligament
- Lienorenal ligament
- Greater omentum
- Mesentery of small and large intestine
What does the ventral mesentery give rise to?
(foregut)
Ligaments around the liver
Falciform ligament
Lesser omentum
Describe lesser omentum
- Attaches lesser curvature stomach to back of liver
- Has a free edge
Where does inguinal ligament attach from and to?
From ASIS to pubic tubercle
What are the attachments of the external oblique?
- Originates from ribs 5-12, and
- Inserts into iliac crest and pubic tubercle
Movement of external oblique
- Contralateral rotation of the torso
Innervation of the external oblique
- thoracoabdominal nerves (T7-T11) and subcostal nerve(T12)
What are the attachments of the internal oblique?
- Originates from the inguinal ligament, iliac crest and lumbodorsal fascia
- inserts into ribs 10-12
Internal oblique function
- Bilateral contraction compresses the abdomen, while unilateral contraction ipsilaterally rotates the torso
Innervation of intenal obliques
- Thoracoabdominal nerves(T7-T11)
- Subcostal nerve(T12)
- Branches of lumbar plexus
Directions of the fibres of internal and external obliques
Internal - Supero-medial
External - Infero-medial
Most superficial anterior muscle
- External oblique
Location of internal oblique with respect to the other muscles
- Lies deep to the external oblique
- It is smaller and thinner in structure
Attachments of the transversus abdominis
- Originates from the inguinal ligament, costal cartilages 7-12, the iliac crest and the thoracolumbar fascia
- Inserts into the conjoint tendon, xiphoid process, linea alba and the pubic crest
Function of transversus abdominis
Compression of abdominal contents
Innervation of transversus abdominis
- Thoracoabdominal nerves(T7-T11)
- Subcostal nerve(T12)
- Branches of the lumbar plexus
Fascia that is deep to the transversus abdominis
Transversalis fascia
What are the attachments of the rectus abdominis
- Originates from the crest of the pubis
- Inserts into the xiphoid process of the sternum and the costal cartilage of ribs 5-7
Functions of the rectus abdominis
- Assists the flat muscles in compressing the abdominal viscera, the rectus abdominis also stabilises the pelvis during walking, and depresses the ribs
Innervation of the rectus abdominis
Thoracoabdominal nerves(T7-T11)
What gives rise to the six pack
- At several places, the rectus abdominis is intersected by fibrous strips, known as tendinous intersections
Describe the pyramidalis
Is a small triangular muscle, found superficially to the rectus abdominis
It is located inferiorly with its base on the pubis bone, and the apex of the triangle attached to the linea alba
Attachments of the pyramidalis
- Originates from the pubic crest and pubic symphysis before inserting into the linea alba
Functions of the pyramidalis
- Acts to tense the linea alba
Innervation of the pyramidalis
- Subcostal nerve(T12)
