Mesentery - structure - two types - function

Structure formed from the double layer of the peritoneum. Can be dorsal or ventral. Function: - Suspends gut organs - Pathway for various structures: blood vessels, nerves, lymphatics.

The peritoneal cavity Flashcards by aderonke adesanoye

Endoderm

The innermost germ layer.

Develops into most of the gut including the epithelium and glands of the digestive tract.

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Mesoderm

The middle layer in a gastrula.

Develops into the muscle layer in the gut.

Includes muscles of the oesophagus, stomach and intestines.

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Ectoderm

The outermost layer of the gastrula.

Develops into the epithelium at the crucial and caudal ends of the digestive tract.

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Membrane that closes the cranial end of the primitive gut.

Buccopharyngeal membrane

Occurs at week 4.

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Membrane that closes the caudal end of the primitive gut.

Cloacal membrane.

Membrane forms at week 4.

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Components of the [5]

Oesophagus

Stomach

Proximal half of the duodenum

Liver

Pancreas

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Components of the midgut [6]

Distal half of the duodenum

Jejunum

Ileum

Cecum

Ascending and 3/4 of the transverse colon (first part of the colon)

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Components of the hindgut [5]

The last 1/4 of the transverse colon

Descending colon

Sigmoid colon

Rectum

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Origin of the mesentery

Mesodermal origin

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Mesentery

structure
two types
function

Structure formed from the double layer of the peritoneum.

Can be dorsal or ventral.

Function:

Suspends gut organs
Pathway for various structures: blood vessels, nerves, lymphatics.

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What mesentery degenerates during development

Ventral mesentery

Only part that remains is the foregut.

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Dorsal mesentery ligaments [4]

Gastrosplenic

Lienorenal

Greater omentum

Mesentery of the small and large intestines.

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Ligaments of the ventral mesentery

Ligaments of the liver

Falciform

Lesser omentum

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Lesser omentum

What mesentery
Function

Of the ventral mesentery.

Attaches the lesser curvature of the stomach to the liver.

Contains a free edge that allows one to reach to the back of the stomach.

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Other term for abdominal cavity

Abdominopelvic

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Inguinal ligament

Ligament that attaches the Anterior, superior iliac spine (ASIS) to the pubic tubercle.

Location of the Inguinal canal.

External oblique

Origin
Insertion [3]
Fibres

Skeletal muscle of the anterior abdominal wall.

Contains fibres going downwards.

Origin:
Outer surface of the lower 8 ribs.

Insertion:

Linea alba
Iliac crest
Pubic tubercle

Internal obliques

Origin [2]
Insertion [3]
Fibres

Muscle of the anterior abdominal wall with upward fibres.

Origin:

Lateral third of linguinal ligament.
Anterior 2/3 of the iliac crest.

Insertion:

Linea alba
Costal margin
Crest of pubic bone

Transversus abdominis

Origin [3]
Insertion [2]
Fibres

Muscle of the anterior abdominal wall with horizontal fibres.

Origin:

Lateral third of the inguinal ligament.
Interior surface of the lower 6 ribs.
Iliac crest.

Insertion:

Linea alba
Crest of pubic bone

Rectus abdominis

Origin [2]
Insertion [2]
Fibres

Anterior abdominal muscle with vertical fibres.

Origin:
Pubic symphysis
Pubic crest

Insertion:
Xyphoid process
5-7th costal cartilages

Arteries that supply the muscles of the anterior abdominal wall.

Superior and inferior epigastric.

Intercostal

Circumflex iliac

Veins that drain the muscles of the anterior abdominal wall.

Thoracoepigastric vein

Innervation of the muscles on the anterior abdominal wall.

Thoracoabdominal nerves

Thoracic and subcostal nerves- supply rectus abdominis

Function of the external oblique muscle

Torsional movement of the trunk- works with internal oblique.

Function of the internal oblique muscle

Flexes and rotate the trunk. Compresses viscera.

Function of the transverse abdominis

Compresses viscera Supports viscera

Function of the rectus abdominis

Flexes the trunk Compresses viscera

Greater and lesser pelvis

Greater pelvis: - Also false pelvis, contains abdominal organs. Lesser pelvis: - Also true pelvis, contains pelvic organs.

Pelvic inlet | - boundaries

Planar surface of the pelvis that separates the abdominal from the pelvic cavity. Posteriorly- promontory Posterio-lateraly- margin of ala Laterally- Arcuate line. Anterolateraly- pecten pubic Anteriorly- pubic crest.

Lesser sac

Formed as a result of organ rotation. The sac is the region behind the stomach.

Greater sac

Formed as a result of organ rotation. The majority of the peritoneal cavity that is not behind the stomach. The greater sac communicates with the epiploic foramen

Inguinal canal - Structures that limit it - Comparison in male vs females - Similarity in males and females

Difference in males and females: - Canal is larger in males. - Passageway for the spermatic cord in males. - Passageway for the round ligament of the uterus in females. Structures that limit it: - Superficial inguinal ring: formed by aponeurosis of the external oblique transversalis fascia - Deep inguinal rings: formed by the transversalis fascia Similarities in males and females: - Genital nerve passes through the canal

Genital nerve - Origin - Innervation in males and females

Branch of the genitofemoral nerve that passes through the inguinal canal. Present in both males and females. - Supplies the cremaster muscle and anterior scrotal skin in males - Supplies the skin of the mons pubis and labia majora in females.

Spermatic cord

Structure that inguinal canal serves as a passageway for. Contains: - Vas deferens: carries sperm to the ejaculatory duct. - Gonadal vessels - Cremaster muscle - Nerves, lymphatics.

Internal spermatic fascia

The innermost covering of the spermatic cord. Derived from the transversalis fascia of the abdominal wall.

Transversalis fascia

An aponeurotic membrane between the inner surface of the transverse abdominis and the parietal peritoneum. Contributes to the internal spermatic fascia.

Cremasteric fascia

The middle covering layer of the spermatic cord. It is a continuation of the aponeurosis of the abdominal internal oblique muscle.

External spermatic fascia

The outer covering of the spermatic cord. It is a continuation of the aponeurosis of the abdominal external oblique muscle.