Theme 1: Lecture 2 - Understanding the peritoneal cavity

Question 1

Which stage is the embryo in when the gut starts to develop

Answer 1

Gastrula

Question 2

Gastrula

Answer 2

The embryo at the stage following the blastula

Question 3

Which parts of the alimentary system develop from the endoderm

Answer 3

majority of gut, including most of epithelium and glands of digestive tract

Question 4

Which parts of the alimentary system develop from the mesoderm

Answer 4

Muscular layers

Question 5

Which parts of the alimentary system develop from the ectoderm

Answer 5

Epithelium at the extremities of tract (cranial and caudal)

Question 6

Describe the primitive gut

Answer 6

Formed as a result of two folds:

• Cranial caudal (head to tail)
• Lateral (side to side

At 4 weeks the cranial ad caudal ends are still closed by membranes:

• Bucco-pharyngeal at the cranial end
• Cloacal at the caudal end (urinary and digestive tract not yet separate)

Held in position by mesenteries

Question 7

What is in the foregut

Answer 7

• Oesophagus
• Stomach
• Proximal half of duodenum
• Liver
• Pancreas

Question 8

What is in the midgut

Answer 8

• Distal half of duodenum
• Jejunum
• Ileum
• Cecum
• Ascending and 3/4 of transverse colon

Question 9

What is in the hindgut

Answer 9

• 1/4 of transverse colon
• Descending colon
• Sigmoid colon
• Rectum

Question 10

What is the cecum

Answer 10

The beginning of the large intestine where the ileum meets the ascending colon

Question 11

Describe the mesentery

Answer 11

• Mesentery – formed by a double layer of peritoneum
• Mesentery – dorsal or ventral according to its relative position with respect to gut tube
• Suspends gut organs
• Pathway for blood innervation and lymphatics to reach the gut

Question 12

What happens to the ventral mesentery during development

Answer 12

It degenerates apart from in the foregut

Question 13

Why doesn’t the ventral mesentery degenerate in the foregut

Answer 13

It allows for more mobility in the intestines

Question 14

Describe an anomaly of gut rotation

Answer 14

• Duodenum constriction

- Midgut volvulus, leading to ischaemia, necrosis or possibly death

Question 15

What is a volvulus

Answer 15

A volvulus is when a loop of intestine twists around itself and the mesentery that supports it, resulting in a bowel obstruction

Question 16

Common symptoms of anomaly of gut rotation

Answer 16

• Vomiting
• Pain
• Abdominal distention

Question 17

What does the dorsal mesentery do

Answer 17

Attaches gut organs to posterior abdominal wall

Question 18

What does the dorsal mesentery give rise too

Answer 18

• Gastrosplenic ligament
• Lienorenal ligament
• Greater omentum
• Mesentery of small and large intestine

Question 19

What does the ventral mesentery give rise to

Answer 19

• Ligaments around the liver
• Falciform ligament
• Lesser omentum

Question 20

What is the greater omentum

Answer 20

large apron-like fold of visceral peritoneum that hangs down from the greater curvature of the stomach

Question 21

What is the gastrosplenic ligament

Answer 21

connects the greater curvature of stomach with the hilum of the spleen

Question 22

What is the falciform ligament

Answer 22

a ligament that attaches the liver to the front body wall, and separates the liver into the left medial lobe and right lateral lobe

Question 23

Describe the lesser omentum

Answer 23

• Attaches lesser curvature of stomach to back of liver

- Has a free edge

Question 24

What is the inguinal ligament

Answer 24

Ligament that runs from the ASIS (anterior superior iliac spine) to the pubic tubercle on the pelvis

Question 25

What makes up the external abdominal wall

Answer 25

- Flat abdominal muscles (anteriorly) | - Lumber vertebral column (posteriorly)

Question 26

What are the muscles of the anterior abdominal wall

Answer 26

- External oblique - Internal oblique - Transversus abdominis - Rectus abdominis

Question 27

Origin and insertion of the external oblique muscles

Answer 27

``` Runs: anteriorly and inferiorly From: outer surface of lower eight ribs To: linea alba iliac crest pubic tubercle ```

Question 28

Origin and insertion of the internal oblique muscles

Answer 28

``` Runs: anteriorly and superiorly From: lat 1/3 inguinal ligament ant 2/3 of iliac crest To: linea alba costal margin crest of pubic bone ```

Question 29

Origin and insertion of the transverse abdominis muscles

Answer 29

``` Runs: horizontally From: lat 1/3 inguinal ligament int surf lower 6 ribs iliac crest To: linea alba crest of pubic bone ```

Question 30

Origin and insertion of the rectus abdominis muscles

Answer 30

Runs: vertically From: pubic symphysis + crest To: xyphoid process 5th-7th costal cartilages

Question 31

Linea alba

Answer 31

a tendinous, fibrous raphe that runs vertically down the midline of the abdomen. It extends between the inferior limit of the sternum and the pubis, separating the rectus abdominis muscles

Question 32

Iliac crest

Answer 32

the most prominent part of the ilium, the largest of the three bones that make up the bony pelvis or hip bone

Question 33

Pubic tubercule

Answer 33

The pubic tubercle is a prominent forward-projecting tubercle on the upper border of the medial portion of the superior ramus of the pubis bone

Question 34

Costal margin

Answer 34

The costal margin is the medial margin formed by the cartilages of the seventh to tenth ribs. It attaches to the manubrium and xiphoid process of the sternum

Question 35

Pubic symphysis

Answer 35

The pubic symphysis is a secondary cartilaginous joint between the left and right superior rami of the pubis of the hip bone

Question 36

Arterial supply for the muscles of the anterior abdominal wall

Answer 36

Sup and Inf epigastric, intercostal, circumflex iliac

Question 37

Venous supply for the muscles of the anterior abdominal wall

Answer 37

thoracoepigastric (between lat thoracic and Superficial epigastric)

Question 38

Innervation of the muscles of the anterior abdominal wall

Answer 38

Thoracoabdominal nerves (also thoracic and subcostal nerves for rectus abdominis)

Question 39

Function of the external obliques

Answer 39

Work with internal obliques for torsional movement of trunk

Question 40

Function of the internal obliques

Answer 40

- Flex and rotate trunk | - Compress viscera

Question 41

Function of the transverse abdominis

Answer 41

Compress and support viscera

Question 42

Function of the rectus abdominis

Answer 42

- Flexes trunk | - Compress viscera

Question 43

Retroperitoneal

Answer 43

Behind the peritoneum

Question 44

Name a retroperitoneal organ

Answer 44

The kidneys

Question 45

Greater and lesser sacs

Answer 45

- The peritoneum can be divided into a greater and lesser peritoneal sac - They are formed as a result of organ rotation

Question 46

Lesser sac

Answer 46

- The area behind the stomach | - Also known as the omental bursa

Question 47

Greater sac

Answer 47

All the peritoneal cavity excluding the area behind the stomach

Question 48

How do the greater and lesser sac communicate

Answer 48

Via the epiploic foramen (aka foramen of Winslow)

Question 49

What does the inguinal canal serve as a passageway for

Answer 49

- spermatic cord to reach the scrotum in the male - the round ligament of the uterus to reach the labia majora in the female - Blood vessels - Lymphatic vessels - The genital nerve

Question 50

What are the boundaries of the inguinal canal

Answer 50

The superficial and deep inguinal rings

Question 51

Which nerve travels through the inguinal canal

Answer 51

The genital nerve (a branch of the genitofemoral)

Question 52

Is the inguinal canal larger in males or females

Answer 52

Males

Question 53

What does the spermatic cord consist of

Answer 53

- Vas deferens - Gonadal vessels - Nerves - Lymphatics - Cremaster muscle

Question 54

Vas deferens

Answer 54

Vessel that carries sperm from the testes and through the urethra

Question 55

Cremaster muscle

Answer 55

Helps move sperm through the vas deferens and can move the testes closer to the body

Question 56

Describe the layers of the spermatic cord and how they arise

Answer 56

As the spermatic cord 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 – the internal spermatic fascia - internal oblique => contributes the middle covering layer to the cord – the cremasteric fascia - the external oblique => contributes the outer covering of the cord – the external spermatic fascia