Abdomen Anatomy and Histology

Question 1

What are flat muscles?

Answer 1

They are muscle required for flexion, lateral flexion and rotation that help compress the abdominal cavity.
They have fibres running in different directions to improve the strength of the abdominal wall

Question 2

Which muscles in the abdomen are ‘flat muscles’?

Answer 2

Transverse abdominus (deepest layer)
Internal oblique (intermediate layer)
External oblique (superficial layer)

Question 3

What are vertical muscles?

Answer 3

These are the muscles responsible for a ‘six pack’

They stabilise the pelvis when walking and depress the ribs.

Question 4

Which muscles of the abdomen are ‘vertical muscles’?

Answer 4

Rectus abdominus (superficial layer)
Pyramidalis (deep layer)

Question 5

What are the four layer of the abdominal wall? (External to internal)

Answer 5

Skin
Superficial fascia
Muscle and associate fascia
Parietal peritoneum

Question 6

What are the four main layers found in the GI tract?

Answer 6

Mucosal layer
Sub-mucosa
Muscularis propria
Adventitia

Question 7

What are the layers found within the mucosal layer?

Answer 7

-Surface epithelium
-Lamina propria
-Muscularis interna
(same lame muscles)

Question 8

What layer are found within the he muscular propria (a.k.a the Muscularis externa)?

Answer 8

-Inner circular muscle
- Outer longitudinal muscle
N.B in the stomach there is an extra middle oblique muscle layer

Question 9

Where are the plexus’ found in the GI wall?

Answer 9

The submuscosal plexus is found between the mucosa and the submuscosa
The myenteric plexus is found between the inner and outer muscle layers in the muscularis externa

Question 10

What is the function of protective mucosa in the GI tract and where is it found?

Answer 10

It has a protective function by reducing the friction as food passes along it.
It is found in the anal canal and oesophagus.
It is non-keratinised stratified squamous epithelium

Question 11

What is the function of absorptive mucosa in the GI tract and where is it found?

Answer 11

This absorbs nutrients and is made up of simple columnar epithelium.
This is found throughout the small and large intestine

Question 12

Describe the epithelial;I’m found specifically in the small intestine.

Answer 12

Simple columnar epithelium lines the long, finer-like villi projections.
The villi are separated by short glands (intestinal crypts) known as the crypts of leiberkuhn
The epithelium is renewed every four to five days, due to the proliferating stem cells found in the intestinal crypts

Question 13

What is the function of secretory mucosa in the GI tract and where is it found?

Answer 13

This mucosa secretes mucous to protect the epithelium from stomach acid.
- some cells also secrete acid and other enzymes to aid digestion
This is only found in the stomach
It has simple columnar epithelium arranged in long tubular glands, arranged closely together

Question 14

Where is the epiplopic foramen?

Answer 14

It is through the lesser omentum - and is the communication between the greater and lesser sacs of the abdomen.
The duodenum passes through this

Question 15

What is the arterial supply to the oesophagus?

Answer 15

Upper third - inferior thyroid artery
Middle third - aortic branches
Lower third - left gastric artery

Question 16

What is the venous drainage of the oesophagus?

Answer 16

Upper third - Inferior thyroid vein
Middle third - Azygos branches
Lower third - Left gastric vein

Question 17

What is the lymph drainage of the oesophagus?

Answer 17

Upper third - deep cervical lymph nodes
Middle third - mediastinal lymph nodes
Lower third - gastric lymph nodes

Question 18

Where does the oesophagus start?

Answer 18

At the cricoid cartilage, posterior to the trachea

Question 19

How far does the abdominal oesophagus extend, and where does it begin?

Answer 19

It starts at the diaphragm, and extends for 3cm before connecting to the stomach

Question 20

Where does swallowed air gather in the stomach?

Answer 20

The fundus

Question 21

Where is the angular notch?

Answer 21

At the base of the lesser curvature of the stomach

Question 22

What does the pylorus area of the stomach mostly produce?

Answer 22

Mucous

Question 23

What parts of the GI tract does the coeliac trunk supply?

Answer 23

The stomach and other parts of the foregut

• oesophagus
• liver
• duodenum
• pancreas
• greater omentum

Question 24

What are the three major branches of the abdominal aorta?

Answer 24

Coeliac (1st branch - foregut)
Superior mesenteric (2nd branch - midgut)
Inferior mesenteric (3rd branch - hindgut)

Question 25

What is the greater omentum?

Answer 25

A large fold of peritoneum that hangs free over the small intestine
It can help arrest inflammation and infection

Question 26

What is the peritoneal cavity?

Answer 26

It’s the cavity found between the parietal and visceral layer of the peritoneum

Question 27

What is the infrasonic compartment?

Answer 27

A compartment beneath the large intestine that contains the small intestine

Question 28

What are parabolic gutters?

Answer 28

They are spaces between the colon and the abdominal wall that allow the drainage/removal of infected fluid
They lead to the hepatorenal pouch

Question 29

What is the lesser sac?

Answer 29

The fold of peritoneum that lies behind the stomach

Question 30

What is the lesser omentum?

Answer 30

A fold between the stomach and the liver