Lecture 5 - Anatomy

Question 1

What are the four layers of the gut tube?

Answer 1

Mucosa
Submucosa
External muscle layers
Serosa

Question 2

Describe the layers of mucosa in the gut tube

Answer 2

• epithelial layer: promote absorption, hormones and mucus
• lamina propria: lymphoid nodules and macrophages and produces antibodies
• muscularis mucosae: smooth muscle in different function, keeps contents dynamic to prevent inflammation

Question 3

Describe the submucosal layer

Answer 3

Dense CT, blood vessels, glands

Contains submucosal plexus

Question 4

Describe the external muscle layers

Answer 4

Inner circular muscle
Outer longitudinal muscle
Myenteric plexus in between

Question 5

Describe the serosal layer

Answer 5

Blood, lymph and adipose

Continuous with mesenteries

Question 6

What is the epithelium in the oesophagus and distal anus?

Answer 6

Stratified squamous to resist frictional forces

Question 7

Which type of epithelium lines the rest of the GI tract?

Answer 7

Simple columnar (for secretion and absorption)

Question 8

What are the types of specialised cells in the GI tract?

Answer 8

Enterocyte
Goblet cell
Foveolar cells

Question 9

Describe enterocytes

Answer 9

Simple columnar epithelial cells for absorption
In SI and colon
Microvilli forms brush border

Question 10

Describe goblet cells

Answer 10

Between enterocytes

Mucus protects epithelia from friction, chemical damage and bacterial inflammation

Question 11

Describe foveolar cells

Answer 11

Secrete mucus/HCO3- that forms barrier to stomach acid

Question 12

What are the permanent folds of the small intestine called?

Answer 12

Plicae circulares

Question 13

What are the temporary folds of the stomach called and what are they needed for?

Answer 13

Rugae

Stomach needs to expand easily to prevent reflux into oesophagus

Question 14

What is the difference between villi and crypts?

Answer 14

Villi in SI, not colon

Crypts in both SI and LI

Question 15

Which cells do the crypts of Lieberkuhn contain?

Answer 15

Stem cells
Paneth cells
Enteroendocrine cells

Question 16

What is the function of the stem cells in the crypts?

Answer 16

Constantly divide every 2-4 days to replace epithelia

Question 17

What is the function of the paneth cells in the crypts?

Answer 17

Secrete antibacterial proteins to protect stem cells

Question 18

What is the function of the enteroendocrine cells in the crypts?

Answer 18

Secrete hormones that control gut function eg gastrin, CCK, secretin

Question 19

What are the three lateral muscles of the abdominal wall?

Answer 19

External oblique
Internal oblique
Transversus abdominus

Question 20

In what direction do the fibres of external oblique run?

Answer 20

Inferomedially

Question 21

What is the innervation of the external oblique muscles?

Answer 21

Ventral branches of lower six thoracoabdominal nerves and subcostal nerve on each side

Question 22

In what direction do the fibres of internal oblique run?

Answer 22

Superomedially

Question 23

What is the innervation of internal oblique?

Answer 23

Lower intercostal nerves

Question 24

What is the innervation of transversus abdominus?

Answer 24

Lower intercostal nerves (T7-T11)

Question 25

In the midline, the aponeuroses of all the flat muscles entwine and form what?

Answer 25

Linea alba

Question 26

What are the vertical muscles of the abdominal wall?

Answer 26

Rectus abdominus | Pyramidalis

Question 27

What innervates rectus abdominus?

Answer 27

Lower intercostal nerves

Question 28

What is the function of rectus abdominus?

Answer 28

Stabilises pelvis during walking and depresses ribs

Question 29

What does the lateral border of the two rectus abdominus muscles create?

Answer 29

Linea semilunaris

Question 30

What innervates the pyramidalis muscle?

Answer 30

Subcostal nerve

Question 31

What does the pyramidalis muscle do?

Answer 31

Tenses linea alba

Question 32

What is the rectus sheath?

Answer 32

Aponeuroses of lateral muscles surrounding rectus abdominus and pyramidalis

Question 33

What is the deep fascia around the abdomen called?

Answer 33

Transversalis fascia

Question 34

What forms the anterior wall of the rectus sheath?

Answer 34

Aponeuroses of external oblique and half of internal oblique

Question 35

What forms the posterior wall of the rectus sheath?

Answer 35

The other half of internal oblique and transversus abdominus

Question 36

What happens below the arcuate line?

Answer 36

Epigastric vessels pierce rectus abdominus | Rectus abdominus touches transversalis fascia

Question 37

What are the two definitions of peritoneal ligament?

Answer 37

- Double fold of peritoneum connecting 2 viscera together | - Double fold of peritoneum connecting viscera to abdominal wall

Question 38

What are the functions of sphincters?

Answer 38

Divide gut tube into sections Control movement of contents Prevent reflux of contents

Question 39

Name some sphincters in the GI tract

Answer 39

``` Upper and lower oesophageal sphincters Pyloric Sphincter of Oddi Ileo-coecal Anal sphincters ```

Question 40

Name the branch of the aorta supplying the foregut

Answer 40

Coeliac trunk

Question 41

Name the branch of the aorta supplying the midgut

Answer 41

Superior mesenteric artery

Question 42

Name the branch of the aorta supplying the hindgut

Answer 42

Inferior mesenteric artery