Session 2: Setting The Scene - Physiology

Question 1

What neurotransmitter do all preganglionic fibres of the ANS release?

Answer 1

Acetyl choline

Question 2

Overall what sort of effect does the sympathetic nervous system have on the gut?

Answer 2

Negative - reduces blood flow to it

Question 3

Which thoracic nerves form the greater splanchnic nerve?

Answer 3

T5-T9

Question 4

Which thoracic nerves form the lesser splanchnic nerve?

Answer 4

T10-T11

Question 5

What thoracic nerve forms the least splanchnic nerve?

Answer 5

T12

Question 6

What nerve supplies innervation to the hindgut?

Answer 6

Least splanchnic nerve

Question 7

Where does the lesser splanchnic nerve supply?

Answer 7

Midgut

Question 8

Which nerve supplies the foregut?

Answer 8

Greater splanchnic nerve

Question 9

Which of the vagus nerves is anterior?

Answer 9

Left vagal nerve

Question 10

Which nerves provide parasympathetic innervation to the gut?

Answer 10

Vagus nerve

Pelvic splanchnic nerves (S2-S4)

Question 11

Give two peptides that the parasympathetic fibres of the GI system release

Answer 11

Gastrin releasing peptide

Vaso-inhibitory peptide

Question 12

Which division of the ANS does the pelvic splanchnic nerve come under?

Answer 12

Parasympathetic

Question 13

Where is Meissner’s plexus located?

Answer 13

Submucosa of the GI tract

Question 14

What is Meissner’s plexus responsible for?

Answer 14

Control of secretions and blood flow

Question 15

Where is Auerbach’s (the myenteric) plexus located?

Answer 15

Between the circular and longitudinal muscle of the GI tract

Question 16

What is Auerbach’s plexus responsible for?

Answer 16

Maintaining motility in the GI tract (muscular action)

Question 17

What cells in the gut secrete histamine?

Answer 17

Enterochromaffin Like Cells (ECL cells)

Question 18

What two categories are the gastrointestinal hormones broadly split into?

Answer 18

Gastrin family

Secretin family

Question 19

Where is gastrin released from?

Answer 19

G cells in the antrum of the stomach

Question 20

Where is CCK released from?

Answer 20

I cells in the duodenum and jejunum

Question 21

What is gastrins main function?

Answer 21

Increasing gastric acid secretion

Question 22

What is the main function of CCK?

Answer 22

Increase pancreatic and gallbladder secretions

Question 23

What is the main function of secretin?

Answer 23

Help neutralise acidic chyme (increases release of HCO3 and decreases gastric acid secretion)

Question 24

Where is secretin released from?

Answer 24

S cells in the duodenum

Question 25

Where is gastric inhibitory polypeptide (GIP) released from?

Answer 25

K cells in the duodenum and jejunum

Question 26

What stimulates release of GIP?

Answer 26

Sugars, amino acids and fatty acids

Question 27

What does GIP cause?

Answer 27

Increased insulin secretion and decreased gastric acid secretion

Question 28

Why does appendicitis initially present with vague central abdominal pain?

Answer 28

Visceral peritoneum is affected which causes the afferent to be sent back and chase the lesser splanchnic nerve, giving pain in the T10-T11 dermatomes

Question 29

Why will appendicitis pain eventually progress to be sharp and in the right iliac fossa?

Answer 29

Parietal peritoneum becomes involved which has a somatic innervation

Question 30

Where will foregut structures present with pain initially?

Answer 30

Epigastric region

Question 31

Where will midgut structures initially present with pain?

Answer 31

Periumbilical

Question 32

Where will hindgut structures initially present with pain?

Answer 32

Suprapubic/hypogastric

Question 33

In which three areas of the GI tract is there not smooth muscle?

Answer 33

Pharynx Upper 1/3 of the oesophagus External anal sphincter

Question 34

In which part of the GI tract are both the outer longitudinal and inner circular muscles complete?

Answer 34

The small intestine

Question 35

Where are tonic contractions used?

Answer 35

Upper stomach Ileocaecal valve Internal anal sphincter

Question 36

Where in the GI tract does mass movement occur?

Answer 36

Distal colon

Question 37

What is a paralytic ileus?

Answer 37

Functional obstruction due to loss of GI contractility

Question 38

What is achalasia?

Answer 38

Failure of relaxation of the lower oesophageal sphincter

Question 39

What is Hirschsprung's disease?

Answer 39

Lack of development of the myenteric and submucosal plexuses

Question 40

Give four functions of mucus

Answer 40

Protection against acid Antibacterial properties Harbouring of bacteria in the large intestine Lubrication

Question 41

In which part of the small intestine are Brunner's glands found?

Answer 41

Duodenum