Physiology GI Book

Question 1

Components of gallstones

Answer 1

Mixed most common- cholesterol, bile pigments and calcium

Cholesterol stones- pure

Pigments- calcium bilirubinate

Question 2

How much bile is produced in 1 day

Answer 2

1L

Question 3

Drugs that induce CYP450

Answer 3

Anticonvulsants: phenytoin, carbamazepine, phenobarbitone. Steroids: dexamethasone, prednisolone, glucocorticoids. Antibiotics: rifampicin

Omeprazole and amiodarone

Question 4

Different cells within the stomach and their function

Answer 4

Chief- pepsinogen in fundus
Parietal- gastric acid and intrinsic factor
Endocrine G cell- gastrin
Goblet cells - mucous
D cells- somatostatin

Question 5

Which cells in stomach contain HK ATPase transporter

Answer 5

Parietal cells

Question 6

Where are G cells located

Answer 6

Stomach
Duodenum
Pancreas

Question 7

How are G cells stimulated, inhibited and function

Answer 7

Stimulated by stomach distention, vagus nerve and partially digested proteins in duodenum

Inhibited by acid in duodenum

Function- to stimulate gastric acid

Question 8

What inhibits gastric acid secretion

Answer 8

Secretin, cholecystokinin and somatostatin

Question 9

How much gastric acid is produced in 1 day

Answer 9

1-1.5L

Question 10

Classification of severe pancreatitis

Answer 10

P- PaO2 <8
A- age >55
N- neutrophils >15
C- Corrected Ca <2
R- renal urea >16
E- enzymes AST/ALT >200
A- albumin <32
S- sugar >10

Question 11

How much salvia is produced in 1 day

Answer 11

800-1500ml

Question 12

pH of saliva

Answer 12

6-7- for enzyme ptyalin (type of amylase)

Question 13

Composition of oxyntic gland

Answer 13

Mucosal cells
Chief cells
Parietal - have cannaliculi

Question 14

Pyloric stenosis biochemistry

Answer 14

Hypokolaemic hypocholaemia alkalosis

Question 15

What is unconjugated bilirubin bound by in the blood and what does it bond with to become conjugated

Answer 15

Albumin

Glucuronic acid

Question 16

Why does cholestatic jaundice present with certain symptoms

Answer 16

Conjugated bilirubin leaks into blood- causing dark urine

Pale stools- no conjugated bilirubin secreted into GI tract

Bile salts leak into blood- causing pruritus

Question 17

What is absorbed, secreted and synthesised in colon

Answer 17

Net absorption water and Na
Net secretion of K and HCO3
Indirect role of synthesis of vit K and B by bacteria

Question 18

Effects of pancreatic tumour resection

Answer 18

Loss of protyletic and lipolytic enzymes- leading to poor digestion of protein and fat
Weight loss and poor absoption of ADEK
Loss of alkaline secretion- failure to neutralise gastric chyme- malabsorption of Ca, Fe and PO4- causing anaemia and osteoporosis

Question 19

Movements in small intestine

Answer 19

Segmentation- main- 9-12 per min
Back and forth
Frequency decreases further down
Paced by depolarisation- slow waves- para increasing activity
(large bowel 3-4 per min)

Peristalsis
Much weaker here than oesophagus or stomach
Stimulated by stretch reflex and serotonin

Question 20

Phases of swallowing

Answer 20

Oral- voluntary
Pharyngeal- shortest, involuntary
Oesophageal - involuntary- lower sphincter pressure 15mmHg§

Question 21

Function and location of cholecystokinin secretion

Answer 21

SI
Increase intestinal motility, contraction o gallbladder, stimulation of pancreatic enzyme release
Inhibits gastric motility and secretion

Question 22

Function and location of secretin secretion

Answer 22

SI
Stimulates water and bicarb secretion in panc
Enhances cholecystokinin
Inhibits gastric motility and secretion

Question 23

Function and location of GLP1 secretion

Answer 23

Ileum and colon
Inhibits gastric motility and secretion
Stimulates secretion of insulin

Question 24

Function and location of guanylin secretion

Answer 24

Ileum and colon
Stimulates intestinal secretion of CL

Question 25

Exocrine cells of pancreas

Answer 25

Acinar- respond to cholecystokinin and Act and release enzymes and CL
Duct- respond to secretin and release HCO3 rich fluid

Ratio of enzymes depends of diet

Question 26

How much bile is produced and secreted in 1 day

Answer 26

250-1500ml

Question 27

pH pepsin works best at

Answer 27

2-3

Question 28

Myenteric plexus function

Answer 28

Also known as Auerbach
Stimulation increases tonic contractions and rapid movements due to peristaltic wave

Question 29

Cranial nerves involved in swallowing

Answer 29

Oral
Trigeminal- mastication and sensation to ant 2/3 tongue
Hypoglossal- tongue movements
Facial- post 1/3 tongue, motor lips, cheek and stylohyoid

Pharyngeal
Glossopharyngeal- sensory to soft palate, post tongue and upper pharynx, motor to stylopharyngess and superior constrictor, salivary
Trigeminal, glosso, vagus (motor to palatoglossus, cricophayngeus, intrinsic muscles of larynx)- autonomic motor

Oesophageal
Sensation- X
Motor- V, IX, X

Question 30

Rate of peristalsis in oesophagus

Answer 30

5cm/sec

Question 31

Metabolic complications of parenteral nutrition

Answer 31

Hyperglycaemia/hypo
Hyperlipidaemia
Essential FA def
Hypercholaemic metabolic acidosis
Hyperammonaemia

Question 32

Vit K is used to make which clotting factors

Answer 32

Factors- 2, 7,9, 10, C

Question 33

What stimulates gastric acid production

Answer 33

Vagus nerve
Histamine - inhibited by nausea