GI

Question 0

What is the name of the ring of lymphoid tissue formed by tonsils at gut tube entrance?

Answer 0

Waldeyer’s ring

Question 1

Where are Paneth cells found and what is their function?

Answer 1

In crypts of lieberkuhn in GALT - synthesise defensins (antimicrobials) and trefoil factors (acid barrier repair)

Question 2

What are Peyer’s patches?

Answer 2

Equivalent of lymph nodes in gut wall of s.i.

Question 3

What are M cells?

Answer 3

Microfold cells in gut epithelium that undertake transcytosis.

Question 4

What is IPEX?

Answer 4

Immune polyendocrinopathy enteropathy x-linked disease (rare) - dysfunction of regulators of Treg cells.

Question 5

Name 4 metabolic actions of colonic bacteria

Answer 5

Ferment CHO (salvage energy), hydrolyse urea (salvage nitrogen), salvage SCFAs (enhance Na and water absorption) and synthesis Vit K and B

Question 6

What is the name of the serious strain of H.Pylori?

Answer 6

CagA

Question 7

Name 3 substances that reduce appetite.

Answer 7

CCK, Insulin, Glucagon

Question 8

Name four substances that increase appetite.

Answer 8

Neuropeptide Y, NA, Insulin, and Ghrelin

Question 9

What is the mechanism behind intrahepatic jaundice?

Answer 9

Cells lining bile ducts swell -> obstruction -> salts absorbed in gall bladder -> concentrates bile

Question 10

What stimulates CCK secretion, and what action does CCK have?

Answer 10

Food in duodenum

Gall bladder contraction and enzyme secretion from pancreas

Question 11

What enzyme does bile acid inhibit in a negative feedback loop?

Answer 11

7a-hydroxylase

Question 12

What is the definition of cirrhosis?

Answer 12

Nodules of hepatocytes are separated by bands of fibrous tissue

Question 13

What is a Kupffer cell?

Answer 13

Resident macrophage of the sinusoid

Question 14

What does secretin lead to?

Answer 14

Salt and water secretion

Question 15

What are 4 things that stellate cells in the sinusoids do?

What happens if they are fibrosed?

Answer 15

Produce collagen and other matrix proteins, store Vit A, control vascular tone, secrete cytokines
Fibrosis leads to increased resistance to flow, so vascular shunts form to bypass normal sinusoidal circulation

Question 16

What are the four types of jaundice?

Answer 16

Haemolytic, hepatocellular (decreased ability to metabolise and/or excrete bilirubin), neonatal, obstructive

Question 17

Raised levels of what substance indicate blocked bile ducts?

Answer 17

Alkaline phosphate

Question 18

What is sitosterolaemia?

Answer 18

Hyperabsorption and decreased biliary excretion of sterols leads to hypercholesterolaemia and atherosclerosis.
Rare autosomal recessive

Question 19

Give 3 things that increase iron uptake and 5 things that decrease uptake.

Answer 19

Increase - acid, sugars, AAs

Decrease - alkali, phosphate, phytates (in food), tannates (in tea) and fibre

Question 20

What is Menke’s disease?

Answer 20

Decreased activity of Menke’s ATPase leads to copper accumulation. This leads to mental retardation and growth failure

Question 21

What is Wilson’s disease?

Answer 21

Autosomal recessive, inability to excrete copper to bile leading to copper accumulation -> liver failure and a ‘Kayser-Fleischer ring’ in cornea

Question 22

Which types of hepatitis lead to a) chronic and b) acute disease?

Answer 22

Chronic - A,BC,E

Acute - B,C,D

Question 23

Which of the shapes of hep B virus contains the genome?

Answer 23

Doughnuts (Dane’s)

Question 24

What does 2,3-DPG do?

Answer 24

Binds between b chains of Hb to reduce affinity for O2 and allow O2 release to tissues

Question 25

Where is erythropoietin produced and what stimulates its release?

Answer 25

Kidneys, stimulated by reduced O2 supply to kidney receptors

Question 26

What is the disease whereupon a foetus dies due to incredibly severe thalassaemia?

Answer 26

Hydrops fetalis

Question 27

Name four instances of necrosis which are therefore common sites of calcium deposition

Answer 27

Atherosclerosis (necrotic core), cancer (necrotic areas of tumour), infarcts, tuberculous lesions (caseous necrosis)

Question 28

What is the medical term for fatty change?

Answer 28

Steatosis

Question 29

What is haemosiderin?

Answer 29

An iron pigment with a golden brown colour that can be deposited

Question 30

Where does amyloidosis occur?

Answer 30

Outside cells within the ECM

Question 31

Name 4 essential AAs

Answer 31

Phenylalanine Valine Leucine Methionine

Question 32

Name 3 non-essential AAs

Answer 32

Alanine, Glutamine Glycine

Question 33

What is the AA precursor to serotonin?

Answer 33

Tryptophan

Question 34

What 4 neurotransmitters is tyrosine a precursor for?

Answer 34

Dopamine Thyroxine NA Adrenaline

Question 35

How many fatty acids can one molecule of albumin carry?

Answer 35

7

Question 36

Which protein tags intracellular proteins targeted for destruction?

Answer 36

Ubiquitin

Question 37

Why does human papilloma virus (HPV) lead to cervical cancer?

Answer 37

HPV encodes a protein that activates an E3 enzyme which ubiquinates tumour suppressor proteins and other DNA repair proteins so they are destroyed in the proteosome.

Question 38

What is it called if the gut tube develops outside the body?

Answer 38

Omphalocele

Question 40

What are the two drugs most commonly used to treat parasites?

Answer 40

Piperazine and Mebendazole

Question 41

What pathology does entamoeba histolytica parasite lead to?

Answer 41

Ulcers (bloody diarrhoea/dysentery) -> peritonitis

Question 42

Name 3 geohelminths

Answer 42

Ascaris Hookworms Strongyloides Stercoralis - 'Threadworm'

Question 43

What three areas of medications can lead to diarrhoea?

Answer 43

Cholinergics, cytotoxic agents, broad spectrum ABs (change in gut flora)

Question 44

Which proteins instruct T cells to go to certain parts of the body?

Answer 44

Integrins

Question 49

What is the proper name for parasites?

Answer 49

Trophozoites

Question 50

How long does chyme take to move through the small intestine?

Answer 50

3-5 hours

Question 51

What are Migrating Myoelectric Complexes (MMCs)? And what are they initiate by?

Answer 51

Bursts of intense activity from stomach to terminal ileum around every 90mins which keep the tract clear of debris. Initiation involves motilin hormone (secreted by duodenum in response to HCO3-)

Question 52

In the stomach what do chief cells secrete?

Answer 52

Pepsinogen ( -> pepsin)

Question 53

Name 4 things that protect the gut from damage from low pH

Answer 53

Mucus HCO3- secretion High epithelial blood flow (wash acid away) High epithelial cell turnover rate

Question 54

What is the physiological response if there is an excess of stomach acid?

Answer 54

Stimulates D cells to release somatostatin which inhibits gastrin secretion which inhibits acid secretion.

Question 55

Name 4 things that Brunner's glands in the duodenum secrete

Answer 55

Mucus, pepsinogen II, epidermal growth factor (EGF) and bicarbonate

Question 56

Which are the main 4 pancreatic proteases?

Answer 56

Trypsin, Chymotrypsin, Carboxypeptidases A and B and Elastase

Question 57

What two molecules is sucrose made up of?

Answer 57

Glucose and fructose

Question 58

Which enzyme breaks down maltriose into three individual glucose units?

Answer 58

Glucamylase

Question 59

Which is the only carbohydrate enzyme that is not stimulated by large intake (there is a limited amount)?

Answer 59

Lactase

Question 60

What are the functions of each of Vits A, D, E and K?

Answer 60

A- retinal pigments and epithelial cell growth D - Ca metabolism E - antioxidant K - clotting factor synthesis

Question 61

What effect do Aldosterone and Angiotensin II have on gut absorption?

Answer 61

Increase absorption

Question 62

What effect does histamine have on gut absorption and secretion?

Answer 62

Increase secretion, decrease absorption

Question 63

Which lipid in gut cell membranes does the cholera toxin recognise so it can enter the cell?

Answer 63

Ganglioside GM1

Question 64

Though Crohn's can affect the entire GI tract, which part does it classically involve?

Answer 64

Terminal ileum

Question 65

Name 4 pathological features of Ulcerative Colitis

Answer 65

Superficial mucosal ulceration, pseudopolyps, Loss of mucosal folds Inflammation

Question 66

Name 4 pathological features of Crohn's

Answer 66

Deep ulceration Bowel wall thickening Abnormal serosa (fat wrapping) Transmural inflammation

Question 67

Other than risk of malignancy, what is the main possible complication of UC?

Answer 67

Toxin megacolon (-> rupture)

Question 68

Other than risk of malignancy, what are three potential complications of Crohn's?

Answer 68

Fistula, abscess/sinus formation, bowel obstruction,

Question 69

Name the 6 constituents of bile

Answer 69

``` Bile acids Phospholipids Cholesterol Bile pigments Proteins Inorganic ions ```

Question 70

What are 8 functions of bile acids

Answer 70

Emulsify fats etc Stimulate colonic motility Stimulate phospholipid secretion Aid absorption of fat soluble vitamins Inhibit 7a-hydroxylase so have negative feedback on their own synthesis Promote bile flow Help to solubilise cholesterol by forming micelles Inhibit salt and water reabsorption in the colon

Question 71

What are 4 deficiencies that can occur from protracted vomiting?

Answer 71

Hypochloraemia -> metabolic alkalosis (loss of gastric acid) Hypovolaemia Hypokalaemia Hyponatraemia

Question 72

Name four hereditary causes of haemolytic anaemias

Answer 72

Hereditary spherocytosis Hereditary elliptocytosis G6PD deficiency Sickle cell disease

Question 73

What is pancytopenia?

Answer 73

A problem with with whole blood system due to bone marrow failure and infiltration (malignancies / drugs)

Question 74

Name the 5 viruses that cause gastroenteritis

Answer 74

``` Rotavirus, Enteric Adenovirus Astrovirus Sapovirus Norovirus ```

Question 75

What are four possible complications of GORD?

Answer 75

Oesophageal ulcer Haematemesis Stricture Barrett's oesophagus -> cancer

Question 76

Which gene deficit of associated with Crohn's and what does it lead to?

Answer 76

NOD2 | Leads to an increased response to normal flora

Question 77

What is Zollinger-Ellison syndrome?

Answer 77

A gastrin-secreting tumour that increases acid secretion