GI

Question 1

Which vitamins are fat soluble?

Answer 1

Vitamins A, D, E & K

Question 2

What substance is secreted by D cells?

Answer 2

Somatostatin

Question 3

Which vitamins are water soluble?

Answer 3

Vitamins B & C

Question 4

How are fat soluble vitamins absorbed?

Answer 4

Follow the pathway of fat absorption*

Question 5

How are water soluble vitamins absorbed?

Answer 5

By diffusion or mediated transport

Question 6

Where is vitamins C absorbed?

Answer 6

Jejunum

Question 7

Where are the B vitamins absorbed?

Answer 7

Ileum

Question 8

What does vitamin B12 require for absorption?

Answer 8

Intrinsic factor

Question 9

What is the role of vitamin A?

Answer 9

Vision (makes rhodopsin in rods cells of retina)
Reproduction (spermatogenesis, prevention of foetal reabsorption)
Growth
Stabilisation of cell membranes

Question 10

What is the role of B vitamins?

Answer 10

Involved in cell metabolism - mainly coenzymes

Question 11

What is the role of vitamin C?

Answer 11

Synthesis of collagen, NT, acts as antioxidant, aids non-heme iron absorption

Question 12

What is the role of vitamin D?

Answer 12

Enhances intestinal absorption of calcium, phosphate
Resorption and formation of bone
Reduced excretion of calcium

Question 13

What is the role of vitamin E?

Answer 13

Antioxidant

Question 14

What is the role of vitamin K?

Answer 14

It is needed for blood clotting (clotting factors 2, 7,9 and 10) & healthy bones

Question 15

What are the sources of vitamin A (Retinoids)?

Answer 15

Retinols:
Liver, Diary products, Oily fish
Carotenoids:
Carrots, tomato

Question 16

What are the sources of B vitamins?

Answer 16

Pulses
Beans
Grains
Potatoes 
Bananas

Question 17

What are the sources of vitamin C?

Answer 17

Fresh citrus fruits

Green veg

Question 18

What are the sources of vitamin D?

Answer 18

SUNLIGHT
Cheese (and some other diary products)
Egg yolks
Cereals
Fatty fish e.g. tuna or salmon

Question 19

What are the sources of vitamin E?

Answer 19

Sunflower seeds
Almond
Spinach
Safflower oil
(stored in non-adipose cells of liver and plasma and adipose cells)

Question 20

What are the sources of vitamin K?

Answer 20

K1:
Green leafy vegetables e.g. kale, spinach, turnip greens or Vegetables e.g. brussel sprouts, broccoli, cauliflower
K2:
Intestinal bacteria
Synthetic K3 or4

Question 21

What can happen if you are deficient in vitamin A?

Answer 21

May occur due to Fat malabsorption
Features: Night blindness, xerophthalmia, blindness
(rare in affluent countries as vit A levers only drop when liver stores are severely depleted)

Question 22

What can happen if you are deficient in B12?

Answer 22

Caused by:
Autoimmune destruction of parietal cells/IF-producing cells. Lack of stomach acid. Pancreatic disease. Small bowel disease. Veganism
Causes:
Macrocytic anaemia
Peripheral neuropathy in prolonged deficiency

Question 23

What can happen if you are deficient in vitamin C? (scurvy)

Answer 23

Easy bruising and bleeding
Teeth and gum disease
Hair loss

Question 24

What can happen if you are deficient in vitamin D?

Answer 24

Demineralisation of bone

e.g. Rickets in children, osteomalacia in adults

Question 25

What can happen if you are deficient in vitamin E and what are causes of this?* (Note vitamin E is relatively safe in excess)

Answer 25

Caused by: Fat malabsorption, Premature infants, rare congenital defects in fat metabolism Causes: Haemolytic anemia, Retinopathy, Ataxia (cerebellum problem), Neuropathy

Question 26

What can happen if you are deficient in vitamin K?

Answer 26

``` Haemorrhagic disease (of newborns) (Rare in adults, unless on warfarin) ```

Question 27

How is vitamin B12 absorbed?

Answer 27

(Aka Cobalamins) Released from food by acid in the stomach. Binds to R-protein to protect from stomach acid. Released from R-proteins by pancreatic polypeptide. Binds to intrinsic factor (IF) produced by parietal cells in stomach. IF-B12 complex absorbed in the terminal ileum. B12 stored in liver.

Question 28

What is folate?

Answer 28

Coenzyme in methylation reactions, DNA synthesis, synthesis of methionine from homocysteine. Found in foods with folic acid.

Question 29

What if have a folate deficiency?

Answer 29

Caused by: Malabsorption, drugs interfering with folic acid metabolism, disease that increase cell turnover Causes: High homocysteine levels Macrocytic anémia Foetal development abnormalities (neural tube defects)

Question 30

What if have a folate deficiency?

Answer 30

Caused by: Malabsorption, drugs interfering with folic acid metabolism, disease that increase cell turnover Causes: High homocysteine levels Macrocytic anemia Foetal development abnormalities (neural tube defects)

Question 31

What is secreted by Enterochromaffin (ECL) cells?

Answer 31

Histamine

Question 32

What is secreted by G cells?

Answer 32

Gastrin

Question 33

How do NSAIDs irritate stomach?

Answer 33

Inhibiting GI mucosal cycle-oxygenase (COX) activity. | *note that NSAIDs lead to production of prostaglandins

Question 34

How many layers of muscle are present in stomach wall?

Answer 34

3 Outer longitudinal Middle circular Inner oblique

Question 35

After prolonged reflux of acid, what is the change in cell type seen in lower oesophagus?

Answer 35

Stratified squamous to columnar | This is Barrett's Oesophagus

Question 36

What is the action of the proton pump of parietal cells?

Answer 36

K+ into cell, H+ out of cell

Question 37

How does Vagus nerve act on parietal cells?

Answer 37

Vagus nerve is part of the parasympathetic system and releases Each onto parietal cells...

Question 38

Where does Gall-Bladder drain into?

Answer 38

Duodenum

Question 39

Which blood vessel supplies most arterial blood to midgut (e.g. jejunum)?

Answer 39

Superior Mesenteric Artery

Question 40

What is the function of Omeprazole on GI tract?

Answer 40

Proton pump inhibitor Inhibits pump proton to reduce acid secretion. Helps treat symptoms of gastroesophageal reflux disease (GERD)

Question 41

Where is fat first acted upon by lipase enzymes when passing through the GI tract?

Answer 41

Oral cavity | Has lingual lipase

Question 42

What is present in Porta Hepatis?

Answer 42

``` Left and Right Hepatic Ducts Left and Right Hepatic Arteries Portal Vein Hepatic branch of Vagus nerve * ```

Question 43

What classifies the foregut?

Answer 43

Oesophagus to proximal 2 parts of duodenum (includes gallbladder and pancreas)