Karl Kingston

Question 1

How much calcium is in blood

Answer 1

10mg/dL

Question 2

What are the forms of calcium in blood, what % do they account for, what is their concentration
3

Answer 2

Protein bound- 41%
1mmol/L

Ionised- 50%
1.2mmol/L

Complexed- 9%
0.2mmol/L

Question 3

What is the average calcium intake a day
How much calcium is absorbed a day from gut
How much calcium is secreted into duct per day
How much calcium is lost in feces per day

Answer 3

1000mg /day
350mg/day
250mg/day
9000mg/day

Question 4

How much calcium is deposited into and absorbed from bone each day

Answer 4

500mg/day

Question 5

What is normal blood calcium concentration

Answer 5

1.2mmol/L

Question 6

What happens when blood calcium level rises

5

Answer 6

Blood calcium rises above 2.25mmol/L
Thyroid gland releases calciforin
Calciforin surpresses reabsorbtion of calcium in bone
Calciforin increases excretion of calcium from kidneys in urine
Calciforin decreases conversion of 25 hydroxyl D3 to 1.25 hydroxyl D3 in kidneys

Question 7

What happens when blood calcium falls

4

Answer 7

Parathyroid secretes parathyroid hormone
PTH stimulates bone resorbtion
PTH stimulates renal reabsorbtion of calcium
PTH stimulates conversion of 25 hydroxyl D3 to 1.25 hydroxyl D3 which promotes calcium absorption in intestine

Question 8

What is the flow of vitamin D into and within the body

Answer 8

Vitamin D synthesised in skin from sunlight and passed to liver
Vitamin D from diet absorbed in intestine and passed to liver
In liver D3 converted to 25 hydroxyl D3 and passed to kidneys
In kidneys PTH received from parathyroid and 25 hydroxyl D3 converted to 1.25 hydroxyl D3
1.25 hydroxyl D3
1.25 hydroxyl D3 increases bone resorbtion and travels to intestine

Question 9

What is the action of vitamin D in the gut

In bone

In parathyroid gland

Answer 9

Stimulates transepithelial transport of calcium and phosphate into duodenum

Stimulates differentiation of osteoclasts which mobilise calcium

Inhibits transcription of PTH

Question 10

What age does skeletal mass peak

Answer 10

30 years

Question 11

What is the interaction between osteoblasts, osteoclasts and osteoprotegrin

Answer 11

Osteoblasts release osteoprotegrin
OPG binds to RANKL receptors on osteoblasts to prevent it binding to RANK on osteoclasts
RANK on osteoclasts complementary to RANKL on osteoblasts

Question 12

What is hypocalcemia

What is hypercalcemia

What is hyperparathyroidism

What is hypoparathyroidism

Answer 12

Low calcium in blood

High calcium in blood

High PTH in blood leading to bone weakness through loss of calcium

Low PTH leading to lack of calcium causing muscle spasm

Question 13

Define heamostasis

Define thrombosis

Define coagulation

Define fibrinolysis

Answer 13

Stopping of bleeding

Formation of blood clot within circulatory system

Process of blood forming solid clot

The enzymatic breakdown of fibrin in blood clots turning them to liquid

Question 14

What are the phases of haemostasis

5

Answer 14

Vascular phase
Platelet plug
Clot formation 
Clot retraction 
Fibrinolysis

Question 15

What happens during vascular phase of haemostasis

Answer 15

Vasoconstriction of vascular smooth muscle to limit blood loss and reduce blood flow

Question 16

How is the platelet plug formed

Answer 16

Collagen of ECM exposed
Von willebrand factor adheres to collagen and attracts platelets
Platelets bond to VWF and each other
Platelets release ADP, thromboxane a2, thrombin and serotonin to attract more platelets and assist vasoconstriction

Question 17

How does aspirin prevent platelet plug formation

Answer 17

Inhibits enzyme that makes thromboxane a2

Question 18

What is the intrinsic pathway of clot formation

Answer 18

Blood exposed to sub endothelial surfaces
Prekallikrien converted to kallikrien
Cascade reaction activates factor 9
Factor 8a is the cofactor for factor 9a

Question 19

What is the extrinsic pathway of clot formation

Answer 19

Tissue factor is released during injury from smooth muscle sup endothelial cells
Thrombin activates factor 7
TF acts as cofactor for 7a

Question 20

What is the common pathway of clot formation

Answer 20

Factor 9a with cofactor 8a from intrinsic pathway or factor 7a with tissue factor cofactor from extrinsic pathway activates factor 10 into 10a
10a with 5a converts prothrombin to thrombin
Thrombin converts fibrinogen to fibrin forming clot

Question 21

What happens during fibrinolysis

Answer 21

Plasminogen in clot converted to plasmin by tissue plasminogen activator and urokinase
Plasmin breaks down fibrin in clot to fibrin degradation products
Clot liquifies

Question 22

What is the interaction of warfarin and vitamin K

Answer 22

Warfarin is a competitive antagonist of vitamin K so k can’t be used to form clotting factors thus increasing INR

Question 23

What are the symptoms of haemophilia
3

What is the treatment of haemophilia
2

Answer 23

Frequent severe bleeding
Bleeding in joints
Intracranial bleeding

Replacement protein factors
Gene therapy

Question 24

What happens in people with haemophilia A

What is the genetics of haemophilia A

Answer 24

Lack of factor 8 leads to failure of intrinsic pathway as factor 8 needed as a cofactor for 9a to activate factor 10 in final pathway

Recessive X linked disease mostly found in males of a family

Question 25

What happens in haemophilia B

What is it’s genetics

Answer 25

Defected factor 9 compromises cascade reaction in intrinsic pathway

X linked recessive

Question 26

What % account for haemophilia A and B

Answer 26

80% A

20% B

Question 27

What happens in Von willebrands disease

What is the genetics

What is it’s prevalance

Answer 27

Lack of vWf compromises platelet adhesion to collagen leading to excessive bruising and bleeding gums

Autosomal dominant

1-2% of population