#32

Question 1

3 Functions of blood

Answer 1

Transport
Defence
Regulation

Question 2

What does blood contain?

Answer 2

plasma [aqueous matrix], cells, platelets and proteins

Question 3

What cells are in blood?

Answer 3

Red Blood Cells and White Blood Cells

Question 4

What does plasma consist of?

Answer 4

water, dissolved substances and proteins

Question 5

Why does plasma have high BCOP

Answer 5

because it has far more protein than other exracellular fluids

Question 6

Haematocrit

Answer 6

packed red blood cell volume

Question 7

Formed elements

Answer 7

cells or cell fragments found in blood which help carry out its varios functions

Question 8

What do platelets do?

Answer 8

Defence against fluid loss

Question 9

What does White Blood Cells do? (Leukocytes)

Answer 9

Defence ahainst pathogens and toxins

Question 10

What do red blood cells (erythrocytes) do?

Answer 10

Transport of dissolved gases and wastes

Question 11

What are notable features of RBCs?

Answer 11

bioconcave shape
lack of nucleus
lack of mitochondria
no other organelles

Question 12

Why are RBCs shaped like that?

Answer 12

for flexibility and stackability for flow

Question 13

Why do RBCs lack organelles?

Answer 13

more space for storage

Question 14

What is responsible for oxygen transport in mature RBCs?

Answer 14

protein haemoglobin

Question 15

What does each haemoglobin have?

Answer 15

4 globin chains, 4 haem units, 4 iron ions

Question 16

What can each haem and iron do?

Answer 16

carry 1 molecule of oxygen

Question 17

What happens to oxygen in the blood?

Answer 17

almost all oxygen is carried by haemoglobin and the rest is dissolved in plasma

Question 18

The carbonic acid-bicarbonate

Answer 18

critical buffer system that maintains the pH of human blood and bodily fluids within a narrow healhy range

Question 19

How does The carbonic acid-bicarbonate work?

Answer 19

When hydrogen ions increase, pH lowers, bicarbonate acts as a base to bind them forming carbonic acid. When pH is too high, carbonic acid releases hydrogen ions

Question 20

How does buffering against changes in pH happen?

Answer 20

• bicarnonate from blood and other body fluids binds to and buffer hydrogen generated from production of metabolic acids
• haemoglobin can bine a significant fraction of the hydrogren ions

Question 21

Haemostasis

Answer 21

physiological processes that limit/halt blood loss through damaged bloos vessels

Question 22

Serum

Answer 22

fluid that is left after blood clotting. contains water solute and blood proteins that are not related to clot formation

Question 23

Whole blood

Answer 23

contains specialized cell fragments, platelets and proteins that give it the bility to form clots

Question 24

Plasma

Answer 24

aqueous component of undistributed blood and contains protein clotting factors

Question 25

What's a major part of haemostasis?

Answer 25

clotting/coagulation

Question 26

Vascular phase of haemostasis

Answer 26

cells in the blood vessel wall undergo rapid changes - 1. contraction (vascular spasm) 2. increased endothelial 'stickiness'

Question 27

Platelet phase of haemostasis

Answer 27

platelets combine at exposed endothelial surfaces to plug the broken vessel - platelets attach to the sticky endothelial cells and basement membrane and become activated - activated platelets change shape and release chemicals that attract other platelets and help them stick to each other

Question 28

What part of blood clotting is a positive feedback loop?

Answer 28

platelet phase

Question 29

Coagulation phase on haemostasis

Answer 29

bibrin mesh netwrok forms around platelets producing a clot

Question 30

Fibrin

Answer 30

protein which binds aggregated platelets and blood cells into a clot

Question 31

What is the ultimate ffect of coagulation?

Answer 31

create strands of insoluble fibrin

Question 32

What is involved in the coagulation phase?

Answer 32

cascade of enzymes that catalyze the formation of fibrin from soluble fibrinogen

Question 33

What do platelets release when they stick to the collagen wall?

Answer 33

Release prothrombin activator (something produced in the liver and requires vitamin K)

Question 34

Thrombin

Answer 34

molecular scissors that cut protein. cuts fibronogen into fibrin

Question 35

Factor X

Answer 35

enzyme in blood coagulation cascade

Question 36

How is prothrombinase complex formation formed?

Answer 36

Activated Factor Xa along with cofactor FVa, calcium ions and platelet phospholipids form prothrombinase complex

Question 37

What does the prothrombinase complex do?

Answer 37

convert prothombin (Factor II) into active thrombin (Factor IIa)

Question 38

What does thrombin do to fibrinogen

Answer 38

converts fibrinogen (factor I) into insoluble fibrin (Factor Ia)

Question 39

Fibrinolysis

Answer 39

opposing process to coagulation that breaks down the fibrin clot to restore blood flow and prevent excessive clotting

Question 40

What does thrombin also activate?

Answer 40

Factor XIII TO XIIIa, with calcium it cross-links the fibrin polymers to form a stable, unsoluble fibrin mesh

Question 41

Tissue plasminogen activator

Answer 41

released from injured endothelial cells, tPA acts as an activator it binds to the fibrin clot and converts the inactive zymogen plasminogen in to the active enzyme plasmin

Question 42

Plasmin

Answer 42

primary protease responsible for degrading the fibrin networld into soluble fragments called fibrin degradation products or fibrin splot products