Lecture 17: Intro To Haemotology

Question 1

3 functions of blood

Answer 1

1. Transport
2. Regulation
3. Protection

Question 2

What does the blood transport

Answer 2

-nutrients and cellular components
-metabolic waste to elimination sites
-hormones to target organs

Question 3

What does the blood prevent

Answer 3

-infection from foreign bodies

Question 4

What does the blood regulate

Answer 4

-pH of body tissues
-BP
-fluid balance and circulation
-body temp

Question 5

How many litres of blood in an adult

Answer 5

4.5-5.5L

Question 6

What’s the pH of the blood

Answer 6

Slightly alkaline
7.35-7.45

Question 7

Fluid components of blood

Answer 7

90% water 10% solutes
- plasma proteins (albumin, fibrinogen, globulins

Question 8

Cellular components of blood

Answer 8

3 main:
1. Platelets
2. Leukocytes (WBC)
3. Erythrocytes (RBC)

Question 9

How much of the blood do erythrocytes compose

Answer 9

45%

Question 10

Avg life span of erythrocytes

Answer 10

120 days

Question 11

Are erythrocytes able to change shape

Answer 11

Yes- to facilitate movement

Question 12

Are erythrocytes true cells

Answer 12

No- anucleuated and no organelles

Question 13

Erythrocytes adaptations

Answer 13

• large sa:v
  -lots of haemoglobin
  -ATP generated by anaerobic mechanisms
  -able to deform yet spring back into shape

Question 14

How many HB molecules per erythrocyte

Answer 14

<250 million

Question 15

How are erythrocytes formed

Answer 15

Haematopoiesis

Question 16

Where does haemotopoiesis occur

Answer 16

Largely in red bone marrow (axial skeleton, girdles, proximal epiphysis of humerus and femur)

Question 17

How many erythrocytes produced each day

Answer 17

100 billion

Question 18

What does erythrocyte production depend on

Answer 18

Body needs and regulatory factors

Question 19

What are the steps in haematopoiesis

Answer 19

1. Stem cell (haemocytoblast)
2. Committed cell (proerythroblast)
3. Developmental pathway

Question 20

What are the 3 steps in the developmental pathway

Answer 20

Phase 1- ribosome synthesis
Phase 2- haemoglobin accumulation
Phase 3- ejection of nucleus

Question 21

Phase 1- ribosome synthesis

Answer 21

Basophilic erythroblast

Question 22

Phase 2- haemoglobin accumulation

Answer 22

Polychromatic erythroblast
Orthochromatic erythroblast

Question 23

Phase 3- ejection of the nucleus

Answer 23

Reticulocyte

Question 24

How do leukocytes leave the circulation

Answer 24

Via diapedesis

Question 25

How much of blood volume do leukocytes account for

Answer 25

<1% (4,800- 10,800 per microliter

Question 26

What 2 categories are leukocytes divided into

Answer 26

Granulocytes and agranulocytes

Question 27

What is categorised as granulocytes

Answer 27

- neutrophils (50-70%) - eosinophils (2-4%) - basophils (0.5-1%)

Question 28

What is categorised as agranulocytes

Answer 28

- lymphocytes (25-45%) - monocytes (3-8%)

Question 29

WBC functions

Answer 29

- protect against bacteria, viruses, toxins, tumour cells - leave circulation at inflammation sites - gather in large numbers due to chemotaxis and destroy foreign substances

Question 30

Neutrophil function

Answer 30

- destroy foreign antigens by phagocytosis - cytoplasmic granules released on lysis with a phagosome

Question 31

Eosinophil function

Answer 31

- parasite protection e.g. worms by releasing granules which digest them

Question 32

Basophil function

Answer 32

- histamine granules (potent vasodilator) to attract other leukocytes to site of infection

Question 33

Lymphocyte function

Answer 33

-immune response T- directly respond to tumour and virus infected cells B- produce specific AB against antigens

Question 34

Monocyte function

Answer 34

- activating lymphocytes in mounting the secondary immune response - those leaving the bloodstream become macrophages - destroy antigen and infected cells by phagocytosis

Question 35

How and where are leukocytes formed

Answer 35

Leukopoiesis in bone marrow of large bones

Question 36

Where do lymphocytes undergo additional maturation

Answer 36

In thymus to T and B lymphocytes

Question 37

Granulocytes life span

Answer 37

<9 days

Question 38

Lymphocytes life span

Answer 38

Hours-decades (memory cells)

Question 39

Monocytes life span

Answer 39

Several months

Question 40

How are platelet cell fragments formed

Answer 40

Budding off a megakaryocyte

Question 41

What do platelets contain

Answer 41

Ca2+ important in coagulation

Question 42

Platelet lifespan

Answer 42

10 days

Question 43

What is haemostasis

Answer 43

Multi step, localised process in stopping bleeding at site of vessel injury

Question 44

Haemostasis overview

Answer 44

Begins with formation of platelet plug, ends with formation of fibrin blood clot to prevent blood loss

Question 45

Coagulation cascade

Answer 45

Formation of a blood clot via the activation of ‘factors’, leading to fibrin formation and resulting clot

Question 46

How is coagulation cascade activated

Answer 46

1. Vessel damage and exposure to underlying tissues- contact or intrinsic pathway 2. Exposure to tissue factor via extrinsic pathway

Question 47

What do both the intrinsic and extrinsic pathway do

Answer 47

Converge to form the common coagulation cascade leading to fibrin clot formation

Question 48

Activation of what initiates the first step of the common pathway

Answer 48

Factor X

Question 49

Final common pathway

Answer 49

Factor X activated Xa which converts prothrombin (II) to thrombin (IIa) via Va Fibrinogen (I) converted to fibrin (Ia) then produces cross-linked fibrin clot via XIIIa