White blood cells – general characteristics. Types of white blood cells and their specific function.

Question 1

BASOPHIL STRUCTURE

Answer 1

• least common type of WBC = making only 1%
• large dark granules of histamine + heparin
• nucleus = bilobular
• lifespan = hours-days in bloodstream

Question 2

BASOPHILS FUNCTION 1

Answer 2

BLOOD CLOTTING

basophils release heparin (anticoagulant) + glycosaminoglycan

this it to prevent blood clotting by activity of antithrombin III

Question 3

BASOPHILS FUNCTION 2

Answer 3

INFLAMMATION

basophils release the histamines / leukotrines = inflammatory mediators

Question 4

BASOPHILS FUNCTION 3

Answer 4

ALLERGIES

basophils release the histamines

• increase vascular permeability
• increase smooth muscle contraction - blood flow to site of damage

Question 5

ESONPHIL STRUCTURE

Answer 5

• form 1-4% of WBC count
• red granules that stained with eosin
• bilobular nucleus
• life span = 10 hours in circulation

Question 6

ESONPHILS FUNCTION 1

Answer 6

PARASITIC INFECTIONS

eosinophils release eosinophils cationic protein + eosinophil perioxidase to kill helminth worms

Question 7

ESONPHILS FUNCTION 2

Answer 7

ASTHMA

more esonphils released during asthma

Question 8

ESONPHILS FUNCTION 3

Answer 8

TISSUE REPAIR + REMODELLING

eosinophils release growth factors + enzymes

Question 9

NEUTROPHILS - STRUCTURE

Answer 9

• make 40-70% of WBC count
• contain granules that stain lightly in dyes
• multi-lobed nucleus
• lifespan in blood is 8 hours

Question 10

NEUTROPHIL - FUNCTION 1

Answer 10

PHAGOCYTOSIS

Question 11

NEUTROPHIL - FUNCTION 2

Answer 11

REACTIVE OXYGEN SPECIES

neutrophils can produce H2O2 which kills bacteria

Question 12

NEUTROPHIL - FUNCTION 3

Answer 12

DEGRANULATION

neutrophils contain enzymatic granules (protease) released when encountering pathogen to clump/ kill

Question 13

NEUTROPHIL - FUNCTION 4

Answer 13

CHEMOTAXIS = response to chemical release

neutrophils travel rapidly to site of infection in response to chemical signal

Question 14

MONOCYTES - STRUCTURE

Answer 14

• 2-8% of total WBC
• largest WBC = lots of cytoplasm
• nucleus = x1 central
• lifespan = few days

Question 15

MONOCYTE - FUNCTION 1

Answer 15

DIFFERENTITATION

a) monocytes can differentiate into macrophages, eg alveolar macrophages in lungs/ kupffer cells in liver/ microglia cells in brain

b) monocytes can differentiate into dendrites
- antigen presentation onto T cells for adaptive immunity

Question 16

MONOCYTE - FUNCTION 2

Answer 16

INFLAMMATION

monocytes release pro-inflammatory cytokines to site of infection

• remove apoptotic cells
• remodel damaged tissue site

Question 17

LYMPHOCYTES

Answer 17

make up 30% of total WBC

shape = spherical

nucleus = spherical

life span = days-weeks

Question 18

B-LYMPHOCYTES

Answer 18

• come from bone marrow
• B cells produce antibodies which bind to antigens = neutralise them
• B memory cells = rapidly respond to same pathogen for next time

Question 19

T-LYMPHOCYTES - 1

Answer 19

originate from thymus

CD4+ helper T cells

• recruit other immune cells like cytokines to help amplify immune response

Question 20

T-LYMPHOCYTES - 2

Answer 20

CD8+ CYTOTOXIC T CELLS

• kill cancer cells by recognising the antigen (MHC + APC) mechanism

Question 21

T-LYMPHOCYTES - 3

Answer 21

REGULATORY CELLS

prevent autoimmune responses to maintain homeostasis

Question 22

NK CELLS

Answer 22

• do not need pathogen exposure to act
• part of innate immunity
• kill viruses/ tumour cells