Leucocytes - Circulatory System 2

Question 1

White blood cells

Answer 1

• Defence cells - defend body against microbes, foreign material, viruses and bacteria
• 1% of the blood volume

Question 2

What are the 3 types

Answer 2

• granulocytes
• lymphocytes
• monocytes

Question 3

Composition of leucocytes

Answer 3

GRANULOCYTES (70%):
- neutrophils
- eosinophils
- basophils
AGRANULOCYTES (30%):
- monocytes
- lymphocytes

Question 4

Granulocytes

Answer 4

• also known as polymorphonuclear leucocytes
• all contain a multi lobular nucleus and have granule in their cytoplasm - help digest invading microbes
• neutrophils, eosinophils and basophils - each named according to the stain or colour they absorb when stained with dyes.

Question 5

Neutrophils

Answer 5

• named after the ‘neutral’ dyes they take up when stained - purple colour
• 65% total cell count
• large numbers attracted to areas of infection by chemical substances released from the damaged cells (chemotaxins)
• this is a ‘chemotactic response’
• engulf and kill microbes by phagocytosis

Question 6

Eosinophils

Answer 6

• 2-5% total cell count
• stain red with eosinophils dye
• protect body from invasion by parasites
• neutralise histamine when released form mast cells as an example
• numbers increase in hypersensitivity reactions - try to modulate immediate reactions released such as histamine

Question 7

Basophils

Answer 7

• 1% of total cell count
• blue stain
• granules contain heparin - anticoagulant and histamine which aids immunity to the pathogen - triggered by an antigen, particular parasites
• similar to mast cells - associated with allergic reactions when enter tissues
• once activated produce cytokines

Question 8

What are the types of agranulocytes

Answer 8

lack specific granules in their cytoplasm
- monocytes
- lymphocytes

Question 9

Monocytes

Answer 9

• 2-8% of total white blood cells
• originate in bone marrow
• motile and phagocytic - become macrophages in tissues
• important in inflammation and immunity, present when the body fights off chronic infections
• when they encounter large amounts of foreign material, multiply at the site and ‘wall off’ the microbes

Question 10

Lymphocytes

Answer 10

• 25% of leucocytes
• have large nuclei
• circulate in blood all over the body
• types - B and T - natural killer cells
• large numbers in lymphatic tissue
• develop in bone marrow and the Thymus
• live in lymph nodes and bloodstream
• cells of immune system and fight infection