Circulatory System II Flashcards
What is a Leucocyte?
- defense cells
- largest of all blood cells
- 1% of the blood volume
What are the 3 main types of leucocytes?
- granulocytes
- lymphocytes
- monocytes
What is margination?
Leucocytes form a layer against the inner surface of capillary walls then migrate
What is migration?
- The cell pass through the capillary wall to reach and engulf infected tissue (i.e neutrophil)
- process occurs as chemical mediators are released by injured tissue to attract new WBC (chemotaxis)
What is chemotaxis?
Movement if a cell as a result of chemical stimulus
What percentage of leucocytes are granulocytes?
70%
What percentage of leucocytes are Agranulocytes?
30%
What cells fall under granulocytes?
- neutrophils
- eosinophils
- basophils
What cells fall under agranulocytes?
- moncytes
- lymphocytes
What is the general structure of granulocytes?
All contain multi lobular nucleus and have granules in their cytoplasm which help digest invading microbes
What is the function of neutrophils?
Majority of the cells phagocytose by surrounding and destroying bacteria/ fungus
- main function is to protect against foreign material entering the body
What is the function of eosinophils?
Responds if parasites enter the body, slightly phagocytose
- main function is to migrate out of blood to external environment, tissues form general immune and inflammatory response
What is the main function of a basophil?
Inc. in number after an allergic reaction, produce substances which aid inflammatory action
Describe the characteristics of a neutrophil?
- named after the natural dyes they take up when stained (purple colour)
- 65% total cell count
- engulf and kill microbes
Describe the characteristics of eosinophils?
- 2-5% of cell count
- stain red with eosin dye
Describe the characteristics of a basophil?
- 1% of total cell count, take up a blue stain
What is the difference between granulocytes and Agranulocytes?
Agranulocytes lack specific granules in their cytoplasm, unlike granulocytes
Where do monocytes originate from?
bone marrow
Describe the characteristics of a monocyte?
- 2-8% of the total leucocytes
- motile and phagocytic
- become macrophages in tissue
What is the function of a monocyte?
when they encounter large amounts of foreign material, they multiply at the site and ‘wall off’ microbes
Where do lymphocytes originate from?
bone marrow and the thymus
Where are lymphocytes found?
lymph nodes and in the blood stream
Describe the characteristics of a lymphocyte
- 25% of leucocytes
- have large nuclei
- large numbers in lymphatic tissue
What are the 2 types of lymphocytes?
T and B lymphocytes
