Blood 2 Flashcards
What are the three major mechanisms of defense?
- Protective surfaces
- Innate immune system
- Adaptive immune system
What are the functions of protective surfaces?
- Secrete antibacterial substance (lysozyme)
- Have acidic pH that inhibits growth of pathogens
What are the protective surfaces?
• Skin • Mucosal linings - Gastrointestinal tract - Respiratory tract - Urinary tract - Reproductive tract
What is the function of innate immune cells
- Complement protein & peptides in blood/tissue
- Beat trivial infections
NB! What are the innate immune cells in blood/tissue? (6)
(1) Neutrophils
(2) Eosinophils
(3) Basophils
(4) M’cyte/Macrophage
(5) Mast cells
(6) Natural killer cells
What are adaptive immune cells?
Cells with ability to learn i.e. subsequent infections produce greater response
What are two adaptive immune cells?
- T lymphocytes (T cells)
- B lymphocytes (B cells)
What is the response of T lymphocytes?
Cellular response
What is the response of B lymphocytes?
Humoral response
What do T cells interact with?
APCs (macrophage & dendritic cells)
What is involved in B cells?
- Involves production of antibodies by B cells
What are the components of blood?
- Red blood cells (erythrocytes)
- Platelets
- White blood cells (leukocytes)
- Plasma
What are white blood cells composed of?
- Granulocytes (neutrophils, eosinophils, basophils)
- Agranulocytes (lymphocytes, monocytes)
What is the function of phagocytosis?
- To acquire nutrients
- To remove pathogens & cell debris
What are the steps in phagocytosis?
- Engulf by endocytosis
- Form an internal phagosome
- Delivered & fusion with lysosome
- Degraded in lysosome
- Released via exocytosis
What are the three types of leukocytes (granulocytes)?
- Neutrophil
- Eosinophil
- Basophil
What is the diameter of neutrophils?
10-12µm
What is the diameter of eosinophils?
10-14µm
What is the diameter of basophils?
8-10µm
What is the % of WBCs of neutrophils?
60-70%
What is the % of WBCs of eosinophils?
1-5%
What is the % of WBCs of basophils?
1-5%
What is the primary function of neutrophils?
1st to encounter pathogens
What is the primary function of eosinophils?
Attack parasites e.g. worms
What is the primary function of basophils?
Release heparin, elastase
What is the nucleus of neutrophils composed of?
Composed of 2-5 lobes
What are 3 functions of neutrophils?
- Acute inflammation
- First line of defence during infection
- Phagocytic activity
What do primary neutrophils contain?
Contain antibacterial and digestive enzymes (eg myeloperoxidase) involved in destruction of invading organisms
What do secondary neutrophils contain?
Contain lyzozymes; involved in phagocytosis
What do tertiary neutrophils contain?
Contain gelatinase; granules involved in insertion of glycoproteins into cell membrane for cellular adhesion
What is the type of nucleus in eosinophils?
Bilobed nucleus
Where do eosinophils enter?
Enter mucosal surfaces of respiratory, lower urinary
and GI tracts
When are eosinophils increased?
Increased in parasitic allergic disease
What do eosinophils phagocytose?
Phagocytose IgE opsonised parasites
How do eosinophils kill?
By granule release
What are the characteristics of basophils?
Large granules (basophilic, dark blue staining & bilobed nucleus
What are basophils similar to?
Mast cells
What do basophils contain?
Histamine
What is the function of histamine?
Dilates blood vessels (inflammation-redness)
When are basophils increased?
In parasitic/allergic disease
What do basophils exocytose? (and via what?)
Exocytose granules (histamine) via contact with IgE complexed allergen
What % of WBC are lymphocytes?
20%
What do lymphocytes cooperate with?
With antigen presenting cells (APCs)
What are two types of lymphocytes?
B-lymphocytes (B cells)
T-lymphocytes (T cells)
What is the function of B-lymphocytes?
Antibody production (plasma cells) antigen presentation
What is the function of T-lymphocytes?
- Priming of innate responses (T-helper 1, TH1)
- Priming of antibody responses (T-helper 2, TH2)
- Direct cell lysis (cytotoxic T’s)
What % of WBC are monocytes?
5%
What are monocytes attracted by?
- Histamine
- Cytokines
Birth etc of monocytes
Emerge from bone marrow while immature; 1-2 days later mature into macrophages
How long do macrophages last?
For months
What do macrophages do before they die?
Digest 100’s bacteria before they die
What do macrophages present?
Present pathogen antigens at cell surface
Where are fixed macrophages stationed?
At strategic points
What are the types of fixed macrophages?
- Dust/Alveolar type (lungs)
- Histiocytes (connective tissue)
- Kupffer cells (liver)
- Microglial cells (nervous)
- Osteoclasts (bone)
- Sinusoidal lining cells (spleen)
What are the characteristics of erythrocytes?
Biconcave, anucleate dics; salmon-colored; diameter 7-8µm
Erythrocyte cellss/mm3 of blood.
4-6 million
Duration of development of erythrocytes.
5-7 days
Life span of erythrocytes
100-120 days
Function of erythrocytes
Transport oxygen and carbon dioxide
Description of leukocytes
Spherical, nucleated cells
Leukocytes cellss/mm3 of blood.
4800-10,800
Description of neutrophil
Nucleus multilobed; inconspicuous cytoplasmic granules; diameter 10-12µm