White cells Flashcards
What type of cell is capable of differentiating into all the different types of circulating blood cell?
The haematopoietic stem cell
Are haematopoietic stem cells easy or difficult to distinguish in the bone marrow using light microscopy?
Difficult
Where do granulocytes spend most of their time?
In the tissues after they transit in the bloodstream
What lineage are granulocytes derived from?
The myeloid series
Which cells do granulocytes have a common precursor with?
Monocytes
What influences what type of granulocyte a granulocyte precursor will be?
Exterior factors such as cytokines
What is the first morphologically discernible member of the myeloid series?
A myeloblast
How long does the process of division and maturation from a myeloblast to a mature effector granulocyte take?
6-8 days
Which granulocytes can stick to vessel walls? What is this called?
Neutrophils
Marginating
What is another name for neutrophils? Why are they sometimes called this?
Polymorphs
They can have different shapes due to different segmentation patterns of their nuclei.
What is an excess of neutrophils called?
Neutrophilia or neutrophil leucocytosis
How long do neutrophils live?
They transit the bloodstream for 6-10 hours then spend a few days in the tissues before dying.
Where is there a pool of nearly mature and mature neutrophils that can be released in times of stress?
The bone marrow
What are the principle roles of neutrophils?
Phagocytosis
Chemoattraction for other parts of the immune system
What parts of the immune system do neutrophils utilise through their surface receptors?
Complement system and immunoglobulins
Compare the granules found in neutrophils to those found in basophils and eosinophils
They are finer and are neutrally staining
List 5 things which can cause neutrophilia.
Neoplasia Tissue necrosis Inflammation Bacterial infection Acute haemorrhage
List 6 common causes of eosinophilia
Allergic reactions to drugs
Severe skin conditions e.g. atopic dermatitis
Asthma, atopy
Parasitic infections
Hodgkin’s lymphoma, T cell lymphomas
Pulmonary syndromes (e.g. eosinophilic pneumonia, Churg strauss)
When may basophilia be seen?
In polycythaemia rubra vera and chronic myeloid leukaemia
Are basophils frequent in the circulation?
No
What is the appearance of basophils?
The nucleus is often obscured by blue/black granules
What do the granules in basophils contain?
Histamine
Heparin
What type of hypersensitivity do basophils mediate? How do they do this?
Type 1 hypersensitivity
IgE receptors on the cell surface allow specific antibody/antigen interactions to cause degranulation
Which tissue resident cells are basophils analogous with?
Mast cells
Which two types of cells have a role in allergy and parasitic infections?
Eosinophils and basophils
What may raised serum levels of mast cells indicate?
Systemic mastocytosis
Recent anaphylactic reaction
What is released when a mast cell degranulates?
Tryptase
Histamine
Heparin
What can be measured as a marker of mast cell degranulation/mast cell numbers?
Mast cell tryptase
What is the name of malignant proliferation of mast cells?
Systemic mastocytosis
What can cause monocytosis?
Chronic bacterial infection
Malignancy e.g. chronic myelomonocytic leukaemia
connective tissue disease e.g. SLE and RA
Which type of white cell may be slightly raised in smokers?
Neutrophils
Describe the appearance of monocytes
Large monolobular cells with plentiful cytoplasm
Do not have prominent granular contents but fine granules can be seen
What do monocytes differentiate into after leaving the bloodstream?
Macrophages
What are the roles of monocytes?
Roles in fighting infection through phagocytosis and antigen processing
Where are lymphocytes produced?
The bone marrow
Where do lymphocytes develop?
In primary lymphoid organs i.e. the bone marrow and thymus.
Where are specific immune responses generated?
Secondary lymphoid organs i.e. lymph nodes, the spleen, mucosal lymphoid tissues of gut and respiratory tract
What causes lymphocytosis?
Infection
Underlying malignant process
Removal of the spleen (hyposplenism)
What is infective mononucleosis?
Describe the appearance of the T cells
What causes this?
Activated T cells responding to EBV infection in B cells
They take on a typical morphological appearance with abundant blue cytoplasm that wraps against neighbouring red cells on blood film
Typically caused by EBV infection
Can also be caused by HIV, CMV, viral hepatitis and toxoplasma
