Introduction to Blood Flashcards

(32 cards)

1
Q

List the qualities of blood that allows it to provide a means for sampling body tissues and fluids.

A

It is largely homogenous
It is in equilibrium with tissues
Shows reactive responses in disease states

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2
Q

List the components of blood.

A

Blood cells
Plasma proteins
Products of metabolism - metabolites, hormones etc.
Leakage from tissue cells - enzymes, other cytoplasmic constituents
May contain pathogens

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3
Q

What is haematology concerned with?

A

Cells of the blood

Haemostasis - control of bleeding & clotting

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4
Q

Name what the haematology laboratory assessment of blood cells involves.

A

Cell counts - quantitative
- red cells: concentration, size, contents
- leucocytes: concentration
Blood film examination to:
- check morphology - qualitative evaluation
- confirm cell count data - quantitative check
Specialized tests

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5
Q

Name the normal lecuocytes and reticulocytes.

A
Band forms and melanocytes
Neutrophil 
Eosinophil 
Basophil 
Monocyte
Lymphocyte 
Reticulocytes
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6
Q

What is the purpose of an Automated Haematology Analyser?

A

Provides an automated count of cells

Single cells assessed by laser beam (cell size, cytoplasmic/nuclear activity, detection of peroxidase enzyme)

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7
Q

Name the parameters of RBCs that are usually examined.

A
Red cell concentration (RBC)
Haemoglobin (Hb)
Haematocrit (Hct) 
Mean cell volume (MCV)
Mean cell Hb (MCH) 
(Mean cell Hb conc.)
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8
Q

Define reference range/interval for a population.

A

The range of values present in 95% of healthy individuals of a specified population, for a test.

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9
Q

Name the factors affecting reference ranges for blood cells.

A

Developmental age
Gender
Psychological changes - pregnancy, high altitude, climate
Ethnic (genetic) differences

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10
Q

Define anaemia.

A

Reduced haemoglobin for age, gender, geography/ethnicity.

Indicates reduced ability to transport oxygen in blood

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11
Q

Name the different cell size types relating to anemia.

A

Microcytic
Macrocytic
Normocytic

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12
Q

Name the different cell concentrations of Hb relating to anaemia.

A

Hypochromic

Normochromic

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13
Q

Define microcytic hypochromic anaemia.

A

Small under filled red cells

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14
Q

Define normochromic normocytic anaemia.

A

Normal red cells

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15
Q

Define macrocytic anaemia (normochromic).

A

Large red cells

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16
Q

Name features of microcytic hypochromic anaemia.

A

Iron Deficiency
Pencil cells and target cells
Erythroblasts show reduced Hb production & no stainable iron in marrow = no stores.
Early response to treatment of iron deficiency - some well-filled RBCs are present

17
Q

Why is MCHC not usually reported?

A

High level of error in calculated data.

18
Q

Discuss the features of normocytic normochromic anaemia.

A

Largest group of anaemias - common
Causes:
- Haemodilution occurring after acute blood loss
- Chronic or persistent inflammation or infection (mechanism - reduced normal red cell production)
- Renal failure
- Usually a secondary feature of an underlying disorder

19
Q

Name the features of macrocytic anaemia.

A

Common in liver disease
Megaloblastic anaemia is an important cause:
- caused by deficiency of vitamins needed for nucleic acid metabolism (folic acid/vit B12)
Delayed and abnormal maturation in marrow:
- many dividing cells die due to DNA errors caused by lack of nucleotides
- affects all tissues but blood abnormalities are usual means for diagnosis

20
Q

What is haemopoiesis?

A

Production of blood cells

21
Q

Where does haemopoiesis occur in fetuses?

A

Liver and spleen in vascular sinuses

Bone marrow - as bones develop

22
Q

Where does haemopoiesis occur in children?

A

Bone marrow - progressive loss from limb bones

23
Q

Where does haemopoiesis occur in adults?

A

Bone marrow - axial skeleton mainly (skull, vertebrae, ribs, sternum, coccyx)

24
Q

Name and describe the different types of stem cells.

A

Totipotent stem cells - embryonic development, can form any tissue
Pluripotent stem cells - increasing specialization to produce a limited range cell types
Adult stem cells (progenitor cells) - present in marrow, low numbers in blood, may be able to enter other tissues & participate in healing
Committed stem cells - myeloid, lymphoid cell lineages

25
What are the key issues surrounding erythroblasts?
Proliferation Iron uptake Haemoglobin production Removal of mitochondria, ER, ribosomes, golgi, loss of nucleus
26
Name the control mechanisms surrounding regulation of haemopoiesis.
Cytokine signals - induce growth and differentiation, produced by peripheral tissues & cells of marrow Marrow stromal cells - cell surface signals
27
What is the result of haemopoiesis? Describe how it is an integrated process.
``` Results in self renewal of pluripotent stem cells Differentiation of some pluripotent stem cells into specific cell lineages = irreversible Feedback signals (cytokines/growth factors) from peripheral tissues provide important regulatory control. ```
28
What type of cells do the regulatory signals in haemopoiesis act on?
Stromal cells - IL-1, TNF Pluripotent stem cells - stem cell factor (SCF), Flt ligand Multipotential progenitor cells - IL-3, GM-CSF, G-CSF, IL-6, TPO Act on committed progenitor cells - G-CSF, M-CSF, IL-5, Erythropoietin, Thrombopoietin
29
List and describe the committed cells of erythropoiesis.
Proerythroblast Basophilic erythroblast (rapid division, iron uptake) Polychromatic erythroblast (divides, Hb synthesized, then starts clearing RNA, mitochondria etc. and buds off nucleus to become a ....) Reticulocyte (immature red cell, completes clearance of RNA, mitochondria, golgi. Migrates into blood 1-2 days) Erythrocyte - 120 days
30
How many red cells are produced each day by an average adult?
2-3 x 10^11
31
Name the difference between an erythroblast and erythrocyte.
``` Erythroblast = nucleated cell Erythrocyte = nucleus is discarded ```
32
Name the flow characteristics of blood.
Viscosity - cells suspended in plasma Red cells larger than some capillaries - elastic deformation to pass through capillaries Flow characteristics in microvasculature (small arteries and arterioles, small veins and venules) - axial streaming of red cells, platelet rich plasma zone at periphery