Introduction to Blood Flashcards
What is the normal distribution of blood in the body?
- Lungs: 1L
- Systemic venous circulation: 3L
- Heart and arterial circulation: 1L
What are 6 functions of blood?
- Carriage of physiologically active compounds
- Clotting
- Defence
- Carriage of gas
- Thermoregulation
- Maintenance of ECF pH
What does blood consist of?
- Plasma
- RBCs
- WBCs
- Platelets
What does plasma do??
Circulates biologically active molecules and compounds
What are the 3 categories of plasma proteins?
- Albumin
- Globulin (a,B, y)
- Fibrinogen (and other clotting factors)
Where do plasma proteins perform their functions?
In the circulation
What do plasma proteins generate?
Colloid oncotic pressure
What is the result of colloid oncotic pressure?
- Concentration of fluid remains unchanged
- Volume of plasma and interstitial fluid alters
What does ISF act as?
Fluid reservoir
What 2 forces is movement of fluid between capillary and interstitial space subject to?
- Hydrostatic pressure
- Colloid oncotic pressure
What does the net movement of fluid depend on?
- Capillary hydrostatic pressure
- Interstitial hydrostatic pressure
- Interstitial fluid protein concentration
- Plasma protein concentration
What is hypoproteinaemia?
Abnormally low levels of circulating plasma protein.
What does hypoproteinaemia cause?
- Prolonged starvation
- Liver disease
- Intestinal diseases
- Nephrosis
What is a common characteristic of hypoproteinaemia?
Oedema due to loss of oncotic pressure
What are erythrocytes?
RBC
What cells are myeloid cells?
- Erythrocytes
- Platelets
- Neutrophils
- Monocytes
- Basophils
- Eosinophils
What cells are lymphoid cells?
- Neutrophils
- Monocytes
- Basophils
- Eosinophils
- Lymphocytes
Describe erythrocytes.
- Most abundant blood cell
- 120 day lifespan
- Highly flexible, biconcave, non-nucleated
- Densely packed with haemoglobin
What are the 2 colours of blood?
- Oxyhaemoglobin: bright red found in arteries
- Deoxyhaemoglobin: cherry red found in veins
What is erythropoiesis?
RBC formation
What is erythropoiesis controlled and accelerated by?
Erythropoietin
Describe leukocytes.
- Nucleated
- Larger than RBCs
What are leukocytes involve in?
Defence against pathogens
Describe neutrophils.
- Most abundant WBC
- Constantly producing them
- Phagocytic
Describe eosinophils.
- Increase in number rapidly during allergy
- Attack pathogens too large for neutrophils and other defence cells
What do basophils do?
- Release histamine and heparin
- Trigger inflammation
Describe monocytes.
- Largest WBC
- Migrate to spleen, liver, lungs and lymph nodes
- Become macrophages once they have reached their destination
Describe macrophages.
- Mature monocytes that has migrated from the blood to the connective tissue
- Mya reside in tissue for up to 3 months
- Phagocytic
Describe lymphocytes.
- Key constituent of adaptive immune system
- B cells and T cells
What is leucopoiesis?
WBC formation
What is leucopoiesis controlled by?
A cocktail of cytokines including colony stimulating factors and interleukins
Where are cytokines released from?
- Endothelial cells
- Fibroblasts
- Mature WBC
What do cytokines do?
Stimulate mitosis and maturation of leukocytes
What happens when someone has a bacterial infection?
Increase in neutrophils
What happens when someone has a viral infection?
Increase in lymphocytes
What does the differential white cell count allow us to do?
Differentiate between infection types
What are platelets?
- Membrane bound cell fragments (from megakaryocytes)
- Rarely nucleated
- Formation governed by thrombopoietin
- 10 day lifespan
What do platelets do?
Adhere to damages vessel walls and exposed connective tissue to mediate clotting
What do platelets not do?
Adhere to healthy intact endothelium
What is haematocrit?
Measurement of the proportion of blood that is made up of cells
Viscosity
How thick/sticky blood is compared to water
What is viscosity dependent on?
- Haematocrit: 50% increase increases viscosity by 100%
- Temperature: Increase in temp decreases viscosity
- Flow rate: decreased flow rate increases viscosity
