Introduction to Blood Flashcards
Average circulating blood volume in a typical adult male
An average, healthy 70kg man has 5 litres of blood in their body:
- 1L in lungs
- 3L in systemic venous circulation
- 1L in heart and arterial circulation
List the functions of blood
Functions of Blood
- Carriage of physiologically active compounds (plasma)
- Clotting (platelets)
- Defence (white blood cells)
- Carriage of gas (red blood cells)
- Thermoregulation
- Maintenance of ECF pH
What does blood consist of?
Plasma, red blood cells, white blood cells and platelets
Plasma composition
5% body weight, 95% water
Circulates biologically active molecules and compounds
Composition normally kept within strict limits
What are the three plasma proteins?
- Albumin
- Globulin - subdivided into a, b, y globulins
- Fibrinogen and other clotting factors
What is the role of albumin?
Transport of steroids and lipids - it is the most abundant plasma protein
What is globulin used for?
Alpha and beta globulin have the same function as albumin
Gamma globulin acts like anti-bodies
What can be said about the volume and the concentration of the fluid in the plasma?
Concentration stays the same since water passes into the plasma, but therefore volume changes
What is fibrinogen?
The major physiological function of fibrinogen is the formation of fibrin that binds together platelets and some plasma proteins in a hemostatic plug.
What is Oncotic pressure/ colloidosmotic pressure?
Osmotic pressure in a blood vessel’s plasma that causes a pull on fluid (water) back into the capillary
Induced by the proteins, notably albumin,
What is meant by hyrdostatic pressure and which direction of fluid movement does it favour?
The pressure created by fluid due to the force of gravity - increases with depth
Favours the movement of water from the capillary to the interstitial fluid (hyrdostatic pressure is greater in the capillary)
Difference between oncotic pressure and hydrostatic pressure
Hydrostatic pressure is the force that pushes the fluid out of blood capillaries whereas oncotic pressure is the force that pushes the fluid into the blood capillaries.
What is hypoproteinaemia?
Abnormally low levels of protein circulating in the plasma
What causes hypoproteinaemia?
Prolonged starvation - breakdown of plasma proteins
Liver failure - reduced synthesis
Kidney disease - sieve holes are bigger
Intestinal disease - reduces the amino acids used for synthesis
Life span of red blood cells
120 days
Life span of platelets
10 days
Another name for red blood cells
Erythrocytes
What is the function of the red blood cell?
Red blood cells are responsible fortransporting oxygen from your lungs to your body’s tissues.
What is the function of erythropoietin?
Where is it produced?
A hormone that the kidneysproduce to stimulate production and maintenance of crucial red blood cells.
When does erythropoietin secretion increase?
EPO levels usually risewhen your body isn’t getting enough oxygen.
What are the five main types of white blood cells?
Agranuloyctes:
- Monocytes
- Lymphocytes - B cells & T cells
Granulocytes:
- Basophils
- Eosinophils
- Neutrophils
What is the difference between agranulocytes and granulocytes?
Agranulocytes are white blood cells that hove no distinct granules in their cytoplasm.
Granulocytes are a type of white blood cell that has small granules. These granules contain proteins.
What do monocytes become?
Monocytes typically circulate through the blood for 1–3 days before migrating into tissues, where they become macrophages ordendritic cells.
Largest WBC
Adaptive immune system
What is a macrophage?
Macrophagesare monocytes that have migrated from the bloodstream into any tissue in the body.
They aid in phagocytosis to eliminate harmful materials.
What is leukopoisis?
White blood cell formation
What is leukopoisis controlled by?
A cocktail of cytokines (proteins/peptides released from one cell type which act on another)
Where are cytokines released from?
Cytokines are released from mature white blood cells
What do cytokines do?
Stimulate mitosis and maturation of leukocyte
What white blood cells are raised in bacterial and viral infections?
Bacterial - increase in neutrophils
Viral - increase in lymphocytes
The cytokine cocktail is dynamic, what does this mean?
It changes its composition in response to infection to influence which white blood cells will be preferentially stimulated to form.
What can differential white cell count allow you to do?
Differentiate between infection types
What are monocytes?
Responsible for attacking and breaking down germs and bacteria that enter the body.
Monocytes are phagocytic cells.
This means they break down infections by “eating” them.
What are lymphocytes?
B cells
T cells
What are basophils?
Basophils are responsible for fighting fungal or bacterial infections and viruses.
They are a granulocyte cell, which means that they release granules of enzymes to fight against harmful bacteria and germs.
What are esinophils?
Most often indicates a parasitic infection, an allergic reaction or cancer.
You can have high levels of eosinophils in your blood (blood eosinophilia) or in tissues at the site of an infection or inflammation (tissue eosinophilia).
What are neutrophils?
Neutrophils area type of white blood cell.
They make up the biggest number of all kinds of white blood cells.
They kill and digest bacteria and fungi to help your body fight infections and heal wounds.
What is the function of platelets?
Adhere to damaged vessel walls and exposed connective tissue to mediate blood clotting
They play an important role incoagulation (blood clotting), helping to stop bleeding when blood vessels are injured.
What type of hormone is thrombopoietin and where is it produced?
Glycoprotein hormone
Produced by the liver and kidney.
What is the role of thrombopoietin?
Stimulates production & differentiation of megakaryocytes - the bone marrow cells that bud off large numbers of platelets.
What is a hematocrit?
A hematocrit is asimple blood test done to measure the red blood cells in a person’s blood.
How is the hematocrit value expressed?
The value is expressed as a fraction of cells in blood.
For example, a Hct of 0.40 means that there are 40 millilitres of cells in 100 millilitres of blood.
What is the normal range for haematocrit?
Normal range: 40-50%
What factors can effect the outcome of a haematocrit test?
- Living at a high altitude.
- Pregnancy.
- Significant recent blood loss.
- Recent blood transfusion.
- Severe dehydration.
What is blood viscosity?
How thick/sticky blood is compared to water
What is the viscosity of plasma and blood?
Plasma - 1.3x thicker than water
Whole blood 3-4x thicker than water
How can viscosity change in certain circumstances?
- Haematocrit - 50% increase in haematocrit 100% increase viscosity
- Temperature - increase in temp decreases viscosity and vice versa - 1 degree C changes viscosity by around 2%
- Flow rate - increase in flow rate decreases viscosity and vice versa
How does prolonged starvation cause hypoproteinaemia?
Breakdown of plasma proteins
How does liver failure cause hypoproteinaemia?
Reduced synthesis
How does kidney disease cause hypoproteinaemia?
Sieve holes bigger
How does intestinal disease cause hypoproteinaemia?
Reduces the amino acids used for synthesis
What is the role of agranulocytes?
Mediate immunological response to foreign pathogens, cancerous and tumour cells, and remove dead cells from the body by releasing antibodies and directly attaching to cells.
What is the role of granulocytes?
Granulocytes, specifically neutrophils, help the body fight bacterial infections.
What are the cells of the innate immune system?
Macrophages
Neutrophils
Dendritic cells
Eosinophils
Basophils
Natural killer cells
What are the cells of the adaptive immune system?
Antigen presenting cells
T cells (memory cell, effector cells. cytotoxic cells, helper cells, regulatory cells)
B cells (memory cells, plasma cells)
