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