MEC322: Cardiovascular System Flashcards
What are the three general functions of blood?
Transportation- of oxygen, carbon dioxide, nutrients, hormones, heat and waste
Regulation- of pH, body temperature and water contents of cells
Protection- against blood loss through clotting, disease through phagocytic white blood cells and proteins such as antibodies, interferons, and complement.
What are the components of whole blood?
Blood plasma – a liquid extracellular matrix that contains dissolved substances.
Formed elements – which are cells (red blood cells or erythrocytes, white blood cells or leukocytes, and platelets) and cell fragments.
What amount of blood loss causes weakness?
15-30%
What amount of blood loss causes shock?
over 30%
shock can be fatal
What are blood transfusions used to treat?
substantial blood loss, severe anaemia or thrombocytopenia (not enough platelets)
What are antigens?
Contained on the surface of red blood cells made up of glycolipids and glycoproteins
What is the ABO blood group?
Based on two antigens A&B these determine blood type
What are anti-A antibodies and anti-B antibodies?
Blood plasma contains antibodies that react with the A or B antigens if mixed.
What is an erythrocyte?
a red blood cell
How is the Rh blood group classified?
People whose erythrocytes have Rh antigens (the Rh factor) are classified as Rh+. Those who lack the antigen are Rh–.
What happens when Anti-B antibody and B antigen mix?
Clotting- adverse affect
What are some characteristics of blood?
Temperature of 38°C
Five times more viscous than water (more viscous due to plasma proteins and formed elements)
pH slightly alkaline 7.35-7.45
What is venipuncture?
Blood collected from veins (as they are more superficial, thinner and lower blood pressure than arteries)
common site- median cubital vein
What are other blood collection methods?
Collected from peripheral capillaries - fingertip or earlobe
Collected from arterial puncture - Required to evaluate efficiency of gas exchange at the lungs
Describe blood in terms of it biomechanics?
Blood is a heterogeneous multi-phase mixture of solid corpuscles suspended in a liquid plasma —> non-Newtonian fluid
What is a Newtonian fluid?
a fluid in which the viscous stresses arising from its flow, at every point, are linearly correlated to the local strain rate- the rate of change of deformation over time
What is the viscosity of blood determined by?
- viscosity of plasma
- The haematocrit level (volume of red blood cells in total volume of blood)
- the mechanical properties of blood cells
- Applied deformation forces (extensional and shearing)
- Ambient physical conditions
Compare plasma to red blood cells
Plasma- Newtonian Red blood cells - Vary in concentration Are elastic Aggregate in 3D structures (rouleaux) at low deformation rates
What is blood modelled as in computational models?
Newtonian fluid
What will blood flow effect?
The mechanical stress on the blood vessel walls and the surrounding tissues
- especially in cases of irregular lumen (inside space of tubular structure) geometry like stenosed (narrowing) arteries
- seems to have the most significant role in facilitating blood flow through stenotic vessels
What is the basic pattern of blood flow?
–> right side of heart –> lungs –> left side of heart –> sytemic cells –>
heart –> arteries –> arterioles –> capillaries–>venules–>veins–>
What does the right atrium do?
- receives and holds deoxygenated blood from the superior vena cava, inferior vena cava and coronary sinus
- sends down to the right ventricle
What does the left atrium do?
- receives the oxygenated blood from the left and right pulmonary veins
- pumps to the left ventricle
Do atria have valves at their inlets?
No