Cardiovascular Flashcards
functions of the cardiovascular system
- bringing nutrient into the body (e.g. from the intestine to liver)
- bring fuel to cells
- bringing O2 to cells from lungs
- removal of waste products
- circulation of hormones
- circulation of immune cells and antibodies
- regulation of electrolytes
- regulation of pH
- H2O balance
- thermoregulation
- …….transport, transport, transport
Does an amoeba need blood
No
Fish Circulatory System
- Closed circulation
- Single loop circulation
- 2 chambers
- has gill capillaries + systemic capillaries
Amphibian & Reptilian Circulatory System
- 3 chambers
- double-loop circulation
- closed circulation
Mammalian Circulatory system
- 4 chamber heart
-double-loop circulation
-closed circulation
Right side
-pulmonary circulation
Left side
-Systemic Circulation
Septum
Part of the heart that separates the two sides
Haemodynamics
- the branch of physioology dealing with the forces involved in the circulation of the blood
- the circulation and movement of blood in the body and the forces involved therein
Volume (blood)
- 75% of weight is blood (75 kg man)
- 60% of blood is in the veins, why venous system is called capacitance
- Arterial system is called resistance, less blood flowing
Flow (blood)
- purpose of the card. system is to create flow
- flow coming into the heart has to be equal to flow coming out of the heart
- Flow = Volume/Time
- Flow = area x (mean)velocity
Flow = perfusion pressure/resistance
Flow from the left Heart
Cardiac Output
Flow from the right heart
Venous return
Total Cross Sectional Area and Flow Velocity
- Total cross section area increases as you go closer to the capillaries
- crs. sct. area decreases as you go towards the vena cava from the capillaries.
- Crs. Sct. area determines the pressure of the flow.
- Low flow velocity allows a more efficient transfer of oxygen
Pressure (blood)
-Pressure = Force/Area
S.I. unit: pascal(Pa) = newton/m^2
-n.m. 120/80 mmHg
Hydrostatic Pressure
Volume = area x height Mass = density x volume F= mass x acceleration due to gravity Pressure = Force/Area
Perfusion Pressure
Perfusion pressure = inlet pressure - outlet pressure
- The thing that will drive the flow is the difference between pressure
= arterial pressure - venous pressure
P = Pa - Pv
Resistance (blood)
Resistance = Perfusion pressure/ flow
Laminar or Parabolic Flow
- Smooth flow: lamiar or parabolic flow
- near the wall velocity decreases
- highest velocity is at the midline of the vessel
Friction losses in a viscous flow
generation of heat –> fall in pressure down the vessel.
Control of vessel resistance
- Vessels can contract or relax
- This changes the radius, thus affecting the flow of blood
Vessels in Series
Resistance = R1 + R2
Vessels in Parrallel
1/R = 1/R1 + 1/R2
Cardiac Valves
- all of the valves sit in the fibrous ring (connective tissue)
- bicuspid = two leaflets
- tricuspid = three leaflets
Injection Phase of the Heart
Ventricle contraction –> pulmonary valve opens –> valve then closes because the pressure in the ventricle falls as the heart stops its contraction process, at this point the pressure in the pulmonary track will be higher.
Chordae Tendinae
little fibers that attach the muscle to the cardiac valves