Cardiovascular 2 Flashcards
Describe End-Diastolic volume
: Normal filling of the ventricles from venous return increases the volume of each ventricle to about 110 to 120 mls
Describe Stroke Volume Output
ventricles contract and empty during systole, the volume decreases Ca 70 mls
Describe End-Systolic Volume
The remaining volume in each ventricle about 40-50 millilitres
Describe Ejection fraction
The fraction of the EDV that is ejected ca 60%
What happens when the heart contracts strongly ?
End-systolic Volume= decreased a lot
End Diastolic volume greatly increased
State the equation for cardiac output
(EDV-ESV) x Heart Rate
State 3 reasons why regulation of the heart is required ?
Energetically expensive
Matching tissue demand
Ventilation perfusion matching
What regulates the heart?
Tissue pH
Nitric oxide
Autonomic nervous system
Describe the Sympathetic autonomic regulation of the heart rate
Sympathetic Neurones- B1 receptors of autorhythmic cells - Increases Na+ and Ca2+ influx- increased rate of depolarisation- Increased heart rate
Describe the Parasympathetic autonomic regulation of the heart rate
Parasympathetic neurones- muscarinic receptors of autorhythmic cells- Increased K+ efflux Decreased Ca2+ influx- Hyperpolarised and Decreased rate of depolarisation- decreased heart rate
What equation links Cardiac output, Pressure difference, Total Peripheral Resistance
Cardiac output =Pressure difference/ Total Peripheral Resistance
Describe the structure of the blood vessel
Tunica Intima, Tunica media, Tunica Externa
What are the 3 circulations?
Pulmonary, Peripheral, Cardiac
What pressure and flow of blood is in the pulmonary circulation?
Low pressure
Right ventricle to lung to left atria.
What pressure and flow of blood is in the peripheral circulation?
high pressure’
left ventricle to capillary bed to right atria
