Cardiovascular system 7 Flashcards
What are the properties of the blood in the major arteries
High pressure
Oscillatory
What are the properties of blood in the arterioles, capillaries and venules
Steep fall in pressure
Oscillatory nature is reduced
What is the property of blood in veins
Very low pressure
What does ‘blood flow in’ do
Fills arteries
Increases arteriole blood volume
Raises arteriole pressure
What does ‘blood flow out’ do
Drains arteries
Decreases arterial blood volume
Lowers arteriole pressure
Describe he equation P = Q x R in context
MAP = CO x TPR
Mean Arterial pressure = Cardiac Output x Total Peripheral Resistance
What is the equation for cardiac output
CO = SV x HR
(Cardiac Output = Stroke Volume x Heart Rate)
Stroke volume - contraction strength
Heart rate - Contraction speed
When would SV and HR be increased
During exercise - we need more blood to be pumped quicker
How is Mean Arterial Pressure (MAP) regulated
Highly regulated in a narrow range.
Coordinated within brainstem - afferent from CNS and ‘periphery’ - efferent to heart and vessels
What are baroreceptors
sensory receptor that detects pressure changes in the walls of blood vessels
Where are baroreceptors located
In the carotid sinus’s and the aortic arch
Where do baroreceptors send feedback to
To the medulla oblongata
What is the ‘accelerator’ of heart electrical conduction and why
Sympathetic - accelerator - Communicates with SA and AV nodes as well as deeper in the ventricular wall - triggers muscles to release more calcium causing a stronger contraction
What is the ‘break’ of heart electrical conduction and why
Parasympathetic - Communicates with SA and AV nodes to decrease heart rate
How does the parasympathetic system signal the heart
Through vagus nerves
