Lecture 10 Flashcards
Is blood pressure high or low in systemic arteries?
High
Is blood pressure high or low in veins?
Low
Where does BP fall steeply?
Across arterioles, capillaries and venules
What does MAP stand for?
Mean arterial blood pressure
What is the driving force for blood flow?
The large difference in pressure between the arterial and venous sides
What is haemodynamics?
How blood flows in a single vessel
What is the blood flow equation? (in relation to pressure and resistance)
Flow = Pressure / Resistance
What is the blood flow equation (in relation to MAP and resistance)
MAP = Flow x Resistance
What is the stroke volume and heart rate of a healthy human heart?
~70mL / beat and ~60-80 beats/min
What is the stroke volume and heart rate of a failing human heart?
~40mL / beat and ~120-130 beats/min
Is cardiac output variable or fixed?
Variable
What is max heart rate in a human?
220 - age
How is arterial BP maintained?
Via the hearts independent electrical system and monitoring from the brain
What are baroreceptors?
blood pressure sensors
What type of receptors are baroreceptors?
Stretch receptors
Where are the baroreceptors found?
In the walls of arteries
What are the two baroreceptors?
Carotid artery and aortic arch
What is the relationship between stretch and signals sent in the baroreceptors?
More stretch from increased blood volume leads to more frequent and stronger signals to the brain
What is afferent flow of information?
Into the brain from the heart and vessels
What is efferent flow of information?
Out of the brain and into the heart and vessels
What is sympathetic information?
Fight and flight, increases heart beat pressure and frequency
What is parasympathetic information?
Rest and digest, decreases heart beat pressure and frequency
What are the two nerves communicating to the heart?
Vagus nerve and Sympathetic cardiac nerve
What happens in the cardiac system when the body goes from lying down to standing up?
Stroke volume decreases
Cardiac output decreases slightly
Heart rate increases significantly
MAP remains relatively constant, small decrease
Ventricular resistance increases
