Regulation of Blood Pressure Flashcards
What are the 3 influences of blood pressure?
Heart activity
Blood volume and viscosity
Blood vessels in particular dismayed of arterioles
What is blood pressure?
The force exerted by blood of the inner walls of blood vessels
When is the pressure in the arteries the highest?
Ventricular systole (contraction)
When is pressure in the arteries the lowest?
During ventricular diastole (relaxation)
How do you calculate blood pressure?
Cardiac output X Total peripheral resistance
What is total peripheral resistance?
Resistance in vessels of blood flow. The friction between blood and the walls of blood vessels
How do you work out cardiac output?
Heart rate X Stroke volume
What is cardiac output?
Total volume of blood pumped at a ventricle in a minute
What is stroke volume?
Amount of blood ejected from the left ventricle at each contraction
What system controls the short term control of blood pressure?
Nervous system
What is the system that controls long term blood pressure?
Endocrine system (hormones)
What is the atrial baroreceptor reflex?
Used in moment to moment control of atrial blood pressure
What is a baroreceptor?
Detect changes in stretch of artery walls due to blood pressure changes,Sending signals to centres in the medulla.
What activity slows the heart rate? (Nerve impulses)
Parasympathetic
Who activity speeds up the heart rate? (Nerve impulses)
Sympathetic
If you have a high peripheral resistance is your blood pressure higher or lower?
Higher
What regulates the diameter of arterioles?
A group of neurones in the medulla called the vasomotor centre
What happens in the cardiac centre when there is a decrease in blood pressure?
Excites sympathetic impulses Inhibits parasympathetic impulses SA node excited Heart rate increases Cardiac output increases Blood pressure increases
What happens in the vasomotor centre when blood pressure decreases?
Excites sympathetic impulses Smooth muscle in arterioles constricts Vasoconstriction Peripheral resistance increases Blood pressure increases
What do antihypertensives do?
Help to control blood pressure
Give some examples of antihypertensives drugs?
Diuretics ACE Inhibitors Beta blockers Calcium channel blockers Beta adrenergic antagonists
What should a normal blood pressure be?
120/80