Unit 6 - Cardiovascular system 3 Flashcards
What is MAP?
Mean arterial pressure
- time weighted average of blood pressure
How is mean arterial pressure calculated?
1/3 (Psystolic - Pdiastolic) + Pdiastolic
What is pulse pressure?
The difference between systolic and diastolic blood pressure
What does blood pressure provide?
The driving force to perfuse organs with blood
- determines perfusion pressure
Why isn’t blood pressure uniform throughout the body?
Effects of gravity
- measure at the level of the heart
Cardiac cycle is cyclical
What factors regulate blood pressure?
Short term - autonomic nervous system
Long term - Renin-angiotensin-aldosterone system
What is cardiac output?
Heart rate x stroke volume
How is MAP calculated?
MAP = CO x TPR (total peripheral resistance)
CO = HR x SV
How does the autonomic nervous system regulate blood pressure?
Smooth muscle tone changes total peripheral resistance
Vasoconstriction = increased resistance = increased blood pressure
Arterioles provide greatest contribution to changes in total peripheral resistance
How can the resistance to flow be calculated?
R = 8nL/pi r^4 R= resistance n = viscosity in blood l = vessel length r = vessel radius
How does the renin-angiotensin-aldosterone system control blood pressure?
Angiotensin II causes arteriolar vasoconstriction, increasing the blood pressure
What factors affect blood pressure?
Age
Sex
Population differences
What is the role of the pharmacist in diagnosing and treating hypertension?
- screening those at risk
- increasing public awareness of risk factors
- promoting appropriate lifestyle changes to limit risk
- no immediate perceivable gain
- regular monitoring and refining of medication
- ensuring compliance
What does hypertension increase the risk of?
Stroke
Coronary heart disease
How can the risk of CV be minimised?
Blood pressure < 120/80 mmHg