Hypertension Flashcards
What is essential (primary) hypertension?
Blood pressure that is associated with significant cardiovascular risk
What is secondary hypertension?
Associated with other conditions such as renal disease, pregnancy & hyperthyroidism
What is the equation for blood pressure?
BP = CO x TPR
Blood Pressure = Cardiac Output x Total peripheral resistance
How can TPR be reduced?
- Blocking of alpha-adrenoreceptors (reduce vasoconstriction)
- Blocking of Angiotension II (reduce vasodilation)
- Vasodilation of Calcium Channel Blockers
How can CO be reduced?
- Reducing blood volume
- Reducing cardiac force and rate
What inhibitor prevents Angiotensin II from forming?
Angiotensin Converting Enzyme Inhibitors (ACEI’s) prevent Angiotensin I being converted into Angiotensin II
What does Angiotensin II do?
It vasoconstricts blood vessels if present
What happens if Angiotensin II is blocked?
- Build up of Angiotensin I
- Reduction in vasoconstriction
- Induced aldosterone release (reduction in salt and water concentration)
What would happen if ACE inhibitors are given to treat hypertension? What would prevent the side effect
Build up of bradykinin would occur due to it using ACE inhibitors to produce inactive bradykinin. This leads to person developing a cough.
By using AT1 receptor antagonists, the production of T2 is reduced but Bradykinin production is able to continue so do not cause cough
How does a calcium channel blocker work?
Prevents the release of internal calcium channel stores into the cell cytosol. This inhibits voltage gated calcium channels on the smooth muscle in the blood vessels which increases vasodilatation.
Do calcium channel blockers have side effects?
- Arrhythmia
- Heart Block
- Hypotension
- Heart Failure
- Headaches
- Flushing
How do diuretics reduce cardiac output?
Help promote the production of urine which in turn:
- Promotes loss of salt
- Reduces cardiac output through blood volume
- inhibits aldosterone (which regulates blood pressure)
How else can cardiac output be reduced?
Use of beta blockers (blocking of b1 and b2 adrenoceptors)
where can b1 and b2 receptors be found?
b1 located in heart
b2 found in peripheries (tissues outside the heart)
b1 blockage - reduced cardiac output
b2 blockage - skeletal muscle vasodilatation and bronchodilatation
