Lecture 3: Hypertension Flashcards
(40 cards)
When a blood pressure is indicated as 120/80, what does each number represent?
- Top number is systolic, which is the pressure during contraction
- Bottom number is diastolic, which is the pressure during rest/filling
What is mean arterial pressure?
The average pressure throughout the entire cardiac cycle
How much of the mean arterial pressure if diastole and how much is systole?
2/3 diastole and 1/3 systole
What does mean arterial pressure determine?
If organs are being perfused
What is the equation for blood pressure?
BP = TPR (total peripheral resistance) x CO (cardiac output)
What is the equation for cardiac output?
Heart rate (how fast) x stroke volume (how much)
What happens to cardiac output and blood pressure when heart rate is increased?
They both increase
What is blood pressure?
The pressure on arterial walls
What are the “big 5” BP mechanisms?
1) RAAS
2) Electrolytes
3) Neuronal signals
4) Vascular
5) Hormonal
What happens in the RAAS?
- Juxtaglomerular cells secrete renin, which converts angiotensinogen to angiotensin 1
- ACE (angiotensin-converting enzyme) converts angiotensin 1 to angiotensin 2
- Angiotensin 2 has a number of effects
What is the main effect of angiotensin 2?
Increased blood pressure
What 6 organs/systems does angiotensin 2 affect?
- Adrenal cortex
- Kidney and intestine
- Central nervous system
- Peripheral nervous system
- Vascular smooth muscle
- Heart
What affect does angiotensin 2 have on the adrenal cortex?
1) Increases aldosterone synthesis
2) Sodium/water reabsorption
3) Increased blood volume
4) Increased TPR
5) Increased blood pressure
What affect does angiotensin 2 have on the kidneys and intestine?
1) Sodium/water reabsorption
2) Increased blood volume
3) Increased TPR
4) Increased BP
What affect does angiotensin 2 have on the CNS?
1) ADH/vasopressin release or sympathetic discharge
2) Increased blood volume
3) Increased TPR
4) Increased BP
What affect does angiotensin 2 have on the PNS?
1) Sympathetic discharge (vasoconstriction)
2) Increased TPR
3) Increased BP
What affect does angiotensin 2 have on vascular smooth muscle?
1) Vasoconstriction
2) Increased TPR
3) Increased BP
What affect does angiotensin 2 have on the heart?
1) Increased force of contractility
2) Increased CO
3) Increased BP
What effect do electrolytes have on BP?
1) Increased sodium = increased water
2) Decreased potassium and decreased calcium can potentially increase PVR
What effect do neuronal/brain signals have on BP?
Sympathetic and parasympathetic produce:
1) Higher order reflexes (mood/emotion)
2) Intrinsic reflexes – inside circulatory system (chemo/baroreceptors)
3) Extrinsic reflexes – outside circulatory system (pain/cold)
What are baroreceptors?
- Pressure receptors
- Ex: juxtaglomerular cells
What 3 hormones in the body cause vasoconstriction?
- Angiotensin 2
- Vasopressin
- Endothelin
What 3 substances cause vasodilation?
- Prostacyclin
- Nitric oxide
- Bradykinin
What are natriuretic hormones?
Hormones that shut down the Na/K pump, leading to vasoconstriction
