A1 Hypertension

Question 1

Role of the bronchial circulation

Answer 1

complementary to pulmonary circulation, supplying lung cells with oxygen and nutrients

Question 2

BP is dependent on

Answer 2

1. TPR
2. CO (amount of blood ejected by heart each minute) (CO = HR x Stroke volume)
   BP = CO x TPR

Question 3

If arterioles are dilated what does that mean for BP

Answer 3

dilated - low resistance to flow: low peripheral vascular resistance –> low BP

Question 4

Factors affecting

1. arterial BP (6)
2. systemic BP

Answer 4

1. Stroke volume, Heart rate, Peripheral resistance, Elastic vessels, Blood volume, Ventricular ejection
2. ANS (immediate), Renin-angiotensin system (slower/ long term reg), Local chemical mediators released from vascular endothelium

Question 5

how do the following influence BP

1. heart
2. arteries
3. veins

Answer 5

1. acts mainly via β1 to increase cardiac contractility and HR = increased CO and BP
2. SNS produces vasoconstriction via α1 (increases BP & afterload on the heart)
3. SNS α1 results in venoconstriction (increases venous return to heart (preload), raises CO and increases BP)

Question 6

explain RAS effect on BP

Answer 6

Na depletion –> kidneys release renin via SNS –> angiotensinogen converts to Ang I. ACE converts to Ang II = vasoconstriction
Renal medulla releases aldosterone = Na retention —> increases BP

Question 7

role of endothelium derived Factors
describe
1. EDRFs
2. EDCFs

Answer 7

Modulation of vascular smooth muscle and vessel diameter

1. NO, Prostacyclin, Hyperpolarising factor
2. Endothelin (ET-1), Thromboxane A2 (TxA2)

Question 8

Define

1. Systolic pressure
2. Diastolic pressure
3. Pulse pressure
4. Mean arterial pressure

Answer 8

1. max arterial P reached during peak ventricular ejection
2. min arterial P just before ventricular ejection begins
3. difference between SP & DP
4. average P in the Cardiac cycle

Question 9

hypertension risk factors

1. primary
2. secondary

Answer 9

1. obesity, lack of exercise, alcohol, non insulin-dependent diabetes, age
2. initiated by other disease:
   Aortic coarctation, Renal disease, Mineralocorticoid excess, Thyroid disease, Eclampsia

Question 10

Anti-hypertensive drugs

describe drugs acting on SNS

Answer 10

1. Beta blockers
   (e.g. atenolol, propanolol)
   Decrease CO, reduce renin production (reduce AngII), can indirectly cause vasodilation of peripheral arteries (CO feeds into BP)
   ((predominate effect on B1 heart (some extra effects via B2 by vasodilation))
2. a-blockers
   (e.g. prazosin (selective))
   Block post-synaptic a1 = dilation of arteriolar resistance vessels and lower peripheral resistance. Also dilate venous capacitance vessels, reducing venous return and CO

Question 11

describe drugs action of RAS

Answer 11

1. ACE inhibitors (e.g. captopril)
2. Ang II receptor antagonists (e.g. losartan)
   selectively block AT1 receptors which mediate the vasoconstrictive effects of AngII

Question 12

describe Vasodilators and give examples

Answer 12

1. Diuretics (e.g. Thiazide)
   Act at varying sites in the kidney to increase Na+ and water depletion = hypotensive effect.
2. Ca channel blockers (e.g. amlodipine)
   Block Ca entry into vascular smooth muscle cells &/or cardiac muscle cells. Promotes relaxation of the muscle and vasodilation.

Question 13

what antihypertensive drugs act at

1. CNS
2. Blood vessels
3. Kidney
4. heart

Answer 13

1. B blockers, a2 agonists
2. a1 blockers, Ca blockers, vasodilators, AT1 antagonists, ACE inhibitors
3. diuretics, B-blockers, ACE inhibitors
4. B-blockers

Question 14

Define

1. Systemic hypertension

Answer 14

1. usually asymptomatic and often diagnosed when patient presents with another condition

Question 15

Define Pulmonary hypertension

Answer 15

common w/ COPD: pulmonary vasculature has been affected = increased vascular resistance
Have shortness of breath/ ~chest pain
Sustained increase in pulmonary vascular resistance –> progressive right HF