Block A - hypertension Flashcards
role of arteries ?
carrying oxygenated blood Away from the heart are Arteries
largest artery ?
Aorta
role of veins ?
Vessels carrying deoxygenated blood from organs/tissues back to the heart for oxygenation are Veins.
pulmonary system ?
The pulmonary system contains a pulmonary vein returning oxygenated blood from the lungs to the heart and a pulmonary artery which sends deoxygenated blood from the heart to the lungs to be oxygenated.
Bronchial circulation ?
Bronchial circulation – complementary to pulmonary circulation, supplying lung cells with oxygen and nutrients.
Blood pressure in arteries vs veins ?
arteriole system carries blood at a much higher pressure, while the blood in the venous system is at a lower pressure
muscle thickness arteries vs veins ?
In arteries there is a much thicker muscular wall, to help withstand the increased pressure along with elasticity in the body.
In the veins, there is a much thinner muscular wall, as the thicker layer is not needed as the blood is at a lower pressure when compared to the arteriole system.
valves arteries vs veins ?
presence of valves in the venous system , which prevents any backflow of blood.
both arteries and veins contain an innermost layer of endothelial cells , why ?
endothelial cells which acts as a barrier between the blood and the vessel. However, it can secrete multiple factors that are chemical mediators which can affect the muscle layer of the vessel which is adjacent to the endothelial layer.
Blood pressure depends upon two factors , what are they ?
Blood pressure depends upon 2 factors: total peripheral resistance (TPR) and cardiac output (CO). BP = CO x TPR.
Cardiac output defined as and formula ?
Cardiac output is defined as the amount of blood ejected by the heart in a minute. CO is influenced by HR x Stroke volume
what is TPR ?
The TPR is the diameter of the arterioles which determines resistance to flow
low TPR ?
dilated this causes low resistance to flow, therefore low peripheral vascular resistance and as a consequence low blood pressure
increase TPR how and effect on BP ?
reduce the size of the lumen this will cause an increase in resistance and as a consequence the BP will increase
what are some factors affecting BP ?
cardiac output
Stroke volume
Heart rate
Peripheral resistance
Elastic vessels
Blood volume
Ventricular ejection
factors affecting systemic BP ?
Autonomic nervous system has an immediate effect to Blood pressure
Renin-angiotensin system has a slower effect to blood pressure
Local chemical mediators released from vascular endothelium to affect smooth muscle in the vessel to alter constriction or dilation.
effect of heart on systemic blood pressure ?
Sympathetic Nervous System acts mainly via noradrenaline acting on b1-adrenoceptors on heart to increase cardiac contractility and HR resulting in increased CO and BP.
effect of arteries and veins on systemic blood pressure ?
SNS produces vasoconstriction (more resistance) by stimulation of a1 adrenoceptors found in the vascular system. This increases BP and afterload on the heart. In a healthy heart CO is maintained via b1 stimulation and increased contractility for example in exercise.
effect of noradrenaline / adrenaline on adrenoreceptors ?
agonist at a and b adrenoceptors
isoprenaline ?
non selective b agonist
phenylephrine ?
a1 agonist
non selective beta blockers such as propranolol ?
non selective beta blockers
metoprolol ?
selective beta one blocker