Hypertension Pathophysiology Flashcards
Define systolic blood pressure
the force that blood exerts on the artery walls as the heart contracts to pump out the blood
Define diastolic blood pressure
the measurement of force as the heart relaxes to allow the blood to flow into the heart. High diastolic pressure is a strong predictor of heart attack and stroke in young adults
What is the equation for mean arterial pressure?
MAP = (CO*SVR) + CVP
How is pulse pressure an indicator of stiffness and inflammation in blood vessel walls?
The greater the difference between systolic and diastolic numbers, the stiffer and more injured the vessels are thought to be
Define peripheral vascular resistance (PVR)
the resistance to flow that must be overcome to push blood through the circulatory system
Define systemic vascular resistance (SVR)
The resistance offered by the peripheral circulation
How do the arterial barorecptors effect BP?
located on the carotid sinus (at the bifurcation of the external and internal carotids) and in the aortic arch. respond to stretching of the arterial wall. Inhibits central sympathetic discharge
Of the arterial barorecptors, which is more important for regulating BP?
The carotid sinus. Aortic arch receptors have a higher threshold pressure and are less sensitive than the carotid sinus receptors
What is the responsibility of the arterial baroreceptors?
Rapid moment to moment adjustments in B/P (Change in position). With chronic changes, the baroreceptors tend to “reset” to adjust to the increasing CO or arterial pressure and are not as good at regulating
What are the chemoreceptors?
Located in the carotid bodies. Sensitive to changes in oxygen, carbon dioxide, and hydrogen ion concentration. Communicate with the vasomotor center and can induce widespread vasoconstriction
What are the autonomic receptors?
Acetylcholine (parasympathetic): Cholinergic receptors. Norepinephrine (sympathetic): Adrenergic receptors. Two types of adrenergic receptors: alpha and beta. stimulation of alpha causes vasoconstriction and beta causes vasodilation
How is PVR determined?
by small arterioles, the walls of which contain smooth muscle cells. Prolonged smooth muscle constriction is thought to induce structural changes with thickening of the arteriolar vessel walls, leading to an irreversible rise in PVR
Explain RAAS
Renin, which is primarily released by the kidneys, stimulates the formation of angiotensin in blood and tissues, which in turn stimulates the release of aldosterone from the adrenal cortex.
Where is renin secreted from?
the juxtaglomerular apparatus of the kidney located in the wall of the afferent arteriole. released in response to glomerular underperfusion or a reduced salt intake
What are the important functions of angiotensin II?
Constricts resistance vessels, Acts on the adrenal cortex to release aldosterone, Stimulates the release of vasopressin, Stimulates thirst centers, and Facilitates norepinephrine release and inhibits norepinephrine re-uptake by nerve endings
