wk 9, lec 1 Flashcards
(101 cards)
how common is hypertension
Affects > 1 billion people, prevalence in those older
than 60 is > 60%
risk factors for hypertension
▪ Ischemic heart disease and congestive heart failure ▪ Peripheral arterial disease
▪ Dementia, stroke, and chronic kidney disease
effects of medications on hypertesnion
antihypertensive therapy reduces the risk of the above complications
▪ However, it is estimated that over half are not treated at all or are inadequately treated
what organ systems are involved in hypertension
▪ Central and peripheral nervous system
▪ Endocrine system
▪ Kidney
▪ Vascular system
▪ Digestive system, microbiome, and DIET
▪ Immune system
common factors in primary hypertension
▪ Arteriolar vasoconstriction and altered endothelial function
▪ Increased sodium retention & increased renin secretion
▪ Increased activation of the sympathetic nervous system
hypertension ____ resistance and ____ lumen size and ____ average resting muscle tone
increase, decrease, increase
increase in vessel wall thickness increases the resistance
what is the major site where total peripheral resistance is regualted
arterioles
what is vascular tone under the control of
hormonal, neural and local endothelial factors
what remodelling happens to the arteriole wall in hypertension
arteriosclerosis;;
▪ Hypertrophy and sometimes hyperplasia of smooth muscle cells
▪ Increased deposition of extracellular matrix
in hypertension the vascular endothelium releases ___ vasodilator susbtances (i.e. Nitric oxide)
less
remodelling of larger vessels in hypertension
become more stiff
arteriosclerosis
what organs can vascular changes to arterioles and arteries be seen in a lot
kidneys (regulate blood pressure)
initial vs chronic hypertesnion changes
initial: hypertrophy of smooth muscle cells –> hypererreactive to vascoactivite stimuli
chronic: arteriosclerosis; fibromuscular intimal thickening by new layers of elastin, reduplication of intimal elastic lamina, increased connective tissue, accumulate plasma proteins and basement membrane deposition
what happens with sodium intake increases beyond usual ability of kidney to excrete sodium
increased sodium –> increased blood volume –> increased mean arterial pressure
▪ Most arterioles will constrict in response to this increased pressure (remember autoregulation) to reduce flow to capillary beds
▪ Increased pressure at the kidney –> increased salt and water loss… however, it is thought that in hypertensive patients over time it takes higher and higher pressures to attain the same level of salt loss
what happens to the nervous system in hypertension? why?
increase SNS outflow; baroreceptors in brainstem reset to new higher normal
what do baroreceptor dysfunction causes
decrease afferent inhibitory signals
increase SNS
decrease limb blood flow
increase vasopressin, renin, angiotensin II
decrease renal blood flow
increase aldosterone secretion, sodium reabsorption, water reabsorption
Increased activation of the sympathetic nervous system leads to:
- Vasoconstriction of systemic arterioles (alpha-1 receptors)
- Increased ADH (vasopressin) release (increased water retention)
- Increased release of renin and AT2 (angiotensin II)
which receptor in RAAS is implicated in hypertension
the aldosterone receptor has been found in blood vessels outside the kidney and has been implicated in abnormal vascular function
where do leukocytes/WBC migrate into in hypertension
▪ The kidneys – well-known
▪ Vascular walls – knowledge is developing
what activates leukocytes (Th17 and ILC3) in hypertension and what are they implicated in
activated by increased extracellular sodium
mplicated and are likely involved in remodeling the vasculature both within and outside the kidney
how do insulin resistance and obesity link to hypertension
mpaired vasodilatory function of the vascular endothelium
▪ Weight loss and improved insulin sensitivity are associated with improved blood pressure, but there are many factors here to consider (i.e. improvements in diet)
▪ Interestingly, renal sodium-glucose cotransporters are closely integrated with sodium handling in the kidney
hypertension and atherosclerosis of renal arteries
Hypertension is one of the major risk factors for development of atherosclerosis, and atherosclerosis of the renal arteries can cause hypertension
▪ Reduced blood flow to the kidney –> increased secretion of renin –>vasoconstriction and sodium retention
primary vs secondary hypertension %
primary 90%
secondary 10%
causes of secondary hypertesnion impact which systems
kidneys and SNS mostly