Lecture 13: Control of Blood Flow II Flashcards
What are the characteristics of hypertension?
increased cardiac output
increased sympathetic nerve activity
increase in angiotensin II and aldosterone levels
impairment of renal pressure natriuresis mechanism
inadequate secretion of salt and water
what is primary hypertension? major factors?
unknown origin
major factors: weigh gain, sedentary lifestyle
What is secondary hypertension?
hypertension second to some other cause such as:
tumor affecting renin secreting juxtaglomerular cells
renal artery constriction
coarctation of the aorta
preeclampsia
neurogenic hypertension
genetic causes
What are the contributing factors to hypertension?
genetic factors single gene disorder that alters sodium reabsorption by the kidneys genetic variants in the renin angiotensin system stress obesity smoking physical inactivity heavy consumption of salt
What are the Factors resulting in decreased peripheral resistance (vessel dilation) leading to decreased blood pressure?
Increased production of nitric oxide
• Increased release of prostacyclin
• Increased release of kinins
• Increase in atrionatriuretic peptide (ANP)
• Decreased neural factors (β-adrenergic)
What factors result in decreased cardiac output leading to decreased blood pressure?
- Decreased blood volume
- Decreased heart rate
- Decreased contractility
Factors resulting in increased cardiac output leading to increased blood pressure:
- Increased heart rate
- Increased contraction
- Increased blood volume (due to aldosterone)
Factors resulting in increased peripheral resistance leading to increased blood pressure:
- Increased angiotensin II
- Increased catecholamines
- Increased thromboxane
- Increased neural factors (α-adrenergic)
What are humoral vasoconstrictors?
- Angiotensin II
- Catecholamines
- Endothelin
What are humoral vasodilators?
- Kinins
- Prostaglandins
- Nitric oxide
What are the renal causes of hypertension?
- Chronic renal disease
- Renal artery stenosis
- Renin-producing tumors
- Acute glomerulonephritis
- Polycystic disease
- Renal vasculitis
What are the endocrine causes of hypertension?
- Cushing syndrome (adrenocortical hyperfunction)
- Exogenous hormones (i.e., glucocorticoids, estrogen)
- Pheochromocytoma
- Acromegaly
- Hypothyroidism (myxedema)
- Hyperthyroidism (thyrotoxicosis) • Pregnancy induced
What are the cardiovascular causes of hypertension?
- Coarctation of the aorta
- Polyarteritis nodosa
- Increased intravascular volume
- Rigidity of the aorta
- Increased cardiac output
What are the neurological causes of hypertension?
- Psychogenic
- Increased intracranial pressure
- Sleep apnea
- Acute stress
What are the lethal effects of chronic hypertension?
- Early heart failure and coronary artery disease
- Cerebral infarct
- Kidney failure
What is atherosclerosis?
type of arteriosclerosis “hardening of the arteries”
presence of lesions within the intimate of the vessel wall that protrude not the vessel lumen
What are the non modifiable risk factors of atherosclerosis?
age
gender
genetics
What are the modifiable risk factors of atherosclerosis?
hyperlipidemia
hypertension
cigarette smoking
diabetes
What are other risk factors of hypertension?
inflammation hyperhomocystinemia metabolic syndrome Lipoprotein (a) Factors affecting hemostasis Life style: • Lack of exercise • Competitive, stressful life style: • Obesity
What is hyperhomocystenima?
inborn error of metabolism
What is metabolic syndrome?
associated with insulin resistance
What is the pathogenesis of atherosclerosis?
endothelial injury or dysfunction of any kind leading to intimal thickening and may lead to formation of atheroma in presence of hyperlipidemia
What does the accumulation of lipoproteins the result of?
chronic hyperlipidemia
What is an atheroma?
a cap of smooth muscle cells, macrophages, foam cells (converted macrophages), and other extracellular components, overlying a necrotic center composed of cell debris, cholesterol, foam cells, and calcium.
What happens in the developmental stage of atherosclerosis?
- earliest lesions are fatty streaks
- plaques appear white or yellow
- plaques enlarge due to cell death and degeneration synthesis/degradation of extracellular matrix
- plaque may undergo calcification
- plaque may rupture, ulcerate, or erode
What the the most common arterial sties (most involved to least)?
- Lower abdominal aorta
- Coronary arteries
- Popliteal arteries
- Internal carotid arteries
- Circle of Willis
Short term control of arterial pressure via _____
sympathetic nervous system effects on:
- Total peripheral vascular resistance and capacitance
- Cardiac pumping ability
Long term control of arterial pressure via _____
Via multiple nervous and hormonal controls
Via local controls in kidney that regulate:
-Salt and water excretion
Return of the arterial pressure always back to the equilibrium point = _______
near infinite feedback gain principle
What is chronic hypertension?
one’s mean arterial pressure is greater than the upper range of the accepted normal measure
What is normal blood pressure?
90 mm Hg (110/70)
What is hypertensive blood pressure?
110 mmHg (135/90)
What is severe hypertension?
150/170 mmHg (250/130)
What are the lethal effects of chronic hypertension?
early heart failure coronary heart disease heart attack cerebral infarct destruction of areas of kidney--kidney failure ---uremia--death
