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Lecture 37
Cardiovascular Regulation-Hypertension
Term | Definition |
---|---|
Local Control | non neural factors. dec P leads to dec flow leads to homeostatic tissue response leads to inc flow autoregulation-each organ controls local blood flow |
Metabolic Vasodilators | active tissues produce vasodilators. ATP use leads to inc adenosine production. adenosine is a strong vasodilator-active hyperemia. |
Endothelial Factors | paracrines.released from endothelium,affect VSM |
Nitric Oxide | hormonal/neural activation. inc NO leads to relaxed VSM leads to inc blood flow |
Endothelium | peptide-constricts VSM. dec flow leads to inc BP. stimulates of E inc gene activity that makes E |
Baroreceptors | stretch receptors in carotid sinus and aortic arch.changes in BP after baroreceptor activity. |
Input to Medulla | baroceptors send neurons to medulla in the brain stem |
Control of Vasoconstriction/Dilation | cardiovascular control center CCC.is in medulla. ccc controls symp and parasymp output.homeostatic short term control of BP. sym: dec BP causes inc baroceptor input causes inc parasymp output causes dec BP (lower HR) |
Resetting | body adjusts to own "normal" BP. adaptation to prolonged BP change occurs over days |
Hypertension | chronic elevated BP. mult causes-several small changes cause large inc in BP. |
Cardiac Effects | hypertrophy against inc load (diastolic pressure) inc oxy use-heart attack when coronaries w/ age inc in systolic pressure inc stroke risk |
Essential Hypertension | cause unknown,treat symptoms. effective-reduces pathology |
Renal Hypertension | also called secondary hypertension. dec blood flow to kidneys cause inc kidney renin release. renin converts anglotensinogen to anglotensin 1 (A1). anglotensin converting enzyme ACE in lung capillaries converts A1 to anglotensin 2. and 2 inc blood pressur |
Renal Hypertension cont | ang 2 is a strong vasoconstrictor and causes aldosteron release from adrenal cortex aldosteron inc na+ reab and h2o reab by kidneys,more volume |
In Pregnancy | placental factor causes vasoconstriction pre-eclampsia is hypertension during pregnancy. magnesium sulfate treatment lowers BP |
Drug Treatments | often used in combo. varying side aeffects |
Diuretics | inc na+ secretion,lowers blood vol/dec BP |
ACE Inhibitors | block conversion of anglotensin 1 to ang 2 |
a-Adrenergic Receptor Blockers | stops symp constriction of VSM,blocks NE effects.fewer ca2+ channels open,less force |
b-Adrenergic Receptor Blocks | blocks NE/Epl effects on heart-less ca2+ entry.dec force of cardiac contractions |
Calcium Channel Blockers | dec VSM contraction,blocks tone |
Shock | very low BP. loss of blood,toxic vasodilation.reversible shock-can recover from. epinepherine inc BP-side effects sig. irreversible shock-mult organ failure due to low BP. death results. |