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Regulation in cardiovascular system

Regulation in cardiovascular system. Types of regulation - general view. 2 basic types : Nervous regulation Humoral regulation Feedback control - negative - positive autoregulation – local regulation – system regulation.

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Regulation in cardiovascular system

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  1. Regulation in cardiovascularsystem

  2. Typesofregulation- generalview 2 basic types: • Nervousregulation • Humoralregulation • Feedback control - negative • - positive autoregulation – localregulation – systemregulation

  3. REGULATION IN CARDIOVASCULAR SYSTEM Mainfunction: • keeprelativelyconstantaneousarterialbloodpressure • Keepperfusionoftissues

  4. Regulationofvessels tone • Tone ofthevessels = basic tensionofthesmoothmuscleinsideofthewall (vasoconstriction x vasodilatation) • Regulation - localautoregulation - systemregulation

  5. Autoregulation Autoregulation – thecapacityoftissues to regulatetheirownbloodflow Myogenictheory – Baylissphenomenon (as thepressurerises, thebloodvessels are distended and thevascularsmoothmusclefibresthatsurroundthevesselscontract; thewalltensionisproportional to thedistendingpressuretimestheradiusofthevessels – lawofLaplace)

  6. Autoregulation • Metabolictheory–vasodilatorsubstancestend to accumulate in activetissue, and these metabolitesalsocontribute to autoregulation • endingproductsofenergeticmetabolism – CO2, lactate acid, K+ • effectofhypoxia(circulation: vasodilatation x pulmonarycirculation: vasoconstriction) • Adenosin – coronarycirculation: vasodilatation

  7. Autoregulation • by substanceswhichreleasingfrom: • endothelium • tissues

  8. Substancessecreted by the ENDOTHELIUM Vasodilatation: Nitric oxide (NO) fromendothelialcells (originallycalled: EDRF) Prostacyclinisproduced by endothelialcells Thromboxane A2 promotesplateletaggregation (importantprostacyclin – thromboxan balance) Vazoconstriction: Endothelins (polypeptids – 21peptides) threeisopeptides: ET 1, ET 2 , ET 3

  9. Substancessecreted by thetissues: Histamine –primarilytissuehormones. General affect: vasodilatation - decreaseperiphery resistence, bloodpressure KININS: 2 relatedvasodilatedpeptides Bradykinin + lysylbradykinin (kallidin). Sweatglands, salivaryglands 10x strongersthan histamine Relaxationofsmoothmuscle, decreasebloodpressure

  10. Systemicregulation By hormones Catecholamines – epinephrine, norepinephrine - effect as activationofsympatheticsystem RAAS - stress situation ADH - generalvasoconstriction Natriuretichormones - vasodilatation

  11. Neuralregulatorymechanism Autonomicnervoussystem Sympathetic: vasoconstriction Allbloodvesselsexceptcapillaries and venulescontainsmoothmuscle and receive motor nerve fibersfromsympatheticdivisionof ANS (noradrenergicfibers) • Regulationoftissuebloodflow • Regulationofbloodpressure Parasympathetic part: vasodilatation Onlysacralparasympatheticcholinergicfibres (Ach) inervatedarteriolsfromexternal sex organs

  12. INTEGRATION ofregulationin cardiovascularsystem Theregulationoftheheart: • Rami cardiaci n. vagi Cardiacdecelerator center - medula oblongata (ncl.dorsalis, ncl. ambiguus) – parasympatheticfibresofnervus vagus : vagal tone (tonicvagaldischarge) Negative chronotropiceffect (on heartrate) Negative inotropiceffect (on contractility) Negative dromotropiceffect (on conductivetissue)

  13. INTEGRATION ofregulationin cardiovascularsystem Theregulationoftheheart: • nn. cardiaci Cardiacaccelerator center – spinalcord, sympathetic ganglia – sympathetic NS Positive chronotropiceffect (on heartrate) Positive inotropiceffect (on contractility) Positive dromotropiceffect (on conductivetissue)

  14. INTEGRATION ofregulationin cardiovascularsystem Vasomotor centre (regulationforfunctionofvessels) Medula oblongata • presoric area (rostral and lateral part –vasoconstriction – increasebloodpressure • depresoric area (medio-caudalis part – vasodilatation, decreaseofbloodpressure)

  15. INTEGRATION ofregulationin cardiovascularsystem • Influence by centralnervoussystem • cerebralcortex • limbiccortex • hypothalamus

  16. Regulationofbloodpressure • Short - term regulation • - baroreflex • Middle - term regulation • - humoralsregulation • sympathetic - catecholamines • RAAS • ADH • Long – term regulation • - kidneyregulation

  17. Classification BP values AccordingtheGuidelinesofEuropean Society ofCardiology 2013

  18. Variability ofcirculatoryparameters • Heartrate • Bloodpressures – systolic and diastolic • variability expresses itsfluctuation around the average value at certain time intervals (or in various conditions)

  19. HeartRate Variability (HRV) • Informsusabout the activity of the vagus nerve (tonicactivityofn.vagus = vagal tone) • Timeanalysis: • fromHolter monitoring ECG or 5 - 30min records ECG • It is basically a statistical evaluation +/-standard deviation • Disables intervals differing by more than 20% from the average, thus further processed only normal(NN)intervals and evaluated by the standard deviation of all NN sequence for 24h

  20. Spectralanalysis: • Carried out under standard conditions at various maneuvers (supine, standing); evaluated with 300 representative intervals RR / NN / • Another mathematical processing (Fourier transform) -length RR intervals are converted to cycles in Hz • The spectrum is divided into several components - low (LF: the sympathetic modulation) and high frequency (HF: vagal modulation) • People with reduced heart rate variability have a 5 times higher risk of death

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