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Cardiovascular Adjustments

Cardiovascular Adjustments

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Cardiovascular Adjustments

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  1. Cardiovascular Adjustments Prof. K. Sivapalan

  2. Cardiovascular adjustment in exercise [isotonic]. • Skeletal muscles require more nutrients and produce more wastes and heat. • CVS, RS, and other systems has to adjust to meet the needs. • The muscles respond to impulses in motor nerves in any exercise: fight of flight. • The needs of muscles are met by various mechanisms. Regional Circulation

  3. Nervous adjustments. • As the brain perceives the idea of exertion and starts planning appropriate movements, hypothalamus also becomes activated. • It activates the sympathetic system and inhibits parasympathetic system. • This brings anticipatory changes in heart and circulation. • These changes are reinforced when exertion begins through impulses from proprioceptors. Regional Circulation

  4. Anticipatory changes. • Heart rate and force increase. • Blood pressure increases- systolic. • Splanchnic, renal, coetaneous flow reduce. • ? Vasodilatation in skeletal muscles. [vaso dilator nerves]. • Dilatation in coronary vessels but no change in cerebral flow. • Adrenal medulla and cortex increase secretions. [detail after study of endocrines] Regional Circulation

  5. Changes due to muscle action. • Muscle pump increases venous return and the cardiac output. • Metabolites cause local vasodilatation. Other effects: • Increased heat stimulates thermo-regulatory center and causes coetaneous vasodilatation. • Respiratory pump. • Increased oxygen extraction. Regional Circulation

  6. Net circulatory changes. • Increased heart rate and force of contraction. • Increased end-diastolic volume. • Decreased end-systolic volume. • Increased cardiac output. • Muscular, skin and coronary vasodilatation. • No significant change in cerebral flow. • All other places- vasoconstriction. • Slightly decreased peripheral resistance. • Increased systolic and decreased diastolic pressure Regional Circulation

  7. Isometric exercise. • Sustained muscle contraction. • Increase in peripheral resistance. • Systolic and diastolic pressure increase. • ? Yoga. Regional Circulation

  8. Effects of training. • Inrease in stroke volume. • Decrease pulse rate. • Quick return to basal valuse after exercise. • Reduced coagulability. • Healthy vessels. • Muscle and bone development. • [Feeling better.] Regional Circulation

  9. Hemorrhage. • Loss of blood- reduced blood volume • Reduced venous return. • Reduced cardiac output. • Reduced blood pressure. • Heart rate increases before pressure drops. Regional Circulation

  10. Compensation to hypovolemia. • Anxiety and excitement stimulate sympathetics and adrenals. • Reduced stretch of baro receptors: • Less inhibition to VMC. • Less stimulation to CIC. • Renal compensation- renin – angeotensin – aldesteron. • Tissue fluid dynamics. Regional Circulation

  11. Severe hemorrhage. • Moderate loss- as in blood donation: • Effective compensation by mobilizing venous reservoir. • If unable to compensate: • Circulation mainly to vital organs. • Severe peripheral vaso constriction. • Tachycardia. • Reduced pulse pressure – thready pulse. • Reduced tissue fluid. • Prolong reduced perfusion – acidosis. Regional Circulation

  12. Shock. • Peripheral circulatory failure. • Emergency- if not recovered goes in irreversible shock and death. • Causes: • Hypovolemic • Cardiogenic. • Distributive. [anaphylactic or septic] • Neurogenic [pain, fear] Regional Circulation