1 / 21

Cardiovascular physiology.

Cardiovascular physiology. Dr James Ker. 2 scenario`s in cardiology:. Systemic diseases affecting the cardiovascular system. Primary cardiovascular diseases. How can these diseases affect the cadiovascular system ?. Components of the cardiovascular system:

neona
Télécharger la présentation

Cardiovascular physiology.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cardiovascular physiology. Dr James Ker

  2. 2 scenario`s in cardiology: • Systemic diseases affecting the cardiovascular system. • Primary cardiovascular diseases.

  3. How can these diseases affect the cadiovascular system ? Components of the cardiovascular system: • Myocardium: myocarditis, cardiac failure etc • Valves: Stenosis, incompetence etc • Electrical system: Dysrhythmias. • Vessels: Arteries, veins, lymphatic vessels.

  4. Physiological disturbances: • Disturbances in the following may occur: • Blood pressure • Cardiac rhythm • Valvular function • Cardiac systole and diastole • Blood flow

  5. Blood pressure: • BP = Cardiac output (CO) x peripheral vascular resistance (PVR) • 3 components of blood pressure: • Systolic component • Diastolic component • Mean arterial pressure

  6. BP = 120/80 mmHg • Mean arterial pressure = (S + 2D)/3 or • D + 1/3 PP • Pulse pressure=S – D (120-80=40 mmHg)

  7. Cardiac output: • CO = Stroke volume x heart rate • Thus: 2 ways to increase CO: SV vs CO Determines systolic BP Systolic vs diastolic HT Normal CO: 5L/min Cardiac index=CO corrected for body surface area

  8. Causes of increased CO: • Fever • Anaemia • Hyperthyroidism • Pregnancy • Exercise • Etc..

  9. Presents as: • Systolic HT with: • ↑ pulse pressure • Stroke volume: Volume of blood pumped by ventricle during systole (70 ml at rest)

  10. Physiological control of CO: • Preload: Venous filling • Afterload: BP against which LV must expel stroke volume • Inotropy: Strength of myocardial contraction. Starling`s law, catecholamines

  11. Physiological control of heart rate: • Intrinsic: SA node • Extrinsic: Hormonal: thyroid, catecholamines Neurological: Autonomic nervous system Fever, electrolytes

  12. Peripheral vascular resistance: • Determined by diameter of peripheral arteries. • Determines diastolic blood pressure

  13. Control of PVR: • Hormonal: AT II, endothelins, NO, bradykinin, catecholamine etc • Neurological: Autonomic nervous system • Myogenic/Local.

  14. The ECG: • Einthoven`s trangle • Einthoven`s law

  15. Einthoven`s triangle: I + - - - III II + +

  16. Einthoven`s law: • Lead II = Lead I + Lead III • Standard limb leads: I, II, III • Lead I: connects 2 arms • Lead II: connects right arm with left leg • Lead III: connects left arm with left leg

  17. aV leads: • Limb leads are bipolar • Unipolar limb leads=aV leads: aVR, aVL and aVF

  18. Precordial (V) leads: • V1: Just to the right of the sternum in the 4`th intercostal space. • V2: Just to the left of the sternum in the 4`th intercostal space. • V3: Halfway between V2 and V4

  19. V4: Left midclavicular line in the 5`th intercostal space • V5, 6: 5`th intercostal space in anterior and midaxillary line respectively

  20. Physiological use of the ECG: • Rhythm: Sinus vs other • Chamber thickening: Atrial and ventricular hypertrophy • Damage: Endocardial, myocardial, pericardial • Info on systemic conditions: Hypothermia, electrolyte disturbances, pH disturbances

  21. Rate, complexes, intervals: • P-wave: Atrial depolarization • QRS-complex: Ventricular depolarization • T-wave: Ventricular repolariation

More Related