1 / 18

Cardiovascular System Part 2

Cardiovascular System Part 2. Circulation Heart Anatomy Contraction Blood Pressure Cardiac Action Potentials EKG. Circulation. Pulmonary Circuit: R. atrium R. ventricle Pulmonary arteries Lung capillaries Pulmonary veins Systemic Circuit: L. atrium L. ventricle Aorta

hien
Download Presentation

Cardiovascular System Part 2

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 System Part 2 Circulation Heart Anatomy Contraction Blood Pressure Cardiac Action Potentials EKG

  2. Circulation • Pulmonary Circuit: • R. atrium • R. ventricle • Pulmonary arteries • Lung capillaries • Pulmonary veins • Systemic Circuit: • L. atrium • L. ventricle • Aorta • Systemic arteries • Organ & tissue capillaries • Systemic veins • Vena cavas

  3. Circulation • Atherosclerosis= cholesterol and lipid buildup on and in the walls of vessels. • Increased thickening  increased pressure  thickening  decreased elasticity potential clotting

  4. Circulation • Aneurysm= swelling or dilation of aorta or other blood vessels • May lead to rupture • May be caused by: • Aging breakdown of elastic fibers • Atheroscleosis • Genetic disorders • Infection

  5. Heart Anatomy • Myocardium= cardiac muscle tissue • Pericardium= tough fibrous sac around the heart

  6. Heart Anatomy

  7. Heart Anatomy

  8. Contraction • Heartbeat= one cardiac cycle; one contraction/ relaxation • Systole= contraction • Diastole= relaxation • Contraction of a chamber causes an increase in pressure that opens the valve to the next chamber. • “Lub-Dub” sound produced by the closing of AV and semilunar valves respectively.

  9. Blood Pressure • Blood pressure= pressure exerted by the blood against the vessel walls • Normal = 120/80 • 120: systolic pressure; highest pressure • 80: diastolic pressure; lowest pressure • Hypertension= high blood pressure  increased resistance to flow  enlargement and weakening of heart

  10. Blood Pressure

  11. Cardiac Action Potentials • Self-excitatory pacemaker cells= • Spontaneously produce action potentials • Intercalated discs= • Bridge plasma membranes between 2 cardiac cells • Offer almost a spontaneous contraction of many cardiac cells at once

  12. Cardiac Action Potentials • Pacemakers: • Sinoatrial (SA) node: • initiates atrial contraction • Sends signal from location in the R. atrium through the left atrium • Atrioventricular (AV) node: • Located in the septum • When SA signal is received at AV node there is a slow response • The AV node sends the signal down the purkinje fibers • Ventricles contract

  13. Cardiac Action Potentials

  14. EKG (aka ECG) • Electrocardiogram • Evaluates electrical events in the heart • Reads a potential difference between electrodes on the skin • Measures change in ECF currents, not in individual cells

  15. EKG (aka ECG) • P-wave= atrial depolarization • QRS-complex= ventricular depolarization (w/atrial repolarization) • T-wave= ventricular repolarization

  16. EKG (aka ECG) • Little to no summation in cardiac muscle: • No tetanic contraction • Refractory period: • Time after excitation when cells can not reach action potential • Allows for ventricular filling • Caused by the slow inactivation of sodium channels

  17. EKG (aka ECG) • Arrhythmia= • Irregular heart rhythms • Pacemakers irregular • Detectable by EKGs • Ex) • Bradychardia – fewer beats/min than average • Tachychardia – many more beats/min than average • Ventricular fibrillation – haphazard contractions

  18. EKG (aka ECG) More arrythmias: http://www.rnceus.com/course_frame.asp?exam_id=16&directory=ekg

More Related