Introduction to the_cardiovascular_system


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Introduction to the_cardiovascular_system

  1. 1. Introduction to the Cardiovascular System Chapter 13 Unit 4: Transport
  2. 2. Introduction <ul><li>Primary function of the cardiovascular system is to pump blood throughout the body </li></ul><ul><ul><li>Recall that blood is a transport medium for oxygen, nutrients, and wastes </li></ul></ul><ul><li>CV System is a closed circuit </li></ul><ul><ul><li>Blood is contained in blood vessels </li></ul></ul>
  3. 3. Introduction <ul><li>There are two main components to the CV system </li></ul><ul><ul><li>Cardio - refers to the presence of the heart, which is the major pump for the body </li></ul></ul><ul><ul><ul><li>Transporting 7,000 liters of blood every day. </li></ul></ul></ul><ul><ul><ul><li>Beats 2.5 billion times in a lifetime </li></ul></ul></ul><ul><ul><li>Vascular - refers to the vessels that contain blood </li></ul></ul><ul><ul><ul><li>Blood is forced from the heart into arteries, arterioles, capillaries, venules, and veins in that order </li></ul></ul></ul><ul><ul><ul><li>Each blood cell circulates through the body’s CV system in about a minute </li></ul></ul></ul>
  4. 4. Circuits of the Cardiovascular System <ul><li>The cardiovascular system can be divided into two circuits: </li></ul><ul><ul><li>Pulmonary Circuit </li></ul></ul><ul><ul><ul><li>Sends deoxygenated blood to lungs to pick up oxygen and unload carbon dioxide </li></ul></ul></ul><ul><ul><ul><li>Involves the right side of the heart </li></ul></ul></ul><ul><ul><li>Systemic Circuit </li></ul></ul><ul><ul><ul><li>Sends oxygenated blood and nutrients to all body cells and removes wastes </li></ul></ul></ul><ul><ul><ul><li>Involves the left side of the heart </li></ul></ul></ul>
  5. 6. Paths of Circulation <ul><li>Pulmonary Circuit: </li></ul><ul><ul><li>Blood in the right side of the heart is O 2 -poor </li></ul></ul><ul><ul><li>Right side of heart pumps blood into the pulmonary trunk/arteries that transport blood to the lungs </li></ul></ul><ul><ul><li>Once blood becomes rich in O 2 it returns to the left side of the heart through the pulmonary veins </li></ul></ul>
  6. 7. Paths of Circulation <ul><li>Systemic Circuit: </li></ul><ul><ul><li>Blood returning to the heart from the lungs enters the left side of the heart </li></ul></ul><ul><ul><li>Heart pumps blood into the aorta , which branches into smaller and smaller arteries throughout the body </li></ul></ul><ul><ul><li>Blood returns to the right side of the heart via the superior and inferior vena cavae after unloading its supply of O 2 in the body’s cells </li></ul></ul>
  7. 8. Paths of Circulation <ul><li>Heart Animation </li></ul>
  8. 9. What would happen without circulation in the body?
  9. 10. Structural Characteristics of the Heart <ul><li>The heart is: </li></ul><ul><ul><li>Hollow </li></ul></ul><ul><ul><li>Cone-shaped </li></ul></ul><ul><ul><li>Muscular </li></ul></ul><ul><ul><li>Found inside the thoracic cavity </li></ul></ul><ul><ul><li>Rests on the diaphragm </li></ul></ul>
  10. 12. Size and Location of the Heart <ul><li>Varies in size and shape, but the average adult heart is about 14 cm long and 9 cm wide. </li></ul><ul><ul><li>About the size of your fist. </li></ul></ul><ul><li>Rests in an opening called the mediastinum </li></ul><ul><ul><li>Bordered laterally by the lungs, posteriorly by the vertebral column, and anteriorly by the sternum </li></ul></ul>
  11. 14. Coverings of the Heart <ul><li>The heart is enclosed in a fibrous sack called the Pericardium (3 layers). </li></ul><ul><ul><li>Consists of an outer bag… </li></ul></ul><ul><ul><ul><li>Two layers </li></ul></ul></ul><ul><ul><ul><ul><li>Fibrous Pericardium - outermost layer </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Parietal Pericardium - deep to the fibrous p. </li></ul></ul></ul></ul><ul><ul><li>… and an inner bag </li></ul></ul><ul><ul><ul><li>Visceral Pericardium - deepest layer, continuous with the outermost layer of the heart. </li></ul></ul></ul>
  12. 17. Coverings Continued <ul><li>The fibrous pericardium serves as a point of attachment to: </li></ul><ul><ul><li>Diaphragm, sternum, vertebral column, and large blood vessels emerging from the heart </li></ul></ul><ul><li>The space between the parietal and visceral pericardia is called the pericardial cavity </li></ul><ul><ul><li>Contains serous fluid secreted by the visceral pericardium </li></ul></ul><ul><ul><li>Fluid serves to reduce friction between the membranes as the heart moves within them </li></ul></ul>
  13. 18. Walls of the Heart <ul><li>The walls of the heart are composed of three distinct layers of tissue: </li></ul><ul><ul><li>Epicardium </li></ul></ul><ul><ul><li>Myocardium </li></ul></ul><ul><ul><li>Endocardium </li></ul></ul>
  14. 20. Epicardium <ul><li>The Epicardium is the outermost layer of the heart muscle. </li></ul><ul><ul><li>Continuous with the visceral pericardium and protects the heart by reducing friction </li></ul></ul><ul><ul><li>Composed of serous membranes (connective tissue), epithelium, and deeper adipose tissue </li></ul></ul><ul><ul><ul><li>Adipose tissue is found predominantly along the paths of coronary arteries and cardiac veins that carry blood to the heart muscle itself </li></ul></ul></ul>
  15. 21. Myocardium <ul><li>The myocardium is the thick middle layer of heart muscle. </li></ul><ul><ul><li>Composed primarily of cardiac muscle tissue . </li></ul></ul><ul><ul><li>Used to pump blood out of the heart chambers </li></ul></ul><ul><ul><li>Myocardial muscle works continuously… needs a good supply of oxygen and sugar </li></ul></ul>
  16. 22. Myocardium <ul><li>These muscles are supplied by the coronary arteries , NOT THE BLOOD THAT IS IN THE CHAMBERS OF THE HEART!!!!! </li></ul><ul><ul><li>Coronary arteries branch off the aorta immediately after leaving the heart </li></ul></ul><ul><ul><li>This is the #1 site for plaque build-up, causing myocardial infarction (heart attack) </li></ul></ul>
  17. 23. Myocardium
  18. 24. Endocardium <ul><li>The endocardium is the innermost layer of the heart muscle. </li></ul><ul><ul><li>Consists of epithelium and connective tissue that contains many elastic and collagenous fibers (helps it stretch) </li></ul></ul><ul><ul><li>Contains Purkinje Fibers (aid in transmission of muscle impulses in heart) </li></ul></ul><ul><ul><li>Continuous with the inner linings of the blood vessels attached to the heart </li></ul></ul>
  19. 25. Heart Chambers <ul><li>The heart is divided into 4 hollow chambers-two on the right and two on the left: </li></ul><ul><ul><li>The upper chambers are called Atria </li></ul></ul><ul><ul><ul><li>Have thin walls and receive blood returning to the heart </li></ul></ul></ul><ul><ul><li>The lower chambers are called Ventricles </li></ul></ul><ul><ul><ul><li>Receive blood from the atria. </li></ul></ul></ul><ul><ul><ul><li>Thick walls that contract to force blood out of the heart into the arteries </li></ul></ul></ul><ul><ul><ul><ul><li>The right and left chambers are separated from one another by a solid, wall-like Septum </li></ul></ul></ul></ul>
  20. 26. Heart Chambers <ul><li>The right side of the heart is part of the pulmonary circuit </li></ul><ul><ul><li>Only deoxygenated blood passes through the right side </li></ul></ul><ul><li>The left side of the heart is part of the systemic circuit </li></ul><ul><ul><li>Only oxygenated blood passes through the left side </li></ul></ul><ul><li>*O 2 -rich and O 2 -poor blood do not mix in healthy individuals </li></ul>
  21. 28. Valves of the Heart <ul><li>Valves are flap-like tissue that prevents backflow of blood </li></ul><ul><ul><li>Keeps blood going in one direction only </li></ul></ul><ul><li>Four valves found in heart </li></ul><ul><ul><li>Tricuspid valve - b/w R. atrium and R. vent. </li></ul></ul><ul><ul><li>Pulmonary valve - at exit of R. vent. </li></ul></ul><ul><ul><li>Mitral (bicuspid) valve - b/w L. atrium and L vent. </li></ul></ul><ul><ul><li>Aortic valve - at exit of L. vent. </li></ul></ul>
  22. 29. Path of Blood Through the Heart <ul><li>Blood that is low in oxygen and high in carbon dioxide enters the right side of the heart and is pumped into the pulmonary circulation. </li></ul><ul><li>After blood is oxygenated in the lungs and some carbon dioxide is removed, it returns to the left side of the heart. </li></ul>
  23. 30. Greater Detail <ul><li>Deoxygenated blood FROM body enters the right atrium through the vena cavae. </li></ul><ul><li>Blood passes through the tricuspid valve and enters the right ventricle </li></ul><ul><li>Blood moves through the pulmonary valve and into the pulmonary trunk and the pulmonary arteries </li></ul><ul><li>Blood enters the capillaries (aveoli) of the lungs </li></ul>
  24. 31. More Detail <ul><li>Blood returns to the heart via the pulmonary veins into the left atrium </li></ul><ul><li>Passes through the mitral valve into the left ventricle </li></ul><ul><li>Blood moves through the aortic valve into the aorta and to the body </li></ul>