1 / 79

Cardiovascular System (A&P)

Cardiovascular System (A&P). The Cardiovascular System. A closed system of the heart and blood vessels The heart pumps blood Blood vessels allow blood to circulate to all parts of the body

elina
Download Presentation

Cardiovascular System (A&P)

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 (A&P)

  2. The Cardiovascular System • A closed system of the heart and blood vessels • The heart pumps blood • Blood vessels allow blood to circulate to all parts of the body • The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

  3. The Heart Figure 11.1

  4. The Heart: Coverings • Pericardium – a double serous membrane • Visceral pericardium • Next to heart • Parietal pericardium • Outside layer • Serous fluid fills the space between the layers of pericardium

  5. The Heart: Heart Wall • Three layers • Epicardium • Outside layer • This layer is the parietal pericardium • Connective tissue layer • Myocardium • Middle layer • Mostly cardiac muscle • Endocardium • Inner layer • Endothelium

  6. External Heart Anatomy Figure 11.2a

  7. Myocardium is criss-crossed and arranged in figure 8-shaped bundles shown in (b). MYOCARDIUM IS CRISS-CROSSED

  8. Intercalated disks convey the force of contraction from cell to cell and propagate action potentials Muscle tissue is CONTRACTILE tissue. Cardiac Muscle Cells are Small, w/ a single nucleus. Short cells. Involuntary contractions Myocardium = Muscular Wall =Cardiac Muscle

  9. The Heart: Chambers • Right and left side act as separate pumps • Four chambers • Atria • Receiving chambers • Right atrium • Left atrium • Ventricles • Discharging chambers • Right ventricle • Left ventricle Figure 11.2c

  10. The Heart: Associated Great Vessels • Aorta • Leaves left ventricle • Pulmonary arteries • Leave right ventricle • Vena cava • Enters right atrium • Pulmonary veins (four) • Enter left atrium

  11. Blood Vessels • Arteries- Are have thick walls and are Elastic. They Carry blood away from the heart. Arteries become smaller arterioles and branch into capillaries. • Veins-Carry blood to the Heart. Veins become smaller venules and and connect with the capillaries • Capillaries - Exchanges between cells and nutrients/oxygen occur here only.

  12. Blood Circulation Figure 11.3

  13. DOUBLE PUMP

  14. Dichotomous Functions for Left & Right Side of Heart • Left Side: Collects oxygen-rich blood, which has just passed through the lungs, and pumps it to the rest of the body and brain. The is called systemiccirculation. • Right Side : Collects oxygen-poor blood from the body and brain and pumps to the lungs where it picks up oxygen. This is called pulmonarycirculation.

  15. What are the Heart Valves? • These ensure that blood flows in one direction..no back flow • 2 are the atrioventricular valves and 2 are the semilunar valves. • Artioventricular: Bicuspid has 2 cusps or valves and Tricupid has 3. • Semilunar valves are found within entrances of arteries extending from ventricles • PULMONARY semilunar and AORTIC semilunar

  16. A Mitral’s Headress

  17. The Heart: Valves • Allow blood to flow in only one direction • Four valves • Atrioventricular valves – between atria and ventricles • Bicuspid valve (left)(also called Mitral) • Tricuspid valve (right) • Semilunar valves between ventricle and artery • Pulmonary semilunar valve • Aortic semilunar valve

  18. The Heart: Valves • Valves open as blood is pumped through • Held in place by chordae tendineae (“heart strings”) • Close to prevent backflow

  19. What Can Go Wrong With Valves? Scarred Valves Sometimes become STENOTIC (THEY CUFFS BECOME STIFFED AND CONSTRICT…DON”T OPEN) Valvular Stenosis Heart then overworks to force blood through and valves become enlarged Backflow (regurgitation) through these new incompetent valves creates turbulence or HEART MURMER.

  20. Mitral Valve Prolapse • One or both of the bicuspid valve cusps bulge into the atrium during vertricular contraction. • Hereditary: 1in 40, more in women • In many cases no serious problems but may cause chest pain , fatigue and shortness of breath.

  21. REGURGITANT VALVE • HEART VALVES THAT STAY OPEN • OR ARE TOO WIDE AND LET BACKFLOW OF BLOOD INTO VENTRICLE

  22. How Does My Heart Beat? Intrinsically by the NODAL System:

  23. Heart Contractions Figure 11.5

  24. The Heart: Conduction System • Special tissue sets the pace • Sinoatrial node • Pacemaker • Atrioventricular node • Atrioventricular bundle • Bundle branches • Purkinje fibers

  25. Vasodilation- BLOOD VESSEL ENLARGES • Vasoconstriction- BLOOD VESSEL CONSTRICTS

  26. Why Does My Heart Beating Faster or Slower? • Several Reasons: But Remember the input of the ANS: The Autonomic Nervous System:Sympathetic Nervous: Fight or Flight- speeds it up Parasympathetic slows it down • Remember that SNS and PNS are for the most part antagonistic.

  27. Sympathetic Nervous System • Epinephrine and Norepinephrine are both produced by the medulla of the adrenal glands. • These hormones are produced during times of stress..such as fear or extreme exercise. • Result: Increase in contraction, heart rate and blood pressure.

  28. Blood Vessels • Arteries- Are have thick walls and are Elastic. They Carry blood away from the heart. Arteries become smaller arterioles and branch into capillaries. • Veins-Carry blood to the Heart. Veins become smaller venules and and connect with the capillaries • Capillaries - Exchanges between cells and nutrients/oxygen occur here

  29. The Pathway Back To the Heart

  30. Critical Factor Concerning Arteries: ELASTICY • If arteries are HEALTHY, they are clear and very elastic. They can accommodate greater CO.as they S..T..R..E..T..C…H • Use equation for Pressure equals F/a to show this.

  31. The Pressure Continuously falls As We Go From Start To Finish !

  32. VITAL SIGNS • PULSE- an alternating expansion and recoil of an artery that occurs with each beat of the left ventricle and creates a pressure wave. • PRESSURE POINT- a point where an artery surfaces an area of the body.

  33. Pressure Points

  34. Resting Heart Rate • The number of beats per minute • Average is 70-80 • Athletes; 50-60 • Well trained Athletes 40-50 Why? As you get in better shape, your heart will automatically pump more blood with each beat; and therefore, the rate of contractions (that’s the number of times it beats) will be less when doing the same amount of work. Less heart stress results in more energy saved.

  35. Cardiac output (CO) • Amount of blood pumped by each side of the heart in one minute • CO = (heart rate [HR]) x (stroke volume [SV]) • Stroke volume • Volume of blood pumped by each ventricle in one contraction

  36. Starling’s Law • States that the critical factor controlling stroke volume is how much the cardiac muscle cells are STRETCHED….just before they contract. • Factors that stretch the heart: • Anything that increases venous return; EXERCISE……INCREASE STROKE VOLUME • .

  37. What would decrease stroke volume? • Anything that decreases venous return ( Blood loss

  38. Factors Affecting Blood Pressure • Neural Factors: The Sympathetic Nervous System • Renal Factors • Temperature • Chemicals (Nicotine, Alcohol, Histamine) • Diet (Na+)

  39. 120/80? Where’d ga get these? • Blood Pressure is calculated as Systolic over Diastolic in mmHg SO we are referring to the CARDIAC CYCLE

  40. The Heart: Cardiac Cycle • Cardiac cycle – events of one complete heart beat • Mid-to-late diastole – blood flows into ventricles • Ventricular systole – blood pressure builds before ventricle contracts, pushing out blood • Early diastole – atria finish re-filling, ventricular pressure is low

  41. SYSTOLE- period when the heart CONTRACTS ( blood pressure is highest when left ventricle is contracting or ejecting into the aorta….120) • DIATOLE- when the heart RELAXES

  42. Blood Pressure • We speak of arterial blood pressure in terms of two measurements; on and off. In other words when the heart contracts or is in SYSTOLE the arterial pressure is highest or at its peak. When the heart is relaxing or in DIASTOLE it BP is at the lowest . • BP is measured in ml. and the Brachial artery of arm is used for this test. • Blood Pressure is related to Cardiac Output times Peripheral Resistance ( the amount of friction encounter as blood tries to flow through the vessel)

  43. So How Doe it Work? 1. Pump cuff until pressure cuts off artery flow. 2. Release cuff SLOWLY so blood will spurt ..this happens only during ventricular contraction ( SYSTOLE) THE FIRST SOUND YOU HEAR 4. Listen until you hear no more clicking. This means blood is flowing continously ..no more spurting…Ventricular relaxation..DIASTOLE

  44. Measuring Arterial Blood Pressure Figure 11.18

  45. Age (years) Systolic pressure (mmHg) Diastolic pressure (mmHg) New-born 80 46 10 103 70 20 120 80 40 126 84 60 135 89 Table 1. Some 'average'

  46. Blood Pressure • Measurements by health professionals are made on the pressure in large arteries • Systolic – pressure at the peak of ventricular contraction • Diastolic – pressure when ventricles relax • Pressure in blood vessels decreases as the distance away from the heart increases

More Related