Understanding the Anatomy and Physiology of the Cardiovascular System

1. Cardiovascular system Anatomy & Physiology

2. Keith & His Gorgeous Cardiac Muscle • http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/circulatory/0_anatomy_circulatorysys_act.shtml

3. Heart General Info • Approximately the size of one’s fist • Found in the mediastinum • Supply blood to the body • Important role in immune system • http://www.phschool.com/science/biology_place/biocoach/cardio1/anatomy.html

4. Anatomy of the Cardiovascular System

5. Heart Anatomy • Covered with 2 linings-pericardium • Parietal layer-outer layer • Visceral layer-aka epicardium, inner layer that is attached to the myocardium • Linings filled with fluid to reduce the friction from beating heart • Heart wall • Myocardium-the heart muscle itself • Endocardium-inside the heart, lines the chambers • Septum-the muscular wall dividing the heart into right and left halves

6. Heart Anatomy • 4 chambers • 2 atria • Upper chambers • Receive blood • Right atria receives deoxygenated blood from the body • Left atria receives oxygenated blood from the lungs • 2 ventricles • Lower chambers • Left wall is 3x as thick as the right • Pumps blood away from the heart • Right ventricle send deoxygenated blood to lungs • Left ventricle sends oxygenated blood to body

7. Great Vessels • Vena cava-largest vein(s) • Superior-receives deoxygenated blood from upper body • Inferior-receives deoxygenated blood from lower body • Pulmonary arteries-carry deoxygenated blood to the lungs from the right ventricle • Pulmonary veins-carry oxygenated blood to the left atrium of the heart from the lungs • Aorta –largest artery, carries oxygenated blood to distribute to the rest of the body • http://www.phschool.com/science/biology_place/biocoach/cardio1/cycle.html

8. Cardiovascular Circuits • Pulmonary Circuit-transports blood from the right side of the hear to the lungs, then back to the left side of the heart • Systemic circuit-transports blood from the left side of the heart to all parts of the body and then backt to the right side of the heart • Coronary circuit-transports blood from the left side of the heart to the heart tissues and back to the right side of the heart

9. Valves • Tough fibrous tissues between the heart chambers and major blood vessels of the heart • Gate-like structures prevent the backflow of blood

10. Valves continued • Atrioventricular valves, or AV valves-between the atria and vetricles. When the ventricles contract, blood is forced upward and the valves close • Tricuspid valve-between the right atrium and the right ventricle • Bicuspid/mitral valve-between the left atrium and the left ventricle

11. Valves continued • Semilunar valves-3 half-moon pockets that catch blood and balloon out to close the opening • Pulmonic semilunar valve-between the right ventricle & the pulmonary arteries • Aortic semilunar valve-between the left ventricle and the aortic arch • http://www.phschool.com/science/biology_place/biocoach/cardio1/cycle.html

12. Cardiac Circulation • The blood supply to the heart • Aorta->coronary arteries->capillaries in the myocardium->coronary veins->coronary sinus->right atrium • Blood in the chambers nourishes the endocardium • The coronary circuit opens only during the relaxation phase of the cardia cycle • Occlusion of the coronary artery-a myocardial infarction (heart attack) occurs if collateral circulation is inadequate

13. Anatomy • Blood • Plasma • Erythrocytes • Hemoglobin – iron containing pigment of the erythrocytes that carries the oxygen • Reticulocyte-immature red blood cells • Macrophages

14. Anatomy • Blood continued • Leukocytes – white blood cells • Neutrophils-an elevation of this type usually indicates infection • Basophils • Eosinophils • Lymphocytes • Monocytes • Thrombocytes • Also known as platelets • Smallest formed elements of the blood

15. Anatomy • Blood continued • Blood types – decided on the presence of the A and/or B antigens on red blood cells. In type O, both antigens are absent. A patient receiving blood incompatible with his or her own can experience serious and possibly fatal reactions. • A • AB • B • O • Study chart on page 91

16. Heart Physiology

17. Nerve Supply to the Heart • Alters the rate & force of cardiac contraction • Vagus nerve (parasympathetic nervous system)-slows the heart rate • Sympathetic nerves-increase the heart rate • Epinephrine/norepinephrine-increases heart rate • Sensory (afferent) nerves-detect atria being stretched and lack of oxygen (changes the rate of contractions) • Angina-chest pain due to a lack of oxygen in coronary circulation

18. Intrinsic Conduction System • Automaticity • Enables the heart to contract without motor nerve impulses • Arrhythmia-irregular heartbeat • SA (sinoatrial) node-known as the pacemaker, located where the superior & inferior vena cava enter the right atrium • AV (atrioventricular) node-sends impulses to the ventricles • Bundle of HIS/bundle branches-in the septum • Purkinje fibers-in the heart wall • http://www.phschool.com/science/biology_place/biocoach/cardio1/electrical.html

19. Overview of Blood Vessels

20. Arteries • ALWAYS carry blood away from the heart • Thicker than veins to withstand pressure exerted during systole • All but the pulmonary arteries carry oxygenated blood • Aorta – the largest artery; 1 inch in diameter • Arterioles-the smallest arteries • Coronary arteries-most important; supply blood to the heart muscle itself

21. Veins • Carry blood toward the heart • All but the pulmonary veins carry deoxygenated blood • Layers are much thinner, and less elastic • Have a series of internal valves that work against gravity to prevent backflow • Superior and inferior vena cava-largest veins • Venules-smallest veins

22. Capillaries • Tiny, microscopic vessels • Walls are one cell layer thick • Function-to transport and diffuse essential material to and from the body’s cells and the blood

23. Trace a drop of blood • Start at the capillaries in your finger

24. Pulse

25. Pulse points • The pressure of blood pushing against the wall of an artery and the heart beats-systole • Common pulse sites • Temporal-side of the forehead • Carotid – neck • Brachial – the medial aspect of the forearm at the antecubital space (crease of the elbow) • Radial – the lateral aspect of the wrist on the thumb side • Femoral – the medial aspect of the upper thigh or groin • Dorsalispedis – on the superior aspect of the foot arch

26. Blood Pressure

27. Blood Pressure • Systole – the maximum pressure against the walls of the blood vessels formed during a ventricular contraction • Diastole – the minimum pressure during ventricular relaxation • Measure in mm of HG

28. Blood Pressure • Normal Ranges • Systolic = 100-140 • Diastolic = 60-90 • Hypotension – systolic < 90 • Hypertension – systolic >150 and/or diastolic >90