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2 Human Biology Concepts and Current Issues PowerPoint Lecture Slide Presentation Robert J. Sullivan, Marist College FOURTH EDITION 8 HEART AND BLOOD VESSELS Michael D. Johnson Copyright 2007 Pearson Education, Inc., publishing as Benjamin Cummings. SCREEN 1 OF 23

3 Major Arteries and Veins Figure 8.10 SCREEN 2 OF 23

4 Blood Vessels Arterial system Structure: endothelium, middle, outer layers Functions: Arteries: carry blood away from heart Arterioles and precapillary sphincters control pressure Capillaries: exchange of nutrients, waste, and defensive cells between vessel and tissue SCREEN 3 OF 23

5 Blood Vessels (cont.) Venous system Structure: veins: three layers, thin-walled Functions: carry blood toward the heart Mechanisms in blood return: Contraction of skeletal muscles One-way valves Pressure changes associated with breathing SCREEN 4 OF 23

6 Arterioles and Capillaries Figure 8.2 SCREEN 5 OF 23

7 Capillary Structure Figure 8.4 SCREEN 6 OF 23

8 Lymphatic System Function: maintain blood volume; also functions in immune system Structure: Blind-ended capillaries Lymphatic vessels Lymph SCREEN 7 OF 23

9 The Heart Figure 8.8 SCREEN 8 OF 23

10 The Heart Structure Layers: epicardium, myocardium, endocardium Chambers: two atrias, two ventricles Valves: Two atrioventricular valves: tricuspid and bicuspid (mitral) Two semilunar valves: pulmonary and aortic SCREEN 9 OF 23

11 Pulmonary Circuit: Oxygenation of Blood Pathway: Deoxygenated blood through the vena cava to the right atrium Deoxygenated blood through the right atrioventricular valve to the right ventricle Deoxygenated blood through the pulmonary semilunar valve to the pulmonary trunk and the lungs Oxygenated blood through the pulmonary veins to the left atrium Oxygenated blood through the left atrioventricular valve to the left ventricle SCREEN 10 OF 23

12 Systemic Circuit: Delivery of Oxygenated Blood to Tissues and Return of Blood to the Heart Pathway: Oxygenated blood through the aortic semilunar valve to the aorta Oxygenated blood through branching arteries and arterioles to the tissues Oxygenated blood through the arterioles to capillaries Deoxygenated blood from capillaries into venules and veins Ultimately to the vena cava and into the right atrium SCREEN 11 OF 23

13 Cardiac Cycle Figure 8.12 SCREEN 12 OF 23

14 Heart Sounds and Heart Valves Lub-dub Heart murmurs SCREEN 13 OF 23

15 Cardiac Conduction System Coordinates Contraction SA node: cardiac pacemaker AV node: relay impulse AV bundle and Purkinje fibers: carry impulse to ventricles Figure 8.14 SCREEN 14 OF 23

16 Electrocardiograms (EKG/ECG) Three formations: P wave: impulse across atria QRS complex: spread of impulse down septum, around ventricles in Purkinje fibers T wave: end of electrical activity in ventricles Arrythmias, ventricular fibrillation SCREEN 15 OF 23

17 Electrocardiograms (EKG/ECG) (cont.) Figure 8.15b,c SCREEN 16 OF 23

18 Blood Pressure Definitions: normal : Systolic pressure Diastolic pressure Measurement: sphygmomanometer SCREEN 17 OF 23

19 Blood Pressure (cont.) Hypertension: high blood pressure: Definition The silent killer Risk factors Hypotension: blood pressure too low: Clinical signs: dizziness, fainting Causes: orthostatic, severe burns, blood loss SCREEN 18 OF 23

20 Regulation of the Cardiovascular System: Baroreceptors Baroreceptors: pressure receptors in aorta and carotid arteries Steps in mechanism: Blood pressure rises, vessels stretched Signals sent to brain in the cardiovascular center Heart signaled to lower heart rate and force of contraction Arterioles vasodilate, increasing blood flow to tissues Combined effect lowers blood pressure SCREEN 19 OF 23

21 Regulation of the Cardiovascular System: Nervous and Endocrine Factors Medulla oblongata signals: Sympathetic nerves: constrict blood vessels, raising blood pressure Parasympathetic nerves: dilate blood vessels, lowering blood pressure Hormones: epinephrine (adrenaline) Local requirements dictate local blood flow SCREEN 20 OF 23

22 Cardiovascular Disorders Angina pectoris: a warning Myocardial infarction/heart attack: permanent cardiac damage Congestive heart failure: decrease in pumping efficiency Embolism: blockage of blood vessels Stroke: impaired blood flow to the brain SCREEN 21 OF 23

23 Reducing the Risk of Cardiovascular Disease Smoking: don t Blood lipids: monitor cholesterol levels Exercise: regular and moderate Blood pressure: treat hypertension Weight: being overweight increases risk of heart attack and stroke Control of diabetes mellitus: early diagnosis and treatment delays onset of related problems Stress: avoid chronic stress SCREEN 22 OF 23

24 Cardiac Anatomy Quiz Test Yourself, page 187 SCREEN 23 OF 23