Transcript Chapter 13
QOD What are the overall functions of the cardiovascular system? What structures comprise the system? Chapter 13 Cardiovascular System I. Introduction Structures – Heart – Arteries Arterioles – Capillaries – Veins Venules Circuits – Pulmonary circuit – Systemic Circuit – Coronary Circuit 13.2: Structure of the Heart Coverings – Visceral pericardium – Parietal pericardium – Pericardial cavity – serous fluid Wall of the heart – Epicardium – Myocardium – Endocardium Purkinje fibers QOD How is the heart’s structure related to it’s function? Heart chambers and valves Atria (Atrium) Ventricles Septum Valves – Tricuspid – Bicuspid (Mitral) – Aortic – Pulmonary – Chordae tendinae – Papillary muscles Blood Vessels to and from Heart Superior and Inferior Vena cavae Cardiac veins – Coronary sinus Pulmonary arteries Pulmonary veins Aorta Coronary arteries Pathway of Blood QOD How does the heart make sure to pump rhythmically and as a unit? 13.3 Heart Actions The Cardiac Cycle The Heartbeat – Atrial systole and ventricular diastole – Atrial diastole and ventricular systole – A-V valves open/close Due to changes in pressure Cardiac Cycle Heart sounds – “Lubb” – ventricular contraction – “Dupp” – ventricular relaxation Cardiac Muscle Fibers – Fibers connect in branching system – Functional syncytium In atrial walls In ventricular walls Cardiac Conduction System S-A node – Located in right atrium – Self-initiate impulses that stimulate cardiac muscle fibers to contract – Rhythmic - Pacemaker A-V node – Located in interatrial septum (inferior) – Impulse is delayed – A-V bundle Purkinje fibers cardiac muscle fibers Fig. 13.11 Fig. 13.12 Electrocardiogram Waves of ECG – P wave – QRS complex – T wave Uses: – Assessment of heart’s conduction of impulses – P-Q interval Fig. 13.14a Regulation of Cardiac Cycle Medulla oblongata Parasympathetic nerve fibers Sympathetic nerve fibers Hypothalamus Temperature change Ions – Potassium ions Hyperkalemia/Hypokalemia – Calcium ions Hypercalcemia/Hypocalcemia Autonomic nerve impulses Slide number: 1 Carotid sinus Cerebrum (coronal section) Sensory fibers Carotid baroreceptors Common carotid artery Hypothalamus Aorta Medulla (transverse section) Cardiac center Aortic baroreceptors Parasympathetic vagus nerve S-A node A-V node Spinal cord (transverse sections) Sympathetic nerve Sympathetic trunk Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. QOD What is atherosclerosis? Causes? Signs/symptoms? Treatments? 13.4 Blood Vessels Arteries – Strong, elastic, under high pressure – 3 layers Tunica interna Tunica media Tunica externa Arterioles – Smaller – Get thinner as they get closer to… Capillaries Gas/nutrient exhchange – Openings – Semi-permeable – Concentration gradient – Filtration and hydrostatic pressure – Osmotic pressure Smooth muscle – regulates blood distribution Water and other substances leave capillaries because of a net outward filtration pressure Slide number: 2 Tissue cells Blood flow from arteriole Lymphatic capillary Capillary Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Water and other substances leave capillaries because of a net outward filtration pressure Slide number: 3 Inward force of osmotic pressure 28 mm Hg Blood flow from arteriole Tissue cells Lymphatic capillary Net outward pressure 13.3 mm Hg Outward force, including hydrostatic pressure 41.3 mm Hg Capillary Net force at arteriolar end Outward force, including hydrostatic pressure = 41.3 mm Hg Inward force of osmotic pressure = 28 mm Hg Net outward pressure = 13.3 mm Hg Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Water and other substances leave capillaries because of a net outward filtration pressure Slide number: 4 Inward force of osmotic pressure 28 mm Hg Blood flow from arteriole Tissue cells Lymphatic capillary Inward force of osmotic pressure 28 mm Hg Net outward pressure Outward force, including 13.3 mm Hg hydrostatic pressure Outward force, 21.3 mm Hg including hydrostatic Capillary pressure 41.3 mm Hg Net inward pressure 6.7 mm Hg Net force at arteriolar end Net force at venular end Outward force, including hydrostatic pressure = 41.3 mm Hg Outward force, including hydrostatic pressure = 21.3 mm Hg Inward force of osmotic pressure = 28 mm Hg Inward force of osmotic pressure = 28 mm Hg Net outward pressure Net inward pressure = 13.3 mm Hg Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. = 6.7 mm Hg Water and other substances leave capillaries because of a net outward filtration pressure Slide number: 5 Inward force of osmotic pressure 28 mm Hg Blood flow from arteriole Tissue cells Lymphatic capillary Inward force of osmotic pressure 28 mm Hg Net outward pressure Outward force, including 13.3 mm Hg hydrostatic pressure Outward force, 21.3 mm Hg including hydrostatic Capillary pressure 41.3 mm Hg Net inward pressure 6.7 mm Hg Blood flow to venule Net force at arteriolar end Net force at venular end Outward force, including hydrostatic pressure = 41.3 mm Hg Outward force, including hydrostatic pressure = 21.3 mm Hg Inward force of osmotic pressure = 28 mm Hg Inward force of osmotic pressure = 28 mm Hg Net outward pressure Net inward pressure = 13.3 mm Hg Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. = 6.7 mm Hg Veins Venules Veins – Thinner than arteries – Less smooth muscle – Valves – Act as blood reservoirs QOD How is blood pressure regulated? 13.5: Blood Pressure Arterial blood pressure: – Systolic pressure – Diastolic pressure – Pulse Factors Influencing Blood Pressure Heart action – Stroke volume – Cardiac output = heart rate x stroke volume Blood volume Peripheral resistance – Vasoconstriction/Vasidilation Blood viscosity – Resistance Control of Blood Pressure Regulation of cardiac output – Baroreceptors – Medulla oblongata (cardiac center) – Kidneys – Exercise, body temp, fear/anger Regulation of peripheral resistance – Vasomotor center Venous Blood Flow Lower blood pressure Skeletal muscle contractions Vasoconstriction