What are the overall functions of the cardiovascular system? What structures comprise the system? QOD

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

How is the heart’s structure related to it’s function? QOD

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

How does the heart make sure to pump rhythmically and as a unit? QOD

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

Fig

Electrocardiogram  Waves of ECG –P wave –QRS complex –T wave  Uses: –Assessment of heart’s conduction of impulses –P-Q interval

Fig a

Regulation of Cardiac Cycle  Medulla oblongata  Parasympathetic nerve fibers  Sympathetic nerve fibers  Hypothalamus  Temperature change  Ions –Potassium ions  Hyperkalemia/Hypokalemia –Calcium ions  Hypercalcemia/Hypocalcemia

Sympathetic nerve Sympathetic trunk Autonomic nerve impulses Slide number: 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cerebrum (coronal section) Medulla (transverse section) Spinal cord (transverse sections) Hypothalamus Cardiac center Parasympathetic vagus nerve S-A node A-V node Sensory fibers Carotid sinus Carotid baroreceptors Common carotid artery Aorta Aortic baroreceptors

What is atherosclerosis? Causes? Signs/symptoms? Treatments? QOD

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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillary Tissue cells Lymphatic capillary Blood flow from arteriole

Water and other substances leave capillaries because of a net outward filtration pressure Slide number: 3 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillary Tissue cells Lymphatic capillary Blood flow from arteriole Outward force, including hydrostatic pressure 41.3 mm Hg Inward force of osmotic pressure 28 mm Hg Net outward pressure 13.3 mm Hg Outward force, including hydrostatic pressure Net outward pressure Inward force of osmotic pressure = 41.3 mm Hg = 13.3 mm Hg = 28 mm Hg Net force at arteriolar end

Water and other substances leave capillaries because of a net outward filtration pressure Slide number: 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillary Tissue cells Lymphatic capillary Blood flow from arteriole Outward force, including hydrostatic pressure 41.3 mm Hg Inward force of osmotic pressure 28 mm Hg Net outward pressure 13.3 mm Hg Outward force, including hydrostatic pressure 21.3 mm Hg Inward force of osmotic pressure 28 mm Hg Net inward pressure 6.7 mm Hg Outward force, including hydrostatic pressure Net outward pressure Inward force of osmotic pressure = 41.3 mm Hg = 13.3 mm Hg = 28 mm Hg Net force at arteriolar end Outward force, including hydrostatic pressure Net inward pressure Inward force of osmotic pressure = 21.3 mm Hg = 6.7 mm Hg = 28 mm Hg Net force at venular end

Water and other substances leave capillaries because of a net outward filtration pressure Slide number: 5 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillary Tissue cells Lymphatic capillary Blood flow to venule Blood flow from arteriole Outward force, including hydrostatic pressure 41.3 mm Hg Inward force of osmotic pressure 28 mm Hg Net outward pressure 13.3 mm Hg Outward force, including hydrostatic pressure 21.3 mm Hg Inward force of osmotic pressure 28 mm Hg Net inward pressure 6.7 mm Hg Outward force, including hydrostatic pressure Net outward pressure Inward force of osmotic pressure = 41.3 mm Hg = 13.3 mm Hg = 28 mm Hg Net force at arteriolar end Outward force, including hydrostatic pressure Net inward pressure Inward force of osmotic pressure = 21.3 mm Hg = 6.7 mm Hg = 28 mm Hg Net force at venular end

Veins  Venules  Veins –Thinner than arteries –Less smooth muscle –Valves –Act as blood reservoirs

How is blood pressure regulated? QOD

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