The Cardiovascular System 11 The Cardiovascular System

NO ASSIGNMENT FOR THIS PPT AORTA SV PA PV LA RA LV RV IV

C. Heart Physiology 1. The Conduction System of the Heart = autorhythmic cardiac cells + special conductive tissue a) Autorhythmic cells

The Heart: Conduction System … b) Special tissue Sinoatrial node = SA node (“pacemaker) Function Atrioventricular node = AV node,

Atrioventricular bundle = AV bundle Function Bundle branches Conduction System … Atrioventricular bundle = AV bundle Function Bundle branches Purkinje fibers

Superior vena cava Sinoatrial (SA) node (pacemaker) Left atrium Atrioventricular (AV) node Right atrium Atrioventricular (AV) bundle (bundle of His) Bundle branches Purkinje fibers Purkinje fibers Interventricular septum Figure 11.7

c) EKG & Heart Contraction Disorders Normal EKG P QRS T MilliVolts P QRS T Time Electrocardiogram

Abnormal Rhythums Heart Block SA node dysfunction Fibrillation Cardiac Arrest Tachycardia— Bradycardia—

2. The Heart: Cardiac Cycle & Heart Sounds Cardiac cycle = events of one complete heart beat BASICS Atria contract simultaneously Atria relax, then ventricles contract Systole = contraction Diastole = relaxation

3. The Heart: Cardiac Output Stroke volume (SV) = Volume of blood pumped by a ventricle in one contraction = 70 mL

Heart rate (HR) = beats per minute: 75 Cardiac output (CO) Amount of blood pumped by each ventricle per minute CO = 70ml x 75 beats/min = 5250 ml/min

4. The Heart: Regulation of Heart Rate Autonomic Nervous System & Endocrine System Increases in Heart Rate Sympathetic NS Hormones Epinephrine Thyroxine Raise HR when: Decreased blood volume or pressure

The Heart: Regulation of Heart Rate … Decrease Heart Rate Parasympathetic Nervous System

II. Blood Vessels (Vascular System) Introduction: General Functions and Anatomy: 1. General Function Arteries Arterioles Veins Venules Capillaries

2. Blood Vessel Structure a. Artery Pressure Wall b. Vein Valves

Valve (open) Valve (closed) Vein Contracted skeletal muscle Valve (closed) Vein Direction of blood flow Figure 11.11

Blood Vessel Structure … c. Cappillaries Thickness Cap. Bed Exchange of substances Precapillary Sphincters