Anatomy & Physiology Chapter 9: Cardiovascular system Waggy

Key Concepts Structure of the heart Protection of the heart Heart chambers & Valves Pathway of the blood Cardiac Cycle The Conduction System Blood Vessels Circulatory Circuits Disorders & Diseases

Structure of the Heart Heart Size – Located in the mediastinum (space between lungs, backbone, sternum),

Structure of the Heart Is about the size of a closed fist Lies between the lungs, superior to the diaphragm It rest on the diaphragm in the region known as the mediastinum in the thoracic cavity About 2/3 of the heart’s mass lies to the left of the midline It is roughly triangular and has a pointed apex (made of ventricles) and a base at the top where the vessels enter

Protection of the heart Fibrous Pericardium visceral pericardium parietal pericardium

Pericardial cavity – Epicardium – Myocardium – Endocardium –

Heart Chambers Heart has 4 chambers: 2 Atria – 2 Ventricles – Septum –

Heart Valves Blood flows in one direction through the heart due to valves There are two groups of valves: 1. 2. Atrioventricular valves

Semilunar valves Pulmonary semilunar valve: Aortic semilunar valve:

Heart Sounds The sound of the heart is actually the sound of the valves opening & closing. Lub: Dub:

Path of Blood Flow

Path of Blood Flow

Cardiac Cycle Cardiac Cycle: Diastole: Systole:

Pulse

Blood Supply to the heart

Heart Conduction System

Sinoatrial (SA) node Atrioventricular (AV) node

Types of Blood Vessels Three types of blood vessels: Arteries :  Veins:

Capillaries: 

Major Blood Vessels Aorta - Pulmonary Trunk – Pulmonary Veins – Superior and Inferior Vena Cava –

Circulatory circuits Your heart is a double pump making two circuits: 1. Pulmonary circuit (lungs only) 2. Systemic circuit (rest of the body)

Pulmonary Circuit

Systemic Circuit

Arterial Branches of Systemic Circulation 4 major divisions of aorta

Veins of the Systemic Circulation All systemic veins merge to form the superior and inferior vena cavas, which empty into the right atrium

Heart Disorders Arrhythmia Includes: Bradycardia Tachycardia Heart flutter Fibrillation

Blood Vessel Disorders Aneurysm Arteriosclerosis Atherosclerosis

Blood Pressure Problems Pre-hypertension - Hypertension Hypotension

Factors affecting blood pressure Cardiac output: Blood volume: Peripheral resistance: Viscosity:

Other cardiovascular disorders MVP - mitral valve prolapse, Heart Murmurs – Myocardial Infarction (MI) - SADS  = (Sudden Arrhythmia/Adult Death Syndrome) -

The End