Anatomy 6 PDF - Cardiovascular System

# Cardiovascular System ## Introduction The cardiovascular system is comprised of the heart, veins, capillaries, arteries, and blood. They work together to supply the body tissues with nourishment and collect waste materials. ## Functions of the Circulatory System 1. Distribute nutrients. 2. Tra...

# Cardiovascular System ## Introduction The cardiovascular system is comprised of the heart, veins, capillaries, arteries, and blood. They work together to supply the body tissues with nourishment and collect waste materials. ## Functions of the Circulatory System 1. Distribute nutrients. 2. Transport and exchange oxygen and carbon dioxide. 3. Remove waste materials. 4. Distribute secretions of endocrine glands. 5. Prevent excessive bleeding. 6. Prevent infection. 7. Regulate body temperature. ## Heart Anatomy - The heart is a funnel-shaped, hollow, muscular organ that is responsible for pumping blood to all parts of the body. - It's approximately the size of your fist. ### Location - The heart is located near the center of the thoracic cavity, between the lungs. - It is contained in the pericardial sac. ### Pericardium - It's a cover to the heart that confines the heart to the mediastinum. - It consists of two parts: the fibrous and serous pericardium. - Fibrous pericardium is the outer layer that helps to protect the heart. - Serous pericardium is the inner layer. ### Parts of the Heart - The heart is divided into a right and left side, and each side is divided into an atrium and ventricle. Therefore, the heart is said to have four chambers: right atrium, right ventricle, left atrium, and left ventricle. ### Atria of the Heart - These are the receiving chambers of the heart. - Each atrium has a protruding auricle. - Pectinate muscles mark atrial walls. #### Right Atrium - Blood enters the right atrium from the superior and inferior vena cavae and coronary sinus. #### Left Atrium - Blood enters the left atrium from the pulmonary veins. ### Ventricles of the Heart - These are the discharging chambers of the heart. - Papillary muscles and trabeculae carnae mark ventricular walls. #### Right Ventricle - The right ventricle pumps blood into the pulmonary trunk. #### Left Ventricle - The left ventricle pumps blood into the aorta. ### Thickness of Cardiac Walls - The myocardium of the left ventricle is much thicker than the right. ## Heart Valves - Heart valves ensure unidirectional blood flow through the heart. ### Atrioventricular (AV) Valves - These are valves between the atria and the ventricles. - AV valves prevent backflow into the atria when ventricles contract. - Chordae tendineae anchor AV valves to papillary muscles. #### Tricuspid Valve - The tricuspid valve is located between the right atrium and right ventricle (RA to RV). #### Pulmonary Valve - The pulmonary valve is between the right ventricle and the Pulmonary trunk (RV to pulmonary trunk). #### Mitral Valve - The mitral valve is located between the left atrium and the left ventricle (LA to LV). #### Aortic Valve - The aortic valve is located between the left ventricle and the aorta (V to aorta). ## Electrical Conduction System - Specialized cardiac muscle cells that carry impulses throughout the heart muscles, signaling the chambers to contract in the proper sequence. ### Conduction System 1. **Sinoatrial (SA) Node:** It's the pacemaker of the heart and is present in the wall of the right atrium, below the opening of the superior and inferior vena cavae. The impulse travels from the SA node to the atria. 2. **Atrioventricular (AV) Node:** This is located in the interatrial septum and the impulse travels from the atria to the AV node via the internodal pathway. 3. **Atrioventricular Bundle (AV Bundle):** It's present in the lower part of the interatrial septum and originates from the AV node and passes in the upper part of the interventricular septum. 4. **Bundle Branches:** Right and left branches of the AV bundle that pass along the right and left sides of the interventricular septum. 5. **Purkinje Fibers:** These are fibers that pass in the walls of the ventricles from the ends of bundle branches. ## Blood Supply of The Heart ### Arterial Supply of the Heart - The heart receives blood through the coronary arteries. 1. **Right Coronary Artery:** The right coronary artery supplies mainly the right atrium, most of the right ventricle, and the sinoatrial node (SAN). 2. **Left Coronary Artery:** The left coronary artery supplies mainly the left atrium and the left ventricle. 3. **Coronary Artery Disease (CAD):** Blockage or narrowing of the coronary arteries, which can reduce blood flow to the heart muscle. ## Types of Blood Circulation 1. **Systemic Circulation:** Systemic circulation is the circulation of blood from the heart to the rest of the body, then back to the heart. This circulation carries oxygenated blood away from the heart and delivers it to the tissues. It then collects deoxygenated blood and carbon dioxide from the tissues and delivers it to the right atrium. 2. **Pulmonary Circulation:** This refers to the circulation of blood between the heart and the lungs. It carries deoxygenated blood from the right ventricle to the lungs, where it picks up oxygen and releases carbon dioxide. The oxygenated blood then returns to the left atrium. 3. **Portal Circulation:** This is the specialized circulation of blood through the liver. It carries blood from the digestive tract to the liver, where it is filtered and processed before returning to the heart. ### Arteries - Arteries are blood vessels that carry blood rich in oxygen away from the heart to peripheral organs. - Pulmonary artery is an exception, it carries deoxygenated blood away from the heart to the lungs. #### Types of Arteries 1. Larger Conducting Arteries 2. Smaller Distributing Arteries 3. Smallest Arteries ### Veins - Veins are blood vessels that carry blood towards the heart. - Most veins carry deoxygenated blood from the tissues back to the heart. - The pulmonary and umbilical veins are exceptions, they carry oxygenated blood to the heart. ### Capillaries - Capillaries are the smallest blood vessels. - They don't have muscular and elastic tissue of other blood vessels. - They connect arteries and venules. - They enable the moving of water, oxygen, carbon dioxide, and many other nutrients and waste chemicals between blood and surrounding tissues.