Cardiovascular System Heart and Blood Vessels

Functions Pump Blood transport system around body Carries O2 and nutrients to cells, carries away waste products Lymphatic system – returns excess tissue fluid to general circulation

Structures Heart Arteries Veins Capillaries Blood and lymph are part of cardiovascular system

Heart Hollow muscular organ Size of a closed fist Weighs 10-13 oz Location – thoracic cavity APEX – conical tip, lies on diaphragm, points left

Heart: Structure PERICARDIUM – double layer of fibrous tissue that surrounds the heart MYOCARDIUM – cardiac muscle tissue ENDOCARDIUM – smooth inner lining of heart

Heart Chambers SEPTUM divides into R and L halves Upper chambers – RIGHT ATRIUM and LEFT ATRIUM Lower chambers – RIGHT VENTRICLE and LEFT VENTRICLE

Heart Valves Four heart valves permit flow of blood in one direction: TRICUSPID VALVE – between right atrium and right ventricle BICUSPID (MITRAL) VALVE – between left atrium and left ventricle Semilunar valves -located where blood leaves the heart PULMONARY VALVE AORTIC VALVE

Coronary Arteries Provide blood supply to the heart muscle

Heart Contractions SYSTOLE = contraction phase DIASTOLE = relaxation phase http://www.natgeoeducationvideo.com/film/1111/the-heart

Control of Heart Contractions SA (sinoatrial) NODE = PACEMAKER Located in right atrium SA node sends out electrical impulse Impulse spreads over atria, making them contract Travels to AV Node AV (atrioventricular) NODE Conducting cell group between atria and ventricle Carries impulse to bundle of His BUNDLE OF HIS Conducting fibers in septum Divides into R and L branches to network of branches in ventricles (Purkinje fibers) PURKINJE FIBERS Impulse shoots along Purkinje fibers causing ventricles to contract

Conduction System Conduction system sets the basic rhythm of the beating heart by generating impulses which stimulate the heart to contract

Major Structures Superior vena cava and inferior vena cava – bring deoxygenated blood to right atrium Pulmonary artery – takes blood away from right ventricle to the lungs for O2 Pulmonary vein – brings oxygenated blood from lungs to left atrium Aorta – takes blood away from left ventricle to rest of the body

Arteries vs Veins ARTERIES Carry oxygenated blood away from the heart to the capillaries Elastic, muscular and thick-walled Transport blood under very high pressure http://www.natgeoeducationvideo.com/film/1110/the-blood-vessels VEINS Carry deoxygenated blood to the heart Veins contain a muscular layer, but less elastic and muscular than arteries Thin walled veins collapse easily when not filled with blood VALVES – permit flow of blood only in direction of the heart

Capillaries Capillaries Smallest blood vessels, can only be seen with a microscope Connect arterioles with venules Walls are one-cell thick– allow for selective permeability of nutrients, oxygen, CO2 and wastes

Aorta Largest artery in the body First branch is coronary artery Aortic arch Many arteries branch off the descending aorta

Vena Cava Largest vein in the body Superior and Inferior portions Subclavian veins Jugular veins – located in the neck Femoral veins

Blood Vessels

Major Circuits PULMONARY CIRCULATION – heart and lungs (R side of heart) Molecular exchange occurs between blood vessels and alveoli SYSTEMIC CIRCULATION – from the heart to the tissues and cells, then back to the heart (L side of heart) Molecular exchange occurs between capillaries and cells

Heart Physiology Right Heart Deoxygenated blood flows into heart from vena cava  right atrium  tricuspid valve  right ventricle  pulmonary valve  pulmonary artery  lungs (for oxygen) www.natgeoeducationvideo.com/film/1109/cardiovascular-system http Left Heart Oxygenated blood flows from lungs via pulmonary veins  left atrium  mitral valve  left ventricle  aortic valve  aorta  general circulation (to deliver oxygen)

Blood Composition: Plasma and Blood Cells straw colored liquid about 55% of total blood volume Components of plasma Water; about 92% Plasma proteins Nutrients (glucose, cholesterol) Electrolytes (potassium) Hormones (melatonin) Metabolic waste products

Blood Cells Erythrocytes (Red blood cells) Thrombocytes (platelets) Contain hemoglobin which carries both O2 and CO2 Thrombocytes (platelets) Cell fragments Lack nuclei Live about 5-9 days Important for clotting

Blood Cells: Leukocytes (white blood cells) Fight infection Neutrophils: phagocyte bacteria Eosinophils: remove toxins and produce antihistamines in an allergic reaction Basophils: inflammatory function Monocytes: phagocyte bacteria Lymphocytes: provide immunity by developing antibodies

Diseases of the Heart CONGESTIVE HEART FAILURE (CHF) Ventricles unable to contract effectively and blood pools in the heart Edema in lower extremities Blood backs up into lungs Tx – drugs to strengthen heart beat (digoxin) and diuretics to reduce fluid

Diseases of the Heart: Myocardial Infarction Blockage in coronary arteries cuts off blood supply to heart muscle causing that area of tissue to die Causes - Smoking, obesity, stressful life style, hypertension, family history, elevated cholesterol and triglycerides, aging Symptoms - Severe crushing pain that radiates to neck, jaw, and left arm; dyspnea; cold, clammy skin; pressure or heaviness in chest; nausea; change in blood pressure Tx – “Clot-busting” drugs if in process of having MI; bedrest; pain medications; oxygen; anticoagulants;

Myocardial Infarction http://www.natgeoeducationvideo.com/film/653/archie-md-segment-heart-bypass-surgery

Disorders of the Heart ARRHYTHMIA (or dysrrhythmia) – any change from normal heart rate or rhythm Treatment: defibrillation or pacemaker http://www.youtube.com/watch?v=xw4nDMgTOrw

Pacemaker

Electrocardiogram (EKG or ECG) The electrocardiogram (ECG, EKG) is used extensively in the diagnosis of heart disease, from congenital heart disease in infants to myocardial infarction and myocarditis in adults. Several different types of electrocardiogram exist.

Disorders of the Vessels ARTERIOSCLEROSIS – arterial walls thicken, lose elasticity; “hardening of the arteries” ATHEROSCLEROSIS – fatty deposits form on walls of arteries ANEURYSM – ballooning of an artery, thinning and weakening PHLEBITIS – inflammation of lining of vein, accompanied by clotting of blood – symptoms are edema, pain and redness EMBOLUS – traveling blood clot VARICOSE VEINS – swollen, distended veins – heredity or due to posture, prolonged periods of standing, physical exertion, age and pregnancy

Angioplasty The coronary arteries supply blood to the heart muscle. The right coronary artery supplies both the left and the right heart; the left coronary artery supplies the left heart.

Angioplasty

Diagnostic Tests: Cardiac Catheterization Patient is awake and pain-free (local anesthesia), a catheter is inserted into an artery at the top of the leg (the femoral artery)

Cardiac Catheterization A catheter is advanced over a guidewire, into the blood vessel. This catheter is then guided to the aorta and the guidewire is removed. Once the catheter is placed in the opening of the coronary arteries, the doctor injects dye and takes a series of X-rays.

Angioplasty A guidewire is advanced across the blocked section of the coronary artery and a balloon -tipped tube is positioned so the balloon part of the tube is beside the blockage. The balloon is then inflated for a few seconds to compress the blockage against the artery wall. Then the balloon is deflated.

Angioplasty A device called a stent may be placed. A stent is a latticed, metal scaffold that is placed within the coronary artery to keep the vessel open.

Cardiac catheterization Once the catheter has been positioned at the coronary artery origin, contrast media is injected and a series of X-rays (film) are taken to check for any change in the arteries. Following this, the catheter is removed and the procedure is completed.

Disorders of the Blood Anemia: Sickle Cell Anemia Inadequate number of erythrocytes, hemoglobin, or both Symptoms: pallor, fatigue, dyspnea, tachycardia Sickle Cell Anemia Chronic, inherited Erythrocytes are abnormally crescent shaped, carry less O2, break easily, and block blood vessels

Disorders of the Blood Hemophilia: inherited disease, seen almost exclusively in males Blood unable to clot due to a lack of plasma protein Leukemia: malignant disease of the bone marrow or lymph tissue High number of immature white blood cells Symptoms: fever, pallor, swollen lymph glands, fatigue, anemia Treatment: chemotherapy, radiation, bone marrow transplant

Diagnostic Test: CBC A complete blood count is a test done on the blood to monitor or detect many different diseases or disorders.