Lecture 06 CH 05 Heart and Blood Vessels PDF

Lecture 06 Chapter 05 CARDIOVASCULAR SYSTEM HEART AND BLOOD VESSELS Copyright © 2009 Pearson Education, Inc.  Points to Ponder § What are the functions of the cardiovascular...

Lecture 06 Chapter 05 CARDIOVASCULAR SYSTEM HEART AND BLOOD VESSELS Copyright © 2009 Pearson Education, Inc.  Points to Ponder § What are the functions of the cardiovascular system? § What is the structure and function of blood vessels? § Anatomy of the heart § Systemic and pulmonary circulation § How is the heart beat regulated? § What is blood pressure? § What are common cardiovascular diseases and how can you prevent them? Copyright © 2009 Pearson Education, Inc.  Test Your Knowledge What the cardiovascular system is? Ø The body’s breathing system Ø The body’s system of nerves Ø The body’s food processing system Ø The body’s blood-transporting system Copyright © 2009 Pearson Education, Inc.  Test Your Knowledge What the cardiovascular system is? Ø The body’s breathing system Ø The body’s system of nerves Ø The body’s food processing system Ø The body’s blood-transporting system Copyright © 2009 Pearson Education, Inc.  Test Your Knowledge Which type of blood vessels is the thickest? Ø Capillaries ‫اﻟﺷﻌﯾرات اﻟدﻣوﯾﺔ‬ Ø Arteries ‫اﻟﺷراﯾﯾن‬ Ø Veins ‫اﻷوردة‬ Ø All have the same thickness Copyright © 2009 Pearson Education, Inc.  Test Your Knowledge Which type of blood vessels is the thickest? Ø Capillaries ‫اﻟﺷﻌﯾرات اﻟدﻣوﯾﺔ‬ Ø Arteries ‫اﻟﺷراﯾﯾن‬ Ø Veins ‫اﻷوردة‬ Ø All have the same thickness Copyright © 2009 Pearson Education, Inc.  Test Your Knowledge How many chambers does the heart have? Ø 4 chambers Ø 3 chambers Ø 2 chambers Ø 1 chambers Copyright © 2009 Pearson Education, Inc.  Test Your Knowledge How many chambers does the heart have? Ø 4 chambers Ø 3 chambers Ø 2 chambers Ø 1 chambers Copyright © 2009 Pearson Education, Inc.  Cardiovascular System § The cardiovascular system consists of the heart which pumps blood, and the vessels through which the blood flows § The beating of the heart sends blood into the blood vessels § Blood is contained within blood vessels Copyright © 2009 Pearson Education, Inc.  What are the Functions of the Cardiovascular System? 1. Transport: oxygen, carbon dioxide and other wastes products, nutrients, and hormones 2. Protection: cells of the immune system (i.e. white blood cells) are transported to help protect the body from infection 3. Regulation: maintain homeostasis of a variety of the body’s conditions That is, temperature, pH balance, water, electrolyte levels. Copyright © 2009 Pearson Education, Inc.  The Cardiovascular System and Homeostasis (Figure 5.1) Copyright © 2009 Pearson Education, Inc. 11  Types of Blood Vessels There are three types of blood vessels that transport blood to and from the tissues of the body: Arteries. Veins. Capillaries Copyright © 2009 Pearson Education, Inc. 12  Arterial System q Structure: 3 layers; the inner layer (endothelium), middle, and outer layers q Functions: § Arteries carry blood away from heart § Large arteries: close to the heart, thick layer of smooth muscle, expendables to support high blood pressure Copyright © 2009 Pearson Education, Inc.  Arterioles and Capillaries q Arteries branch into arterioles and arterioles branch again into capillaries q Arterioles: blood pressure falls considerably q Arterioles and pre-capillary sphincters ‫ اﻟﻌﺿﻠﺔ اﻟﻌﺎﺻرة‬control blood pressure q Capillaries exchange water, solutes, nutrients, waste, and immune cells between vessels and tissues Copyright © 2009 Pearson Education, Inc.  Capillary System q Capillaries: where blood exchanges substances with tissues q The wall of capillaries is thin and made of 1 layer Copyright © 2009 Pearson Education, Inc.  Venous System From the capillaries, blood flow back to the heart through the venules (small veins) and veins q Structure: 3 layers (same as arteries) § The middle and outers layers are much thinner than arteries: larger diameter than arteries, high expandability, low blood pressure q Function: back transport of blood from organs to the heart § Blood volume reservoir: contains 2/3 q Blood Pressure is too low in of the entire blood of the veins (lower than capillaries) cardiovascular system q How does blood flow back to the heart from the veins? Copyright © 2009 Pearson Education, Inc.  Blood Pressure is Low in Leg Veins q If blood pressure is so low in the veins, how does blood flow back to the heart? q They have help: 1- Contraction of skeletal muscles 2- One-way valves 3- Breathing: pressure changes in thoracic and abdominal cavities associated with breathing causes a pressure change Ø Incompetence of the valves causes leg veins to become weak, large, and twisted causing varicose veins and spider veins Copyright © 2009 Pearson Education, Inc.  Blood Vessels: Summary Direction of blood flow Outer layer: Connective tissue Middle layer: Smooth muscle with elastic fibers Inner layer: Endothelium Vein Artery Connective tissue Smooth muscle Endothelium Venule Arteriole Capillary Tissue Epithelial cells of cells capillary endothelium Copyright © 2009 Pearson Education, Inc.  The Heart q The heart is a special pump because: § It can easily withstand for 100 years of continuous service without stopping. Its output can be fully adjustable (5-25 liters/min) § The heart supplies every region of the body with just the right amount of blood § The heart provides the power to move the blood and the vascular system represent the network through which the blood flows b) The human heart Copyright © 2009 Pearson Education, Inc.  Heart Structure q 3 layers: epicardium, myocardium, and endocardium q 4 chambers: two atrium, two ventricles separated by the septum q 4 valves: one-way blood flow v 2 atrioventricular valves (AV) ‫اﻟﺻﻣﺎﻣﺎت اﻷذﯾﻧﯾﺔ اﻟﺑطﯾﻧﯾﺔ‬ § Lie between the atria and their corresponding ventricles § Right AV lies between the right atrium and the right ventricle § Left AV lies between the left atrium and the left ventricle § Role: prevent blood from flowing back into atria after they contract Copyright © 2009 Pearson Education, Inc.  Heart Structure v 2 semilunar valves: ‫اﻟﺻﻣﺎﻣﺎت اﻟﮭﻼﻟﯾﺔ‬ § Connect the heart ventricles and main arteries § Pulmonary semilunar valve connects the right ventricle and the pulmonary artery § Aortic semilunar valve connects the left ventricle and the aorta § Role: prevent blood backflow into the ventricles after they contract Copyright © 2009 Pearson Education, Inc.  Heart Valves Copyright © 2009 Pearson Education, Inc.  Heart Anatomy Copyright © 2009 Pearson Education, Inc.  Pulmonary and systemic Circuits Copyright © 2009 Pearson Education, Inc.  Systemic Circuit: Delivery of Oxygenated Blood to Tissues q ‫اﻟدورة اﻟدﻣوﯾﺔ اﻟﻛﺑرى‬ § Oxygenated blood from the heart to tissues Left ventricle → (aortic semilunar valve) → aorta → arteries → arterioles → capillaries → tissues § Deoxygenated blood returns to heart From tissues → capillaries → venules → veins → vena cava (superior and inferior) → right atrium → (right AV valve) → right ventricle Copyright © 2009 Pearson Education, Inc.  Pulmonary Circuit: Oxygenation of Blood q ‫اﻟدورة اﻟدﻣوﯾﺔ اﻟﺻﻐرى‬ § Deoxygenated blood goes from the heart to the lungs From the right ventricle → (pulmonary semilunar valve) → pulmonary trunk → pulmonary arteries→ lungs (blood oxygenation) § Oxygenated blood returns back from lungs to heart Pulmonary veins → left atrium → (left AV valve) →left ventricle Copyright © 2009 Pearson Education, Inc.  Cardiac Cycle https://www.youtube.com/watch?v=_qmNCJxpsr0 Copyright © 2009 Pearson Education, Inc. Copyright © 2009 Pearson Education, Inc.  Cardiac Cycle: The Heart Contract and Relax Copyright © 2009 Pearson Education, Inc. Figure 8.11  Heart Sounds and Cardiac Cycle q Heart sounds reflects events that occur during the cardiac cycle-specifically the closing of the heart valves § Lub-Dub-Lub-Dub: Ø Lub: closure of the two AV valves during ventricular systole Ø Dub: closure of the aortic and pulmonary semilunar valves during ventricular diastole § Heart murmurs: disturbed blood flow due to incomplete closing of the heart valves Copyright © 2009 Pearson Education, Inc.  Cardiac Conduction System Coordinates Contraction The cardiac conduction system consist of 4 structures: 1- SA node: cardiac pacemaker initiates the heart beat every 0.8s 2- AV node: relays impulses 3- AV bundle 4- Purkinje fibers: transmit impulses to ventricles https://www.youtube.com/watch?v=RYZ4daFwMa8 Copyright © 2009 Pearson Education, Inc.  Cardiac Conduction Copyright © 2009 Pearson Education, Inc.  Electrocardiogram (ECG) q ECG records the heart’s electrical activity q Arrhythmia and ventricular fibrillation are detected by ECG § Arrhythmias ‫ﻋدم اﻧﺗظﺎم ﺿرﺑﺎت اﻟﻘﻠب‬: abnormality of the rhythm or rate of the heartbeat § Ventricular fibrillation ‫اﻟرﺟﻔﺎن اﻟﺑطﯾﻧﻲ‬: irregular ventricular contraction Copyright © 2009 Pearson Education, Inc.  An Electrocardiogram Is a Record of the Heartbeat Electrocardiogram (ECG). A recording of the electrical changes in the heart muscle during a cardiac cycle. The atria produce an electrical current, called the P wave, when stimulated by the SA node. QRS complex—wave of electrical current traveling through the ventricles. Signals that the ventricles are about to contract. The recovery of the ventricles is represented as the T wave. Copyright © 2009 Pearson Education, Inc. 34  Electrocardiogram (cont.) Copyright © 2009 Pearson Education, Inc. Figure 8.14  Blood Pressure q Blood pressure is the force that blood exerts on the wall of blood vessels as a result of the pumping action of the heart q Blood pressure is not the same in all blood vessels q Systolic pressure: pressure reached during ventricular systole (when ventricles contract to eject blood from the heart) q Diastolic pressure: lowest pressure which occurs during ventricle diastole (when the ventricle relax) Copyright © 2009 Pearson Education, Inc.  How Blood Pressure is Measured? Digital Blood Pressure Monitor Sphygmomanometer Copyright © 2009 Pearson Education, Inc.  Are you Hypertensive? What is your Normal Blood Pressure? Systolic? Diastolic? Systolic ? ……… Diastolic ? ………. Normal Blood Pressure: 120/80 mm Hg (Systolic/Diastolic) Copyright © 2009 Pearson Education, Inc.  Are you Hypertensive? Copyright © 2009 Pearson Education, Inc.  Why Should We Care About Blood Pressure? § Hypertension: high blood pressure § The silent killer § Hypotension: blood pressure too low § Clinical signs: dizziness, fainting § Causes: standing up suddenly, severe burns, blood loss Copyright © 2009 Pearson Education, Inc.  Risk Factors for Hypertension Copyright © 2009 Pearson Education, Inc.  Baroreceptors: Sensors of Blood Pressure Baroreceptors are a type of mechanoreceptor located within the carotid ‫اﻟﺷرﯾﺎن‬ ‫ اﻟﺳﺑﺎﺗﻲ‬and the aorta ‫اﻷﺑﮭر‬ They become activated by the stretching of the vessel Baroreceptors allow for the relay of information derived from blood pressure within the autonomic nervous system Copyright © 2009 Pearson Education, Inc.  Regulation of Blood Pressure: Nervous and Endocrine Factors 1- Nervous Control Ø Medulla oblongata ‫اﻟﻧﺧﺎع اﻟﻣﺳﺗطﯾل‬: cardiovascular center in the brain Medulla oblongata receives and emit signals through: -Sympathetic signals: increase heart rate, constrict blood vessels, raising blood pressure -Parasympathetic signals: slow heart rate, dilate blood vessels, lowering blood pressure 2- Hormonal Control Ø Adrenaline and noradrenaline secreted by the adrenal glands § Exercise: increased blood flow and cardiac output Copyright © 2009 Pearson Education, Inc.  Why We Should Care about Cardiovascular Disease? Cardiovascular disease is the most common cause of death in the Western World and the Gulf countries are particularly affected Most common cardiovascular diseases are: § Hypertension/high blood pressure ‫ارﺗﻔﺎع ﺿﻐط اﻟدم‬ § Atherosclerosis ‫ ﺗﺻﻠب اﻟﺷراﯾﯾن‬: The buildup of fats, cholesterol and other substances in and on the artery walls. § Stroke ‫اﻟﺳﻛﺗﺔ اﻟدﻣﺎﻏﯾﺔ‬ § Heart attack ‫ﻧوﺑﺔ ﻗﻠﺑﯾﺔ‬/‫ذﺑﺣﺔ ﺻدرﯾﺔ‬ § Heart valve diseases ‫أﻣراض ﺻﻣﺎم اﻟﻘﻠب‬ Copyright © 2009 Pearson Education, Inc.  Reducing the Risk of Cardiovascular Disease § Smoking: Don’t § Blood lipids: Monitor cholesterol levels § Blood pressure: Treat hypertension § Diet: Eat heart-healthy foods § Exercise: Do regular and moderate exercise to increase blood flow and cardiac output Copyright © 2009 Pearson Education, Inc.  Reducing the Risk of Cardiovascular Disease (Cont.) § Weight: being overweight increases risk of heart attack and stroke § Control of diabetes mellitus: early diagnosis and treatment delays onset of related problems § Stress: avoid chronic stress Copyright © 2009 Pearson Education, Inc.  Reducing the Risk of Cardiovascular Disease Take Home Message Copyright © 2009 Pearson Education, Inc.