Lesson 9 Circulatory System Pt 2 The Heart PDF

(Circulatory System Pt 2) The Heart Unit D Lesson 9 10.2 Lesson 9 Goals Definitions Curriculum ○ Pulmonary system ○ Systemic system ○ D 2.1k - identify the principal structures of the ○ Septum...

(Circulatory System Pt 2) The Heart Unit D Lesson 9 10.2 Lesson 9 Goals Definitions Curriculum ○ Pulmonary system ○ Systemic system ○ D 2.1k - identify the principal structures of the ○ Septum heart and associated blood vessels; i.e., atria, ○ Atria ventricles, septa, valves, aorta, venae cavae, ○ Ventricle ○ Vena cava pulmonary arteries and veins, sinoatrial node, ○ Tricuspid valve atrioventricular node, Purkinje fibres ○ Semilunar valve ○ Bicuspid valve ○ D 2.2k - describe the action of the heart, blood ○ Aorta pressure and the general circulation of blood ○ Coronary pathway through coronary, pulmonary and systemic ○ Heart attack ○ Myogenic muscle pathways ○ SA node ○ AV node ○ Purkinje fibers ○ Sympathetic nervous system ○ Parasympathetic nervous system  Before we start… The colours of text used in this lesson are very important!!!!! Red text means that the blood is oxygenated Blue text means that the blood is deoxygenated  Divisions of the Circulatory System The circulatory system is split into two circuits to maximize oxygenation of blood The pulmonary circuit circulates blood from the heart to the lungs and back ○ Carries deoxygenated blood to the lungs and oxygenated blood back to the heart  Divisions of the Circulatory System The circulatory system is split into two circuits to maximize oxygenation of blood The systemic circuit circulates blood from the heart to the body and back ○ Carries oxygenated blood to the body and deoxygenated blood back to the heart  Anatomy of the Heart The heart consists of 2 pumps separated by the septum Each pump contains two chambers An atrium that receives blood from veins A ventricle that pumps blood to the arteries Blood ALWAYS flows from atrium → ventricle Pg. 320  Anatomy of the Heart Valves prevent blood from flowing through the heart in the wrong direction Atrioventricular (AV) valves prevents the backflow of blood from a ventricle into an atrium Semilunar valves prevent the backflow of blood from an artery into a ventricle Pg. 320  Anatomy of the Heart IMPORTANT NOTE!!! Diagrams of the heart will always be from the front view, meaning that the left side of the heart is on the right, and the right side of the heart is on the left Pg. 320  Anatomy of the Heart Pg. 320  Anatomy of the Heart The right pump receives deoxygenated blood from the body and pumps it to the lungs (pulmonary system) The left pump receives oxygenated blood from the lungs and pumps it to the cells of the body (systemic system) Pg. 320  Anatomy of the Heart The Right Side of the Heart The right atrium receives deoxygenated blood from the body from the vena cava ○ The superior = upper body ○ The inferior = lower body Blood passes through the tricuspid valve and into right ventricle where it is pumped through the semilunar valve and into the pulmonary arteries → lungs Pg. 320  Anatomy of the Heart The Right Side of the Heart Deoxygenated blood from body → Superior/Inferior Vena Cava → Right Atrium → Tricuspid Valve → Right Ventricle → Semilunar Valve → Pulmonary Artery → Lungs Pg. 320  Anatomy of the Heart The Left Side of the Heart The left atrium receives oxygenated blood from the body from the pulmonary veins Blood passes through the bicuspid valve and into left ventricle where it is pumped to the aorta and into the body Pg. 320  Anatomy of the Heart The Left Side of the Heart Oxygenated blood from the lungs → Pulmonary Veins → Left Atrium → Bicuspid Valve → Left Ventricle → Semilunar Valve → Aorta → Body Pg. 320  Anatomy of the Heart Pg. 320 Blood Flow Summary  Simplified Path of Blood Through the Body Pulmonary System Systemic System  The Third Blood Pathway The coronary pathway supplies the muscle cells of the heart with oxygen As with other arteries, fat deposits can collect in coronary arteries (atherosclerosis) Unlike other muscles, the heart cannot stop. If blood flow is cut off in the coronary arteries it can lead to a heart attack Heart Attacks  Muscles of the Heart The muscles of the heart are called cardiac muscle (Lesson 12) Cardiac muscle is a type of myogenic muscle that contracts without external nerve stimulation This is why the heart will continue to beat (for a short time) if removed from the body  Setting the Hearts Tempo The sinoatrial (SA) node is a bundle of specialized nerves in the upper right atrium that sets the hearts tempo ○ The heart's pacemaker, causes the atria to contract  Setting the Hearts Tempo The atrioventricular (AV) node receives nerve impulses from the SA node and passes them onto the Purkinje fibers ○ Delays the impulse for a split second so that the atria contract before the ventricles  Setting the Hearts Tempo The Purkinje fibers carry the nerve signal to the ventricles, causing them to contract Electrical Wiring of the Heart and Pacemakers  Electrocardiograms (ECG/EKG) Electrocardiograms are used to record the electrical activity of the heart P Wave = contraction of atria QRS Complex = contraction of ventricles T Wave = relaxation of ventricles Electrocardiograms (ECG/EKG)  Setting the Hearts Tempo Heart rate is influenced by two divisions of the autonomic (involuntary) nervous system Sympathetic Nervous System Parasympathetic Nervous System Prepares the body for stress, Returns the body to resting levels increases heart rate after stress  What Part of the Heart Makes the “Lub-Dub” Noise? The familiar “lub-dub” sound of the heart is caused by the closing of the heart's valves The “lub” is produced by the closing of the AV valves when the ventricles contract The “dub” is produced by the closing of the semilunar valves when the ventricles relax Lesson 9 Summary Definitions ○ Pulmonary system: between the heart and lungs ○ Systemic system: between the heart and the body ○ Septum: divides the left and right sides of the heart ○ Atria: collect blood from veins ○ Ventricle: push blood into arteries ○ Vena cava: brings deoxygenated blood from the body to the right atrium ○ Tricuspid valve: in between the right atrium and ventricle ○ Semilunar valve: in between ventricles and arteries ○ Bicuspid valve: in between the left atrium and ventricle ○ Aorta: delivers blood to the rest of the body ○ Coronary pathway: delivers blood to cardiac muscle ○ Heart attack: occurs when the heart cannot receive oxygenated blood ○ Myogenic muscle: contracts without external nerve signal ○ SA node: pacemaker of the heart, causes atria to contract ○ AV node: delays signal from SA node ○ Purkinje fibers: causes ventricles to contract ○ Sympathetic nervous system: increases heart rate ○ Parasympathetic nervous system: decrease heart rate Lesson 9 Summary Important Concepts ○ The circulatory system is split into the pulmonary that pumps blood through the lungs and the right side of the heart, and the systemic which pumps blood through the body and the left side of the heart ○ Left and right are swapped on heart diagrams ○ Atria receive blood from veins, ventricles push blood into arteries ○ Blood flow throughout the body can be summarized by: Deoxygenated blood from body → Superior/Inferior Vena Cava → Right Atrium → Tricuspid Valve → Right Ventricle → Semilunar Valve → Pulmonary Artery → Lungs → Pulmonary Veins → Left Atrium → Bicuspid Valve → Left Ventricle → Semilunar Valve → Aorta → Body ○ Coronary arteries provide heart muscles with oxygen, their blockage leads to heart attack Lesson 9 Summary Important Concepts ○ The SA node stimulates the atria to contract, the nerve signal goes through the AV node which delays it and passes it onto the Purkinje fibers which stimulate the ventricles to contract ○ The echocardiogram graph and what each part represents ○ The sympathetic nervous system increases heart rate and the parasympathetic nervous system decreases heart rate ○ The “lub” in the hearts sound is the closing of the AV valve and the “dub” is the closing of the semilunar valve