Essentials of Human Anatomy Physiology Unit 7 Cardiovascular

  • Slides: 45
Download presentation
Essentials of Human Anatomy & Physiology Unit 7 Cardiovascular System http: //www. youtube. com/watch?

Essentials of Human Anatomy & Physiology Unit 7 Cardiovascular System http: //www. youtube. com/watch? v=4 wu-aw. Jxnv 0&feature=related box

Intro to the Cardiovascular System The CVS is a closed system. The major function

Intro to the Cardiovascular System The CVS is a closed system. The major function of the CVS is to circulate substances throughout the body. Blood circulates through 2 circuits: Pulmonary Circuit Systemic Circuit

Pulmonary Circuit Pulmonary arteries, arterioles Carry blood from heart to lungs Blood enters circuit

Pulmonary Circuit Pulmonary arteries, arterioles Carry blood from heart to lungs Blood enters circuit from R ventricle at pulmonary trunk PT extends upward and posteriorly from heart PT divides into R and L pulmonary arteries, then into arterioles Pulmonary capillaries Site of gas exchange Associated with alveolar walls Pulmonary venules, veins Four veins return blood to L atrium Two veins arise from each lung

Systemic Circuit Systemic arteries, arterioles Carries blood from heart to body (except lungs) Includes

Systemic Circuit Systemic arteries, arterioles Carries blood from heart to body (except lungs) Includes coronary circulation Blood enters circuit from L ventricle at the aorta Systemic capillaries Aorta branches to all body tissues Systemic venules, veins Vena cavae Return blood to R atrium http: //www. youtube. com/watch? v=H 04 d 3 r. JCLCE

Location/Size of the Heart Size 14 cm long; 9 cm wide (closed fist) 1

Location/Size of the Heart Size 14 cm long; 9 cm wide (closed fist) 1 pound (300 g adult) Location Enclosed within the mediastinum Bordered laterally by lungs, posteriorly by vertebral column, anteriorly by sternum Base Attaches to several blood vessels Wide superior border; Lies beneath 2 nd rib Apex Directed toward left hip Apex rests on diaphragm; ends at 5 th intercostal space

The Heart

The Heart

Coverings of the Heart Serous Pericardium Visceral pericardium Innermost layer of ET & CT

Coverings of the Heart Serous Pericardium Visceral pericardium Innermost layer of ET & CT covering surrounding heart muscle Also called the epicardium (outer layer of heart) Parietal pericardium Inner lining of fibrous pericardium Outside layer; loosely fitting superficial sac At base of heart, folds in on itself to become epicardium Fibrous Pericardium Outermost tough, fibrous protective dense CT layer that prevents overstretching of the heart

Coverings of the Heart The pericardial cavity is filled with serous fluid for lubrication

Coverings of the Heart The pericardial cavity is filled with serous fluid for lubrication Reduces friction between membranes Pericarditis: Inflammation of the pericardium. Adhesions attach layers of pericardium together Interferes with heart movements Fibrous Pericardium

The Heart Wall Three layers Epicardium Outside layer This layer is the visceral pericardium

The Heart Wall Three layers Epicardium Outside layer This layer is the visceral pericardium Serous membrane; connective tissue beneath epithelium Myocardium Thick, middle layer of cardiac muscle tissue; bulk of heart Endocardium Inner layer Endothelium Lines heart chambers; is continuous with the blood vessels leaving and entering heart & valves Contains elastic and collagenous fibers as well as blood vessels

Chambers of the Heart The upper chambers are called atria(singular atrium) R & L

Chambers of the Heart The upper chambers are called atria(singular atrium) R & L atrium are separated by the interatrial septum Atria receive blood from veins (PASSIVE) Receiving chambers; blood enters under low pressure from veins of the body Atria are thin walled chambers Auricles: reservior to prevent backflow of blood into vena cava Fossa ovale: remnant of foramen ovale used to shunt blood away from R ventricle

Chambers of the Heart Ventricles R & L ventricles are separated by interventricular septum

Chambers of the Heart Ventricles R & L ventricles are separated by interventricular septum Ventricles pump blood from the heart into arteries (ACTIVE) Ventricles are thick walled chambers; Left is thicker than right to push blood further Trabeculae carneae are irregular inner surfaces (ridges and folds) of the ventricles

Valves of the Heart General function: prevent backflow of blood Atrioventricular valves The tricuspid

Valves of the Heart General function: prevent backflow of blood Atrioventricular valves The tricuspid AV valve lies between the R atrium and R ventricle; 3 flaps The bicuspid AV valve lies between the L atrium and L ventricle (mitral valve); 2 flaps Structures associate with AV valves Chordae tendineae – fibrous cords connect the cusps of AV valves to papillary muscles of ventricles Papillary muscles – muscular columns located on the inner surface of the ventricles Semilunar valves Pulmonary semilunar valve lies within the pulmonary trunk Aortic semilunar valve lies within the aorta

Blood Vessels associated with the Heart Arteries carry blood away from the heart Must

Blood Vessels associated with the Heart Arteries carry blood away from the heart Must be strong, but stretchable Aorta Carries blood from the left ventricle to the body Pulmonary arteries Carry blood from the right ventricle to the lungs via the PT Coronary arteries Carry blood to myocardium Veins carry blood toward the heart Collapsible, contain valves to prevent backflow Superior Vena Cava Brings blood from the head and upper limbs; enters right atrium Inferior Vena Cava Brings blood from the trunk and lower limbs; enters right atrium Coronary sinus (posterior surface) brings blood from the myocardium via the cardiac veins to the right atrium Pulmonary veins 2 Right and 2 Left Brings oxygen rich blood from the lungs to the left atrium Ligamentum arteriosum-remnant of fetal ductus arteriosus

Blood Flow Right Atrium Receives blood (low [O 2] , high [CO 2]) from

Blood Flow Right Atrium Receives blood (low [O 2] , high [CO 2]) from Superior and Inferior vena cava, and coronary sinus Tricuspid valve Between right atrium and right ventricle Prevents back flow Right ventricle Thin muscular wall Pumps blood short distance to lungs Contraction puts blood under pressure Tricuspid valve closes passively Only exit for blood pulmonary trunk At base of trunk is pulmonary SL valve; blood must pass thru before entering pulmonary trunk, pulmonary arteries & pulmonary arterioles Pulmonary Capillaries Gas exchange between blood and alveoli air occurs Pulmonary Venules & Pulmonary Veins

Blood Flow Left atrium Receives blood (high [O 2] , low [CO 2]) from

Blood Flow Left atrium Receives blood (high [O 2] , low [CO 2]) from lungs through 4 pulmonary veins Bicuspid valve Between left atrium and left ventricle Prevents back flow Left ventricle Thick muscular wall Pumps blood to all other parts of the body Contraction puts blood under pressure Mitral valve closes passively Only exit for blood aorta At base of trunk is aortic SL valve; blood must pass thru before entering aorta, systemic arteries & systemic arterioles Valve closes when ventricular muscles relax Systemic Capillaries Gas exchange between blood and body tissue cells occurs Systemic Venules & Systemic Veins Vena Cava Superior Vena Cava -- drains upper body to right atrium Inferior Vena Cava – drains lower body to right atrium

Coronary Circulation • Ascending aorta (oxygenated blood) • Coronary arteries (1 st & 2

Coronary Circulation • Ascending aorta (oxygenated blood) • Coronary arteries (1 st & 2 nd branch of ascending aorta) – Left coronary artery • Anterior interventricular artery • Circumflex Artery – Right coronary artery • Posterior interventricular artery • Marginal Artery • Capillaries in myocardium (exchange of gases) • Cardiac veins (deoxygenated blood) – Great cardiac vein – Small cardiac vein • Coronary sinus • Right atrium

The Heart – note Coronary Circulation

The Heart – note Coronary Circulation

Conditions of the Heart Ischemia Reduction of blood flow Hypoxia Reduced oxygen supply due

Conditions of the Heart Ischemia Reduction of blood flow Hypoxia Reduced oxygen supply due to ischemia Angina pectoris “strangled chest” Severe pain that accompanies ischemia Labored breathing, weakness, dizziness, perspiration Occurs during exertion; fades with rest Relieved by nitroglycerin Myocardial infarction Death of portion of myocardium caused by thrombus or embolus in a coronary artery May cause sudden death if conduction system is distrupted and V-fib occurs Treated with clot-dissolving agents (TPA & streptokinase), heparin & angioplasty Reperfusion damage Occurs when hypoxic tissue’s blood supply is reestablished Damage to enzymes, NT, nucleic acids and phospholipids Implicated in diseases such as heart disease, Alzheimer’s, Parkinson’s, cataracts, rheumatoid arthritis Anti-oxidants (Catalase, Vit. E & C, beta-carotene) defend against damage

Cardiac Cycle Cardiac cycle – all the events associated with one heart beat both

Cardiac Cycle Cardiac cycle – all the events associated with one heart beat both electrical and mechanical. a. b. Electrical = Mechanical = Cardiac Conduction System recorded on an ECG Heart Actions & Heart Sounds recorded using sphygmomanometer & stethoscope The atria & ventricles alternately contract & relax. a. When the two atria contract, the two ventricles relax. b. When the two ventricles contract, the atria relax. Blood flows from areas of high pressure to areas of low pressure. a. As a chamber of the heart contracts, pressure increases. b. As a chamber relaxes, pressure decreases. Definitions: a. b. Systole = phase of heart’s contraction Diastole = phase of heart’s relaxation A complete cardiac cycle includes systole and diastole of both atria, and systole and diastole of both ventricles.

Cardiac Cycle Phase Ventricular Contraction (SYSTOLE) Atrial Relaxation (diastole) Ventricular Relaxation (DIASTOLE) Atrial Contraction

Cardiac Cycle Phase Ventricular Contraction (SYSTOLE) Atrial Relaxation (diastole) Ventricular Relaxation (DIASTOLE) Atrial Contraction (systole) Blood Flow Blood is forced Atria fill with from ventricles blood into arteries Ventricles fill with blood Blood is forced from atria into ventricles Valves SL open AV closed AV open SL closed Pressure Ventricles high Atria low but rises as filling continues SL open AV closed Ventricles low Atria high but rises as filing continues http: //www. youtube. com/watch? v=j. LTdgrhp. DCg How the Heart Works animation video

Cardiac Cycle Specific Phases of the Cardiac Cycle 1. Ventricular Diastole (Mid-to-Late) / Atrial

Cardiac Cycle Specific Phases of the Cardiac Cycle 1. Ventricular Diastole (Mid-to-Late) / Atrial Systole a. Rapid ventricular filling occurs just after AV valves open (remember atria had filled during ventricular contraction); b. SA Node fires (P wave), atria contract, and remainder of ventricular filling occurs; c. Atria relax, ventricles depolarize (QRS complex). d. 0. 1 seconds.

Cardiac Cycle 2. Ventricular Systole / Atrial Diastole (Early) a. Impulse passes through AV

Cardiac Cycle 2. Ventricular Systole / Atrial Diastole (Early) a. Impulse passes through AV Node and then through ventricles; b. Ventricles contract; c. Ventricular pressure increases rapidly; d. AV valve close: Isovolumetric Contraction Phase (constant volume) = start of contraction to opening of SL valves = 0. 05 sec; Ventricular Ejection Phase = opening of SL valves to closing of SL valves; 0. 3 seconds. e.

Cardiac Cycle 3. Ventricular Diastole (Early) / Atrial Diastole (Mid-to-Late) * a. k. a.

Cardiac Cycle 3. Ventricular Diastole (Early) / Atrial Diastole (Mid-to-Late) * a. k. a. Relaxation (Quiescent) Period a. follows T-wave; b. Ventricular pressure drops; c. SL valves close; d. isovolumetric relaxation for brief time; e. When ventricular pressure drops below atrial pressure, AV valves open; f. 0. 4 seconds.

Operation of Heart Valves http: //www. youtube. com/watch? v=rguzt. Y 8 aqpk&feature=related Cardiac Cycle

Operation of Heart Valves http: //www. youtube. com/watch? v=rguzt. Y 8 aqpk&feature=related Cardiac Cycle

Heart Sounds Through stethoscope, vibrations in heart due to closing of valves Sounds like

Heart Sounds Through stethoscope, vibrations in heart due to closing of valves Sounds like “lub dup” Lub 1 st part of heart sound; loud and long Occurs with closing of A-V valves during ventricular contraction Dup 2 nd part of heart sound; short and sharp Occurs with closing of S-L valves during ventricular relaxation Significance: sounds provide info on condition of heart valves Heart murmur Valvular cusps do not close completely Blood leaking back through valve creates murmur sound http: //www. med. ucla. edu/wilkes/intro. html heart sounds web site

Heart Sounds Functional Syncytium: Mass of merging cells that function as a unit to

Heart Sounds Functional Syncytium: Mass of merging cells that function as a unit to create the lub-dup sound Two in heart Atrial syncytium Ventricular syncytium Separated except for a small area in right atrial floor

Cardiac Conduction System Intrinsic conduction system (nodal system) Specialized cardiac muscle tissue (1%) in

Cardiac Conduction System Intrinsic conduction system (nodal system) Specialized cardiac muscle tissue (1%) in the heart that are autorhythmic (self-exciting); that are initiating and distributing cardiac electrical impulses causing the heart to beat; and coordinate the events of the cardiac cycle. Sinoatrial node 60 bpm a. b. c. located in right uppermost atrial wall; PACEMAKER = self-exciting tissue (rhythmically and repeatedly [60100 per minute] initiates cardiac impulses); Impulse travels throughout atrial fibers via gap junctions in intercalated discs to the. . .

Cardiac Conduction System Atrioventricular node 40 bpm a. located in interatrial septum; b. serves

Cardiac Conduction System Atrioventricular node 40 bpm a. located in interatrial septum; b. serves as a delay signal that allows for ventricular filling; c. Cardiac impulse then enters the. . . Atrioventricular bundle (bundle of His) 20 -40 bpm a. only electrical connection between the atria and ventricles; b. located in the superior interventricular septum; c. Impulse enters both. . . Bundle branches a. lead downward through interventricular septum toward apex, and impulse finally reaches. . . Purkinje fibers a. large diameter conduction myofibers; b. located within the papillary muscles of the ventricles; c. conduct the impulse into the mass of ventricular muscle tissue. d. cause ventricles to contract which forces blood out.

Cardiac Conducton System The Pacemaker of the Heart http: //www. youtube. com/watch? v=te_SY 3

Cardiac Conducton System The Pacemaker of the Heart http: //www. youtube. com/watch? v=te_SY 3 Me. Wys

Electrocardiogram (ECG) A recording of the electrical changes during a cardiac cycle - Recordings

Electrocardiogram (ECG) A recording of the electrical changes during a cardiac cycle - Recordings taken with electrodes on skin Instrument used to record an ECG is an electrocardiograph Used to determine if: The conduction pathway is normal The heart is enlarged Certain regions are damaged Rules to Remember: Depolarization precedes contraction Repolarization precedes relaxation

Electrocardiogram (ECG) P wave a. b. represents atrial depolarization (spreads from SA node throughout

Electrocardiogram (ECG) P wave a. b. represents atrial depolarization (spreads from SA node throughout both atria); 0. 1 sec after P wave begins, atria contract. QRS complex a. c. begins as a downward deflection; continues as large, upright, triangular wave; ends as a downward wave; represents onset of ventricular depolarization (spreads throughout ventricles); shortly after QRS begins, ventricles start to contract. a. b. c. d. dome-shaped, upward deflection; represents ventricular repolarization; occurs just before ventricles start to relax; shape indicates slow process. b. T wave

Normal Sinus Rhythm

Normal Sinus Rhythm

Sinus Tachycardia Elevated impulses originating from SA node (above 100 bpm)

Sinus Tachycardia Elevated impulses originating from SA node (above 100 bpm)

Sinus Bradycardia Sinus bradycardia a sinus rhythm with a resting heart rate of 60

Sinus Bradycardia Sinus bradycardia a sinus rhythm with a resting heart rate of 60 beats per minute or less.

Atrial Flutter Atrial flutter is an abnormal heart rythym that occurs in the atria.

Atrial Flutter Atrial flutter is an abnormal heart rythym that occurs in the atria. It is typically not a stable rhythm, and frequently degenerates into atrial fibrillation.

Atrial Fibrillation During atrial fibrillation, the heart's two small upper chambers (the atria) quiver

Atrial Fibrillation During atrial fibrillation, the heart's two small upper chambers (the atria) quiver instead of beating effectively. Blood isn't pumped completely out of them, so it may pool and clot. .

Ventricular Tachycardia fast heart rhythm that originates in one of the ventricles. This is

Ventricular Tachycardia fast heart rhythm that originates in one of the ventricles. This is a potentially life-threatening arrhythmia

Ventricular Fibrillation condition in which there is uncoordinated contraction of the ventricles, making them

Ventricular Fibrillation condition in which there is uncoordinated contraction of the ventricles, making them tremble rather than contract properly. Ventricular fibrillation is a medical emergency. If this continues for more than a few seconds, blood circulation will cease, and deathmay occur in a matter of minutes.

AV Blocks is a type of heart block involving impairment of the conduction between

AV Blocks is a type of heart block involving impairment of the conduction between the atria and ventricles of the heart. Signal stops at AV node

Bundle Branch Block When a bundle branch or fascicle becomes injured, it may cease

Bundle Branch Block When a bundle branch or fascicle becomes injured, it may cease to conduct electrical impulses appropriately. This results in altered pathways for ventricular depolarization

Regulation of the Cardiac Cycle Definition of Cardiac output (CO) Amount of blood pumped

Regulation of the Cardiac Cycle Definition of Cardiac output (CO) Amount of blood pumped by each side of the heart in one minute CO = (heart rate [HR]) x (stroke volume [SV]) Stroke volume Volume of blood pumped by each ventricle in one contraction healthy heart pumps out about 60% of its volume in each contraction Normal CO = 5. 25 L Ex of avg adult: 75 beats/min x 70 ml/beat = CO = 5250 ml/min With ~5000 ml of blood in the body, this means that the entire blood supplies passes through the body each minute Volume of blood pumped changes to meet cellular requirements Startling’s Law of the Heart: the more that the cardiac muscle is stretched, the stronger the contraction; dependent upon the venous return Stroke volume-usually remains relatively constant so changing heart rate is the most common way to change cardiac output Example: a drop in blood volume will decrease the stroke volume. In order to maintain cardiac output the heart rate increases.

Cardiac Output Regulation

Cardiac Output Regulation