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25 Cards in this Set
- Front
- Back
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Where is the heart located?
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-Lies in the mediastinum
-from sternum to vertebral column between the lungs -2/3 of heart is to the LEFT of the body's midline |
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What are the borders of the heart?
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Base:
-directed posteriorly, superiorly and to the right -most of it is formed by left atrium Apex: -directed anteriorly, inferiorly, and to the left -most of it is formed by left ventricle |
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What is the Pericardium?
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covering of the heart. provides enough space for heart to contract while minimizing friction between different layers of heart
outer = fibrous layer (dense irregular CT) inner = serous layer Serous has 2 layers: Parietal - fuses with fibrous pericardium (creating a cavity below called pericardial cavity) Visceral - known as epicardium which rests over heart Pericardial fluid = 5-30 ml -reduces friction during contraction |
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What are the layers of the Cardiac Wall?
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Epicardium:
-out layer, smooth slippery texture Myocardium: -bulk of hear and responsible for pumping action -has myocytes which are involuntary and striated Endocardium: -inner later and continuous with large blood vessels |
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What is Pericarditis?
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inflammation of the pericardium
Acute: -viral infections -irritation of pericardium --> chest pain similar to heart attack -friction rub between parietal and visceral pericardium which is scratchy sound heard on stethoscope Chronic: -TB -cardiac tamponade = accumulation of the pericardial fluid -this leads to cardiac compression, Decrease Cardiac output, venous return and blood pressure |
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What are some disorders of the CVS?
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Rheumatic heart disease:
-in young children -results from untreated infection with Streptococcus -causes fever and inflammation of endocardium -narrowing of bicuspid valve causing incompetence of that valve Endocarditis: -inflammation of endocardium -results in pathological heart sounds (heart murmurs), fever, irregular heart beat Myocarditis: -can cause heart attack -severe cases can lead to cardiac failure |
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What are auricles and sulci?
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auricles:
-pouch like structures which increase the volume of the atrium sulci: -mark external boundary between two chambers of heart -contain blood vessels and fat -coronary is between atria and ventricles |
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What are characteristics of the Right Atrium?
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receives blood from 3 veins:
-SVC, IVC, and coronary sinus (CS) interatrial septum (IS): -contains Fossa Ovalis (FO) which is the remnant of the foramen ovale Pectinate muscles: -on anterior wall and in auricle only Tricuspid valve: -right atrioventricular valve -unidirectional passage of blood from RA to RV -has 3 leaflets -valve = flaps of dense CT and endocardium |
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What are characteristics of the Right Ventricle?
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walls contain trabeculae carneae - ridges of cardiac muscle fibers for contraction and conduction of impulses, apex is papillary mm
chordae tendineae - tendon like cords which attach tricuspid valve to papillary muscles of wall, attaches to leaflets interventricular septum pulmonary semilunar valve: -3 leaflets -blood from RV --> pulmonary trunk --> R & L pulmonary arteries of lungs |
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What are characteristics of the Left Atrium and Ventricle?
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LA:
-forms most of heart base -receives OXYGENATED blood through 4 pulmonary veins -pectinate muscles are only confined to left auricle -contains Left AV valve (bicuspid, mitral), takes blood from LA to LV Left Ventricle: -forms apex of heart -contains trabeculae carneae and cordae tendinae, papillary muscles -contains aortic semilunar valve which connects LV to ascending aorta Ligamentum Ateriosum: -remnants of closes ductus arteriosus -this is when blood is shunted during the gestational period in the pulmonary trunk |
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What are Pulmonary and Systemic Circulation?
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Pulmonary:
RV --> Pulmonary trunk & arteries --> pulmonary vascular bed --> pulmonary veins --> LA -low resistance and pressure -functions to supply lungs with blood oxygenation Systemic: LV --> Aorta --> systemic vascular bed --> SVC and IVC --> RA -high pressure and resistance -supplies nutrients and removes waste from body |
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What is coronary circulation?
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L and A coronary arteries branch from ascending aorta
branches of Left: -Circumflex branch - lies in coronary sulcus and supplies LV and LA -Anterior Interventricular branch (Left Anterior Descending Artery) - lies in anterior interventricular sulcus and supplies both ventricles Right branch: -Atrial branches - supply the RA -Posterior Interventricular branch - lies in posterior interventricular sulcus and supplies walls of 2 ventricles -Marginal Branch - lies in coronary sulcus an supplies RV There are also numerous anastomoses between different coronary arteries to provide safety |
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What are the Coronary veins?
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Coronary sinus:
-receives venous blood from the myocardium (great, middle, small, anterior and posterior cardiac veins) -lies on posterior surface -drains into RA Smallest Cardiac veins (Thebesian veins): -drain into the heart chambers where they are located Small cardiac vein: -receive blood from RA and RV and drain into coronary sinus Anterior Cardiac Vein: -receive blood from RA and RV and drain along with small cardiac into Coronary sinus Middle Cardiac V: -receive blood from RV and LV and drain into coronary sinus Great Cardiac V: -receive blood from RV and LV and ventricular septum and empty into coronary sinus Posterior Cardiac V: -receives blood from LV and drains into coronary sinus along with greater cardiac Oblique Cardiac V: -receives from LA and drains along with great cardiac into coronary sinus Thebesian V: -drain LOCALLY into heart chambers where they are located |
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What are Myocardial ischemia, hypoxia, angina pectoris, and myocardial infarction?
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Myocardial ischemia:
-low blood flow to the myocardium due to partial obstruction of coronary artery Hypoxia: -low O2 supply (due to ischemia) Angina Pectoris: -"strangled chest" -severe pain with accompanied myocardial ischemia Myocardial infarction: -heart attack -necrosis of an area of myocardial tissue due to interrupted blood supply, complete occlusion of a coronary artery -this leads to infarction of myocardial area distal to occlusion -dead myocardium is replaced with non-functional connective (scar) tissue |
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What is Myocardial Reperfusion and some adverse effects?
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Reperfusion:
-reestablishment of blood flow -reintroduction of O2 which cause dangerous oxygen free radicals -converted to less reactive substances by enzymes (superoxide dismutase and catalase) Natural Antioxidants: -remove oxygen free radicals from body (Vitamins, Se, Zn) |
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What are some of the morpho-functional properties of the Myocardium?
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Heterogeneity:
Contractile system (typical cardiomyoctyes) - contracts, produces force and does mechanical work of pumping Pacemaker and conducting system (atypical cardiomyocytes) - autorhytmic intercalated discs: -contain gap junctions which allow action potenials to conduct -contain desmosomes which hold the cells together |
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How are skeletal, smooth, and cardiac muscles compared to each other?
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Skeletal:
-voluntary -elongated cell -multiple peripheral nuclei -visible striations Cardiac: -involuntary -branching cell -single central nucleus -visible striations Smooth muscle: -involuntary -spindle shaped cell -single central nucleus -lack visible striations |
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Where are the SA node, AV node, and the AV Bundle of His located?
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SA Node:
-right atrial wall inferior to the open of SVC AV node: -interatrial septum anterior to opening of coronary sinus AV Bundle of His: -interventricular septum |
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What is the conducting system of the heart?
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SA Node (First order ) --> AV Node (Second order with delay) --> AV Bundle of HIS (3rd order) --> Purkinje Fibers (4th order, directly to myocardium)
AV Bundle is the ONLY muscular connection between atria and ventricles. elsewhere the FIBROUS SKELETEON electrically insulates the atria and ventricles |
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WHat is the pathway of the conduction of impulses in the heart?
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Self-activation of the SA Node ( 2 pathways )
Conduction of impulses to atrial myocardium --> excitation and contraction of atrial myocardium (0.08 sec) --> 2 atria depolarize and contract simultaneously conduction of impulses to AV node --> AV activation and AV delay (0.13 sec) --> ventricles are relaxed during atrial contraction Activation of AV node and conduction of impulses after a delay also active bundle of HIs and P fibers --> activation of contractile cardiomyocytes of ventricular walls The AV delays makes sure that the atrial contraction completes PRIOR to ventricular contraction |
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What are characteristics of the development of the heart?
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begins at day 18-19 and first heart beat is at 21-22 and originates in sinus venosus which receives venous blood
source: mesoderm cardiogenic area in head end of embryo --> a pair of cardiogenic cords --> canalisation of cords --> 2 endocardial tubes sinus venosus = part of RA, coronary sinus, SA node Atrium --> part of RA, LA Ventricle --> LV Bulbous cords --> RV Truncus arteriosus --> ascending aorta and pulmonary trunk by day 28: reorientation of atria and ventricle to assume final adult position 4 chambers by week 4-7: -formation of interatrial septum and foramen ovale -formation of interventricular septum -AV valves = 5-8 week, semilunar = 5-9 week |
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What is Atrial Septal Defect?
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results from failure of foramen ovale to close after birth
associated with left-to-right shunts ASD is most common congenital heart defect found in adults during fourth decade, pulmonary hypertension and arrhythmias arise |
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What is Ventricular Septa Defect?
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Left to right shunt - flow of oxygenated blood from LV to RV
Tetralogy of Fallot: (right to left shunt) 1. Overriding Aorta (emerges from both ventricles) 2. Pulmonary stenosis (decrease blood flow to the lungs and low blood oxygenation leading to cyanosis (blue baby) 3. Ventricular Septal defect (mixing of blood from 2 ventricles) 4. Right Ventricular Hypertrophy (due to increase resistance of blood flow to lungs) |
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What is a Coarctation of the Aorta?
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Congenital narrowing of a segement of the aorta --> increase work load for LV and decrease flow of oxygenated blood to regions distal to narrowing
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What is Patent Ductus Arteriosus?
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results from failure of ductus arteriosus (temporary blood vessel between aorta and pulmonary trunk) to close after birth --> shunting of blood from aorta to pulmonary arteries (left-to-right shunt) --> pulmonary hypertension
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