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ch. 19
heart circulatory system
| Term | Definition |
|---|---|
| cardiovascular system | heart and blood vessels, artieries and veins and capillaries |
| circulatory system | heart, blood vessels, and the blood |
| pulmonary circuit | right side of heart, blood low in oxygen returned to right atrium, carries blood to lungs for gas exchange and back to heart |
| systemic circuit | left side of heart, supplies oxygeniated blood to all tissues of the body and returns to the heart |
| mediastinum | thick partition that holds the heart between the two lungs |
| left side of heart | fully oxygenated blood arrives from the lungs via pulmonary veins, blood high in oxygen returns from lung to right atrium, then blood is sent to all organs via aorta |
| right side of heart | oxygen-poor blood arrives from the inferior and superior venae cavae to right atrium, then blood sent to lungs from right ventricle via pulmonary trunk |
| base | wide, superior portion of the heart, large vessels attach here |
| apex | tapered inferior end, tilts to the left |
| pericardium | where the heart is enclosed in a double-walled sac |
| pericardial sac, parietal pericardium | outer wall of heart, lines this bag holding the heart, produces serous fluid |
| visceral pericardium or epicardium | serous layer covering surface of heart, more serous fluid, coronary blood vessels travel through this layer |
| pericardial cavity | space inside the pericardial sac filled with 5-30 ml of pericardial fluid |
| pericarditis | painful inflammation of the membranes |
| endocardium | smooth inner layer of heart chambers and blood vessels, covers the valve surfaces |
| myocardium | layer of cardiac muscle proportional to work load, fibrous skeleton of heart; framework of collagenous and elastic fibers, structural support and electrical transmission |
| 2 superior chambers | right and left atria, receive blood returning to heart, |
| 2 inferior chambers | right and left ventricles, pump blood into arteries |
| atrioventricular sulcus | valley on heart surface that separates atria and ventricles |
| interventricular sulcus | valley on heart surface that is over the interventicular septum that divides the right ventricle from the left |
| interatrial septum | wall that separates atria |
| interventricular septum | muscular wall that separates ventricles |
| trabeculae carnae | internal ridges on inner surface of both ventricles, may prevent ventricle walls from sticking together after contraction |
| valves | make sure that blood is one way flood of blood through heart |
| atrioventricular valves | control blood flow between atria and ventricles |
| chordae tendineae | cords connect av valves to papillary muscles on wall of ventricles |
| semilunar valves | control flow into the great arteries, open and close because of blood flow and pressure |
| pulmonary semilunar valve | in opening between right ventricle and pulmonary trunk |
| aortic semilunar valve | in opening between left ventricle and aorta |
| ventricles relax | pressure drops inside ventricles, semilunar valves close, av valves open, blood flows from atria to ventricles |
| ventricles contract | av valves close, pressure rises inside ventricles, semilunar valves open and blood flows in great vessels, right ventricle to pulmonary trunk and left ventricle into aorta |
| angina pectoris | chest pain from partial obstruction of coronary blood flow |
| myocardial infarction | sudden death of a patch of myocardium resulting from long term obstruction circulation |
| coronary sinus | large transverse vein in coronary sulcus on posterior side of right atrium, collects blood from heart muscle and empties into right atrium |
| cardiac muscle cells (cardiomyocytes) | striated, short, thick, branched cells, one central nucleus surrounded by light-staining mass of gylcogen |
| intercalated discs | join cardiac muscle cells end to end with three features; interdigitating folds, mechanical junctions and electrical junctions |
| interdigitating folds | The plasma membrane at the end of the cells is folded somewhat like the bottom of an egg carton, interlock with each other and increase the surface area |
| mechanical junctions | cells are tightly joined by two types of mechanical junctions, fascia adherens and desmosomes |
| electrical junctions | gap junctions allow ions to flow between cells, into stimulating neighboring cells , 2 atria or 2 ventricles act together on sequence |
| cardiac conduction system | heartbeat is coordinated by, composed of an internal pacemaker and nervelike conduction pathway through the myocardium |
| sinoatrial node SA, | PRIMARY PACEMAKERmodified cardiomyocytes, initiates each heartbeat and determines heart rate |
| atrioventricular node AV | secondary pacemaker, electrical gateway to the ventricles |
| atrioventricular bundle | bundle of HIS, bundle forks into left and right branches |
| purkinje fibers, subendothelial conducting networks | nerve like processes spread throughout the lateral walls of the ventricular myocardium |
| sympathetic nerves | increase heart rate and contraction strength |
| parasympathetic nerves | slow heart rate |
| systole | contraction of heart muscle of Ventricles |
| Diastole | relaxation of heart muscle of Ventricles |
| Sinus rhythm | normal heartbeat triggered by the SA node |
| Signal from SA node | stimulates Both Atria to Contract almost simultaneously |
| Electrocardiogram (ECG or EKG) | Composite of all action potentials of nodal and myocardial cells detected, amplified and recorded by electrodes on arms, legs, and chest |
| P wave | SA node fires, atriadepolarize and contract–Atrial systole begins 100 ms after SA signal |
| QRS complex | Ventricular depolarization–Complex shape of spike due to different thickness and shape of the two ventricles |
| ST segment | ventricular systole: Ventricles contract –Corresponds to plateau in myocardial action potential |
| T wave | Ventricular repolarization and relaxation |
| Ventricular fibrillation | Serious arrhythmia caused by electrical signals traveling randomly |
| Defibrillation | strong electrical shock with intent to depolarize entire myocardium and reset heart to sinus rhythm |
| Cardiac cycle | one complete contraction and relaxation of all four chambers of the heart |
| Pressure | causes flow |
| Resistance | opposes it |
| Valvular insufficiency (incompetence) | any failure of a valve to prevent reflux (regurgitation), the backward flow of blood |
| Valvular stenosis | cusps are stiffened and opening is constricted, narrowed by scar tissue |
| Mitral valve prolapse: | insufficiency in which one or both mitral valve cusps bulge into atria during ventricular contraction |
| Auscultation | listening to sounds made by body |
| step 1 of cardiac cycle | Ventricular filling (during diastole: relaxation of ventrcle) |
| step 2 of cardiac cycle | Isovolumetric contraction (during systole: contraction of ventricle) |
| step 3 of cardiac cycle | Ventricular ejection (during systole) |
| step 4 of cardiac cycle | Isovolumetric relaxation (during diastole) |
| Congestive heart failure | results from the failure of either ventricle to eject blood effectively |
| Left ventricular failure | blood backs up into the lungs causing pulmonary edema |
| Right ventricular failure | blood backs up in the vena cava causing systemic or generalized edema |
| Cardiac output | amount ejected by each ventricle in 1 minute heart rate x stroke volume About 4 to 6 L/min at rest–A RBC leaving the left ventricle will arrive back at the left ventricle in about 1 minute |
| Cardiac reserve | the difference between a person’s maximum and resting CO |
| Pulse | surge of pressure produced by heart beat that can be felt by palpating a superficial artery Infants have HR of 120 bpm or more–Young adult females average 72 to 80 bpm–Young adult males average 64 to 72 bpm–Heart rate rises again in the elderly |
| Tachycardia | resting adult heart rate above 100 bpm–Stress, anxiety, drugs, heart disease, or fever–Loss of blood or damage to myocardium |
| Bradycardia | resting adult heart rate of less than 60 bpm In sleep, low body temperature, and endurance-trained athletes |
| Cardio stimulatory effect | some neurons of the cardiac center transmit signals to the heart by way of sympathetic pathways |
| Cardioinhibitory effect | others transmit parasympathetic signals by way of the vagus nerve |
| sympathetic postganglionic fibers | adrenegic, release norepinephrine, increases heart rate |
| parasympathetic vagus nerve | cholinergic inhibitory effect, heart slows down |
| Vagal tone | holds down the heart rate to 70 to 80 bpm at rest Steady background firing rate of the vagus nerves |
| cardiac centers in medulla | Sensory or emotional stimuli, Proprioceptors, Baroreceptors, chemoreceptors |
| chemicals affect heart rate | Autonomic neurotransmitters (NE and Ach) , Other Chemicals Speed up Heart rate:1. Nicotine 2. Thyroid hormone 3. Caffeine |
| Hyperkalemia | excess K + (potassium) heart rate slows down and becomes irregular |
| Hypokalemia | deficiency in K + (potassium), cells hyperpolarized, require increased stimulation |
| Hypercalcemia | excess of Ca2+ (calcium) decreases heart rate and contraction strength |
| Hypocalcemia | deficiency in Ca2+ (calcium) increases heart rate and contraction strength |
| Coronary artery disease (CAD) | a constriction of the coronary arteries Usually the result of atherosclerosis: an accumulation of lipid deposits that degrade the arterial wall and obstruct the lumen |
| LDLs | protein-coated droplets of cholesterol, neutral fats, free fatty acids, and phospholipids |
| sympathetic nervous system | can raise heart rate to as high as 230 bpm, increases the contraction strength of the heart, dilates the coronary arteries to increase mycardial blood flow, orginates the lower cervical and upper thoracic segments, fibers pass through cardiac plexus |
| parasympathetic nervous sytem | pathway begins w/the nuclei of the vagas nerves in the medulla oblongata, little or no innervation to the myocardium, slows the heart rate to as little as 20 bpm |
| When atrial pressure is greater than ventricular pressure, the BLANK valves open. | AV |
| When ventricular pressure rises above atrial pressure, the blood in the ventricle pushes the AV valves BLANK | closed |
| In the SL valves, when the pressure in the BLANKis greater than the pressure in the arteries, the SL valves are forced open. | ventricles |
| When ventricular pressure is lower than BLANK pressure, arterial blood holds the SL valves closed. | arterial |
Created by:
tnrogan
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