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Beschreibung
Karteikarten von Airen Smith, aktualisiert more than 1 year ago
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Erstellt von Airen Smith
vor mehr als 8 Jahre
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| Frage | Antworten |
| The heart is located | in the middle mediastinum between 2nd rib & 5th intercostal space |
| the heart is about the size of | a closed fist |
| where does the apex of the heart point | it points down and to the left |
| what amount of the heart is on the left? | two thirds |
| tell me about the base of the heart in comparison to the apex | it is larger and less pointy, has several large vessels attached to it. |
| what is the heart enclosed by? | the heart and proximal portions of the vessels are enclosed by a loose fitting double layered sac called the pericardium. |
| what is another term for the pericardium? | the pericardial sac |
| what are the two types of pericardium? | a fibrous pericardium and a parietal pericardium |
| another term for outer epicardium? | visceral pericardium |
| what is the out epicardium? (aka the visceral pericardium) | a serous membrane of connective tissue covered by simple squamous epithelium. it firmly attaches to the underlying muscle. |
| what do blood vessels in the outer epicardium do? | they nourish the heart |
| how much of the heart wall does the middle myocardium take up? | the bulk of it. |
| what is the middle myocardium made up of? | cardiac muscle tissue |
| what does contraction of the myocardium provide? | the force necessary for the ejection of blood from the heart and the movement of blood through the vessels. |
| what width is the middle myocardium? | the thickest layer |
| is the middle myocardium muscular? | yes, it's the most muscular layer. |
| what properties do the cells in the middle myocardium possess? | they contain electrical properties to conduct impulses from one muscle cell to another. that enables the heart to contract. |
| what is the inner endocardium? | the smooth inner lining of the heart wall |
| what is the inner endocardium comprised of? | simple squamous epithelium |
| what does the smooth surface of the inner endocardium allow? | it allows blood to easily flow throughout the heart. |
| what does the inner endocardium form? | it forms the heart valves and is continuous with the lining of the blood vessels |
| what is the right atrium and what does it do? | thin walled chamber that receives deoxygenated blood from 3 different places. |
| where are the 3 places the right atrium receives blood from? | the superior vena cava, inferior vena cava, and the coronary sinus |
| the superior vena cava returns blood to the heart from where? | the head, neck, and upper extremeties. |
| what is the coronary sinus? | it's a small venous structure located in the posterior region of the heart that returns blood to the right atrium from the myocardium. |
| where does the right ventricle receive blood from? | the right atrium |
| when the right ventricle receives blood from the right atrium, what happens next? | blood is pumped out to the lungs to receive oxygen. |
| what is the left atrium? | thin walled chamber that receives oxygenated blood from the lungs through the pulmonary vein |
| how many pulmonary veins are there and where are they located? | 4. two are located on the left side of the heart and 2 are located in the right. |
| what does the left ventricle do? | it has the thickest myocardium and receives oxygenated blood from the left atrium and pumps it out systematically |
| which side of the heart is oxygenated and which is deoxygenated? | the right side is deoxygenated and the left is oxygenated. the only exception to this are the pulmonary veins which are all oxygenated. |
| where is the atrioventricular valve (av valve) located? | between the atria and the ventricles. |
| what is the purpose of the atrioventricular valves (av valves)? | they prevent blood from flowing back into the atria when the ventricles contract. |
| what is the atrioventricular valve (av valve) of the right side of the heart called? | tricuspid |
| what is the atrioventricular valve (av valve) of the left side of the heart called? | the bicuspid or mitral valve |
| where are semilunar (sl valves) located? | at the exits from ventricles |
| what is the purpose of semilunar (sl) valves? | they prevent blood from flowing back into ventricles when they relax. **they prevent the blood flow from a large vessel back into ventricles. |
| where is the pulmonary (sl) valve located? | at the exit of the right ventricle |
| where is the aortic (sl) valve located? | at the exit of the left ventricle |
| what do the right and left coronary arteries branch off of? | the ascending aorta that supply blood to the myocardium |
| deoxygenated blood from the capillaries in the myocardium enters where? | the coronary sinus |
| from the coronary sinus where does deoxygenated blood go? | it enters the right atrium |
| what is digoxin derived from and what is it used for? | derived from the foxglove plant, today we use it to treat CHF (congestive heart failure). it increases strength and regularity of contractions to strengthen cardiac output. it also slows impulse conduction speed and lowers heart rate to allow more time for ventricular filling. |
| nitroglycerin | a vasodilator, it dilates the coronary artery and provides more efficient blood flow through the coronary arteries |
| quinidine | a group I antidysrythmic drug, results in decreasing of conduction velocity broadening of QRS complex indicates slower conduction. the SA node is able to reestablish normal cardiac rythms. |
| what does the conduction system consist of? | specialized cardiac muscle cells that act in a manner similar to neural tissue. the conduction system coordinates the contraction and relaxation of the heart chambers. |
| has the fastest rate of depolarization (contraction). it is aka the **pacemaker** in the conduction system because it establishes the basic rhythm of the heart beat. | the sinoatrial (SA) node |
| where is the SA (sinoatrial) node located and what is its function? | located at the right atrial posterior wall. without any neural/nervous stimulation it rhythmically initiates impulses 70-80 times per min. impulses from the SA node travel rapidly throughout the atrial myocardium which causes them both to contract simultaneously. |
| where is the location and function of the atrioventricular (av) node | located in the floor of the right atrium, it conducts impulses more slowly allowing a brief time delay as the impulse travels through the node, this allows time for the atria to finish contraction before the ventricle contracts. |
| AV bundle (bundle of His) | right and left bundle branches, they extend along the right and left side of the interventricular septum |
| what happens if the SA node is unable to function? | another area, such as the AV node, becomes the pacemaker. this results in a heart rate that is slower than normal. |
| what is an electrocardiogram? (ECG) | record of electrical activity of the heart. |
| what does a normal electrocardiogram (aka ECG, aka ECG) consist of? | waves or deflections that correlate with the depolarization and repolarization events of the cardiac cycle. |
| what is a P wave? | a small upward deflection produced by depolarization of the atrial myocardium just before contraction |
| what is the QRS complex? | a large upward deflection produced by depolarization of the ventricle myocardium immediately preceding contraction of the ventricles. |
| what is the T wave? | it is due to the repolarization of the ventricles that occurs just before the ventricles relax. |
| draw a picture of the PQRST waves that occur during an electrocardiogram | |
| arrhythmia/dysrhythmia | variation in normal contraction pattern |
| what is a cardiac cycle? | the alternating contraction and relaxation of the myocardium in the walls of the heart chambers coordinated by the conduction system during 1 heart beat |
| systole | contraction phase of the cardiac cycle |
| diastole | relaxation phase of the cardiac cycle |
| at a normal heart rate, I complete cardiac cycle lasts how long? | 0.8 seconds |
| how long does systole (the contraction phase of the heart) last? | lasts for 0.1 seconds |
| how long does ventricular systole last? | 0.3 seconds |
| how long are all the chamber's relaxing for at the same time? | 0.4 seconds |
| when does most ventricular filling occur? | while all the chambers are relaxed together. |
| what is systolic pressure? | the top number when you take a BP. refers to the amount of pressure in your arteries during contraction of heart muscle |
| what is the diastolic number? | the bottom number when taking a BP. the pressure in the arteries when the heart rests between beats. |
| what is pulse pressure and around what number is it, usually? | the difference between the systolic and diastolic pressure. you just subtract. it's usually around 40 |
| what is the "lubb-dupp" noise caused by? | it is due to vibrations or turbulence in the blood caused by the valves closing |
| "lubb" is | the closure of the AV (atrioventricular valves), the first sound |
| "Dubb" is | closure of the semilunar valves (SL valves), the 2nd sound. |
| cardiac output= | stroke volume (sv) X heart rate |
| what is cardiac output? | the volume of blood pumped by a ventricle in 1 min |
| what does cardiac output measure? | the effectiveness of the hearts ability to pump blood |
| SV (stroke volume)= | the amount of blood ejected from a ventricle each time a ventricle contracts (not every minute, every time it contracts) |
| SV (stroke volume) is influenced by | end diastolic volume and contraction strength. |
| what is end-diastolic volume? | amount of blood remaining in the ventricles at the end of diastole. |
| what directly influences cardiac output? | heart rate |
| what is the cardiac center? | the medulla oblongata |
| what nervous systems does the medulla oblongata use to influence heart rate? | the autonomic nervous system (sympathetic and parasympathetic nervous systems) |
| what does the autonomic N.S. do in coordination with the medulla oblongata? | adjust the heart rate to meet the changing needs of the body. |
| what is the sympathetic nervous system? | fight or flight. heart rate increases, increases force of contraction, increases cardiac output & stroke volume, increases BP. |
| what is the parasympathetic nervous system and what does it effect? | rest/repose, negative feedback. lowers heart rate, lowers force of contraction, lowers BP, lowers cardiac output nd stroke volume |
| what is starlings law of the heart? | the more cardiac muscle fibers are stretched, the greater will be the contraction strength of the heart. |
| what happens when increased volume fills the ventricles? | the cardiac muscle fibers stretch to accommodate the increased volume in response to the stretching. the fibers contract with great force which increases the amount of blood ejected from the ventricle (stroke volume) |
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