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Cardi - Timby Ch22/2
Introduction to Cardio TJC VNE Rusk
Term | Definition |
---|---|
Function of the Cardiovascular System | Supply the body cells and tissues with oxygen rich blood and eliminate carbon dioxide and cellular wastes. |
Cardiovascular System consists of | Heart, major blood vessels that empty into or exit directly from the heart, vast network of smaller peripheral blood vessels. |
Location of the heart | lies below and slightly to the left of the midline of the sternum in the mediastinum. |
The upper portion the heart | is the base. |
The tip of the heart | is the apex. |
Four chambers of the heart | right and left atria, the right and left ventricles. |
Separates the right side of the heart from the left side. | a wall or thick septum. |
The right atrium receives what kind of blood? | dexoygenated blood from the venous system |
The right ventricle(deoxygenated) pumps | the blood to the lungs to be oxygenated. |
The left ventricle receives | oxygenated blood from the lungs, then pumps the blood to the cells and tissues of the body. |
Right side | facilitates pulmonary circulation |
Left Side | responsible for systemic circulation. |
Three distinct layers of tissue make up the heart wall | epicardium, endocardium, myocardium |
epicardium | outer layer consist of fibrous and loose connective tissues. also called visceral pericardium |
endocardium | inner layer, thin, smooth layer of endothelial cells. Folds of endocardium form the hearts vavles. It is in direct contact with the blood that passes through the heart. |
myocardium | middle layer, consists of muscle tissue and is the force behind the heart's pumping action. |
pericardium | saclike structure that surrounds and supports the heart. Formed by two membranous layers called parietal pericardium and visceral pericardium. |
parietal pericardium | outer tough layer |
visceral pericardium | inner serous layer, also called epicardium |
The density of the parietal pericardium safeguards the heart | invasion by infectious microorganism. |
Serous fluid | fills the pericardial space between the two layers, lubricating the heart and reducing friction with each heartbeat. |
What are the valves of the heart | membranous structures that ensure that the blood passes through the heart in a one way, forward direction. |
In a normal heart | valves do not allow blood to backflow, regurgitate into the chamber from which it comes. |
What valves separate the atria from the ventricles? | Atrioventricular (AV) Node |
What is the purpose of the AV Node? | Prevents the blood from returning to the atria when the ventricles contract. |
What is the valve between the right atrium and right ventricle? | Tricuspid Valve - three cusps |
What is the valve between the left atrium and the left ventricle? | bicuspid Valve - two cusps; also known as the mitral valve. |
What are the atrioventricular valves? | tricuspid and bicuspid |
What is chordae tendineae and papillary muscles? | chordae tendinaea - cordlike structures that attach to papillary muscles. The contraction of the papillary muscle and the firm support of the chordaea tendineae prevent eversion of the valves and regurgitation of blood back into the atria. |
What are the semilunar valves? | Pulmonic & Aortic Valve, look like crescent shaped moons, valves named for the blood vessel into which they deposit blood. |
Pulmonic valve or Pulmonary valve | Valve between the right ventricle and pulmonary artery. |
Aortic valve | Valve between the left ventricle and aorta |
What forces the blood into the pulmonary and aortic valve? | Contraction of the ventricles |
What do arteries do? | Carry oxygenated blood from the heart. |
What do veins do? | Return deoxygenated blood to the heart. |
arterioles | smallest arteries |
venules | smallest veins |
What are arteries and arterioles? | they are elastic and dilate or constrict to accommodate changes in blood flow. |
Why do veins have thinner walls than arteries? | Venous pressure is lower than arterial pressure, because the arteries are coming from the push of the heart and the veins are carrying it back. Even though thinner, they are larger in diameter. |
What is capillaries? | microscopic vessels that form a connecting network between the arterioles and venules. one cell layer thick, in direct contact with the cells of all tissues. Delivers oxygen and metabolic substances to the cells. |
What propels the blood back to the heart? | skeletal muscle contraction. |
What is the only artery in an adult that carries deoxygenated blood? | pulmonary artery |
What are the largest veins? | inferior vena cava and superior vena cava |
What do the inferior vena cava and the superior vena cava(largest veins) do? | bring venous(dexoygenated) blood from all areas of the body into the right atrium. |
What supplies oxygenated blood to cardiac muscles? | left and right coronary arteries |
coronary ostia | openings of the coronary arteries. |
What happens when the left ventricle is filling with blood? | the coronary ostia dilates and fill with blood. |
What is the first tissue to receive oxygenated blood from the heart with each heartbeat? | myocardium |
What happens after oxygenated blood to the myocardial cells? | the coronary veins carry away the CO2 produced by cellular metabolism. |
Where do the coronary veins empty? | Coronary sinus in the right atrium |
Cardiac Output | contraction (systole) and relaxation(diastole) of both atria and both ventricles. The atria fills and then contracts simulataneously; as they relax, the ventricles contract and relax. |
What is the wavelike impulse? | the pulse |
What is the pause between pulsations? | ventricular diastole |
Atrial diastole | Atria fill with blood, which begins to flow into ventricles as soon as their walls relax |
Ventricular diastole | contraction of atria pumps blood into the ventricles |
ventricular systole | contraction of ventricular pumps blood into the aorta and pulmonary arteries? |
What does the conduction system contain of? | SA Node, AV Node, bundle of HIS, bundle branches, and Purkinje fibers |
SA Node | area of nerve tissue located in the posterior wall of the right atrium. called the pacemaker of the heart. Initiates the electrical impulses that cause the atrial and ventricles to contract. - 60-100 impulses per minute, avg. 72/min |
Does the pulmonary vein have oxygenated or deoxygenated blood? | In adults: the pulmonary vein is the only vein that has oxygenated blood. |
What is the pathway of the normal sequence of impulse? | Cardiac input starts in the SA Node then spreads thoughout the atria, over intranodal and interatrial pathways, once cells in atria excited, then they contract in unison. When reaches the AV Node, it is delayed few hundredths of a second, the impulse then |
polarization | During diastole, while the myocardial cells are at rest, before impulse is generated the cells are in polarization. Positive ions predominate outside myocardial cell membranes and negative ions predominate inside. Nothing going on, the cells are at rest - |
depolarization | impulse initiated, spreads from cell membrane causing a transfer of ions. positive ions move inside and the negative move outside. |
repolarization | ions realign themselves in their original position and wait for another electrical impulse. |
refractory period | The period of time that normal cardiac impulses cannot be carried out until the ions are again in polarized alignment. they are resistant to electrical stimulation. |
What causes the heart to fluctuate? | Stimulation from the autonomic nervous system,baroreceptors, and chemoreceptors. |
What does the Autonomic Nervous System affect? | heart rate through sympathetic and parasympathetic nervous system innervation. |
baroreceptors | pressure sensitive nerve ending in the walls of the atria and major blood vessels. |
What is the main function of baroreceptors? | sense the pressure from blood as it stretches vascular tissues containing the baroreceptors |
heart rate increases, a baroreceptor response... | to compensate for drop in bp. When bp stabilizes the heart rate returns to normal range. |
Chemoreceptors | structures that are sensitive to the ph and CO2 and oxygen levels of blood. They are located in the carotid bodies, aortic bodies, and medulla of the brain. Regulate sympathetic stimulation or inhibition. |
A fall in pH, a rise in CO2, and decrease in oxygen levels in the blood results in | increased heart contraction. |
Cardiac Output | amount of blood pumped out of the left ventricle each minute. |
Health Cardiac Output | ranges from 4 to 8L/min; average of 5L/min |
During active exercise, cardiac output may be | 5 to 7 times the normal amount. |
How can cardiac output be increased? | increasing the heart rate and by increasing the stroke volume. |
Stroke Volume | amount of blood pumped per contraction of the heart, stroke volume averages 65 to 70mL. Formula is Cardiac Output= heart rate x stroke volume. |
What increases heart rate? | Exercise, Fever, Hyperthyroidism, Hypoxia, Dehydration, Shock and Hemorrhage, Anxiety, Caffeine, Drugs, Alcohol Withdrawal. |
What decreases heart rate? | Rest, hypothermia, hypothyroidism, athletic conditioning, Drugs |
Physical Examination of Cardiovascular System | General Appearance - anxious, depressed, pain? Pain - poor circulation, chest pain, leg pain? Vital Signs - Temp, pulse, Resp Rate, Blood Pressure? |
What is a classic sign of ischemia? | pain, which results from lack of oxygen in the tissue. |
What are characteristics of fever in heart disease? | It can accompany the inflammatory response with myocardial cells are damaged after an acute MI or infections such as Rheumatic fever or bacterial endocarditis. |
Pulse | pattern of pulsations and the pauses between them. |
What is pulse volume | feeling full, weak, thready, or barely palpable. |
pulse deficit | the difference between the counted heartbeat and peripheral pulse. |
dyspneic | effortless or labored breathing |
What is indication that the client is having difficulty breathing? | The use of accessory muscles. neck or abdominal muscles. |
Orthostatic vital signs | BP assessed lying, sitting, and standing postitions. |
Systems of postural hypotension | dizziness or lightheadiness when changing postitions. |
How do you obtain mechanical activity? | must palpate a peripheral pulse or auscultate the apical heart rate to obtain. |
What does Cardiac telemetry do? | Sends ECG information over radio waves to a monitor that is distant from the client. Electrodes are attached to a battery pack, which is secured inside a pocket on the client. |
An increase in fat deposits, collagen, and elastic fibers in the SA Node leads to? | higher risk for cardiac dysrhythmias. |
S1 is? | the first heart sound you hear, called Lub. It is the closing of the mitral and tricuspid valve. It is the loudest over the apex of the heart and occurs nearly simultaneously with the palpated pulse. |
S2 | the second sound, dub. closing of the aortic and pulmonic valves. It is heard loudest with stethoscope in the aortic area, the second intercostal space to the right of the sternum. |
What are abnormal sounds of the heart? | Anything other than the sound of S1 and S2. |
S3 | although normal in children, often is an indication of heart failure in an adult. Sounds like Ken-tuck-y. |
s4 | Associated with hypertensive heart disease. |
What does friction rub indicate? | May cause a rough, grating, or scratch sound that is indicative of pericarditis. |
pericarditis | inflammation of the pericardium |
How can cyanosis be detected? | assessing skin color, color changes in the oral mucous membranes as well as the lips, earlobes, skin, and nail beds. Darkskinned: grayish cast to the skin usually indicates pallor. |
varicosities | enlargement of the veins |
When does edema occur? | When blood is not pumped efficiently or plasma protein levels are inadequate to maintain osmotic pressure. When fluid has no where to go, it enters the tissue. |
Areas prone to edema? | feet, ankles, fingers, hands, over the sacrum. |
How do you assess for edema? | gently press finger into skin, the effect is pitted edema, evaluated based on the scale of +1 to +4, depending on the depth of the pit and the amount of time it takes to disappear. |
Indication of edema? | Weight gain |
What happens if the right side of the heart fails to pump efficiently? | blood becomes congested in the neck veins. Distention of the external juglar vein indicates increased fluid volume and pressure in the right side of the heart. |
If the left side of the heart fails to pump efficiently | Blood backs up into the pulmonary veins and lung tissue. |
When auscultating, what does the nurse hear if client is experiencing left sided CHF? | crackling sound and possibly weezes and gurgles. |
The circulatory system is a continuous loop so left sided heart failure, when uncorrected is followed by | right sided heart failure |
What causes confusion in cardiac clients? | Confusion and disorientation can result from decrease in the oxygen supply to the brain as a result of poor circulation. |
Elevated Enzymes | Response to Cardiac or other organ damage. |
Echocardigram | uses US waves to determine the functioning of the left ventricle and to detect cardiac tumors, congenital defects, and changes in the tissue layers of the heart. |
transesophageal echocardiography | involves passing a tube with a small transducer internally from the mouth to the esophagus. It obtains images of the posterior heart and its internal structures. |
Electrocardiography (ECG) | graphic recording of the electrical currents generated by the heart muscle. |
Drug Induced Stress Testing | Adenosine, Persantine, Dobutamine - Dilates the coronary arteries to increase the heart's muscle blood supply. Thallium is injected a few minutes later, a scan of the heart can detect compromised blood flow. |
Cardiac Catheterization | performed in operative setting, long flexible catheter is inserted from a peripheral blood vessel in the groin, arm, neck into one of the great vessels (superior or inferior vena cava) and then into the heart. |
Instructions for client and family following Cardiac Cath. | Keep extremity straight for several hours, Report warm, wet feeling, numbness, tingling, sharp pain. Drink large volume of fluids to promote excretion of dye and follow discharge instructions for home care. |
Arteriography | instills dye, (contrast medium) into an artery. occlusive heart disease is indicated if one or more coronary arteries appear narrow or do not fill. |
angiocardiography | radipaque dye injected into a vein, its course through the heart is recorded by a series of pictures taken in rapid succession. pictures reveal the size and shape of the heart chambers and great vessels and the sequence and time of their filling with dye. |
Aortagraphy | detects aortic abnormalities, such as aneurysms, contrast medium is injected and radiographic films are taken of the abdominal aorta and major arteries in the legs. |
Measured Blood Pressure reflects? | the ability of the arteries to stretch and fill with blood. The efficiency of the heart as a pump. Volume of circulating blood. |
BP is affected by? | Age, Body size, diet, activity, emotions, pain, position, gender, time of day, disease. |
Normal Range of BP? | from 100/60 to 119/79 mm/Hg |
What is systolic blood pressure determined by? | the force and volume of blood that the L ventricle ejects during systole. 2. ability of the arterial system to distend at the time of ventricular contraction. |
Narrowing of the arterioles causes? | Increase in peripheral resistance which in return increases BP. |
Diastolic Blood pressure | Reflects arterial pressure during ventricular relaxation. If arterioles are resistant, blood is under greater pressure. |
Prehypertensive | 120/80 to 139/89 |
Hypertensive | 140/90 to 159/99 |
Stage 2 hypertension | greater than 160/100 |
What two main categories is hypertension divided into? | Primary (Idiopathic) and Secondary |
What are causes of hypertension? | BP increases with age, Hereditary, common in African Americans, obesity, inactivity, smoking, ETOH, Ineffective stress management, hypernatremia. |
Hypernatremia | elevated serum sodium levels, increases blood volume, raises BP |
Renin | chemical that the kidneys release to raise BP and increase vascular fluid volume in response to renal hypoperfusion |
What causes the heart to work harder to pump against the increased resistance? | hypertenstion |
When does heart failure occur? | when the heart can no longer pump adequately to meet the body's metabolic needs. |
Extra work and greater mass increase what? | The heart's need for O2 |
MI occurs when? | myocardium does not receive sufficient oxygenated blood. |
HTN | Can damage arterial vascular system. Accelerates athersclerosis. Serious complications to other organs. |
HTN can also affect what part of the body? | eyes, brain, heart, and kidneys |
How does a CVA result? | from hemorrhage or occlusion of a blood vessel in the brain. |
Renal failure | caused by impaired circulation to the kidneys |
Many clients with HTN may be | asymptomatic |
HTN is considered | the silent killer |
S/S of elevated BP | Throbbing or pounding HA, Dizziness, Fatigue, insomnia, nervousness, nosebleeds, blurred vision. |
Nonpharmacologic interventions used for clients with prehypertension | weight reduction, decreased sodium intake, excerise, reduced contributing factors (smoking) |
What type of drug is clients with HTN usually started on? | diuretic |
What do adrenergic Blockers do? | Relax vascular smooth muscle by blocking receptor sites for epinephrine and norepinephrine. |
What do Ace Inhibitors do? | Prevents ACE from converting Angiotensin 1 to Angiotensin 2. Promote fluid and sodium loss and decrease peripheral vascular resistance. |
Angiotensin Receptor Blockers | Blocks affect of Angiotensin 2, Relax vascular smooth muscle, Increase salt and water excretion. Reduce plasma volume. |