Term
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Definition
| the volume of blood pumped by the heart per minute CO = SV * HR It normally equals the total blood volume of about 5.5 liters |
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Term
| What part of the nervous system influences the heart rate? |
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Definition
| the Autonomic Nervous System |
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Term
| What factors influence the stroke volume? |
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Definition
| A. the mean arterial pressure B. the end diastolic volume and contraction strength |
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Term
| (T or F) Without neuronal influences the heart beats according to the rhythm set by the SA node |
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Definition
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Term
| Define chronotropic effect |
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Definition
| regulation of the heart rate (it may be positive or negative) |
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Term
| What is the major means by which the heart rate is regulated? |
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Definition
| sympathetic and parasympathetic neurons to the SA node |
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Term
| Describe the chronotropic effect of the sympathetic and parasympathetic |
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Definition
| sympathetic - postive chronotropic effect parasympathetic - negative chronotropic effect |
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Term
| What area in the brain contains the cardiac control center that coordinates the activity of the autonomic innervation of the heart? |
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Definition
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Term
| What three variable regulate stroke volume? |
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Definition
| A. END DIASTOLIC VOLUME - the volume of blood in the ventricles at the end of diastole B. TOTAL PERIPHERAL RESISTANCE - the frictional resistance to the blood flow in the arteries C. CONTRACTILITY - the strength of ventricular contraction |
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Term
| What does the EDV represent? |
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Definition
| The EDV represents the workload on the heart prior to contraction |
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Term
| What is the result of an increased EDV? |
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Definition
| An increase in EDV results in greater stroke volume |
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Term
| What is directly proportional to the stroke volume? |
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Definition
| stroke volume is directly proportional to the contractility |
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Term
| With what does the strength of contraction vary directly with? |
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Definition
| The strength of contraction varies directly with the EDV |
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Term
| What is ejection fraction? What is its normal value? |
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Definition
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Term
| What is total peripheral resistance? What causes the resistance? |
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Definition
| TPR is the resistance to the ejections of blood from the ventricle TPR is due to the diameter of the arteries |
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Term
| The pressure in the arteries before the ventricle contracts is a function of the __________. |
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Definition
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Term
| The SV is inversely proportional to the ________. The greater the TPR, the lower the _________. |
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Definition
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Term
| Is the Frank-Starling law of the heart an intrinsic or extrinsic mechanism? |
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Definition
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Term
| Explain the Frank-Starling law of the heart. |
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Definition
| a. there are varying degrees of stretching of the myocardium by the EDV b. as the EDV increases it contracts more forcefully c. as the ventricles fill, the myocardium stretches d. it allows more force to develop and explains how the heart can adjust to a rise in TPR |
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Term
| Define contractility Is it controlled intrinsicly or extrinsicly? |
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Definition
| the strength of contraction at any given fiber length Contractility is controlled extrinsicly by the sympathetic and adrenal hormones |
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Term
| What hormones increase contractile strength? What is this effect called? |
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Definition
| NE and Epi Positive intropic effect NOTE: the parasympathetic stimulation has a negative CHRONOTROPIC effect and DOES NOT directly influence contraction strength |
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Term
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Definition
| the return of blood to the heart via the veins |
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Term
| What is the driving force for the return of blood to the heart? |
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Definition
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Term
| Do veins have a higher compliance or stretchability than arteries? |
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Definition
| Yes They also have thinner walls |
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Term
| At any one time, about how much of the total blood volume is in the veins? |
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Definition
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Term
| What three things are controlled by factors that affect the venous return? |
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Definition
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Term
| About how much of the total body water is within the intracellular compartment? |
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Definition
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Term
| About how much of the total body water is within the extracellular compartment? How much of that is in the interstitial fluid and the blood plasm? |
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Definition
| One-third 80% in the interstitial fluid and 20% in the blood plasma NOTE: there is a constant balance between water loss and gian in these compartments |
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Term
| What is the net filtration pressure? |
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Definition
| It is the hydrostatic pressure of the capillaries minus the hydrostatic pressure of the interstial fluid |
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Term
| What is the colloid osmotic pressure? |
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Definition
| It is the pressure exerted by plasma proteins or interstitial proteins |
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Term
| What is the oncotic pressure? |
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Definition
| The difference between the plasma osmotic pressure and interstitial osmotic pressure |
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Term
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Definition
| Edema is excessive accumulation of tissue fluid |
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Term
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Definition
| a. high arterial blood pressure b. venous obstruction (flebitis, blood clot) c. leakage of plasma proteins into interstitial fluid (holds fluid in those spaces) d. myxedema in hypothyroidism e. decreased plasma protein concentration (caused by liver failure) f. obstruction of lymphatic drainage in elepantiasis or cancer |
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Term
| Where does filtration begin in the kidneys? |
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Definition
| Filtration begins when plasma runs through the glomerular capillary pores |
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Term
| How can the volume of urine excreted be varied? |
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Definition
| By changes in reabsorption of filtrate It is adjusted according to the needs of the body by the action of hormones |
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Term
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Definition
| ADH is released by the posterior pituitary when osmoreceptors detect an increase in plasma osmolality It makes the collecting duct more permeable to water by making pores |
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Term
| What is aldosterone? How does it work? |
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Definition
| Aldosterone is a steroid hormone secreted by the adrenal cortex It stimulates a mechanism to maintain blood volume and pressure through the reabsorption and retention of sodium and chloride ions It stimulates the reabsorption of sodium chloride It indirectly increases the reabsorption of water It DOES NOT dilute the osmolarity |
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Term
| What types of conditions cause the release of aldosterone? |
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Definition
| salt deprivation reduced blood volume and pressure |
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Term
| Explain the Renin-angiotensin-aldosterone system |
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Definition
| 1. When the blood pressure and flow are reduced in the renal artery, the juxtaglomerular apparatus (responsive to stress) secretes renin 2. Renin converts angiotensinogen to angiotension I 3. Angiotensin I is converted to angiotensin II by ACE (angiotensin converting enzyme) located within the lungs 4. Angiotensin II is a powerful vasoconstrictor, it stimulates the production of aldosterone, and it stimulates thirst. These both result in increased fluid retention and an increase in blood volume and pressure |
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Term
| What is a typical drug that lowers blood pressure? |
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Definition
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Term
| What is ANP? Where is it produced and how does it work? |
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Definition
| Atrial natriuretic peptide 1. Produced in the atria of the heart when they are stretched 2. It is antagonistic to aldosterone and angiotensin II 3. It promotes sodium and water excretion in the urine by the kidney 4. It promotes vasodilation |
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Term
| The amount of blood that the heart pumps/min is equal to _______. |
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Definition
| The rate of venous return |
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Term
| The flow of blood throught the vascular system is due to _______. |
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Definition
| the pressure difference between the two ends of the system |
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Term
| What is the simplified equation that determines the "flow" of blood |
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Definition
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Term
| Resistance is directly proportional to the _____ of the vessel and to the ________ of the blood Resistance is inversely proportional to the _______ _______ of the ______ of the vessel |
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Definition
| length, viscosity 4th power, radius |
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Term
| What are the main regulators of blood flow through an organ? |
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Definition
| a. mean arterial pressure b. vascular resistance to flow c. these are controlled by the ANS |
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Term
| Discuss how the ANS regulates blood flow |
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Definition
| 1. sympathoadrenal stimulation increases cardiac output and the TPR 2. Alpha-adrenergic stimulation causes vasoconstricition of arteries in the skin and viscera 3. cholinergic sympathetic fibers cause vasodilation of skeletal muscles 4. the parasympathetic innervation is limited. It promotes vasodilation in the digestive tract, external genital, and the salivary glands |
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Term
| Give two examples of paracrine regulation of blood flow What produces paracrine regulators? |
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Definition
| 1. nitric oxide diffuses into the smooth muscle of the t.media and causes vasodilation 2. bradykinin and prostacyclin also cause vasodilation The endothelium produces several paracrine regulators |
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Term
| Give an example of intrinsic regulation of blood flow |
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Definition
| The intrinsic myogenic control mechanism It occurs because of the stretch of the vascular smooth muscle A decrease in systemic arterial pressure causes cerebral vessels to dilate |
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Term
| What are some examples of metabolic control mechanisms that cause vasodilation? How does it work? |
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Definition
| A. decreased oxygen B. increased carbon dioxide C. decreased pH D. increased potassium ion Intrinsic receptors sense chemical changes in the environment to cause vasodilation |
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Term
| What physiological adaptations allow for the constant supply of aerobic requirements of the heart? |
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Definition
| 1. The coronary arteries supply an enormous number of capillaries 2. The myocardium contains large amounts of myoglobin to store oxygen to be released during systole 3. The heart contains an increased number of mitochondria and aerobic enzymes |
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Term
| Give examples of how coronary blood flow is regulated |
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Definition
| 1. The sympathetic nervous system a. alpha receptors stimulate vasoconstriction at rest b. beta receptors stimulate vasodilation in flight or flight 2. Intrinsic regulators: a. increased metabolism of the myocardium causes increased carbon dioxide and potassium ion, and decreased oxygen b. these cause vascular smooth muscle to relax |
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Term
| Give examples of how blood flow is regulated through the skeletal muscles |
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Definition
| 1. During rest, ??sympathetic alpha-adrenergic receptors stimulate vasoconstriction 2. During fight or flight, cholinergic and beta-adrenergic receptors stimulate vasodilation INTRINSIC mechanisms... During exercise decreased oxygen, increased carbon dioxide, increased potassium ion and a decreased pH all cause vasodilation of the arterioles |
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Term
| Detail how circulation changes during exercise with respect to vascular resistance |
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Definition
| vascular resistance decreases to skeletal muscles and blood flow increases The stroke volume and cardiac output increase Blood flow to the brain remains constant The heart rate increases to a max of 190 beats per minute The ejection fraction increases Vascular resistance to the GI tract and the skin increases and blood flow descreases |
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Term
| What happens to cerebral circulation when exercising? |
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Definition
| 1. Cerebral blood flow is not normally influenced by sympathetic nerve activity 2. At a normal range of arterial pressures the cerebral blood flow is regulated by intrinsic mechanisms: a. myogenic - increased stretch decreases flow b. metabolic - increased carbon dioxide increases flow and other products |
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Term
| When exercising how is cutaneous blood flow manipulated? |
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Definition
| 1. Thermoregulation - blood flow through the skin is adjusted to maintain deep body temperatures at about 37 degress Celsius 2. Bradykinin is secreted by sweat glands that increase blood flow to the skin and sweat glands 3. Changes in cutaneous blood flow occur as a result to changes in sympathetic nerve activity |
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Term
| When exercising how is cutaneous blood flow manipulated? |
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Definition
| 1. Thermoregulation - blood flow through the skin is adjusted to maintain deep body temperatures at about 37 degress Celsius 2. Bradykinin is secreted by sweat glands that increase blood flow to the skin and sweat glands 3. Changes in cutaneous blood flow occur as a result to changes in sympathetic nerve activity |
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Term
| What three things determine the pressure of arterial blood |
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Definition
| blood volume TPR (diameter) cardiac rate |
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Term
| Why is arteriolar resistance the greatest? |
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Definition
| because they have the smallesst diameter |
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Term
| What body systems can regulate the blood pressure? |
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Definition
| kidneys and sympathoadrenal systems |
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Term
| Describe the Baroreceptor reflex (KNOW THIS!) |
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Definition
| 1. Stretch receptors are located in the aortic arch and the carotid sinus 2. An increase in BP stretches the wall and increases the frequency of action potentials 3. The baroreceptors send action potentials to the vasomotor control and cardiac control centers in the medulla 4. The baroreceptor reflex is activated with changes in BP |
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Term
| Describe atrial stretch reflexes |
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Definition
| 1. Receptors located in the atria of the heart 2. The receptors are activated by an increase in venous return 3.This stimulates reflex tachycardia 4. Inhibits ADH release 5. Promotes secretion of ANP |
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Term
| How can we measure blood pressure? |
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Definition
| 1. Done by ascultation 2. Turbulent blood flow due to use of sphygmomanometer produces vibrations in the vessels that can be heard as Korotkoff sounds |
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Term
| What is the average pulmonary BP? |
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Definition
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Term
| What is pulse pressure? What is it normally? |
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Definition
| Pulse pressure is the systolic pressure minus the diastolic pressure It is normally about 40 mm Hg |
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Term
| What is the mean arterial pressure? How is it measured? |
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Definition
| the average arterial pressure during the cardiac cycle it's the diastolic pressure plus one-third of teh pulse pressure It's usually 93mm Hg |
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Term
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Definition
| blood pressure in excess of normal range for age and gender Usually greater than 130/90 mm Hg |
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Term
| What is essential hypertension? |
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Definition
| primary or essential hypertension is the result of complex or poorly understood processes |
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Term
| What is secondary hypertension? |
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Definition
| hypertension due to a known disease process, usually the kidneys |
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Term
| What kind of hypertension do most people have? |
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Definition
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Term
| Give some characteristics of hypertension |
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Definition
| A. increase in TPR is a universal characteristic B. the CO and the HR are elevated in many C. secretion of renin, angiotensis II, and aldosterone is variable D. sustained high stress and high sodium ion intake act to develop hypertension E. the adaptive response to hypertension is a thickening of the arterial wall causing atherosclerosis F. the kidneys may not be able to properly excrete sodium ion and water |
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Term
| What are some of the dangers of hypertension? |
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Definition
| a. it is a silent killer as patients are asymptomatic until the damage has occurred b. atherosclerosis c. increases workload of the heart d. causes congestive heart failure e. it damages the cerebral blood vessels |
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Term
| How can one moderate lifestyle in the treatment of hypertension? |
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Definition
| a. cease smoking b. moderate alcohol intake c. weight reduction d. programmed exercise e. a reduction in salt intake f. a diet high in potassium ion |
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Term
| What are some medications for hypertension? |
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Definition
| 1. diuretics to increase urine volume 2. beta-blockers to decrease the HR 3. Calcium antagonists to block calcium ion channels (decrease response to stress)4. ACE inhibitors to inhibit the conversion to angiotensin II 5. Angiotensin II receptor antagonists |
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Term
| What causes hypovolemic shock? What are some compensations made? |
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Definition
| Low blood volume causes a decreased CO and blood pressure Compensations are tachycardia and vasoconstriction of the GI tract, the skin, kidneys, and muscles Also the kidneys stimulate the production of the renin-angiotensin-aldosterone system resulting in vasoconstriction an increase in ADH also occurs |
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Term
| What is septic shock? How does it occur? How is it treated? |
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Definition
| Dangerously low BP as a result of sepsis It occurs through the action of baterial endotoxins that activate NO and cause vasodilation It is treated with drugs that inhibit the production of NO |
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Term
| Describe congestive heart failure |
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Definition
| Cardiac output is insufficient to maintain the blood flow needed by the body There is increased venous volume and pressure |
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Term
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Definition
| a. myocardial infarction b. congenital defects c. hypertension d. aortic semilunar valve stenosis e. disturbed potassium and calcium ion concentrations |
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Term
| What are the compensations to CHF? What are the treatments? |
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Definition
| Compensations are tachycardia and vasoconstriction of the GI tract, the skin, kidneys, and muscles Also the kidneys stimulate the production of the renin-angiotensin-aldosterone system resulting in vasoconstriction an increase in ADH also occurs CHF is treated with digitalis, vasodilators, and diuretics |
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