NRSG2350 Exam 3 Key Terms

Module 6, 7, 8

adrenergic receptor–site specificity

a drug’s affinity for only adrenergic receptor sites; certain drugs may have specific affinity for only alpha- or only beta-adrenergic receptor sites

alpha1-selective adrenergic blocking agents

drugs that block the postsynaptic alpha1-receptor sites, causing a decrease in vascular tone and vasodilation that leads to a fall in blood pressure; these drugs do not block the presynaptic alpha2-receptor sites, and therefore, the reflex tachycardia that accompanies a fall in blood pressure is less likely to occur

beta-adrenergic blocking agents

drugs that, at therapeutic levels, block the beta-receptors of the sympathetic nervous system

beta1-selective adrenergic blocking agents

drugs that, at therapeutic levels, specifically block the beta1-receptors in the sympathetic nervous system while not blocking the beta2-receptors with resultant effects on the respiratory system

bronchodilation

relaxation of the smooth muscles in the bronchi, resulting in a widening of the bronchi; an effect of sympathetic stimulation

pheochromocytoma

tumor of the chromaffin cells of the adrenal medulla that periodically releases large amounts of norepinephrine and epinephrine into the system with resultant severe hypertension and tachycardia

sympatholytic

drug that lyses, or blocks, the effects of the sympathetic nervous system

actin

thin filament, a component of a sarcomere, or muscle unit

aldosterone

hormone released from the adrenal cortex that acts in the distal convoluted tubule of the kidney to increase retention of sodium and water

angiotensin

peptide hormone that causes vasoconstriction and stimulates aldosterone and ADH release; part of the renin–angiotensin system

antidiuretic hormone (ADH)

hormone released from the posterior pituitary that acts in the distal convoluted tubule of the kidney to increase water retention

arrhythmia

disruption in cardiac rate or rhythm, also called dysrhythmia

arteries

vessels that take blood away from the heart; muscular, resistance vessels

atrium

top chamber of the heart, receives blood from veins

auricle

appendage on the atria of the heart, holds blood to be pumped out with atrial contraction

automaticity

property of heart cells to generate an action potential without an external stimulus

capacitance system

the venous system; distensible, flexible veins that are capable of holding large amounts of blood

capillary

small vessel made up of loosely connected endothelial cells that connect arteries to veins

cardiac cycle

period of cardiac muscle relaxation (diastole) followed by a period of contraction (systole) in the heart

conductivity

property of heart cells to rapidly conduct an action potential of electrical impulse

diastole

resting phase of the heart; blood is returned to the heart during this phase

dysrhythmia

disruption in cardiac rate or rhythm, also called an arrhythmia

ectopic focus

shift in the pacemaker of the heart from the sinoatrial node to some other site

electrocardiogram (ECG)

electrical tracing reflecting the conduction of an electrical impulse through the heart muscle; does not reflect mechanical activity

hydrostatic pressure (HP)

pushing force of fluid against solid objects

myocardium

muscle of the heart

myosin

thick filament with projections; a component of a sarcomere, or muscle unit

natriuretic peptide

peptide produced by the brain, heart, and vasculature that causes natriuresis, excretion of sodium in the urine; degraded by the enzyme neprilysin

oncotic pressure (OP)

pulling pressure of the plasma proteins, responsible for returning fluid to the vascular system at the capillary level

pulse pressure

systolic blood pressure minus the diastolic blood pressure; reflects the filling pressure of the coronary arteries

resistance system

the arteries; the muscles of the arteries provide resistance to the flow of blood, leading to control of blood pressure

sarcomere

functional unit of a muscle cell, composed of actin and myosin molecules arranged in layers to give the unit a striped or striated appearance

sinoatrial (SA) node

normal pacemaker of the heart; composed of primitive cells that constantly generate an action potential

Starling’s law of the heart

addresses the contractile properties of the heart

systole

contracting phase of the heart during which blood is pumped out of the heart

troponin

chemical in heart muscle that prevents the reaction between actin and myosin, leading to muscle relaxation; inactivated by calcium during muscle stimulation to allow actin and myosin to react, causing muscle contraction

veins

vessels that return blood to the heart; distensible tubes

ventricle

bottom chamber of the heart, which contracts to pump blood out of the heart

angiotensin-converting enzyme (ACE) inhibitor

drug that blocks ACE, the enzyme responsible for converting angiotensin I to angiotensin II in the lungs; this blocking reduces the vasoconstriction and aldosterone release related to angiotensin II

angiotensin II receptors

specific receptors found in the vascular smooth muscle of the blood vessels and in the adrenal gland that react with angiotensin II to cause vasoconstriction and release of aldosterone

baroreceptor

pressure receptor; located in the arch of the aorta and in the carotid artery; responds to changes in pressure and influences the medulla to stimulate the sympathetic system to increase or decrease blood pressure

cardiovascular center

area of the medulla at which stimulation will activate the sympathetic nervous system to increase blood pressure and heart rate

essential or primary hypertension

sustained blood pressure above normal limits with no discernible underlying cause

hypotension

sustained blood pressure that is lower than that required to adequately perfuse all of the body’s tissues

peripheral resistance (PVR)

force that resists the flow of blood through the vessels, mostly determined by the arterioles, which contract to increase resistance; important in determining overall blood pressure

renin–angiotensin–aldosterone system (RAAS)

compensatory process that leads to increased blood pressure and blood volume to ensure perfusion of the kidneys; important in the continual regulation of blood pressure

shock

severe hypotension that can lead to accumulation of waste products and cell death

stroke volume

amount of blood pumped out of the ventricle with each beat; important in determining blood pressure

afterload

resistance/pressure against which the heart has to push

cardiac output

volume of blood being pumped by the heart; cardiac output = heart rate × stroke volume

cardiomegaly

enlargement of the heart, commonly seen with chronic hypertension, valvular disease, and heart failure

cardiomyopathy

disease of the heart muscle that leads to a weakened heart and can eventually lead to complete heart muscle failure and death

dyspnea

discomfort with respirations, often with a feeling of anxiety and inability to breathe; seen often with left-sided heart failure

heart failure (HF)

condition in which the heart muscle has less ability to adequately pump blood around the cardiovascular system, leading to a backup or congestion of blood in the system

hemoptysis

blood-tinged sputum seen in left-sided heart failure when blood backs up into the lungs and fluid leaks out into the lung tissue

nocturia

getting up to void at night, reflecting increased renal perfusion with fluid shifts in the supine position when a person has gravity-dependent edema related to heart failure or other medical conditions, including urinary tract infection, increasing the need to get up and void

orthopnea

difficulty breathing when lying down, often referred to by the number of pillows required to allow a person to breathe comfortably

positive inotropic

describes an agent that causes an increased force of muscle contraction

preload

amount of blood that is brought back to the heart to be pumped throughout the body; this blood exerts pressure on the heart ventricles

pulmonary edema

increased fluid in the lung tissue that can be due to left-sided heart failure

tachypnea

rapid and shallow respirations that can be seen with left-sided heart failure

antiarrhythmics

drugs that affect the action potential of cardiac cells and are used to treat arrhythmias and restore normal rate and rhythm

bradycardia

slower-than-normal heart rate (less than 60 beats/min)

cardiac output

amount of blood the heart can pump per beat (stroke volume) x heart rate

heart blocks

blocks to conduction of an impulse through the cardiac conduction system; can occur at the atrioventricular node, interrupting conduction from the atria into the ventricles, or in the bundle branches within the ventricles, preventing the normal conduction of the impulse

hemodynamics

the forces that move blood throughout the cardiovascular system

premature atrial contraction (PAC)

an early contraction caused by an ectopic focus in the atria that stimulates an atrial response

premature ventricular contraction (PVC)

an early contraction caused by an ectopic focus in the ventricles that stimulates the cells

proarrhythmic

tending to cause arrhythmias; many of the drugs used to treat arrhythmias have been found to generate them

tachycardia

faster-than-normal heart rate (greater than 100 beats/min)

angina pectoris

“suffocation of the chest”; pain caused by the imbalance between oxygen being supplied to the heart muscle and demand for oxygen by the heart muscle

atheromas

fatty tumors in the endothelial lining of arteries; contain fats, blood cells, lipids, inflammatory agents, and platelets; lead to narrowing of the lumen of the artery, stiffening of the artery, and loss of distensibility and responsiveness

atherosclerosis

narrowing of the arteries caused by buildup of atheromas, swelling, and accumulation of platelets; leads to a loss of elasticity and responsiveness to normal stimuli

coronary artery disease (CAD)

characterized by progressive narrowing of coronary arteries leading to a decreased delivery of oxygen to cardiac muscle cells

myocardial infarction

end result of vessel blockage in the heart; leads to ischemia and then necrosis of the area cut off from the blood supply; dead cells replaced by scar tissue

Prinzmetal angina

drop in blood flow through the coronary arteries caused by a vasospasm in the artery

pulse pressure

the systolic blood pressure minus the diastolic blood pressure; reflects the filling pressure of the coronary arteries

stable angina

pain due to the imbalance of myocardial oxygen supply and demand; the pain is relieved by rest or stoppage of activity

unstable angina

episode of myocardial ischemia with pain due to the imbalance of myocardial oxygen supply and demand when the person is at rest and/or at unpredictable times

antihyperlipidemic agents

general term used for drugs used to lower lipid levels in the blood

bile acids

cholesterol-containing acids found in the bile that act like detergents to break up fats in the small intestine

cholesterol

necessary component of human cells that is produced and processed in the liver and then stored in the bile until stimulus causes the gallbladder to contract and send the bile into the duodenum via the common bile duct; has a steroid nucleus made from fatty acids; essential for the formation of steroid hormones and cell membranes; produced in cells and obtained from dietary sources

chylomicron

carrier for lipids in the bloodstream, consisting of proteins, lipids, cholesterol, and other components

high-density lipoprotein (HDL)

loosely packed chylomicron-containing fats, able to absorb fats and fat remnants in the periphery; thought to have a protective effect, decreasing the development of atherosclerotic cardiovascular disease

hydroxymethylglutaryl–coenzyme A (HMG–CoA) reductase

enzyme that regulates the last step in cellular cholesterol synthesis

hyperlipidemia

increased levels of lipids in the serum, associated with increased risk of development of atherosclerotic cardiovascular disease

low-density lipoprotein (LDL)

tightly packed fats that are thought to contribute to the development of atherosclerotic cardiovascular disease when remnants left over from the LDL are processed in the arterial lining

metabolic syndrome

collection of factors, including insulin resistance, abdominal obesity, low high-density lipoprotein, high triglyceride levels, hypertension, and proinflammatory and prothrombotic states, that increase the incidence of atherosclerotic cardiovascular disease

phospholipids

type of fat with a phosphate group; important structure to make lipoproteins, blood-clotting components, the myelin sheath, and cell membranes

proprotein convertase subtilisin/kexin type 9 (PCSK9)

an enzyme that binds to LDL receptor on liver cells, which causes higher LDL levels in the blood

triglycerides

type of lipid that is also called “neutral fat”; composed of fatty acids and a glycerol molecule; primarily used in the body as a source of energy

alkalosis

a rise in serum pH to an alkaline state

edema

increased movement of fluid into the interstitial spaces from the blood vessels

fluid rebound

reflex reaction of the body to the loss of fluid or sodium; the hypothalamus causes the release of antidiuretic hormone, which promotes water retention, and stress related to fluid loss combines with decreased blood flow to the kidneys to activate the renin–angiotensin–aldosterone system, leading to further water and sodium retention

high-ceiling diuretics

powerful diuretics that work in the loop of Henle to inhibit the reabsorption of sodium and chloride, leading to a sodium-rich diuresis

hyperaldosteronism

excessive output of aldosterone from the adrenal gland, leading to increased sodium and water retention and loss of potassium

hypokalemia

low potassium in the blood, which may occur with some diuretic treatment; characterized by weakness, muscle cramps, trembling, nausea, vomiting, diarrhea, and cardiac arrhythmias

osmotic pull

drawing force of large molecules on water, pulling it into a tubule or capillary essential for maintaining normal fluid balance within the body; used to draw out excess fluid into the vascular system or the renal tubule

acute respiratory distress syndrome (ARDS)

progressive loss of lung compliance and increasing hypoxia typically due to a severe insult to the body, such as cardiovascular collapse, major burns, severe trauma, or rapid depressurization

alveoli

respiratory sacs, the smallest units of the lungs, where gas exchange occurs