PART 2 CARDIOVASCULAR SYSTEM Flashcards by Rebecca Esplana

four-chambered muscular organ approximately
the size of a fist. It is positioned in the mid-mediastinum of the
chest, behind the sternum

heart

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Approximately two-thirds
of the heart lies to the left of the midline of the sternum between what ribs?

2nd and 6th ribs

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The apex of the heart is formed by the
____________ and lies above the diaphragm at the level
of the _________ to the left

a.tip of the left ventricle
b.5th intercostal space

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The base of the heart is
formed by the atria and projects to the right,___________. Posteriorly, the heart rests at the level of the ____________

a. lying below the 2nd rib
b.5th -8 thoracic vertebrae

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Compressions must be done
at a depth of at least___________) for an average adult, avoiding excessive
chest-compression depths.

2 inches (5 cm

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Externally, surface grooves called ______ the boundaries
of the heart chambers.

sulci mark

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The heart is enclosed in a sac called

pericardium

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Tough, loose-fitting and inelastic sac
surrounding the heart

Fibrous pericardium

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Consisting of two layers:

Serous pericardium

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Inner lining of the fibrous pericardium

parietal layer

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Covering the outer surface
of the heart and great vessels

Visceral layer or epicardium

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A thin layer of fluid called the __________ separates the
two layers of the serous pericardium.

pericardial fluid

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abnormal amount of fluid can accumulate between the layers,
resulting in a

pericardial effusion

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compresses the heart muscle, leading
to a serious decrease in blood flow to the body. This, ultimately,
may lead to shock and death.1,4

cardiac tamponade

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The heart wall consists of three layers

(1) outer epicardium,
(2) middle myocardium, and (3) inner endocardium.

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Support for the four interior chambers and valves of the heart
is provided by ___________, which form a
fibrous “skeleton.”

four atrioventricular (AV) rings

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is the backflow of blood through a malfunctioning
leaky valve

REGURGITATION

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is a pathologic narrowing or constriction
of a valve outlet, which causes blood to back up and
increased pressure in the proximal chamber and vessels

STENOSIS

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______________
causes high resistance to the blood flow into the left ventricle from the left
atrium. This increased resistance causes a backflow into the pulmonary circulation,
leading to pulmonary edema with fluid collecting in the alveoli and interstitial
spaces in the lungs, impairing oxygenation and breathing.

Mitral stenosis

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(decreased oxygen supply

Tissue Ischemia

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Complete obstruction of a coronary
artery may cause tissue death or infarct, a condition called

Myocardial Infarction

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___________ is the name given to three
types of coronary artery diseases (CAD) that are associated with
gradual and/or sudden obstruction of the coronary arteries

a. Acute Coronary Syndrome (ACS)

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three
types of coronary artery diseases (CAD)

(1) unstable angina or angina pectoris, (2) Non-ST segment elevation myocardial infarction (NSTEMI) and (3) ST-segment
elevation myocardial infarction (STEMI).

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Classic signs of tissue ischemia (decreased oxygen
supply) are chest pain and shortness of breath resulting in a clinical condition
called

angina pectoris

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Symptoms of a _________ include tightness or pain in the chest, neck, back or arms, as well as fatigue, lightheadedness, abnormal heartbeat and anxiety. Women are more likely to have atypical symptoms than men

myocardial infarction

Because the thebesian veins bypass or shunt around the pulmonary circulation as part of the normal anatomy, this phenomenon is called an anatomic shunt.

a.thebesian veins

myocardial tissue possesses the following four key properties:

* Excitability * Inherent rhythmicity or automaticity * Conductivity * Contractility

is the ability of cells to respond to electrical, chemical or mechanical stimulation

excitability

is the unique ability of the cardiac muscle to initiate a spontaneous electrical impulse (depolarization and repolarization). Although such impulses can arise from anywhere in the cardiac tissue. This ability is highly developed in specialized areas called the _____________

a. Inherent rhytmicity or automaticity b. heart pacemaker or nodal tissues.

are the heart’s primary pacemakers

The sinoatrial (SA) node and the atrioventricular (AV) node

is the ability of the myocardial tissue to spread and conduct electrical impulses. This property allows the myocardium to contract without direct neural innervation (as required by skeletal muscle).

Conductivity

When the electrical signals of a wave reach the contractile cells they contract _________. When the repolarization signals reach the myocardial cells they relax _________ and thus the electrical signals cause the mechanical pumping action of the heart; mechanical events always follow the electrical events.

systole diastole

Abnormal conductivity can affect the timing of chamber contractions and decrease cardiac efficiency. True or false?

true

in response to an electrical impulse, is the primary function of the myocardium. Contrary to the contractions of other muscle tissues, cardiac contractions cannot be sustained or tetanized because myocardial tissue exhibits a prolonged period of inexcitability after contraction

contractility

The period during which the myocardium cannot be stimulated is called the _______ and lasts approximately ____, nearly as long as the heart contraction or systole.

refractory period 250 ms

begins with the aorta on the left ventricle and ends in the right atrium

systemic circulation

begins with the pulmonary artery out of the right ventricle and ends in the left atrium

pulmonary circulation

The systemic circulation has three major components:

1) the arterial system, (2) the capillary system, and (3) the venous system.

consists of large, highly elastic, lowresistance arteries and small, muscular arterioles of varying resistance.

arterial system

With their elasticity, the large arteries help transmit and maintain the head of pressure generated by the heart. Together, the large arteries are called ____

conductance vessel

_______ provide this control by varying their flow resistance; they play a major role in the distribution and regulation of blood pressure and are referred to as resistance vessels.

arterioles

maintains a constant exchange of nutrients and waste products for the cells and tissues of the body. For this reason, the ______ are commonly referred to as exchange vessels.

capillary

____maintains a constant exchange of nutrients and waste products for the cells and tissues of the body. .

The vast capillary system, or microcirculation

the capillaries are commonly referred to as ____

exchange vessel

Direct communication between these vessels is called an

arteriovenous anastomosis

Contraction of _________ decreases blood flow locally, whereas relaxation increases local perfusion. In combination, these various channels, sphincters and bypasses allow precise control over the direction and amount of blood flow to a given organ or area of tissue.

precapillary sphincter

consists of small, expandable venules and veins and larger, more elastic veins. Besides conducting blood back to the heart, these vessels act as a reservoir for the circulatory system.

venous system

At any given time, the veins and venules hold approximately _________ of the body’s total blood volum

three-quarter

Vascular space decreases when vasoconstriction (constriction of the smooth muscles in the peripheral blood vessels) occurs, which causes blood pressure to _______ even though blood volume is the same

increase

Vascular space increases when _____ (relaxation of the smooth muscles in the arterioles) occurs, which causes blood pressure to ______ even though blood volume has not changed (e.g., during septic shock).

a.vasodilation b. decreases

The following four mechanisms aid the venous return to the heart:

(1) sympathetic venous tone; (2) skeletal muscle pumping or “milking” (combined with one-way venous valves); (3) cardiac suction; (4) thoracic pressure differences caused by respiratory efforts.5

The right side of the heart generates a systolic pressure of approximately ___ to drive blood through the low-resistance, low-pressure pulmonary circulation

25mmhg

The left side of the heart generates systolic pressures of approximately ____ to propel blood through the higher pressure, high-resistance systemic circulation.

120 mmhg

regulates blood flow mainly by altering the capacity of the vasculature and the volume of blood it holds.The goal is to maintain adequate perfusion to all tissues according to their needs

cardiovascular system

____ plays only a secondary role in regulating blood flow; the ____ tells the heart how much blood it needs, rather than the heart dictating what volume of blood the vascular system will receive.

heart vascular system

____operate independently without central nervous system control. It alters perfusion under normal conditions to meet metabolic needs.

Intrinsic control

involves both the central nervous system and circulating humoral agents. It maintain a normal level of vascular tone; however, central control mechanisms take over when the competing needs of local vascular beds must be coordinated.

Central or Extrinsic control

Smooth-muscle relaxation and vessel dilation is caused by stimulation of either _____ _____

cholinergic or specialized β-adrenergic receptors.Release of norephinephrine

involves the relationship between vascular, smooth-muscle tone and the level of local cellular metabolites. High amounts of carbon dioxide (CO2) or lactic acid, low pH levels, low partial pressures of O2 levels, histamines (released during an inflammatory response), endothelium-derived relaxing factor, and some prostaglandins all cause relaxation of the smooth muscle and vasodilation, increasing blood flow to the affected area.

Metabolic control

mainly affects the highresistance arterioles and capacitance veins.

central control

In a healthy person at rest, the EDV ranges from _____.

110 to 120 mL

a healthy heart ejects approximately ___ of its stored volume ____.

two-thirds(60% to 66%)

the force the ventricle can generate results from the length (or stretch) of the myocardial fibers just before contraction. As the ventricle fills with blood, the myocardial fibers are stretched and as the stretch increases, the tension (force) within the walls of the heart increases (analogous to stretching a rubber band).1

Frank Starling Law

can be described as the combined force of all the factors that the left ventricle encounters and must overcome when stimulated to contract and achieve the end of systole.

afterload

Increases in afterload can decrease _____, especially in the failing heart by increasing the ___

Stroke volume End diastolic volume

represents the amount of systolic force exerted by the heart muscle at any given preload

contractility

A higher SV for a given preload (increased slope) indicates a state of increased contractility, often referred to as

positive inotropism

A lower SV for a given preload indicates decreased contractility, referred to as

negative inotropism

is the resistance the ventricle must overcome or the forces that oppose ejection of blood pressure generated as the heart works to eject its SV.

Afterload

blood rushes in from the atria to fill the ventricles

diastole

respond to pressure changes

baroreceptors

respond to changes in blood chemistry.4

chemoreceptors

SV is affected primarily by intrinsic control of these 3 factors

preload, afterload, contractility

PART 2 CARDIOVASCULAR SYSTEM Flashcards

(73 cards)