A&P - Heart

cardiovascular system

heart, blood, blood vessels2 circulatory patterns: pulmonic and systemic

pulmonic circulation

RV (DOB) -> lungs (exchange) -> LA (OB)

systemic circulation

LV (OB) -> body (exchange) -> RA (DOB)


located in mediastinumbehind sternum, between lungsleft of midline, tipped to front4 chambers

base of the heart

superiorall blood vessels enter and exit

apex of the heart


right atrium

upper right chamberreceives DOB from body

right ventricle

lower right chamberreceives DOB from RApumps DOB to lungs

left atrium

upper left chamberreceives OB from lungs

left ventricle

lower left chamberlargest chamber, thickest wallreceives OB from LApumps OB to body


on top of RA and LAincreases volume

interventricular septum

septum between the ventricles

interatrial septum

septum between the atria

foramen ovale

hole in the IAS of a fetusallows blood to move from R to L (fetal lungs immature)

fossa ovalis

closed foramen ovale

atrial septum defect

foramen ovale fails to close after birthmust be surgically repaired


superior vena cavareturns DOB to the RA from all regions above the heart


inferior vena cavareturns DOB to the RA from all regions below the heart


coronary sinusreturns the DOB to the RA from the heart itself


pulmonary trunkDOB from RV to lungssplits into L & R pulmonary arteries


pulmonary veins (4 - 2R, 2L)returns OB from the lungs to the LA


OB from LV to bodylargest BV in the body


R atrioventricular valvebetween RA/RV


aka mitra or L atrioventricularbetween LA/LV

aortic semilunar valve

entrance to aorta

pulmonary semilunar valve

entrance to pulmonary trunk

chordae tendineae

heart strings that attach valves to papillary muscleskeep valves moving one waymaintain tension


outer thin covering of the heart


thick middle muscle layer of the heart


thin, shiny inner lining of the heartlines all cavities and vessels that enter/exit the heart

pericardial sac

thick CT bag2 layers: fibrous (outer) & serous (inner)

conduction system

several masses of nerve tissuecontrols rate, rhythm, force of HBSA -> AV -> Bundle of His -> purkinje fibers

SA node

sinoatrial node aka pacemaker of the heartlocated in upper RAreceives impulses from ANSsends impulses to LA and AV node

AV node

atrioventricular nodelocated in lower RAreceives impulses from SA nodesends impulses down Bundle of His

Bundle of His

runs transverse through IV septumR and L branchesreceives impulses from AV nodesends impulses to apex of heart

purkinje fibers

terminal branch of conduction systemreceives impulses from Bundle of Hissends impulses into ventricular myocardium


graphical record of electrical activity of the ehart3 waves: P wave, QRS complex, T wave

P wave

atrial depolarizationelectricity moves through both atriaend of P wave - atria contract

QRS complex

ventricular depolarizationelectricity moves through both ventriclesend of QRS complex- ventricles contract

T wave

ventricular repolarizationend of T wave - ventricles relax


listening to heart sounds


heart sound produced when AV valves closelonger, louder sound


heart sound produced when semilunars closeshorter, softer sound

heart murmur

abnormal heart sounds (swishing)

cardiac cycle

all events associated with blood moving through the heart3 stages: ventricular filling, ventricular systole, isovolumetric relaxation

ventricular filling

P-waveoverall pressure in the heart is lowblood enters atria, moves through to ventriclespassive filling (70%) due to gravity and weight of bloodboth cuspids open, both semilunars closedatria contract to empty remaining 30%atria relax

ventricular systole

pressure in ventricles risescuspids closefor 1/10 second, ventricles are completely closed chamberspressure opens semilunarsventricles contract to force blood into aorta and pulmonary trunk (called ventricular


isovolumetric relaxation

ventricles rekaxpressure in ventricles dropssemilunars closeventricles again closed chambers

heart rate

normal 75 bpmaffected by age (decreases with age), gender (increased in women), exercise, body temp,

chemicals, ANS


HR > 100


HR < 60

cardiac output

total volume of blood pumped out of each ventricle per minuteformula: CO = HR x SV

stroke volume

amount of blood pumped out of each ventricle per beat3 factors that affect SV: preload, contractility, afterload

cardiac reserve

ability to push cardiac output far above normalseen during exercise, emergency, and stress


amount of stretch on cardiac fibers just before contraction

Frank-Starling Law of the Heart

the greater the strecth, the stronger the contractionexplains why R & L ventricles eject the same volume despite size differences


strength of contraction of individual cardiac fiberscontrolled by positive and negative inotropic agents

positive inotropes

increase strength of contractionex: epinephrine, norepinephrine, digitalis

negative inotropes

decrease strength of contractionex: anesthesia


amount of pressure needed in both ventricles to open semilunars

blood pressure

the force exerted on vessel walls by contained bloodaffected by:-blood volume (^ vol ^ BP)-cardiac output (^ output ^ BP)-peripheral resistance (^ resistance ^ BP)-diameter of vessel (small diameter ^ BP)

peripheral resistance

friction encountered by blood as it moves through vessel walls


in aorta and pulmonary trunk just after ventricles contract


in SVC, IVC, CS, pulonary veins before blood enters atria


in atria just before contraction

pulse pressure

difference between systolic and diastolicworking pressure of the blood that moves through the vessels


systolic > 140


systolic < 100

essential hypertension

BP 220/120 or greater


stationary internal blood clot


thrombus that dislodges and moves


thin spot in the wall of a vessel that causes it to bulge and possible rupture

blood vessels

3 major groups: arteries, veins, capillaries


carry blood (usually OB) away from the heartlarger of the vesselsempty into arterioles


carry blood (usually DOB) to the heartsupplied by venulesless elastic than arterieslower BP than arterieshave valves to prevent backflow


connect arteries and veinsmade of endothelium (simple squamous ET)called microcirculationallows for passage of O2, CO2, nutrients, waste between blood and tissues

tunica interna/intima

inner layer of arteries and veinssimple squamous

tunica media

middle, thickest layer of arteries and veinssmooth muscle w/elastic fibers

tunica externa/adventitia

strongest, outer layer of arteries and veinscollagen w/elastic fibers


life sustaining structures are supplied by a network of several arteriesprovides alternate ways for structures to receive bloodex: circle of willis in the brain

trunk arteries

ascending aorta--R & L coronaryarch of aorta--brachiocephalic----R common corotid----R subclavian--L subclavian--L common corotidabdominal descending--renal arteries--R & L common iliacPIC

trunk veins

----R & L subclavian--brachiocephalic--internal/external jugularsSVC----R & L coronary veins--coronary sinusRA--R & L common iliacIVCPIC


liquid connective tissuecarries O2, nutrients, hormones to tissuescarries waste to lungs, kidneys, sweat glands38.0C, 100.4F55% plasma, 45% formed elementspH 7.35 - 7.453 functions: --transportation--regulation (pH, temp, water content)--protection (antibodies, clotting)


thin, watery, yellowish liquid92% H20, 8% solute (protein, hormones, vitamins, nutrients, electrolytes)3 groups of proteins: albumin, globulins, fibrinogen


54% of plasma proteinsmaintains blood volume, water balance, amount of water entering cells, carrier molecules for facilitated diffusion


38% of plasma proteinsproduce antibodies


7% of plasma proteinsclotting


formation of blood or blood cellsin embryo: cells formed in liver, spleen, thymus, lymph nodes, bone marrow, and yolk sacafter birth: cells formed in red bone marrow (proximal epiphysis of humerus & femur, flat bones (sternum, ribs), cranial bones, vertebra, and pelvis)

pleuripotent hematopoeitic stem cells

cells that make all blood cells--myeloid stems-----RBCs-----WBCs (neutro, eosino, baso, monocytes)-----thrombocytes--lymphoid stems-----lymphocytes---------plasma cells------------B&T cells


no nucleus - ejected before reticulocyte stagelive 120 days - broken down in liver or spleen2 million produced per secondsurrounded by selectively permeable membrane that enclose cytoplasm and hemoglobin

RBC counts

female: 4.8 million/mm3male: 5.4 million/mm3


made of heme (iron) + globin (protein)O2 binds to iron, CO2 binds to proteintakes up most space inside RBC (1/3 of weight)when RBC destroyed in liver, Hgb breaks down into hemosiderin, bilirubin, globin


iron pigment that remains in the liverstored and eventually used to make new Hgb


waste productmoves from blood into bile


protein metabolized in the liver


production of RBCscontrolled by erythropoietin

renal erythropoietic factor

enzyme produced and released by the kidneys that causes the production of more erythropoietintriggered by excessive blood loss


fight infectionall have nucleuslive a few days to several monthscan leave circulatory system and move to sites of infection2 classes: granular and agranular

WBC count

5,000 - 10,000/mm3


WBC > 10,000


WBC < 5,000

granular WBCs

small grains in cytoplasm3 types: neutrophils, eosinophils, basophils


nucleus has 2-6 lobesfirst WBC to reach site of infectionphagocytes


nucleus has 2 lobesfights parasites and worms


irregular shaped nucleusinvolved in allergic reactionsproduce 3 chemicals that aid in allergic response: histamine, heparin, seratonin

agranular WBCs

do not have grains in cytoplasm2 types: monocytes and lymphocytes


major phagocytes of the bodymore will arrive to site of infection than neutrophilsturn into macrophages on the way to site of infection


most active phagocytes in the bodynucleus is kidney shaped2 types: fixed and wandering


become B cells and T cells

B cells

become plasmal cells that make antibodies to kill bacteria

T cells

make cells that attack and kill viruses


WBC slides out of vessel wall


WBC moves to site of infection


plug damaged vessels and secrete chemicals needed for clottingmade from megakaryocytes that shed pieces of cytoplasm, which becomes enclosed by a cell membraneno nucleusoval or disk shapedproduction controlled by thrombopoietinlive 5-9 days - destroyed by liver and spleen

platelet count

250,000 - 400,000/mm3

reticulocyte count

measurement of speed of RBC formation


test for anemia


# of RBCs/total blood volumemale: 42-54%female: 37-47%

differential WBC

# of each type of WBC per 100neutrophils - 60 - 70basophils - 0.5 - 1eosinophils - 2-4monocytes - 8-10lymphocytes - 20-25


stoppage of bleedingposiive feedback loop that occurs when blood vessel is injured3 steps: vascular spasm, platelet plug formation, clotting

vascular spasm

as blood escapes, it activates stretch receptors in vessel wallvessel contracts rapidly to temporarily reduce blood lossspasm most effecient if injury is cause by dull, blunt object (more receptors stimulated)

platelet plug formation

in a normal vessel, wall and platelets have "+" chargein an injured vessel, "-" charged collagen in tunica adventita is exposed"-" collagen attracts "+" platelets to siteplatelets swell, stick to each other and the collagen, and then blow upgranules inside platelets release more "-" chemicals to attract more "+" platelets

degranulation of the platelet

positive feedback loop that plugs injury


a process that involves 20+ clotting factors2 pathways: intrinsic, extrinsic

clotting factors

a large group of chemicals that are ALL necessary for proper and efficient clotting

intrinsic clotting

occurs inside blood vesselsmore complex than extrinsic


occurs outside blood vesselfaster than intrinsic

common clotting pathway

both pathways merge

clotting factors

prothrominase - relased when platelet degranulatesprothrombinvitamin kthrombincalciumfibrinogenfibrin