CV System I

Question 1

left main coronary artery

Answer 1

arises from left ostium w 2 main branches

Question 2

anterior interventricular artery (LAD)

Answer 2

on front and runs between the ventricles; supplies interventricular septum & portions of the right & left ventricle

Question 3

circumflex artery

Answer 3

runs around the heart; supplies left atrium & left lateral wall of left ventricle

Question 4

right coronary artery

Answer 4

arises from right ostia, follows right coronary sulcus; supplies right atrium, left ventricle, bottom portion of both ventricles & back of septum

Question 5

baroreceptors

Answer 5

aorta & carotid sinus; lowers BP when stretched (vasodilation/constriction)

Question 6

diastole

Answer 6

ventricles relax, ventricular pressure drops, atrial pressure rises, blood volume from atria to ventricles rises, semilunar valves close, AV valves open, blood flows from atria to ventricles

Question 6

chemoreceptors

Answer 6

medulla oblongata, aortic arch, & coronary arteries
important for respiratory control
BP increases w hypoxemia, hypercapnia, ↓pH

Question 7

systole

Answer 7

ventricles contract, ventricular pressure rises, atrial pressure drops, blood volume from atria to ventricles drops, AV valves close, semilunar open, blood flows into arteries

Question 8

fibrous cords that connect the papillary muscles to the atrioventricular valves in the heart, aid papillary muscles in preventing AV valves from prolapsing during contraction

Answer 8

chordae tendineae

Question 9

prevent backflow of blood

Answer 9

heart valves

Question 10

receive signals to contract sooner than rest of ventricles, allowing chordae tendineae to stabilize AV valves and prevent AV valves from prolapsing

Answer 10

papillary muscles

Question 11

irregular muscular ridges that line the inner surfaces of the heart’s ventricles. enhance ventricular contraction, connect to the papillary muscles to help prevent AV valve inversion

Answer 11

trabeculae carneae

Question 12

blood flow through heart

Answer 12

sup & inf VC -> RA -> tricuspid valve -> RV -> pulmonic valve -> pulmonary artery -> lungs oxygenation -> pulmonary veins -> left atrium -> mitral valve -> left ventricle -> aortic valve -> aorta -> rest of body

Question 13

SA node in electrical impulse

Answer 13

-pacemaker
-in RA
-60-100 impulses
-fastest rate of spontaneous depolarization

Question 14

AV node in electrical impulse

Answer 14

-backup pacemaker (if SA fails)
-junction btwn atria & ventricles
-40-60 impulses
-no input from NS needed

Question 15

purkinje fibers in electrical impulse

Answer 15

-ventricular pacemakers
-in distal conduction system in ventricles
-20-40 impulses
-plan C (takes over if SA & AV fail)

Question 16

NS control of blood pressure

Answer 16

-baroreceptors: lowers BP when stretched
-chemoreceptors: medulla oblongata, aortic arch, coronary arteries, important for respiratory control, BP increases with hypoxemia, hypercapnia, lowered pH

Question 17

What effect does SNS stimulation have on conduction time of action potential thru the heart?

Answer 17

activation increases electrical conductivity and strength of myocardial contraction, induces influx of Ca2+ ions to cardiomyocytes in action potential
-epi & norepi are NT, increase CO
-alpha or beta adrenergic receptors

Question 18

alpha receptor function

Answer 18

a1 = irises, bladder, bronchioles, blood vessels
a2 = smooth muscle, brain

Question 19

beta receptor function

Answer 19

b1 = atria of heart, kidneys
b2 = lungs, blood vessels

Question 20

What effect does PSNS stimulation have on conduction time of action potential thru the heart?

Answer 20

activation decreases conduction of action potentials thru the heart & decreases strength of contraction, lowering HR
-acetylcholine released by vagal nerve is NT

Question 21

frank starling law of heart

Answer 21

-SV proportional to EDV
-ventricles eject as much blood volume as they receive, the more ventricles are stretched (preload ↑) the greater the force of the contraction
-like stretching a rubber band, more stretch = more forceful snap

Question 22

what 3 factors govern stroke volume?

Answer 22

-preload (proportional)
-contractility (proportional)
-afterload (inverse)

Question 23

stretch of the ventricular muscle fibers at the end of diastole (immediate moment just before systole)

Answer 23

preload

Question 24

what effect does preload have on SV and CO

Answer 24

increased preload increases SV and CO

Question 25

resistance ventricles must overcome to eject blood during systole

Answer 25

afterload

Question 26

what effect does afterload have on SV and CO?

Answer 26

high afterload = decreased SV and CO, unless heart compensates w greater contractile force

Question 27

What does neurohormonal control of blood pressure allow?

Answer 27

-blood flow response to body's needs -redistribute blood volume during hemorrhage or shock -regulate heat loss

Question 28

Explain RAAS

Answer 28

activated from decreased blood flow to the kidney, renin released in circulation as a response -> converts angiotensinogen -> angiotensin I, ACE converts angiotensin I -> angiotensin II (potent vasoconstrictor) causes higher BP and increased flow to kidneys. Agt II also stimulates adrenal glands to release aldosterone- acts on kidneys to make them reabsorb more sodium and water into blood stream (↑BV = ↑BP)

Question 29

laminar flow

Answer 29

occurs when concentric layers of molecules move straight ahead

Question 30

turbulent flow

Answer 30

occurs when flow is obstructed, the vessel turns, or blood flows over rough surfaces, producing a murmur or bruit and blood stasis (virchows triad)

Question 31

physiological changes of CV system w aging

Answer 31

-Myocardial and blood vessel stiffening (less elastic, higher risk for MI or stroke) -Changes in neurogenic control over vascular tone -Increased occurrence of atrial fibrillation -Loss of exercise capacity -Left ventricular hypertrophy and fibrosis (aortic stenosis)

Question 32

fetal circulation

Answer 32

-oxygenated blood in RA -> foramen ovale -> LA where mixes w blood returning from pulmonary veins -> thru mitral valve into LV -> ascending aorta -> coronary and cerebral circulation -becomes progressively deoxygenated in lower body before returning thru umbilical arteries -> placenta -> ductus venosus -> IVC -> RA

Question 33

intracardiac, opening in btwn RA and LA, directs oxygenated blood from IVC -> RA -> LA, bypassing pulmonary circulation

Answer 33

foramen ovale

Question 34

extracardiac, connects umbilical vein to the inferior vena cava, functions by allowing oxygenated blood from placenta to bypass liver and flow directly into IVC, ensures oxygenated blood reaches heart & brain quickly

Answer 34

ductus venosus

Question 35

extracardiac, connects pulmonary artery to descending aorta, functions by shunting blood away from lungs (lungs are collapsed)

Answer 35

ductus arteriosus

Question 36

congenital heart defect where aorta is narrowed, after birth this causes obstruction of blood flow to lower body need IV prostaglandin

Answer 36

coarctation of aorta

Question 37

-failed postnatal closure of ductus arteriosus -↑pulmonary blood flow due to ↓PVR and ↑SVR - persistent and increasing L->R shunt to pulmonary circuit -results in atrial & ventricular distension & pulmonary overcirculation

Answer 37

patent ductus arteriosus

Question 38

-opening anywhere in the atrial septum -L->R shunting across atria -tachypnea, ↓activity levels -80% close on their own by age 2, surgery indicated for older

Answer 38

arterial septal defect

Question 39

-abnormal ventricular septation -> openings in ventricular septum -mixing of oxygenated blood w deoxygenated blood -left side becomes dominant postnatally, allows L->R shunting and pulmonary overcirculation -↑risk for CHF -may close over time

Answer 39

ventricular septal defect

Question 40

-4 anatomic findings: pulmonary artery stenosis, VSD, overriding aorta, RV hypertrophy -defect is RV outflow tract obstruction - limits pulmonary blood flow & impedes oxygenation -"boot shaped" on x ray

Answer 40

tetralogy of fallot

Question 41

-most common cyanotic heart defect in neonatal period -aorta rises from RV & pulmonary artery from LV (2 independent & parallel circulations)

Answer 41

mixed blood flow - transposition of the great arteries

Question 42

abnormal development of left side of heart -aortic valve atresia -mitral valve atresia -severe LV hypoplasia -aortic hypoplasia -leads to pulmonary edema, restricted pulmonary blood flow, ↑work of breathing, tachypnea, cyanosis & acidosis

Answer 42

hypoplastic left heart syndrome

Question 43

-occurs when the heart is unable to maintain sufficient cardiac output to meet metabolic demands of the body -neurohumoral & hemodynamic changes create abnormal ventricular wall stress and cause the myocardium to hypertrophy -poor feeding, sucking, failure to thrive, dyspnea, tachypnea, diaphoresis, cyanosis, skin changes

Answer 43

heart failure

Question 44

-acute, self-limiting systemic vasculities that can result in cardiac sequelae -unknown cause -fever (>5days), conjunctivitis, strawberry tongue, rash, lymphadenopathy -treatment: aspirin, IV immunoglobulins

Answer 44

kawasaki disease