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The Conduction System of Heart
diastole,systole, formulas, properties, EKG Stuff do only flagged
77
Anatomy
Undergraduate 1
10/07/2012

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Term
Atrial systole means
Definition
atrial contraction begins atria eject blood in ventricles
Term
Give order of steps in cardiac cycle
Definition
atrial systole ventricular systole ventricular diastole
Term
EDV stands for + means
Definition
end diastolic volume blood recieved by ventricles from atria (aka they have to end their nap(diastole) b/c atria is giving them blood.
Term
EDV, S1 are in what step?,
Definition
atrial systole
Term
SV stand for + means
Definition
Stroke volume volume of blood ejected by ventricle through semilunar valves
Term
formula for SV
Definition
= EDV-ESV
Term
SV, isovolumetric contractions semilumar valves close (S2) ESV ventricles release blood are in what step?,
Definition
ventricular systole
Term
ESV stands for + means
Definition
end systolic volume volume of blood remaining after ventricle ejects blood through semilunar valves
Term
the beginning of ventricular diastole what occurs?,
Definition

high ventricular pressure

low atrial pressure

all valves closed isovolumetric relaxation

Term
near the end of ventricular diastole what occurs?,
Definition
high atrial pressure low ventricular pressure AV open passive atrial + ventricular filling begin
Term
define ejection fraction
Definition
% of EDV represented by SV
Term
If SV is increased?
Definition
ventricles are ejecting more blood through semilunar valves = increased cardiac output
Term
If ESV is increased?
Definition
there is more blood left in ventricles (instead of being released through semilunar valves) = decreased cardiac output
Term
ESV is usually what % of EDV
Definition
40 ESV (blood ejected through semilunar valve) is 40% of EDV (blood ventricle recieved from atria)
Term
S1
Definition
first sound, lub, loud AV close
Term
S2
Definition
second sound, dub, loud
semilunar valves close
Term
atrial systole
Definition
S1
Term
ventricular systole
Definition
S2
Term
S3,S4
Definition
soft sounds heard during blood flow into ventricles, atrial contraction
Term
sounds heard because of regurguitation of blood is
Definition
heart mumur
Term
heart mumurs are caused by
Definition
,valve prolapse
Term
If you have a heart attack patient with an end-diastolic volume of 125 ml and an end systolic volume of 40 ml. Calc stroke volume
Definition
SV= EDV-ESV SV=125-40 =85
Term
cardiac output def
Definition
vol of blood pumped by left ventricle in 1 min
Term
cardiac output formula
Definition
= HR x SV heart rate (bpm) x stroke volume (ml/beat)
Term
A patient has a heart rate of 125 beats/min, EDV of 130 mL and ESV of 40mL. What is cardiac output?
Definition

CO= HR x SV

SV= EDV-EDV

130-40=90

CO=125 x 90= 11250 mL/min

Term
factors affecting heart are
Definition
autonomic innervation hormones
Term
factors affecting stroke volume
Definition
EDV & ESV
Term
Give an alternate but equal formula for CO
Definition
=
HR x (EDV-ESV)
Term
name the nervous system component in heart
Definition
cardiac plexus
Term
which part of the brain also affects heart
Definition
medulla oblongata with its
cardio acceleratory
cardio inhibitory centers
Term
resting tone is maintained by
Definition
,aCH (acetylocholine)
NE (norepiphrine)
Term
tell flow in cardioacceltory center
Definition
impulses sent to sympathetic neruons
cardiac plexus
signal goes to AV & SA node
Term
tell flow in cardioinhibitory center
Definition
impulses sent to parasympathetic vagus

inhibitory impulses sent to heart.
Term
why do pacemaker cells make the 1st heart beat?
Definition
pacemaker cells in SA node have a membrane potential closer to threshold potential
(-60 mV instead of -80 mv)

depolarizes fastest at a rate of 80 beats/min
Term
sympathetic & parasympathetic stimulation is greatest at
Definition
the SA node
Term
Ach is what branch of nervous system

has what effect on heart
Definition
parasympathetic, slows heart
NE is part of what branch of nervous system
Term
NE is part of what branch of nervous system

has what effect on heart
Definition
sympathetic, speeds up heart
Term
the atrial reflex is also called the
Definition
Bainbridge reflex
Term
fcn of atrial reflex
Definition
adjusts heart rate in response to increased venous return
Term
When you excercise how does heart increase?
Definition
Sympathetic nervous system kicks in
stretchreceptors (mechanoreceptors) in r. atrium
cause increase in HR
Term
these hormones stimulate SA node and increase heart rate?
Definition
epinephrine

norepinephrine
thyroid hormone
Term
factors that influence Stroke Volume
Definition
duration of ventricular diastole
(filling time)

rate of blood flow during ventricular diastole
(venous return)
Term
preload def
Definition
how much ventricle stretches during ventricular diastole

(aka how stretched are they before they contract (fill with blood)
Term
if preload increases then EDV,
Definition
increases
Term
how does preload affect muscle cells
Definition
ability to produce tension
Term
at rest,
EDV is
myocardium stretches is
stroke volume is
Definition
low
less
low
Term
with excercise,
EDV is
myocardium stretches
stroke volume,
Definition
high
more
high
Term
Frank Starling principle
Definition
EDV increases
SV increases
Term
the most important factor for controlling stoke volume is
Definition
preload
Term
ventricular expansion is limited by
Definition
myocardial connective tissue

cardiac (fibrous) skeleton

pericardial sac
Term
factors that affect ESV
Definition
preload,contractility,afterload

afterload :tension the ventricle produces to open semilunar valve and eject blood.
contractility def: ,force produced during contraction
Term
afterload def
Definition
tension the ventricle produces to open semilunar valve and eject blood
Term
at a given preload
contractility depends on
Definition
autonomic activty (symp/parasymp)
hormones
Term
sympathetic stimulation effect on contractility
Definition
ventricles contract with more force
increases ejection fraction
decreases ESV (less blood left in ventricles that should have been pumped)
Term
parasympathetic stimulation effect on contractility
Definition
ach released by vagus nerves

reduces force of cardiac contractions
Term
if afterload increases then SV?
Definition
increases
Term
afterload can be increased by
Definition
any factor that restricts arterial flow
Term
cardiac reserve
Definition
difference btwn resting and maximal cardiac output
Term
drugs that stimulate or block beta adrenergic receptors causes
Definition
beta -one recepetors to be activated and heart rate increases
Term
calicum channel blockers
Definition
decrease force of cardiac contraction

decrease BP

dilate coronary arteries

weaken contractions
Term
what is negative ionotropic effect?,
Definition
contractions are weakened

can be due to Ca2+ channel blockers
Term
q wave
Definition
depolarization of inventricular septum at left bundle branch
Term
what would occur if valve was clogged with Ca2+?
Definition
prolapse of valve & regurgitation of blood
Term
Q-T interval
Definition
start of ventricular depolarization to end of ventricular repolarization
Term
P-R interval
Definition
start of atrial depolarization to start of ventricular depoloarization(qrs)
Term

block in SA node?

 

what will ekg show?

Definition
no P wave
Term
if there is a heart block in AV node, what would ECG show?
Definition
additional P waves (2 or 3)then a QRS

(aka QRS is delayed)
Term
size of the T wave depends on
Definition
1/3 to2/3 size of r wave
Term
T wave means
Definition
Ventricles repolarize/relax
Term
QRS complex means
Definition
ventricles depolarize/contracting
Term
P wave means
Definition
atria depolarize/contracting
Term
Name all waves on ECG
Definition
P wave

QRS complex

T wave
Term
when heart rate increases ___ cycle(s) shorten especially ____
Definition
all;diastole
Term
cardiac cycle lasts about ___ msec
Definition
800
Term
___ liters of blood/day
Definition
8000
Term
at 75 beats per minute, the heart beats __ times in a day
Definition
10000
Term
blood flows from
Definition
high to low
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