Download Heart Physiology Notes for students

Heart Physiology: Electrical Events

Intrinsic cardiac conduction system

Composed of _________________________ found nowhere else
in the body

Causes _____________________________ in only one
direction--from ________________________________________

Sets the heart's basic ________________
Heart Physiology: Sequence of Excitation

Sinoatrial (SA) node (____________________)

Generates impulses about ____ times/minute (sinus rhythm)

Depolarizes ___________ than any other part of the myocardium

From SA node, impulse spreads through atria to AV node and
then atria ____________

Atrioventricular (AV) node

Delays impulses to give atria time to finish _________________
Impulse then passes rapidly through __________________________

Atrioventricular (AV) bundle (bundle of His)

Only ____________ connection between the atria and ventricles

Right and left bundle _________________________

Two pathways in the interventricular septum that carry the
impulses toward the __________ of the heart

Purkinje fibers

Complete the pathway into the apex and ___________________

Contraction ejects blood _________________ into the large
____________________ leaving the heart
Homeostatic Imbalances

Defects in the intrinsic conduction system may result in

_________________________: irregular heart rhythms

Uncoordinated atrial and ventricular ___________________

___________________: rapid, irregular contractions; useless for
pumping blood
________________________: rapid heart rate (over 100 beats per minute)
_________________________: heart rate substantially slower than normal
(less than 60 beats per minute)
Electrocardiography

Electrocardiogram (ECG or EKG): a composite of all the
_________________________ generated by nodal and contractile
cells at a given time

Three waves

_________________: depolarization of SA node

_________________: ventricular depolarization

_________________: ventricular repolarization
Heart Sounds

Two sounds (lub-dup) associated with _________________________

First sound occurs as AV valves close and signifies beginning of
__________________________

Second sound occurs when SL valves close at the beginning of
_____________________________________

Heart murmurs: abnormal heart sounds most often indicative of
__________________ problems
Mechanical Events: The Cardiac Cycle

Cardiac cycle: all events associated with blood flow through the heart
during _______________________________________

Systole—____________________________

Diastole—____________________________
Phases of the Cardiac Cycle

Mid-to-late diastole

heart in complete _________________________

pressure in heart is ____________

blood is flowing passively into and through atria into ventricles
from pulmonary and systemic circulations

semilunar valves are _____________

AV valves are _____________

atria ____________________ forcing blood remaining in their
chambers into the ventricles

Ventricular systole

Atria ________________ and ventricles begin to _____________

Rising ventricular pressure results in ___________ of AV valves

Isovolumetric contraction phase (all valves are ____________)


In ejection phase, ventricular pressure _________________
pressure in the large arteries, forcing the SL valves open and
blood rushes out of ventricles

during ventricular systole, atria are _______________ and filling
up with blood
Early diastole

Ventricles ______________

semilunar valves snap shut (preventing ________________)

intraventricular pressure ___________ below pressure in atria

AV valves ____________ causing ventricles to refill with blood,
completing the cycle
Blood Vessels
_____________________: carry blood away from the heart
walls usually ________________ than those of veins
________________________: extend and branch through tissues and
directly serve the needs of the body cells
___________________: drain the tissues and return the blood to the heart

have ______________ that prevent backflow of blood
Physiology of Circulation
__________________: rhythmic expansion and recoil of arteries resulting
from heart contraction

normal resting pulse is _____________________ beats per minute
_______________________________: pressure the blood exerts against
the inner walls of the blood vessels

force that keeps blood _________________ continuously even
between heartbeats
Measuring Blood Pressure
systolic pressure:

pressure in the arteries at the peak of _________________________

in normal adults __________ mmHg
diastolic pressure:

pressure when the ________________________________________

in normal adults _________ mmHg
The Lymphatic System

The primary function is to _________________________, a clear,
colorless fluid containing _____________________ that helps rid the
body of toxins, waste and other unwanted materials

subset of the ______________________ system

______________________________ serve as multiplication sites for
agranular WBCs (lymphocytes)

The tonsils, adenoids, ______________ and thymus are all part of the
lymphatic system