Anatomy And Physiology Of The Heart Flashcards
Systole
The rhythmic contraction of the heart muscle
Diastole
The period in the complete heart beat when the heart muscle releases and the chambers fill with blood
Stenosis
A narrowing canal or vessel
Physiology of the Heart: The Cardiac Cycle
All the events that occur in one heartbeat
Phases of the Cardiac Cycle: All Valves Closed (diastole)
Atria filling
All valves closed
Atrial pressure increasing
Short phase
Phases of the Cardiac Cycle: A-V Valves Forced Open
Heart is still in diastole
Atrial Pressure> Ventricular Pressure
Atria approximately 95% full
ventricular about 70% full
Phases of the Cardiac Cycle: Atria Contract
Ventricle still in diastole
Atrial systole
Right atrium starts before left atrium
Remaining 30% forced into ventricles
Phases of the Cardiac Cycle: Atria Relaxed
Atria and Ventricle are both diastole
Ventricular pressure> atrial pressure
Phases of the Cardiac Cycle: Ventricles Contract
Ventricle Systole
AV valves close
Aortic and Pulmonary valves forced open
Ventricle contract, beginning at apex
Phases of the Cardiac Cycle: Relaxation of Ventricles
Arterial Pressure> Ventricular Pressure
Blood flows back towards ventricles
Pulmonary and Aortic valves are shut
AV Valves still closed
Valves of the Heart: Function of AV valves
Permissive: open property
Prohibitive: close property
Valves of the Heart: Valvular Damage
Valvular Insufficiency or Incompetence…valve not closing properly…allowing blood to return where it came from
stenosis: narrowing of a canal or vessel
Endocarditis: inflammation in the heart
Erysipelas: scar tissue developing around the valve
Rheumatic Fever: diagnosed with a heart murmur
Intrinsic
Belonging naturally to a part or individual
Extrinsic
Being outside of the nature of something
Brady-
The combining form of the word “slow”
Tachy-
The combining form of the word “fast”
Intrinsic Conduction System: Sino-Atrial Node
Between cranial vena cava and right atria wall
Pacemaker of the heart
Consists of cells with the fastest rate of firing
Lowest threshold of depolarization
Intrinsic Conduction System: Inter Nodal Fiber Bundles
In wall of atria
Spreads impulses throughout atria
Intrinsic Conduction System: Atrioventricular Node
Collects waves of depolarization
In atrial septum near ventricles
Gathers impulse to be sent to a AV bundle
AV Bundle
In ventricular septum
Composed of small diameter cardiac muscle fibers
Conducts impulse towards apex
Purkinje Fibers
Third form of cardiac muscle
Mammals have in ventricle
In ventricular walls
Conducts Impulse from AV bundle to muscle fibers to ventricles
Twists..blood is pushed upward and is forced out
Functions of the Ventricle Septum
Separates oxygen rich from oxygen poor
Composed of myocardium…aids in contraction of heart
Site of AV bundle…transmits wave of depolarization
Extrinsic Conduction System
Autonomic portion of the peripheral nervous system (ANS)
Sympathetic…drift increases causes heart to speed up
Parasympathetic…drift decreases caused heart to slow down
Endocrine
ECG: P Wave
Spread of depolarization throughout the atrial muscle ( precedes atrial systole)
ECG: QRS Wave
Spread of depolarization throughout the ventricular muscle (precedes ventricular systole)
ECG: T Wave
Repolarization of ventricles (follows ventricular systole
ECG: PR Interval
The time from the onset of the P-Wave to the beginning of the QRS
ECG: ST interval
The time at which the ventricle is depolarized (plateau phase of the ventricular action potential)
ECG: QT Interval
The time for both ventricular depolarization and repolarization (duration of ventricular action potential)
Heart Block
Intrinsic: AV Node and AV Bundles are affected
Extrinsic: interference from autonomic systems or adrenal medulla (tumor)…often in vagus nerve
Cardiac Output
CO=volume of blood pumped by the heart in a unit measure of time
CO=beats per min times volume pumped by heart per beat
Fibrillation
Heart is depolarizing while other part is repolarizing
Have to change heart to make beats normal
Starlings Law
Force of contraction heart = stretch of heart muscle
