Heart Flashcards
Describe the blood flow through the heart
R atria-tricuspid valve-R ventricle-pulmonary valve-L atria-mitral valve-L ventricle-aortic valve
Describe the pulmonary circulation
R atria-tricuspid valve-R ventricle-pulmonary valve-lungs-L atria
Describe the systemic circulation
L atria-mitral valve-L ventricle-body-R atria
What are the three types of cardiac muscle?
Atrial M
Ventricular M
Excitatory/conductive muscle fibers
Autorythmic cells
1%
Pacemaker cells
Conductive system
What are the conductory pathway?
SAN-AVN-bundle of HIS-L+R bundle branches-purkinje fibers
Contractile cells
99%
Muscular walls of atria and ventricles
Where do you perform auscultation?
Left- pulmonary, aortic, mitral
Right- tricuspid
Phases of cardiac cycle
S1- systolic, closure of T+M valves, systole starts by opening of P+A valves
S2- diastolic, closure of P+A valves, systole ends, opening of M+T valves
S3- fast ventricle filling
S4- atrial contraction
Stenosis
Valves rigid, not opening enough
Leaky valves
Regurgitation (re-pumping blood)
Mitral valve prolapse- backflow
Cardiac output
Stroke volume*heart rate
Amount of blood ejected by each ventricle per minute
Cardiac output: Intrinsic regulation
Preload
Contractility
Afterload
Cardiac output: extrinsic regulation
Cardiovascular center
Hormones
Preload
Volume of blood entering ventricles
Myocardial stretching
End diastolic volume EDV
Increase when hypervolemia, valves regurgitation, heart failure
Frank starlings law
Amount to f blood entering heart=blood leaving heart
Ionotropy
Contractility
How hard the myocardium contracts for a given preload
Depends on integrity of myocardial fibers and Ca++ available
Increase with sympathetic stimulation, hypercalcemia, hyperkalemia, low O2
Decrease with parasympathetic stimulation, hypocalcemia, hypokalemia
Afterload
The restistance/pressure ventricles must overcome to circulate blood
Arterial pressure related ESV
Increase caused by hypertension and narrowing of arteries
Cardiovascular center
Part of CNS (medulla oblongada)
Regulates heartbeat through nervous and endocrine systems
Input/to brain- chemoreceptors, baroreceptors
Output/to heart- ANS= sympathetic and parasympathetic fibers
Hormonal control
Epinephrine, norepinephrine, ADH, angiotensin II
Other control
Age Sex Temperature Drugs Pain Emotions Exercise
ECG
Representation of electrical events of cardiac cycle
Record of potential differences in AP in heart muscle contraction
Major components of ECG
Atrial depolarization- atrial systole
Ventricular depolarization- ventricular systole
Ventricular repolarization- ventricular diastole
P-wave
Atrial activation
QRS-complex
Activation of ventricles
T-wave
Recovery wave
Respiratory sinus arrhythmia
Irregular heartbeat
Speeds up with inhale, slows with exhale
Normal for dogs
Tachycardia
Increased heart rate
Bradycardia
Decreased heart rate
