Heart A&P Flashcards
Pericardium
Double-layered membrane surrounding the heart
Parietal pericardium
Outer layer of pericaridum
Anchors heart to surrounding tissue
Visceral pericardium
Inner layer of the pericardium that forms the outer layer of the heart
Produces pericardial fluid
Purpose of pericardial fluid
Lubricates epicardial surface
Reduces friction with pericardium
Epicardium
Outer epithelial layer of the heart
Myocardium
Thick middle cardiac muscle layer of the heart
Endocardium
Inner heart layer of endothelial cells.
Trabeculae carnea
muscular ridges
prevent suction that could occur between sides of ventricles
Chordae tendinea
holds AV valves in place
Papillary muscles
Contract to prevent inversion of AV valves
Coronary artery disease (CAD)
coronary arteries become narrowed and hardened, weakens the myocardium and contributes to heart failure
Angina pectoris
Temporary deficiency in myocardial blood supply during increased physical activity
thoracic pain
Myocardial infarction
Prolonged coronary artery blockage
Myocardial cell death
Impaired cardiac function
Cardiac cycle
- Ventricular filling
a) Passive filling
b) Articular systole - Ventricular systole
a) Isovolumetric contraction
b) ventricular systole - Ventricular diastole
a) Ventricular diastole (early)
b) Isovolumetric diastole
Sound 1
Closure of AV valves
Sound 2
Closure of SL valves
Intrinsic conduction steps
- Sinoatrial (SA) node = pacemaker = depolarises A 100/min
- Artioventricular (AV) node = delays depolarisation
- AV bundle = conducts
- Bundle branches (R and L) = apex
- Purkinje fibres = sides of V walls
P wave
Atrial depolarisation (SA node)
QRS complex
Ventricular depolarisation (AV node, bundle branches, P fibres) Atrial repolarisation
T wave
Ventricular repolarisation
Cardioacceleratory centre
Sympathetic
Increases HR and force
SA and AV nodes
Ventricular myocardium
Cardioinhibitory centre
Parasympathetic
Decreases HR
SA and AV nodes