A&P Flashcards
Conduction system supplied by the RCA
Sinoatrial (SA) node (55%)
Atrioventricular (AV) node and bundle of His (90%)
Posterior fascicle of the LBB
Conduction system supplied by the LCA- ANTERIOR descending branch
Majority of RBB
Anterior fascicle of LBB
Portion of posterior fascicle of LBB
Conduction system supplied by the LCA- CIRCUMFLEX branch
SA Node (45%)
AV node and bundle of His (10%)
The outer fibrous pericardium is attached at what points
Inferior: center of diaphragm
Anterior: sternum
Posterior: esophagus, trachea, and main bronchi
Approx wall thickness of the RA
2mm
Approx wall thickness of the LA
3mm
Approx thickness of the RV
3-5 mm
Approx wall thickness of the LV
13-15 mm
What governs the opening and closing of heart valves?
Changes in chamber pressure
T/F
The tricuspid valve orifice is smaller than the mitral valve
F
Tricuspid- 11cm circumference, 3 leaflets
Mitral- 9cm circumference, 2 leaflets
The atrial kick adds what percentage to ventricular capacity?
30%
The ventricles are 70% filled before atrial contraction
Constitutes the first heart sound (S1)
Closure of AV valves
Constitutes the second heart sound (S2)
Closure of the SL valves
T/F
Right-side and left-sided events in the heart occur simultaneously
True
Where do the right and left coronary arteries arise?
From the aorta just above and behind the aortic valve
The coronary artery that gives rise to the ________ is usually considered the dominant coronary artery
Posterior descending artery
Right dominance (the PDA being the terminal branch of the RCA) occurs in what percentage of the population?
85-90%
Left dominant (10-15%) is when the PDA is a continuation of the left circumflex branch
Myocardial blood flow (flow through coronary arteries) is ____ during ventricular diastole than during ventricular systole
Greater
The integration center for cardiac sensory info
The medulla
Stimulation of the sympathetic nervous system releases
Norepinephrine
Effect of sympathetic nervous system stimulation on HR, conduction through AV node and ventricular contraction
Increases HR
Speeds conduction through AV node
Increases for of ventricular contraction
Result of norepinephrine
Effect of parasympathetic nervous system stimulation on HR, conduction through AV node and ventricular contraction
Decreases HR
Slows AVN conduction
Small decrease in force of ventricular contractions (minimal parasympathetic innervation in ventricles)
Release of acetylcholine
Stimulation of the parasympathetic nervous system releases
Acetylcholine
Why is cardiac pain often referred to areas such as the epigastric area, anterior chest wall, sternum, jaw, shoulders, arms, etc.?
These are areas innervated by thoracic segments T1-T4 where the sensory nerve fibers/cells for the heart relay info to the medulla
