Chapter 20 Flashcards
Fibrous pericardium (what layer, tissue, function)
Superficial
DICT
Prevents overstretching of heart, provide protection, anchor heart to mediastinum
Serous pericardium
Deep
Parietal (outer)/visceral (inner) layer
Epicardium
Inner visceral layer of the serous pericardium
Layers of heart wall
Epicardium (visceral layer of serous pericardium)
Myocardium
Endocardium
Fossa ovals (what/where)
Remnant of foramen ovale (interatrial septum) in right atrium
Trabeculae carnae
I’m right ventricle
raised bundles of cardiac muscle fibers
Chordae tendineae
In ventricles
Tendonlike cords connected to cusps of tricuspid/bicuspid valve and to papillary muscles in ventricles
Ductus arteriosus
In fetus connects pulmonary trunk to aorta so only small amount of blood goes to non functioning fetal lungs
Ligamentum arteriosum
Ductus arteriosus (pulmonary trunk to aorta) closes and leaves this remnant
Fibrous rings
Supper the four valves of the heart and are fused to one another DCT
Semilunar valves
Aortic and pulmonary valves
How does blood not back flow into venae cavae (R) or the pulmonary veins (L) without a valve
When Artis contract it compresses and nearly collapses the weak walls of the veins so not much blood can escape
Left coronary artery divides into and what they supplu
Anterior interventricular branch (supplies walls of ventricles)
Circumflex branch (supplies L ventricle and L atrium)
Right coronary artery branches into and what they supply
Posterior interventricular branch (supplies walls of ventricles)
Marginal branch ( R ventricle)
Coronary sinus
Vascular sinus in coronary sulcus on post heart that deoxygenated blood from myocardium flows into
Intercalated discs (what/contain)
Sarcolemma thickening that holds ends of cardiac MF
Desosomes (hold fibers together)
Gap junctions (AP to conduct)
What is larger/more numerous in cardiac muscle fibers than skeletal
Mitochondria
Sarcoplasmic reticulum in cardiac vs skeletal (and what it means)
Cardiac is smaller=less Ca2+ reserve
What percent of CMF are autonomic fibers
1 percent
Two functions of autonomic fibers
Pacemaker: set rythym of electrical excitation
Form cardiac conduction system: provide path for each cycle of cardiac excitation to progress through heart (chambers contract in right order)
Conduction system sequence
SA node (atria contract)
AV node (slow down AP to allow atria to empty all blood)
AV bundle (AP from atria to ventricles)
R/L bundle branches (to apex)
Purkinje fibers (rest of ventricles to contract them)
AP occurs steps
Depolarization: voltage gated Na+ open (in)
Plateau: voltage gated Ca2+ open (in)
Voltage gated K+ open (out)
=Balanced
Repolarization: voltage gated K+ open (out)
Contractile resting membrane potential
-90mV
Is contraction or refractory longer in CMF
Refractory
