Exam 1 Flashcards
Major Functions of Cardio System
Transport
- Take in materials
- Move materials within the body
-Remove materials
Pulmonary Circuit
Arteries carry O2 poor blood to the lungs
Veins carry O2 rich blood to heart
Systemic Circuit
Arteries carry O2 rich blood to the body
Veins carry O2 poor blood to heart
Superficial to Deep Layers of the Heart
Fibrous Layer
Parietal Layer of Serous Pericardium
Pericardial Activity
Visceral Layer of Serous Pericardium (Epicardium)
Chordae Tendinae (explain what they are)
collagenous tendons that attach valves to walls of ventricles
Prevents valves from opening into the atria –> no backflow
Papillary Muscles
Anchoring Point for chordae tendinae which regulate tension of cords
Right Coronary Artery (what does it supply and branches of it)
Supplies the SA and AV node, parts of the right atrium, interventricular septum, and both ventricles
Marginal Branch: anterior right ventricle
Posterior IV Branch: posterior portions of both ventricles
Left Coronary Artery
Supplies SA node, left atrium, interventricular septum, and both ventricles
Circumflex Branch- left atrium and posterior left ventricle
Anterior Interventricular Branch- anterior portions of both ventricles
Important Cardiac Muscle Features
Intercalcated Disc Structure
- Interdigitating Folds: increase contact surface area between cells
- Mechanical Junctions: fascia adherenes act like Velcro to stick cells together–> Mechanical connection & desmosomes anchor cells together
Pacemaker Cells
1% of myocardial cells are specialized to generate action potentials (aka autorhytmic cells –> and not started by the nervous system)
Electrical Events Leading to a Heartbeat
-Initiated by pacemaker cells in SA node
- Spread via gap junctions and conducting network
Mechanical Events Leading to a Heartbeat
-Caused by electrical events
-Includes contraction (systole) and relaxation (diastole)
Pacemaker Potential Steps
- Slow influx of Na +
- # 1 + voltage gated Ca2+ channels open –> rapid depolarization
- Efflux of K+ –> repolarization
Electrical Signal Conduction
1) SA node fires
2) Excitation spreads through atrial myocardium
3) AV node fires
4) Excitation spreads down AV bundle
5) Subendocardial conducting network distributes excitation through ventricular myocardium
Key Difference between Cell Excitation in Cardio
Ca2+ signaling
Contractile Cell Excitation
- Voltage gated Na+ channels open
- Fast depolarization of membrane
- Closing of Na+ channels
- Opening of slow Ca2+ channels
- Ca2+ channels close and K+ channels open –> repolarization
P-Wave
AP generated in SA node –> atrial depolarization
PQ Segment
pause at AV node and conduction through septum
QRS Complex
ventricular depolarization + atrial repolarization
ST segment
corresponds to plateau of ventricular cardiomyocytes APs
T Wave
ventricular repolarization
TP Segment
period of rest and filling