Cardiovascular System: ECGs, Cardiac Arrhythmias, & Arterial & Venous Systems, Flashcards
Functions of the Heart
What are the components of the ECG?
The P wave represents depolarization of the atria on an ECG. This is followed by the QRS interval, which |
The P wave –> the QRS interval ———-> the ST segment —-> T wave ————-> U wave
P Wave
ECG - Represents atrial depolarization
QRS Interval
ECG - Represents ventricular depolarization
ST Segment
ECG - Represents the period between ventricular depolarization and repolarization.
T Wave
ECG - Represents ventricular repolarization.
Elastic Arteries
Largest arteries (includes the aorta and major branches). Stretch when blood forced out of heart + recoil under low pressure.
Tunic Media
Middle layer of blood vessels; smooth muscle and elastic fibers, regulate vessel diameter. More elastin than any other vessels.
Cardiac arrhythmias
Abnormal heart beats; damage to the conduction system during major cardiac surgery or result of a myocardial infarction
Bradyarrhythmias
Abnormally slow pulse rates
Complete atrioventricular block (AV block)
Bradyarrhythmia: may be congenital or a response to surgical trauma.
hypotension and decrease in oxygenation. |
What are 3 types of bradyarrhythmia
- Complete atrioventricular block (AV block)
- Sinus bradycardia
- Junctional/nodal rhythms
hypotension and decrease in oxygenation. |
Sinus bradycardia
Bradyarrhythmia: caused by autonomic nervous system or hypotension and decrease in oxygenation.
Junctional/nodal rhythm
Bradyarrhythmia: occur post-surgical patients with no P wave.
Tachyarrhythmias
Abnormally fast pulse rates
Sinus tachycardia
Tachyarrhythmia: caused by fever and infection
Supraventricular tachycardia
Tachyarrhythmia (200-300 BPM) may have a sudden onset and result in congestive heart failure.
heart failure.
Conduction irregularities
Type of cardiac arrhythmia; Post-operative insignificant irregular pulses
Premature contractions
Type of cardiac arrhythmia; may arise from the atria or ventricles.
What are the 3 layers of the walls of blood vessels?
- Tunica intima
- Tunica media
- Tunica adventitia
Tunica intima
Innermost wall of blood vessel
Tunica media
Middle wall of blood vessel; smooth muscle cells and elastic fibers
Tunica adventitia
Outermost wall of blood vessel
5 Types of Blood Vessels
- Elastic arteries
- Muscular arteries
- Arterioles
- Venules
- Veins
Elastic arteries
The aorta and major branches.
1. Largest vessels
2. Tunica media = more elastin than any other blood vessel
3. They STRETCH & Recoil
Muscular arteries
The arteries branching off elastic arteries.
- Tunica media = more smooth muscle cells, less elastic fibers
- Regulate blood flow by vasoconstriction/vasodilation.
Arterioles
Tiny vessels - LEAD to capillary beds + PRIMARILY vasoconstriction and vasodilation; control blood flow to capillaries.
- Tunica media = thin/composed
- Made of smooth muscle cells.
Venules
Tiny vessels - EXIT capillary beds + empty blood into larger veins.
- Thin, porous walls
- Few muscle cells and elastic fibers.
Veins
Vessels that carry blood back to heart.
- Thin tunica media and tunica intima
- wide lumen
- valves prevent backflow of blood.
Blood pressure is highest in ________; Lowest in ________.
Aorta; Vena Cava
Where does the steepest drop in blood pressure occur?
Arterioles
2 Types of blood flow?
- Turbulent
- Laminar
Turbulence (blood flow)
Unsteady, swirling flow of blood occurring because 1. high velocity, 2. blood encounters obstruction, 3. vessels take sharp turn or narrow suddenly. PRODUCES SOUNDS.
Laminar blood flow
Steady, streamlined flow of blood occurring throughout most of the
circulatory system. SILENT.
