Medical-Surgical Nursing: Cardiovascular System Week 1

Study Notes

The heart is a muscle that pumps blood and is located slightly behind the left sternum, with the left lung being smaller to make room for it.
The heart weighs around 10 ounces and is approximately the size of two clenched fists in adults and one clenched fist in children.

Endocardium: the inner layer of the heart
Myocardium: the middle layer, which is muscular
Pericardium: the outer layer, which is serous and acts as a protective sac that covers the heart
Epicardium: the outer layer, which is visceral and adheres to the myocardium, lubricating the heart to avoid rubbing against other organs

Atrioventricular (AV) Valves:
- Bicuspid (Mitral) Valve: closes during systole, allowing blood to flow from the left atrium to the left ventricle
- Tricuspid Valve: closes during systole, allowing blood to flow from the right atrium to the right ventricle
Semilunar Valves:
- Aortic Valve: opens during systole, allowing oxygenated blood to flow from the left ventricle to the aorta
- Pulmonic Valve: opens during systole, allowing deoxygenated blood to flow from the right ventricle to the pulmonary artery

Coronary Artery: supplies oxygenated blood to the heart
Left Coronary Artery:
- Circumflex Artery: supplies blood to the left atrium and left ventricle (side, back)
- Left Anterior Descending Artery (LAD): supplies blood to the septum (front) and left ventricle (bottom)
Right Coronary Artery:
- Supplies blood to the septum (back), left ventricle (bottom), right ventricle, and right atrium

Right Atrium: receives deoxygenated blood from the superior and inferior vena cava and pumps blood to the right ventricle
Right Ventricle: pumps deoxygenated blood to the lungs through the pulmonary artery
Left Atrium: receives oxygenated blood from the pulmonary veins and pumps blood to the left ventricle
Left Ventricle: pumps oxygenated blood to the whole body through the aorta
Coronary Vein: returns blood from the heart muscles

Blood pressure is the pressure pushing against arterial walls
Preload: initial stretching of the heart muscles prior to systole (pressure at the end of diastole)
Afterload: pressure that the heart muscles must generate to contract against aortic pressure
Contractility: intrinsic strength of the heart muscles, affected by serum calcium and dependent on preload

Speed: 25 mm/sec or 5 large squares per second
Voltage: 1 mV equals 10 mm or 2 large squares per second
ST-segment: period of complete ventricular depolarization, used to diagnose ventricular ischemia or hypoxia
T-Wave: ventricular repolarization, affected by serum potassium### Respiratory System
Respiration is the gas exchange between atmospheric air (O2) and blood
Types of respiration:
- Internal respiration: involuntary process in cells, occurs without breathing
- External respiration: voluntary and involuntary process involving breathing

Obstruction by a thrombus in the pulmonary artery
Causes include lung disorders, cardiac disorders, infections, thromboembolism, sickle cell disease
Clinical manifestations: pain in calf/leg, Hampton's hump, ECG abnormalities, hypoxemia

Administer oxygen therapy
Provide airway management (intubation, mechanical ventilation)
Monitor ventilator settings and alarms
Implement collaborative interventions (anticoagulants, thrombolytics, embolectomy)

Cessation of breathing during sleep due to upper airway obstruction
Causes include obesity, male gender, advanced age, post-menopause
Clinical manifestations: snoring, excessive daytime sleepiness, frequent nocturnal awakenings
Assessment: polysomnography (PSG)
Treatments: weight loss, oral appliances, CPAP, BiPAP, surgical interventions