Activity
The Cardiovascular System
Bien Troy B. Torres
In the following conditions, indicate what factor/s influence the cardiac output: PRELOAD, CONTRACTILITY, AFTERLOAD, HEART RATE. Explain the why the factor/s affects cardiac output in 1 to 2 sentences.
High blood pressure
- Due to the constriction of the heart and reduced elasticity of the arteries during high blood pressure, the heart experiences difficulty to function normally and would result in reduced cardiac output.
Massive bleeding
- When massive bleeding happens, it disrupts and reduces the blood flow of oneself. It causes a fall in cardiac filling and central venous pressure and therefore can result in decreased cardiac output.
The drug Dopamine
- Dopamine is usually a prescripted medicine to cure low blood pressure and low cardiac output. When using moderately, it increases the cardiac output but using it excessively increases afterload and worsens heart failure.
Running a sprint
- When exercising, such as running a sprint, the muscles requires more oxygen and therefore increases the heart's workload. This increases heart rate and cardiac output.
Hyperthryoidism with increased secretion of thyroid hormones
- Hyperthryoidism increases preload and contractility of the heart. Because of this, it also decreases systemic vascular resistance that causes increased cardiac output.
Massive myocardial infarction (cardiac tissue death)
- Heart attack or massive myocardial infarction happens when the blood flow to the heart's muscles is deprived of oxygen due to reduced blood supply. Due to this, the preload and contractility of the heart decreases and therefore reduces cardiac output.
Hypothermia
- When the body is exposed to cold temperature, the body loses heat faster than it is supposed to lose in a specific time frame. Due to this, the heart cannot function normally and may result in slow heart rate and may ultimately lead to death.
Emotional distress
- When experiencing emotional distress, the body secretes adrenaline and cortisol. This narrows blood vessels, increases heart rate and therefore increases the cardiac output.