Post-lecture activity (Week 10)

Jardeleza, Bielle Ezra M- The Cardiovascular System

Jardeleza, Bielle Ezra M- The Cardiovascular System

by Bielle Ezra Jardeleza -
Number of replies: 0

In the following conditions, indicate what factor/s influence the cardiac output: PRELOAD, CONTRACTILITY, AFTERLOAD, HEART RATE. 

Blood pressure

  • High blood pressure or hypertension causes the heart to become constricted and the arteries' elasticity to be reduced. This makes it difficult for the heart to function, thus, reducing cardiac output. 

Massive bleeding

  • Massive bleeding reduces the blood flow, which causes a fall in central venous pressure and cardiac filling. This leads to decreased cardiac output and arterial pressure.

Drug: Dopamine

  • Moderate doses of dopamine increase heart rate and contractility, increasing cardiac output. On the other hand, high doses produce vasoconstriction to enhance blood pressure, reducing cardiac output.

Running a sprint

  • During physical activities such as running a sprint, your muscles require more oxygen, increasing the heart's workload. Thus, increasing heart rate and cardiac output. 

Hyperthyroidism with increased secretion of thyroid hormones

  • Hyperthyroidism causes increased preload and contractility, and decreased systemic vascular resistance causes increased cardiac output.

Massive myocardial infarction (cardiac tissue death)

  •  massive myocardial infarction (heart attack) causes the preload and contractility of the heart to decrease, thus, reducing cardiac output.

Hypothermia

  • An increase in the body core temperature (hyperthermia) from approximately 36.5 to 39 degrees C causes a doubling of the cardiac output.

Emotional distress

  • Experiencing emotional distress causes our body to secrete cortisol and adrenaline, which causes an increase in our heart rate, narrowing of blood vessels, and an increase in cardiac output.

 

References

CV Physiology | Hemorrhagic Shock. (2021). Retrieved from Cvphysiology.com website: https://www.cvphysiology.com/Blood%20Pressure/BP031#:~:text=The%20reduction%20in%20blood%20volume,cardiac%20output%20and%20arterial%20pressure.

Deussen A. (2007). Hyperthermie und Hypothermie. Auswirkungen auf das Herz-Kreislauf-System [Hyperthermia and hypothermia. Effects on the cardiovascular system]. Der Anaesthesist56(9), 907–911. https://doi.org/10.1007/s00101-007-1219-4

Dopamine HCl |. (n.d.). http://shadwige.sites.truman.edu/cardiac-medications/hemodynamic-medications/dopamine-hcl/

Ertek, S., & Cicero, A. F. (2013). Hyperthyroidism and cardiovascular complications: a narrative review on the basis of pathophysiology. Archives of medical science : AMS9(5), 944–952. https://doi.org/10.5114/aoms.2013.38685