Question

Which of the following is NOT directly linked to catecholamines

a. Increased cardiac output

b. Hb-O2 binding affinity

c. Increased heart rate

d. Increased systemic vascular resistance

e. Increased MAP

Answer 1

Answer

Option B) Hb-O2 binding affinity

• Catacholamines such as epinephrine and norepinephrine are released from the adrenal medulla upon activation of sympathetic nervous system.
• They are fight or flight hormones and cause increase in blood pressure, heart rate, cardiac output.
• Hb-O2 affinity is not directly affected by catacholamines. The factors affecting affinity of hemoglobin for oxygen are : pH of blood, temperature, carbon monoxide and carbon dioxide levels in blood.