Circulatory responses to exercise and special circulations Flashcards
What is the first stage in the ‘evaluation of a collapsed athlete’?
Assess their consciousness -> assess for pulse
What is cardiac arrest, and how do you determine someone has it?
Cardiac arrest = sudden unexpected loss of contractile function of the heart.
No pulse = cardiac arrest = life support measure (CPR)
What does an AED do?
Applies an electrical shock to body to reverse abnormal arrhythmia to restore ability of the heart to pump blood.
How much CO is directed to muscle during rest, and during maximal exercise?
Rest - 15-20%
Maximal exercise -80-85%
Decreased blood flow to less active organs - depends on metabolic rate + exercise intensity
What is skeletal muscle vasodilation during exercise due to?
Autoregulation
- blood flow increase to meet metabolic demands of tissue.
- Magnitude of vasodilation in proportion to size of recruited muscle mass.
What is visceral organs and inactive tissue vasoconstriction during exercise due to?
SNS vasoconstriction
How does blood flow, O2 consumption, and O2 extraction change during exercise in splanchnic circulation?
flow - decreases
consumption - stays the same
extraction - increases
What does constriction in splanchnic circulation do?
Add blood volume into circulation back to the heart - increase venous return.
- Vasoconstricts even more during exercise in heat (more CO available for skin).
What happens to skin uptake of blood during exercise?
Increases a lot - rest = 100-300ml/min
- maximal = 7-8 L/min
Cutaneous circulation (skin) - what does hot and cold stress lead to, respectively?
Heat - vasodilation
Cold - vasoconstriction
