Week 1 Cardiovascular Response to Exercise: Control and regulation Flashcards
What is the difference between homeostasis and steady-state?
Homeostasis: Maintaining a constant internal environment
Steady-state: Internal environment is unchanging BUT the physiological system adjusts to the environmental demand to achieve balance.
What’s a biological control system
A series of integrated components that maintain a physical or chemical parameter of the body.
Give examples of Homeostasis, Steady-state, and Biological control system
Homeostasis: Arterial blood pressure at rest
Steady-State: Heart rate while jogging
Biological control system: Co-ordination of the nervous system and the cardiovascular system
Why is it called negative feedback?
Because the response of the feedback is opposed to the stimulus
What are the sympathetic and parasympathetic neurotransmitters? Do each of them usually activate or inhibit organs?
Sympathetic: Noradrenaline/adrenaline (activate)
Parasympathetic: Acetylalcholine (inhibit)
What is the biggest influence against blood flow resistance?
Radius. Vasodilation allows blood flow to move faster
Why is blood flow in the capillary slower?
Because capillaries need to offload oxygen into active muscle cells
What are the functions of the CV system?
- Transport of O2 to tissues
- Transport of nutrients to tissues
- Removal of waste products
- Regulation of body temperature
What is the CV drift and why does it happen?
CV drift is when the heart rate doesn’t enter steady-state, and continues to increase slowly. This happens because blood volume is decreased due to sweat, where an increase in heart rate acts as a compensation.
After 50% VO2max, What becomes the main contributor for cardiac output, Heart rate or stroke volume in untrained or moderately trained individuals?
Heart rate
How is cardiac output increased during exercise (in terms of nerves)?
Parasympathetic withdrawal: Nerves decreases the amount of ACH
Sympathetic stimulation: Nerves release more NorAd that act on beta receptors of the heart
How to increase Cardiac output (Stroke Volume)?
- Increase Venous return causing an increase in EDV
- Decrease resistance by dilating arterioles
- Releasing Ad, and NorAd causing increased contractility of the heart because of increase Ca2+
Why does the brain need blood during exercise?
Because all of the control center is in the brain
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How to increase muscle blood flow?
Hypothesized that Sympathetic withdrawal causes immediate vasodilation of arterioles.
Autoregulation via local feedback
Increased capillary recruitment.
How does blood flow decrease in inactive areas?
Adrenergic sympathetic stimulation causes vasoconstriction of the arterioles and pre-capillary sphincters
