Alam & Smirk Outcomes Flashcards
Occluding blood flow at the thighs showed that there is a gradual increase in blood pressure throughout (figure 1). Figure 2 however occluded the forearm while having the subject squeeze a rubber ball; what did this show?
Showed that blood pressure rose a significant amount/increased while it was still occluded
Why did they perform a study investigating the duration of circulatory arrest?
the rise in blood pressure of exercising muscles totally DEPENDS on the arrest of circulation (occlusion)
They wanted to see where the rise of BP was greater; was greater in areas where the blood was occluded
BP did not return to normal until the free circulation was restored, so ultimately blood pressure depends on if occlusion is still there or not
Why did they use a mercury bath?
submersion in a mercury bath cuts off circulation similarly to BP cuff occlusion; helped to eliminate the modality variable, bc the effects were the same
What was the goal of the mercury bath experiment? (main finding)
To determine that when you stop exercising, there is a drop in blood pressure
What did they find from the workload experiment?
Investigated the amount of work done on muscle blood pressure response –> rise in BP reported in SBP –> the more weight lifted, the higher the systolic BP
The R point = point where circulation was restored and exercise finished
Helped to determine that more work = greater BP rise
Why did they investigate BP and pain? What were the results?
to determine if the increase in BP was a response to pain from the occlusion of blood, or if it was just occurring despite pain
As patients reached discomfort, bp increased (only 25% of subjects tho)
Patients went through the 3 phases of abnormal sensation and BP increased in all 3 phases
Regardless of pain, blood pressure increases systolically AND diastolically
What was the purpose of the experiment on mental effort and the pressor reflex? What did they find?
Showed that the results of squeezing a ball RAPIDLY –> increase in blood pressure after mental effort was done so…
Increase in blood pressure is NOT caused by the effects of mental effort
Motor centers were affected the MOST, not mental effort
The occlusion increases volume of metabolites in the muscle which then increase NTS signaling which heavily stimulates sympathetic excitation
What are the major differences in BP with unobstructed circulation vs. obstructed circulation?
With obstructed circulation, the metabolites are able to build up in working muscle much more.
Unobstructed circulation allows excess metabolites to be washed out via reabsorption, filtration, capillary fluid dynamics, etc.
What were the main myths/factors examined related to blood pressure in this lab?
- Mechanism of Occlusion
- Mental Processes
- With and Without Occlusion
- Different Metabolites
- Amount of Work Done
- Pain
What were the MAIN conclusions of this paper?
- BP increases with activity with systolic bp MORE
- BP increase occurs from an accumulation of metabolite byproducts
- BP will stay at that level with occlusion until it is removed due to the inability to remove metabolite wastes
- Pressor Reflex can explain why whole-body changes
What is the pressor reflex?
The pressor reflex comprises all the cardiovascular changes reflexively induced from contracting skeletal muscle responsible for increasing arterial blood pressure
What is the result of the pressor reflex during exercise?
Increase in muscle contraction -> increase in metabolites, -> no blood flow due to occlusion -> bigger metabolite stimulus -> metaboreceptors send signals even more strongly and so on
