https://www.youtube.com/watch?v=CMZ2AormwgU 1. Using the information in the vide
ID: 71360 • Letter: H
Question
https://www.youtube.com/watch?v=CMZ2AormwgU 1. Using the information in the video about the maintaining of a constant GFR over a range of MAP, determine what adjustments would have to be made if a person has a MAP of: a. 85 b. 130 2. What stimuli would be used to trigger autoregulatory adjustments in wach of the above situations? 3. If a person has a blood pressure reading of 80/45, would autoregulation be able to maintain his GFR at 180 L/day? Explain how you got the answer. You will need to calculate MAP in order to answer this question. practice MAP maintaining for upcoming final. please help!
Explanation / Answer
Determine what adjustments would have to be made if a person has a MAP of: a. 85 b. 130? 2. What stimuli would be used to trigger auto regulatory adjustments in the above situations?
Mean arterial pressure (MAP) is the average blood pressure in an individual and it is normally between 65 and 110 mmHg.
[MAP = CO x SVR]
CO- Cardiac Output and
SVR- Systemic Vascular Resistance
The MAP should be controlled tightly to ensure adequate blood flow to the organs and it is done through negative feedback systems. Baroreceptors are responsible for the regulation of arterial blood pressure and produce vasoconstrictor activity tonically. These baroreceptors can be found within the walls of the carotid sinus near the bifurcation of the common carotid arteries.
When the MAP is 85: Whenever there is an increase in the pressure, it causes the stretching of the walls of the carotid sinus. The additional baroreceptors in the aortic arch will also respond and the stretch will increase the firing rate of the carotid sinus nerve, which carries information to the vasomotor center in the brainstem.
When the MAP is 130: The maximum mean arterial blood pressure in a person is 100mm Hg, it will go beyond 100 mm Hg, a series of autonomic responses will be coordinated by the vasomotor center and measures will be taken to reduce the pressure.
The vasomotor center will try to reduce the arterial pressure to 100 mm Hg through increased parasympathetic outflow to the heart and decreased sympathetic outflow to the heat and blood vessel.
Activation of thevagus nerve typically leads to a reduction in heart rate and Sympathetic stimulation of the heart increases heart rate.
3. If a person has a blood pressure reading of 80/45, would autoregulation be able to maintain his GFR at 180 L/day?
First calculate the MAP,
MAP= SBP+ 2(DBP)/3
SBP-Systolic blood pressure
DBP-Diastolic blood pressure
MAP= 80 + (2x45)/3=57 mm Hg.
But the normal value of MAP is 65-110 mm Hg.
As the MAP in this case is 57, the person may not be able to maintain the GFR at 180L/day.
If you see renal auto regulation, it control glomerular filtration rate (GFR). At 100 mm Hg, it will be 180 L/day. When there is fall in our pressure values, the glomerular filtration pressure will decrease and in turn the GFR also decreases. Proximal convoluted tubule will try to retain more sodium and water and there is a decrease of passage of Sodium to Macula Densa. The afferent arteriole will dilates and at the same time efferent arterioles constrict. The bigger arteriole allow more blood to enter the glomerulus. Because of the above measures, the GFR will increase to its normal homeostatic range.
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