01:146:356 Lecture Notes - Lecture 12: Latvian Lats, Adrenergic, Prefrontal Cortex

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Physiology Notes Control of Heart Rate (Day 2)
Some Comparisons:
Exercise: 25L/min, ending to a return of about 20 L/min
From all the blood flow, less goes to function of major organs, such that
the heart gets about 4 to 5 percent and then most is distributed to heavy
muscle (about 80 to 85%)
Rest: 0.75 L/min
There’s a greater distriutio of lood to the ajor orgas, espeiall to
the brain which will be receiving 15% instead of the mere 3 to 4 during
exercise
The worst thing you can do is go from not having ANYTHING to eat and then
performing physical activity
More O2 can only be delivered by:
1) increased oxygen supply by more blood flow
2) increased AVO2, there will be greater absorption
Arterial O2 content cannot exceed about 20 ml / min for circulative
Venus O2 content = 15ml/min
Therefore, the difference is 5 ml/minute
NOTE: during rest, the prefrontal cortex receives more blood flow
Reactive Hyperemia (figure 18.23)
This phenomenon can apply to any organ
Kidneys are the most profused per gram of tissue
Heart is the least profused
Defiitios…
Ischemia: periods when body experiences lack of oxygen
Reperfusion: returning the blood supply/flow
So a reperfusion injury: the injury/danger caused when re-establishing
blood flow to a tissue after period of ischemia
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Recall we said before that reintroducing blood can be MORE
damaging than the initial cut off of said blood flow
Definition of reactive hyperemia: the increase of blood flow in the body for a
period of time, usually after ischemia
The period of ischemia is directionally proportional to the period of hyperemia
that occurs when restoring blood flow
This is to restore the body to the normalization point/ volume of blood
pushed through
BIG POINT TO BE MADE: Nitric Oxide has no more proof than any other
explanation for the cause of post ischemia hyperemia activity/ blood flow
It’s also reall hard to easure the aout of NO i lood eause it has
a half-life of milliseconds
MERRILL’s eplaatio or theor for the irease i lood flo after
ischemia is Adenosine
Adenosine fact!!!!!
When Adenosine is brought through the blood, the
Occlusion: the blockage or closing of a vessel or hollow organ
Figure 17.35: Explanation of myocardial oxygen consumption vs coronary blood flow
As blood flows through the heart, O2 increase linearly, a direct and proportional
relationship
Figure 18. 22: pressure-flow auto regulation
A type of local flow mechanism
Controlling dP into 3 ml/ minute per 100 grams of mass
By increasing pressure to 100-140 range
The blood flow increases to about 10 ml/min for the first few seconds
Then after this period, it works back toward normalized state of 3ml or just
aoe, thik stead state si set after ou do the rae pae set so that
your heart rate moves back to the normal/slightly elevated state
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