Physiology Test 2: Bp Control

Front 1

What is meant by autoregulation?

Back 1

It is the ability of a blood vessel to maintain a constant deliver of blood flow despite large variations in perfusion pressure. Usually localized tissue reactions accomplish this by regulation of arteriolar resistancy and NOT inflow pressure using stretch receptors.

Front 2

What is reactive hyperemia(debt repayment)?

Back 2

It means that when you stop the blood flow there will be an equal and opposite reaction. Showing that stoppage and restarting is proportional is a major indication of metabolic activity in tissue as a major blood regulation factor.

Front 3

What is active hyperemia(pay as you go)?

Back 3

It is a more active blood flow based on an increase in metabolic deman.

Front 4

Why is adenosine a vasodialtor?

Back 4

ATP is the energy currency of the cell and when it is reduced down to adenosine the cell knows you need more blood to get more energy. Adenosine formation increases during hypoxia.

Front 5

What are some neurogenic and local effects on blood flow and locations of each in the body?

Back 5

1. In tissues in the heart and brain there are mostly local effects.
2. In tissues like active SKM, kidney and GI there is a balance of neuro and local
3. In skin there is mostly neurogenic

Front 6

Relationships between radius, resistance and flow?

Back 6

1. Resistance in inversely related to raidus and changes by a factor of 4 with a corresponding change in r.
2. Resistance = pressure
3. Flow change is inversely proportional to resistance change

Front 7

What do the carotid baroreceptors do?(CN9)

Back 7

They monitor the central arterial pressure and are very sensitive. They are stretch receptors in the carotid sinus.

Front 8

What are the carotid bodies?

Back 8

They are chemoreceptors that sense the PO2

Front 9

What are the aortic receptors?(CN10)

Back 9

They are also stretch receptors that monitor arterial pressure but they have less of an effect than the carotid. They are located near non-carotid pathways that can influence HR.

Front 10

How do other brain centers affect cariac function?

Back 10

1. The cerebral cortex by emotion
2. The motor areas can increase BP
3. Emotional response can increase BP
4. Pain raises BP
5. Lung inflation = vasodilation
6. Lung deflation = vasoconstriction

Front 11

What do the sympathetic and parasympathetic pathways do to the circulation?

Back 11

Sympathetic is fight or flight and parasympathetic is rest and relax.

Front 12

NTS(nucleus tractus solitarus) and how its signals affect BP

Back 12

1. Afferent signals from the baroreceptors reach this via the CN9(glossopharyngeal) and from the aortic bodies through the CN10(vagus)
2. Inhibits sympathetic nerves and increase relaxation of BVs.
3. Decreases BP
4. Stimulates the parasympathetic decelerator

Front 13

What is the response to high blood pressure in the baroreceptor sinus of the carotid artery?

Back 13

At low Bp they are silent. At high Bp they have a threshold.
2. They have a sigmoidal operating range curve that means that with a small change in pressure there is a high response in BP regulation
3. The mean arterial blood pressure is about halfway through at the set point

Front 14

Heart rate versus BP?

Back 14

1. Increased HR increases BP
2. Increased BP will cause a decrease in HR
3. If the pulse(sys-dias) is too low and the BP is still high then something besides the heart is causing the hypertension

Front 15

What do stretch receptors in the carotid artery and aorta do in response to accomdation?

Back 15

1. Eventually an increased MAP will be accomodated for by baroreceptors
2. This will shift the BP v. Carotid impulse curve to the right.
3. The body will get used to a higher pressure
4. Must treat a chronic hypertensive person by gradual introduction to therapy

Front 16

Baroreceptors or fluid balance as a responder to BP?

Back 16

1. Acute short term control of BP is accomplished by barorecpetors
2. Long term control of BP is determined by fluid balance and the kidney

Front 17

How to calculate BP in the body?

Back 17

1. Total BP = (CO)(TPR)
TPR = total peripheral resistance
CO = (HR)(SV)
SV= (preload)(contractility)(force)

Front 18

Vagus nerves do what to the heart rate?

Back 18

1. They are parasympathetic nerves that stimulate rate by innervating the AV and SA nodes
2. Stimulate = brake
reduce HR and contraction frequency

Front 19

What do the stellate ganglion(sympathetic nerves do the HR)?

Back 19

1. Stimulate = run
2. Increase HR. They innervate the muscles of the ventricles and they are longer lasting

Front 20

Inject Atropine into the heart and what happens?

Back 20

1. Blocks parasympathetic nerves
2.Increase HR and BP

Front 21

Inject propanol into the heart and what happens?

Back 21

1. It blocks sympathetic stimulation
2. Decreases BP, contractility and conductivity

Front 22

Neural control and HR regulation

Back 22

1. Sympathetic control over the heart influences the rate of spontaneous depolarization of the muscles using threshold control. More stimulation = quicker depolarization
2. Parasympathetic control influences the action potentials of the pacemaker by using hyperpolarization. More stimulation = less depolarization

Front 23

What is the pacemaker of the heart?

Back 23

It is the SA node that depolarizes the fastest and why it sets the pace. If this is damaged then the next fastest cells take over which are the AV, then the purkinje fibers.

Front 24

What is the Bundle of His?

Back 24

It is also known as the AV node and its job is to slow down electrical impulses from the pacemaker just long enough to finish artial systole.

Front 25

What does and ECG measure?

Back 25

It measures the aggregate potentials of the different heart muscle fibers.

Front 26

What is a P wave?

Back 26

It is the atrial depolarization

Front 27

What is the PR segment?

Back 27

It is the time of conduction of the first impulse through the AV node and bundle.

Front 28

What is the QRS wave?

Back 28

It is the depolarization and contraction of the ventricles

Front 29

What is the T wave?

Back 29

It is the ventricular repolarization

Front 30

When does atrial repolarization show up on the ECG?

Back 30

It occurs during ventricular depolarization and so the impulse is masked?

Front 31

How to read standard ECG paper?

Back 31

Each grid is 1mm = .4sec
Every 5mm = .2 sec
Every 2 big boxes = 1mV