Regional Circulation Of Brain Splanchnic Skin And Skeletal Muscle

Front 1

What does it mean by "tone"?

Back 1

blood vessel tone, or contraction of certain arterioles. They are constantly contracted

Front 2

How many types of Tones do we have?

Back 2

Resting myogenic tone, resting vasoconstriction, and reflex vasoconstriction

Front 3

What is the resting myogenic tone?

Back 3

smooth muscle cells containing muscle contraction. It is not Dependent on innervation or hormones.

Front 4

What is resting vasoconstriction?

Back 4

It is caused by sympathetic nerve fibers constantly firing leading to continuous contraction of blood vessels.

Front 5

What is reflex vasoconstriction?

Back 5

occurs with pressor response leading to increase sympathetic nerves leading to more vasoconstriction.

Front 6

What is very high in the brain tone? What determines the resting myogenic tone?

Back 6

Resting myogenic tone is very high. Metabolites.

Front 7

What are the metabolites in the brain tone?

Back 7

hypoxia, hypercapnia, acidosis, high temp, adenosin (from ATP metabolism), and high potassium.

Front 8

What do the metabolites do in the brain?

Back 8

They decrease the resting myogenic tone leading to vasodilation.

Front 9

What happens when there is high resting myogenic tone?

Back 9

There is a high sensitivity to vasodilators

Front 10

What is the strongest vasodilator in the brain? What happens when it is present in the brain?

Back 10

Hypercapnia which is high carbon dioxide leading to improved perfusion in the brain.

Front 11

What tone is not present in the brain? Since there are no sympathetic nerve fibers here, what happens?

Back 11

The resting vasoconstriction tone not in the brain. There is systemic vasodilation seen.

Front 12

What is Monroe's Kelly's principle?

Back 12

The volume in the brain is constant because of the skull. A tumor will cause pressure increasing in the head leading to the perfusion affected. If the intercranial pressure is increased, the transmural pressure is decreased, leading to resistance increased and perfusion impaired.

Front 13

What is perfusion determined by?

Back 13

It is determined by the transmural pressure (Hydrostatic - intercranial pressure)

Front 14

What tries to account for the decrease in perfusion in the head?

Back 14

Cushing's reflex Receptors throughout the body send info to pressor center to send info via sympathetic nervous system to heart, arterioles, and veins leading to vasoconstriction

Front 15

When we increase MAP, what happens? (review notes)

Back 15

The baroreceptors are activated stimulating the depressor center.

Front 16

What does the depressor center do during a tumor?

Back 16

Inhibit pressor center(doesnt work), inhibit SMS (but doesnt work), and increase Vagus N activity, decreasing HR. Decreasing HR will lead to increased intercranial pressure.

Front 17

What occurs during coning?

Back 17

The foramen magnum and medulla are pressed together and the patient will die because vasocenter and respirator centers in medulla are compressed.

Front 18

Where can the receptors be found for increased transmural pressure?

Back 18

They can be found in venous sinuses or arterioles of the brain

Front 19

What happens when we increase the HR?

Back 19

Diastole length decreases leading to inappropriate coronary profusion and less CO because ventricles aren't filled completely.

Front 20

What happens when the heart is working harder?

Back 20

More oxygen needed, and higher HR. Higher HR is a problem and will lead to decreased diastole. Resting myogenic tone will sense hypoxia and cause vasodilation leading to greater perfusion.

Front 21

What is not existent in the brain?

Back 21

Resting vasoconstriction and reflex vasoconstriction. The pressor response will have nothing.

Front 22

What are the most important factors affecting vasodilation?

Back 22

Metabolites (hypoxia and adenosin).

Front 23

What is Arteriovenous oxygen difference?

Back 23

(The partial pressure of oxygen in arteriole) - ( partial pressure of oxygen in veins)

Front 24

What is the significance of the Arteriovenous oxygen difference?

Back 24

Higher numbers correspond to better utilization of oxygen. In the heart it is very high.

Front 25

What phenomenon works in the kidneys?

Back 25

The Bayliss effect. Stretching caused by increased blood pressure. This will activate calcium stretch channels leading to increase intracellular concentration leading to contraction.

Front 26

What is the renal plasma flow?

Back 26

It is the amount of plasma leaving kidney in 1 minute.

Front 27

What is the significance of the Regulatory region in the kidneys?

Back 27

It is necessary for primary ultrafiltrate for urine formation. Primary ultrafiltrate increases as MAP increases.

Front 28

What tone is present in the kidney? What is not present and what is strong?

Back 28

Resting myogenic tone is present in the kidney. No resting vasocontraction tone and no depressor reflex (no vasodilation). There is strong reflex vasoconstrictor tone

Front 29

What happens when the pressor response occurs here?

Back 29

Vasoconstriction of kidney leading to more blood elsewhere such as skeletal muscles.

Front 30

What are the tones in the splanchnic area?

Back 30

There is small resting myogenic tone, small resting vasoconstrictor tone, and the reflex vasoconstriction is very high. The pressor response strongly influences this.

Front 31

In the skin, what tone is not present? What is very high?

Back 31

There is no resting myogenic tone and the resting vasoconstrictor tone is very high.

Front 32

Where is the depressor reflex seen mainly?

Back 32

In the skin

Front 33

What is seen because of the pressor response?

Back 33

The reflex vasoconstriction

Front 34

What happens during cold and warm environment?

Back 34

Cold leads to vasoconstriction leading to decreased perfusion to keep heat. Warm leads to vasodilation to increase perfusion to skin to release heat.

Front 35

What tones are moderate here?

Back 35

The resting myogenic tone and the resting vasoconstriction tone are moderate here.

Front 36

What does the depressor response lead to in skeletal muscle?

Back 36

Vasodilation

Front 37

What will the resting myogenic tone and metabolites lead to?

Back 37

Vasodilation

Hypoxia and hypercapnia

Front 38

What happens when we activate Alpha-1 receptors in skeletal muscles?

Back 38

Vasoconstriction of smooth muscle cells.

Front 39

What will Beta 2 and epinephrine cause in skeletal muscles?

Back 39

vasodilation

Front 40

What is used before exercising?

Back 40

Sympathetic cholinergic innervation. When activated they will lead to vasodilation