Renal Physl 17 Flashcards

1
Q

What is normal body pH?

A

7.4

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2
Q

What do we measure to asses the whole body pH?

A

The pH of the plasma

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3
Q

What happens to neurons if pH is too low?

A

Neurons are less excitable, and CNS depression occurs

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4
Q

What happens to neurons if pH is too high?

A

Neurons are highly excitable

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5
Q

What is the largest source of H+ ions?

A

Acid production from carbon dioxide during aerobic respiration

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6
Q

How is acid produced in aerobic respiration?

A

Carbon dioxide from respiration combines with water to form carbonic acid which then dissociates into hydrogen ion and bicarbonate ion

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7
Q

What are the three key process in pH homeostasis?

A
  • Buffer systems
  • Ventilation
  • Renal regulation of hydrogen and bicarbonate ions
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8
Q

What do buffers do?

A

Prevent large fluctuations in pH

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9
Q

What is a buffer?

A

A molecule that can modulate pH in response to a disturbance

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10
Q

How do buffers tend to modulate pH?

A

By combining with hydrogen ions or releasing hydrogen ions

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11
Q

What is the first, second, and third line of defense in pH homeostasis?

A

1st - Buffer systems
2nd - Ventilation
3rd - Renal regulation

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12
Q

Where are buffers of the body located?

A
  • In cells

* In circulating plasma

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13
Q

What kind of buffers are located in cells?

A
  • Cellular proteins
  • Phosphate ions
  • Hemoglobin
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14
Q

What kind of buffers are located in plasma?

A

HCO3-

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15
Q

What happens to bicarbonate ions for every hydrogen ion?

A

For every hydrogen ion a bicarbonate remains in the RBC

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16
Q

How can a bicarbonate ion leave the RBC?

A

In exchange from a chloride ion

17
Q

What is chloride shift?

A

When for every bicarbonate ion able to leave the RBC a chloride ion enters

18
Q

What represents the most important extracellular buffer system in the body?

A

Large amounts of plasma bicarbonate produced from metabolic carbon dioxide

19
Q

What are bicarbonate ions in the plasma able to buffer?

A

Hydrogen ions from non respiratory sources like metabolism

20
Q

How would an increase in carbon dioxide affect the reaction?

A

It would cause an increase in hydrogen and bicarbonate ions decreasing pH

21
Q

How would an increase in hydrogen ions shift the equation?

A

Bicarbonate ions bind with the H+ to form carbonic acid and both carbon dioxide and water increase

22
Q

How does an increase in carbon dioxide affect ventilation?

A

It increases ventilation

23
Q

What can acidosis induce in the lungs?

A

Respiratory compensation

24
Q

What is ventilation?

A

A homeostatic approach for adjusting pH

25
What can stimulate respiratory compensation?
Hydrogen ions and carbon dioxide
26
What directly alters ventilation at the carotid and aortic chemoreceptors?
Plasma hydrogen ion levels
27
What stimulates chemoreceptors?
Increased hydrogen ions
28
What does stimulation of chemoreceptors by hydrogen ions do?
Sends information to medullary control centers which stimulates the muscles of ventilation and increase the rate and depth of breathing
29
What does increased ventilation permit?
Loss of carbon dioxide at the lungs and conversion of hydrogen ions to carbon dioxide and water in order to restore pH
30
Why don't central chemoreceptors in the medulla oblongata respond directly to hydrogen ions?
Because H+ does not cross the blood brain barrier
31
What happens to the pH and carbon dioxide if ventilation is depressed in hypoventilation?
Carbon dioxide increases and causes an acidotic state
32
What happens to the pH and carbon dioxide if ventilation is increased in hyperventilation?
Carbon dioxide is decreased and pH increases