6. Overview
⢠What is regulated for
ECF: (outputs)
â water
â Na+
â K+ Text
2
7. Overview
⢠What is regulated for
ECF: (outputs)
â water
â Na+
â K+ Text
â other solutes (glucose,
amino acids, etc.)
2
8. Overview
⢠What is regulated for ⢠Sensors for ECF
ECF: (outputs) composition: (inputs)
â water
â Na+
â K+ Text
â other solutes (glucose,
amino acids, etc.)
2
9. Overview
⢠What is regulated for ⢠Sensors for ECF
ECF: (outputs) composition: (inputs)
â water â baroreceptors
â Na+
â K+ Text
â other solutes (glucose,
amino acids, etc.)
2
10. Overview
⢠What is regulated for ⢠Sensors for ECF
ECF: (outputs) composition: (inputs)
â water â baroreceptors
â Na+ â volume receptors
â K+ Text
â other solutes (glucose,
amino acids, etc.)
2
11. Overview
⢠What is regulated for ⢠Sensors for ECF
ECF: (outputs) composition: (inputs)
â water â baroreceptors
â Na+ â volume receptors
â K+ Text â osmoreceptors
â other solutes (glucose,
amino acids, etc.)
2
12. Overview
⢠What is regulated for ⢠Sensors for ECF
ECF: (outputs) composition: (inputs)
â water â baroreceptors
â Na+ â volume receptors
â K+ Text â osmoreceptors
â other solutes (glucose, â K+
amino acids, etc.)
2
13. Overview
⢠What is regulated for ⢠Sensors for ECF
ECF: (outputs) composition: (inputs)
â water â baroreceptors
â Na+ â volume receptors
â K+ Text â osmoreceptors
â other solutes (glucose, â K+
amino acids, etc.) â Na+
2
15. As BP goes up, glomerular filtration goes
up 4
16. Keep a list of autoregulation
Autoregulation
5
17. Keep a list of autoregulation
Autoregulation
Apart from neural regulation, there are
2 ways that the kidneys âself-
regulateâ.
5
18. Keep a list of autoregulation
Autoregulation
Apart from neural regulation, there are
2 ways that the kidneys âself-
regulateâ.
1. myogenic autoregulation â
responses to stretch of the arteriolar
smooth muscle
5
19. Keep a list of autoregulation
Autoregulation
Apart from neural regulation, there are
2 ways that the kidneys âself-
regulateâ.
1. myogenic autoregulation â
responses to stretch of the arteriolar
smooth muscle
2. tubuloglomerular autoregulation â
responses to ďŹow through the distal
tubules
5
22. Myogenic autoregulation
⢠Arteriolar smooth muscle responds to
stretch like other muscles â by
contracting.
⢠Therefore, â BP ď â stretch ď
6
23. Myogenic autoregulation
⢠Arteriolar smooth muscle responds to
stretch like other muscles â by
contracting.
⢠Therefore, â BP ď â stretch ď
â contraction ď â ďŹltration pressure
6
24. Myogenic autoregulation
⢠Arteriolar smooth muscle responds to
stretch like other muscles â by
contracting.
⢠Therefore, â BP ď â stretch ď
â contraction ď â ďŹltration pressure
ď â GFR (constant)
6
25. Myogenic autoregulation
⢠Arteriolar smooth muscle responds to
stretch like other muscles â by
contracting.
⢠Therefore, â BP ď â stretch ď
â contraction ď â ďŹltration pressure
ď â GFR (constant)
⢠The reverse, â BP ď little myogenic
response, because the renal arterioles
are normally nearly completely
relaxed;
6
26. Myogenic autoregulation
⢠Arteriolar smooth muscle responds to
stretch like other muscles â by
contracting.
⢠Therefore, â BP ď â stretch ď
â contraction ď â ďŹltration pressure
ď â GFR (constant)
⢠The reverse, â BP ď little myogenic
response, because the renal arterioles
are normally nearly completely
relaxed;
net effect is â GFR due to â BP directly.
6
29. Tubuloglomerular Feedback
⢠This effect depends on special
structure â the juxtaglomerular
apparatus.
⢠macula densa cells of the distal
convoluted tubule (the sensor)
7
30. Tubuloglomerular Feedback
⢠This effect depends on special
structure â the juxtaglomerular
apparatus.
⢠macula densa cells of the distal
convoluted tubule (the sensor)
⢠neighboring juxtaglomerular cells of
the afferent arteriole of the same
nephron (the effector)
7
31. Thousands of nefrons are all regulated to give regular flow.
Increased flow to the glomerulus leads to increased filtration. This
leads to more flow of fluid through the nefron.
Tubuloglomerular (2)
8
32. Thousands of nefrons are all regulated to give regular flow.
Increased flow to the glomerulus leads to increased filtration. This
leads to more flow of fluid through the nefron.
Tubuloglomerular (2)
â ďŹow of ďŹuid through the distal
tubule
8
33. Thousands of nefrons are all regulated to give regular flow.
Increased flow to the glomerulus leads to increased filtration. This
leads to more flow of fluid through the nefron.
Tubuloglomerular (2)
â ďŹow of ďŹuid through the distal
tubule
ď stimulation of macula densa cells
8
34. Thousands of nefrons are all regulated to give regular flow.
Increased flow to the glomerulus leads to increased filtration. This
leads to more flow of fluid through the nefron.
Tubuloglomerular (2)
â ďŹow of ďŹuid through the distal
tubule
ď stimulation of macula densa cells
ď release of paracrine secretions
8
35. Thousands of nefrons are all regulated to give regular flow.
Increased flow to the glomerulus leads to increased filtration. This
leads to more flow of fluid through the nefron.
Tubuloglomerular (2)
â ďŹow of ďŹuid through the distal
tubule
ď stimulation of macula densa cells
ď release of paracrine secretions
(including NO)
8
36. Thousands of nefrons are all regulated to give regular flow.
Increased flow to the glomerulus leads to increased filtration. This
leads to more flow of fluid through the nefron.
Tubuloglomerular (2)
â ďŹow of ďŹuid through the distal
tubule
ď stimulation of macula densa cells
ď release of paracrine secretions
(including NO)
The neighboring afferent arteriole cells
respond with â constriction ď â GFR &
â ďŹow
8
37. Thousands of nefrons are all regulated to give regular flow.
Increased flow to the glomerulus leads to increased filtration. This
leads to more flow of fluid through the nefron.
Tubuloglomerular (2)
â ďŹow of ďŹuid through the distal
tubule
ď stimulation of macula densa cells
ď release of paracrine secretions
(including NO)
The neighboring afferent arteriole cells
respond with â constriction ď â GFR &
â ďŹow
This is a simple negative feedback to
maintain ~ constant ďŹow through the 8
41. Sympathetic nerves
⢠The sympathetic division of the ANS
innervates both:
â afferent arterioles
â efferent arterioles
9
42. Sympathetic nerves
⢠The sympathetic division of the ANS
innervates both:
â afferent arterioles
â efferent arterioles
⢠ι receptors mediate vasoconstriction
in response to sympathetic activity.
9
43. Sympathetic nerves
⢠The sympathetic division of the ANS
innervates both:
â afferent arterioles
â efferent arterioles
⢠ι receptors mediate vasoconstriction
in response to sympathetic activity.
⢠The 2 types of arterioles can be
separately controlled.
9
46. Sympathetic nerves (2)
⢠Vasoconstriction of the afferent
arteriole ď â blood ďŹow & â GFR
⢠Constricting the efferent arterioles ď
â ďŹltration pressure & â GFR
10
47. Sympathetic nerves (2)
⢠Vasoconstriction of the afferent
arteriole ď â blood ďŹow & â GFR
⢠Constricting the efferent arterioles ď
â ďŹltration pressure & â GFR
⢠Most of the important regulation
involves the afferent arterioles.
10
48. Sympathetic nerves (2)
⢠Vasoconstriction of the afferent
arteriole ď â blood ďŹow & â GFR
⢠Constricting the efferent arterioles ď
â ďŹltration pressure & â GFR
⢠Most of the important regulation
involves the afferent arterioles.
⢠But a large â in systemic BP ď strong
sympathetic vasoconstriction ď â
GFR
10
49. Hormonal regulation
mainly, effects on the
movement of speciďŹc
substances
11
52. Hormone overview:
⢠Any hormone that affects average systemic BP
ď effects on GFR:
especially Ang II
12
53. Hormone overview:
⢠Any hormone that affects average systemic BP
ď effects on GFR:
especially Ang II
⢠3 hormones ď selective effects on the kidneys:
12
54. Hormone overview:
⢠Any hormone that affects average systemic BP
ď effects on GFR:
especially Ang II
⢠3 hormones ď selective effects on the kidneys:
â antidiuretic hormone (ADH, vasopressin)
12
55. Hormone overview:
⢠Any hormone that affects average systemic BP
ď effects on GFR:
especially Ang II
⢠3 hormones ď selective effects on the kidneys:
â antidiuretic hormone (ADH, vasopressin)
ď regulation of water reabsorption
12
56. Hormone overview:
⢠Any hormone that affects average systemic BP
ď effects on GFR:
especially Ang II
⢠3 hormones ď selective effects on the kidneys:
â antidiuretic hormone (ADH, vasopressin)
ď regulation of water reabsorption
â aldosterone ď
12
57. Hormone overview:
⢠Any hormone that affects average systemic BP
ď effects on GFR:
especially Ang II
⢠3 hormones ď selective effects on the kidneys:
â antidiuretic hormone (ADH, vasopressin)
ď regulation of water reabsorption
â aldosterone ď
⢠â Na+ retention
12
58. Hormone overview:
⢠Any hormone that affects average systemic BP
ď effects on GFR:
especially Ang II
⢠3 hormones ď selective effects on the kidneys:
â antidiuretic hormone (ADH, vasopressin)
ď regulation of water reabsorption
â aldosterone ď
⢠â Na+ retention
⢠â K+ excretion
12
59. Hormone overview:
⢠Any hormone that affects average systemic BP
ď effects on GFR:
especially Ang II
⢠3 hormones ď selective effects on the kidneys:
â antidiuretic hormone (ADH, vasopressin)
ď regulation of water reabsorption
â aldosterone ď
⢠â Na+ retention
⢠â K+ excretion
â atrial natriuretic peptide (ANP) opposite effects to
aldosterone
12
62. Remember diuresis to remember antiduresis
ADH naming
⢠ADH = anti-diuretic hormone
⢠diuresis is a condition
13
63. Remember diuresis to remember antiduresis
ADH naming
⢠ADH = anti-diuretic hormone
⢠diuresis is a condition
ď â volume of dilute urine
13
64. Remember diuresis to remember antiduresis
ADH naming
⢠ADH = anti-diuretic hormone
⢠diuresis is a condition
ď â volume of dilute urine
⢠ADH at physiological concentrations
prevents diuresis
13
65. Remember diuresis to remember antiduresis
ADH naming
⢠ADH = anti-diuretic hormone
⢠diuresis is a condition
ď â volume of dilute urine
⢠ADH at physiological concentrations
prevents diuresis
⢠âvasopressinâ describes an
âemergencyâ action at unphysiological
LARGE concentrations of ADH
13
67. ADH mechanism of action
ď â water permeability of collecting
tubules
14
68. ADH mechanism of action
ď â water permeability of collecting
tubules
ď â passive diffusion of water
(âosmosisâ) due to the concentration
of NaCl in the ECF of the medulla of
the kidney
14
69. ADH mechanism of action
ď â water permeability of collecting
tubules
ď â passive diffusion of water
(âosmosisâ) due to the concentration
of NaCl in the ECF of the medulla of
the kidney
ď â net water reabsorption from
kidneys
ď â osmotic pressure of
plasma and ECF
14
71. Regulation of ADH
⢠â osmotic pressure ď âosmoreceptorsâ
of the hypothalamus with no blood-
brain barrier
15
72. Regulation of ADH
⢠â osmotic pressure ď âosmoreceptorsâ
of the hypothalamus with no blood-
brain barrier
⢠The osmoreceptors:
15
73. Regulation of ADH
⢠â osmotic pressure ď âosmoreceptorsâ
of the hypothalamus with no blood-
brain barrier
⢠The osmoreceptors:
are close to the cell bodies that synthesize
ADH
15
74. Regulation of ADH
⢠â osmotic pressure ď âosmoreceptorsâ
of the hypothalamus with no blood-
brain barrier
⢠The osmoreceptors:
are close to the cell bodies that synthesize
ADH
ď â ADH secretion from pituitary
15
75. Regulation of ADH
⢠â osmotic pressure ď âosmoreceptorsâ
of the hypothalamus with no blood-
brain barrier
⢠The osmoreceptors:
are close to the cell bodies that synthesize
ADH
ď â ADH secretion from pituitary
⢠[negative feedback for regulation of
osmotic pressure via a
neurohormone] 15
82. Aldosterone
⢠Aldosterone acts on cells of the distal
tubules ď
â K+ excretion
â Na+ retention
⢠Aldosterone is secreted by cells of the
adrenal cortex in response to:
18
83. Aldosterone
⢠Aldosterone acts on cells of the distal
tubules ď
â K+ excretion
â Na+ retention
⢠Aldosterone is secreted by cells of the
adrenal cortex in response to:
â [K+] or chronically â [Na+]
18
84. Aldosterone
⢠Aldosterone acts on cells of the distal
tubules ď
â K+ excretion
â Na+ retention
⢠Aldosterone is secreted by cells of the
adrenal cortex in response to:
â [K+] or chronically â [Na+]
â Ang II
18
89. Renin-angiotensin system
An example of a regulatory cascade:
Liver ď Angiotensinogen in blood
plasma
JG cells of afferent arterioles ď renin
20
90. Renin-angiotensin system
An example of a regulatory cascade:
Liver ď Angiotensinogen in blood
plasma
JG cells of afferent arterioles ď renin
Renin cleaves angiotensinogen ď Ang
I
20
91. Renin-angiotensin system
An example of a regulatory cascade:
Liver ď Angiotensinogen in blood
plasma
JG cells of afferent arterioles ď renin
Renin cleaves angiotensinogen ď Ang
I
Angiotensin converting enzyme (ACE)
from endothelial cells cleaves Ang I ď
Ang II
20
94. Ang II actions
⢠Ang II is a powerful vasoconstrictor
â Ang II also âresetsâ the sensitivity of the
CV regulatory region in the RF of the
medulla
21
95. Ang II actions
⢠Ang II is a powerful vasoconstrictor
â Ang II also âresetsâ the sensitivity of the
CV regulatory region in the RF of the
medulla
â both work together ď â BP
21
96. Ang II actions
⢠Ang II is a powerful vasoconstrictor
â Ang II also âresetsâ the sensitivity of the
CV regulatory region in the RF of the
medulla
â both work together ď â BP
⢠Ang II stimulates â aldosterone
secretion
21
97. Ang II actions
⢠Ang II is a powerful vasoconstrictor
â Ang II also âresetsâ the sensitivity of the
CV regulatory region in the RF of the
medulla
â both work together ď â BP
⢠Ang II stimulates â aldosterone
secretion
â ď â Na+ reabsorption in the distal tubules
21
98. Ang II actions
⢠Ang II is a powerful vasoconstrictor
â Ang II also âresetsâ the sensitivity of the
CV regulatory region in the RF of the
medulla
â both work together ď â BP
⢠Ang II stimulates â aldosterone
secretion
â ď â Na+ reabsorption in the distal tubules
â and â K+ excretion
21
99. Ang II actions
⢠Ang II is a powerful vasoconstrictor
â Ang II also âresetsâ the sensitivity of the
CV regulatory region in the RF of the
medulla
â both work together ď â BP
⢠Ang II stimulates â aldosterone
secretion
â ď â Na+ reabsorption in the distal tubules
â and â K+ excretion
⢠Ang II acts in the hypothalamus ď
thirst 21
112. Maintaining ECF
⢠Maintenance of the ECF operates on:
â concentrations of electrolytes (& water)
â volume of water in plasma & ECF
25
113. Maintaining ECF
⢠Maintenance of the ECF operates on:
â concentrations of electrolytes (& water)
â volume of water in plasma & ECF
⢠Regulation of plasma and ECF
composition depends mainly on:
25
114. Maintaining ECF
⢠Maintenance of the ECF operates on:
â concentrations of electrolytes (& water)
â volume of water in plasma & ECF
⢠Regulation of plasma and ECF
composition depends mainly on:
â kidneys
25
115. Maintaining ECF
⢠Maintenance of the ECF operates on:
â concentrations of electrolytes (& water)
â volume of water in plasma & ECF
⢠Regulation of plasma and ECF
composition depends mainly on:
â kidneys
â but also, thirst
25
116. Maintaining ECF
⢠Maintenance of the ECF operates on:
â concentrations of electrolytes (& water)
â volume of water in plasma & ECF
⢠Regulation of plasma and ECF
composition depends mainly on:
â kidneys
â but also, thirst
⢠Emergency conditions also involve the
cardiovascular system.
25
119. Regulation involved
⢠Renal regulation involves a number of
hormonal and paracrine mechanisms,
â and is therefore somewhat slow
(minutes).
26
120. Regulation involved
⢠Renal regulation involves a number of
hormonal and paracrine mechanisms,
â and is therefore somewhat slow
(minutes).
⢠Cardiovascular reďŹexes respond to
some of the same hormones,
26
121. Regulation involved
⢠Renal regulation involves a number of
hormonal and paracrine mechanisms,
â and is therefore somewhat slow
(minutes).
⢠Cardiovascular reďŹexes respond to
some of the same hormones,
â but also are exquisitely responsive to NS
commands;
26
122. Regulation involved
⢠Renal regulation involves a number of
hormonal and paracrine mechanisms,
â and is therefore somewhat slow
(minutes).
⢠Cardiovascular reďŹexes respond to
some of the same hormones,
â but also are exquisitely responsive to NS
commands;
â fast (seconds)
26
126. Shock
⢠Clinically, shock describes a
condition in which the
cardiovascular system is failing:
â â BP
28
127. Shock
⢠Clinically, shock describes a
condition in which the
cardiovascular system is failing:
â â BP
â HR often â (especially in hypovolemic)
28
128. Shock
⢠Clinically, shock describes a
condition in which the
cardiovascular system is failing:
â â BP
â HR often â (especially in hypovolemic)
⢠It is named by its cause.
(âcardiogenicâ, âhypovolemicâ, etc.)
28
129. Shock
⢠Clinically, shock describes a
condition in which the
cardiovascular system is failing:
â â BP
â HR often â (especially in hypovolemic)
⢠It is named by its cause.
(âcardiogenicâ, âhypovolemicâ, etc.)
⢠It can be life threatening because â
CO ď â tissue perfusion and
damage.
28
130. Shock
⢠Clinically, shock describes a
condition in which the
cardiovascular system is failing:
â â BP
â HR often â (especially in hypovolemic)
⢠It is named by its cause.
(âcardiogenicâ, âhypovolemicâ, etc.)
⢠It can be life threatening because â
CO ď â tissue perfusion and
damage.
28
â ď dangerous positive feedback