Renal System
The goal of these lectures is to discuss
basic renal physiology. This lecture will
present the regulation of H and Ca ions
as well as discuss the hormonal and
neural regulation of renal function. The sections for this lecture are:
Regulation of H and Ca ions
Hydrogen ions and homeostatic control, integration
Metabolic and respiratory acidosis / alkalosis, integration
Effectors for Ca homeostasis, sites and hormonal control Calcium related metabolic bone diseases, integration
Hormonal and neural control of renal function 17
Life is a series of chemical reactions occurring in
compartmentalized environments.
The main purpose of life is to keep itself alive
Physiology, the study of how life works, is based on
the simultaneous occurrence of the following three
concepts:
levels of organization
structure / function relationship
homeostatic regulation
Renal System
levels of
organization
structure
- function
homeostatic
regulation
1
Renal System
what it actually is (info from
feedback), is compared with what it
should be (info from set-point) in a …
Homeostasis, or constancy
of the internal environment,
is needed for chemical
reactions underlying life
to occur. It is maintained,
predominantly, through
negative feedback
mechanisms
S
comparator /
integrator
E
effect
error signal
amplification
effectors mechanism
integrators compare what it should be with what it actually is and generate an error signal
Renal System
Homeostatic
Control
central integration center
efferent
afferent
S
E
receptor
effector
negative feedback signal
integrators compare what it should be with what it actually is and generate an error signal
2
Renal System
systemic
blood
pressure
BLOOD
extrinsic
control
ADH
ALD
autoregulation
valves
FF
GFR
1
GLOM
BLOOD
S
PCT
2
3
4
5
HL JGA/MD
DCT
CD
1 reabsorption / secretion
2 concentration
3 sensors
4 solute rectifier
5 water rectifier
URINE
E
receptor
Renal System
Introduction, first lecture
Nephron structure and functions
Diabetes (mellitus vs insipidus), diuretics,
renal disease, previous lecture
Filtration, reabsorption and secretion
Clearance (inulin, glucose, PAH, creatinin)
Micturition, control of bladder input / output
sphincters
Regulation of hydrogen ions and calcium
ions, this lecture
Hydrogen ions and homeostatic control,
integration
Metabolic and respiratory acidosis/alkalosis,
integration
Basic renal regulation, previous lecture
Balance of Na / H2O and countercurrent mechanism
Renal Na / K regulation, aldosterone and the RA
system
Renal H2O regulation, baro / osmo receptors
and AVP
Effectors for Ca homeostasis, sites &
hormonal control Calcium related signal transduction, bone
diseases, integration
Hormonal and neural control of renal
function, this lecture
3
Renal System
Sources of Hydrogen Ion Gain or Loss
Regulation
Hydrogen ions and
homeostatic control,
integration
(chloride shift)
Metabolic and respiratory
acidosis/alkalosis,
integration
Effectors for Ca
homeostasis, sites &
hormonal control Calcium related signal
transduction, bone
diseases, integration
(from the respiration lectures)
4
Regulation
Hydrogen ions and
homeostatic control,
integration
Metabolic and respiratory
acidosis/alkalosis,
integration
Effectors for Ca
homeostasis, sites &
hormonal control Calcium related signal
transduction, bone
diseases, integration
(from the respiration lectures)
Regulation
Hydrogen ions and
homeostatic control,
integration
Metabolic and respiratory
acidosis/alkalosis,
integration
HC03HP042NH3
Effectors for Ca
homeostasis, sites &
hormonal control Calcium related signal
transduction, bone
diseases, integration
5
Regulation
Hydrogen ions and
homeostatic control,
integration
Metabolic and respiratory
acidosis/alkalosis,
integration
Effectors for Ca
homeostasis, sites &
hormonal control Calcium related signal
transduction, bone
diseases, integration
Regulation
Hydrogen ions and
homeostatic control,
integration
1, respiratory acidosis
2, respiratory alkalosis
3, metabolic acidosis
4, metabolic alkalosis
PCO2
40
mmHg
20
mmHg
Metabolic and respiratory
acidosis/alkalosis,
integration
Effectors for Ca
homeostasis, sites &
hormonal control 60
mmHg
4
1
HCO3
24
Calcium related signal
transduction, bone
diseases, integration
2
3
pH = pK + log
7.2
7.4
HCO3
PCO2
7.6
pH
6
Regulation
1, respiratory acidosis
2, respiratory alkalosis
3, metabolic acidosis
4, metabolic alkalosis
Hydrogen ions and
homeostatic control,
integration
60
mmHg
PCO2
40
mmHg
20
mmHg
Metabolic and respiratory
acidosis/alkalosis,
integration
4
1
Effectors for Ca
Change
in Arterial
homeostasis,
sites level
&
hormonal
control
of H, HCO3 and CO2
HCO3
24
Calcium related signal
transduction, bone
diseases, integration
2
3
pH = pK + log
7.2
7.4
HCO3
PCO2
7.6
pH
Regulation
Hydrogen ions and
homeostatic control,
integration
Renal Response
to Acidosis and to Alkalosis
Metabolic and respiratory
acidosis/alkalosis,
integration
Effectors for Ca
homeostasis, sites &
hormonal control Calcium related signal
transduction, bone
diseases, integration
7
Regulation
Hydrogen ions and
homeostatic control,
integration
Metabolic and respiratory
acidosis/alkalosis,
integration
Effectors for Ca
homeostasis, sites &
hormonal control Calcium related signal
transduction, bone
diseases, integration
Regulation
Hydrogen ions and
homeostatic control,
integration
Metabolic and respiratory
acidosis/alkalosis,
integration
Effectors for Ca
homeostasis, sites &
hormonal control Calcium related signal
transduction, bone
diseases, integration
8
Regulation
Hydrogen ions and
homeostatic control,
integration
Metabolic and respiratory
acidosis/alkalosis,
integration
Effectors for Ca
homeostasis, sites &
hormonal control Calcium related signal
transduction, bone
diseases, integration
Regulation
Hydrogen ions and
homeostatic control,
integration
Metabolic and respiratory
acidosis/alkalosis,
integration
Effectors for Ca
homeostasis, sites &
hormonal control Calcium related signal
transduction, bone
diseases, integration
PTH increases blood Ca and Calcitonin decreases it
Vit. D
PTH
blood
Ca
calcitonin
calcitonin
calcitonin
PTH
bone
intestine
kidney
9
Regulation
Hydrogen ions and
homeostatic control,
integration
PTH increases blood Ca and Calcitonin decreases it
blood Ca
Calcitonin r
decrease
Gs /
bone formation, osteoblast
AC
kidney, Ca filtration
intestine, Ca secretion
Metabolic and respiratory
acidosis/alkalosis,
integration
Effectors for Ca
homeostasis, sites &
hormonal control Calcium related signal
transduction, bone
diseases, integration
receptor
Calcitonin
parathyroid gland thyroid gland
PTH
receptor
bone resorption, osteoclast
kidney, Ca reabsorption, Vit. D
intestine, Ca absorption
PTHr
Gs / AC
Gq / PLC
blood Ca
increase
Control of renal function
systemic
blood
pressure
BLOOD
extrinsic
control
ADH
ALD
autoregulation
valves
FF
GFR
1
Mechanism of action
Renin is a protein
Angiotensin is a peptide
Aldosterone is a steroid
ANP = ANF is a peptide
Sympathetic ANS
AVP = ADH is a peptide
GLOM
BLOOD
PCT
2
3
4
5
HL JGA/MD
DCT
CD
1 reabsorption / secretion
2 concentration
3 sensors
4 solute rectifier
5 water rectifier
URINE
10
Control of renal function
11