2. Types of regulation of kidney
functioning
regulation of
kidney functioning
nervous
regulation
filtration
processes
Sympathetic
system
decrease in urine output
(diuresis)
Humoral
regulation
reabsorption
processes
Parasympathetic system
Increased urine output (decreased
absorption of chlorides)
cerebral
cortex
hypothalamus
centers of
ANS
3.
4. NERVOUS REGULATION OF
KIDNEY FUNCTION
• The central nervous system regulates the work of the kidneys
either directly through the autonomic nerves (sympathetic and
parasympathetic), or through the neurons of the hypothalamus,
altering the secretion of hormones.
• This shows the unity of the nervous and humoral regulation.
• A decrease or increase in diuresis can be caused by a
conditioned reflex pathway (the influence of the cerebral
cortex).
5. NERVOUS REGULATION OF
KIDNEY FUNCTION
• When the sympathetic nerves that innervate the kidneys are irritated, the
renal vessels are narrowed.
• If the afferent arteriole has undergone a narrowing, then the filtration
pressure in the glomeruli decreases and a corresponding decrease in the
filtration of primary urine occurs.
• If the efferent arteriole has undergone a narrowing, then the filtration
pressure in the glomeruli increases and a corresponding increase in the
filtration of primary urine occurs.
• When the parasympathetic nerves are irritated, the excretion of urine and
sodium ions increases by reducing their reabsorption in the kidney tubules.
6. Painful anuria
• With painful irritations, diuresis reflexively decreases (painful
anuria).
• The mechanism is a narrowing of the renal vessels as a result
of excitation of the sympathetic nervous system, increased
secretion of catecholamines by the adrenal glands and an
increase in the production of ADH (vasopressin) by the
supraoptic nucleus of the hypothalamus.
• ADH is secreted into the blood and increases the reabsorption
of water by the walls of the end parts of the distal segment and
collecting tubes.
7. HUMORAL REGULATION
• ADH interacts with the receptors of cells in the end parts of the distal
segment and collecting ducts.
• With the participation of G-proteins, the enzyme AC (adenylate cyclase) is
activated and cAMP (cyclic adenosine monophosphate )
is formed from ATP.
• cAMP promotes the activation of the enzyme hyaluronidase.
• Hyaluronidase depolymerizes hyaluronic acid, which is part of the
intercellular substance of the distal segment walls and collecting ducts, as a
result of which the walls become porous and allow water to pass through.
• With a lack of ADH - polyuria ("diabetes insipidus“ ): the release of a
large amount of light, unconcentrated urine (up to 20-25 liters per day).
• With an excess of ADH - oliguria, up to anuria.
8. Mechanism of action of ADH
ADH tubular epithelial
membrane receptor
ATP
AC activation
Formation of c AMP
Hyaluronidase activation
breakdown of
hyaluronic acid
in the
intercellular
spaces
Increasing of permeability for Н2О
9. HUMORAL REGULATION
• Aldosterone increases the reabsorption of sodium ions and the
secretion of potassium ions by the cells of the renal tubules. At
the same time, the reabsorption of water increases, which is
absorbed passively along the osmotic gradient created by
sodium ions, which leads to a decrease in diuresis.
• Atrial natriuretic hormone (ANP) reduces sodium and water
reabsorption, increases urine output.
• Thyroxine increases urine output by enhancing metabolic
processes and reducing the binding of water and salts by
tissues, causing them to pass into the blood.
10. The process of urination
The urine formed in the renal tubules is excreted into the renal calyx,
and then, in the systole phase of the renal calyx, emptying into the
renal pelvis occurs. The latter is gradually filled with urine, and when
the stimulation threshold is reached, impulses from baroreceptors
arise, the musculature of the renal pelvis contracts, the lumen of the
ureter opens, and urine, due to the contractions of its wall, moves into
the bladder.
sympathetic nerves
bladder
external sphincter
Parasympathetic
nerves
11.
12. Urinary excretion
• The bladder is a hollow, smooth muscle organ.
• When filling, the bladder can increase its volume without a noticeable
increase in the tension of its walls - a property of plastic tone.
• Therefore, the pressure in the bladder increases in proportion to the
amount of urine that has entered it.
• As the bladder fills, the pressure in it does not change at first, and then
increases quite sharply.
• The first urge to urinate appears when 150 ml of urine accumulates in the
bladder.
• An increased flow of impulses occurs with an increase in the volume of
urine to 200-300 ml.
13. Urinary excretion
• This is a complex reflex act.
• There is a simultaneous contraction of the bladder, relaxation
of the sphincter vesicae and sphincter uretrae.
• Spinal urinary center - SII - SIY.
• This center is influenced by impulses coming from the centers
of the medulla oblongata and midbrain, as well as from the
cerebral cortex.
• Cortical control of urination is manifested in the retention,
intensification or even voluntary induction of urination.
14. Regulation of the ureters and bladder
ANS
Sympathetic Division
Sympathetic hypogastric
fibers
Increased
peristalsis of the
ureters
Wall
relaxation
Accumulation
of urine
Increased tone of
the sphincter
Parasympathetic Division
Parasympathetic pelvic fibers
Relaxation of
the sphincters
Wall
contraction
The expulsion of
urine
15. INFLUENCE OFANS ON URINARY
• Sympathetic impulses:
• increase the peristalsis of the ureters,
• inhibit tonic contraction of the bladder walls, causing it to
relax,
• increase the tone of the sphincter vesicae.
• The sympathetic nerves create the conditions for the filling of
the bladder.
16. INFLUENCE OF ANS ON URINARY
• Parasympathetic impulses:
• stimulate contractions of the muscles of the bladder
(m.detrusor vesicae),
• relax the sphincter vesicae.
• The parasympathetic nerves create the conditions for the
emptying of the bladder.
• The action of the parasympathetic system on the urinary tract
is opposite to the action of the sympathetic system.
