The urinary system, components, the urine formation process, The gross structure of the kidney, Microscope structure of the kidney, Renin-Angiotensin Aldosterone System

1. The Urinary System
Prepared by,
Mr. Abhay Shripad Joshi
Assistant Professor
Yash Institute of Pharmacy, Aurangabad
abhay.joshirss@gmail.com
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2. Objectives
• Definition
• Functions of Urinary system
• Components of Urinary system
• Gross structure of Kidney
• Microscopic structure of kidney
• Process of urine formation
• Renin Angiotensin Aldosterone System (RAAS)
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3. Expected Outcomes
After the lecture the students able to explain
• Functions of Urinary system
• Components of Urinary system
• Gross structure of Kidney
• Microscopic structure of kidney
• Process of urine formation
• Renin Angiotensin Aldosterone System (RAAS)
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4. Definition
• The urinary system is the main
excretory system of the body, which
expel the waste and excess material
from the body.
• The Urinary system is also known as
Excretory system or Renal system.
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5. Functions of Urinary system
• Maintaining homeostasis of water &
electrolyte concentration.
• Excretion of metabolic waste material from
the body in the from of urine.
• Excretion of nitrogenous compounds urea and
uric acid.
• Excretion of excess ions and some drugs.
• Maintain acid-base balance.
• Production & secretion of erythropoietin.
• Production & secretion of Renin. 5

6. Components of Urinary system
• 2 kidneys, which
secrets urine.
• 2 Ureters, which
transport urine from
kidney to urinary
bladder.
• The Urinary bladder,
where urine collects
and temporarily stored.
• The urethra, through
which the urine is
discharged .
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7. • Location: The kidneys lie on the posterior
abdominal wall, one each side of the vertebral
column, behind the peritoneum and below
the diaphragm.
• The right kidney is usually slightly lower than
the left.
• Kidney is bean-shaped organ, about 11cm
long, 6cm wide, 3cm thick and weigh 150gms.
The Kidney
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8. Gross structure of Kidney
• The longitudinal section of the
kidney shows the three areas
of tissue.
1. A fibrous capsule, surrounding
the kidney.
2. The cortex, a reddish brown
layer of tissue immediately
below the capsule & outside
the pyramids.
3. The medulla, the innermost
layer, consisting of pale
conical-shaped striations, the
renal pyramids.
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9. Microscopic structure of Kidney
• Nephrons is the smallest functional unit of the
kidney.
• The kidney is composed of about 1 million
functional units, the nephrons & a smaller
number of collecting ducts transports urine
through the pyramids to the renal pelvis.
• The tubules are surrounded by a small amount
of connective tissue, containing blood vessels,
nerve and lymph vessels.
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10. The Nephron
• The nephron consist of a tubule closed at one
end and other end opens in collecting tubule.
• The closed end is intended to form the cup-
shaped glomerular capsule is also known as
Bowman’s capsule.
• From the Bowman’s capsule the remainder of the
nephron is about 3cm long and described in 3
parts
1. The proximal convulated tubule (PCT)
2. The medullary loop (Loop of Henle)
3. The distal convulated tubule (DCT)
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11. The nephron
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12. The process of urine formation
• The main function of kidney is formation of
urine and it is divided in to 3 process.
1.Filtration
2.Selective reabsorption
3.Secretion
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13. The process of urine formation
1. Filtration (Glomerular filtration):
• Beginning of the process
• A process by which the blood courses
through the glomeruli, much of its
fluid, contain both useful chemicals
and dissolve waste materials, soaks
out the blood through membranes
where it is filtered and then flows into
Bowman’s capsule
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14. Continue…
• Filtration is assisted by the difference between
the blood pressure in the glomerulus and the
pressure of the filtrate in the glomerular
capsule.
• The volume of the filtrate formed by both
kidneys each minute is called Glomerular
Filtration Rate (GFR).
• In healthy adult the GFR is about 125 ml/min
i.e. 180 lit./day by both kidney in one day.
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15. The process of urine formation
2. Selective reabsorption:
• A movement of substances out of the renal
tubules back into the blood capillaries
located around the tubules (peritubular
capillaries.
• Some constituents of glomerular filtrate
(e.g. glucose, amino acids) do not
normally appears in the urine because
they are completely reabsorbed unless
blood levels are excessive.
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16. Continue…
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17. Tubular Secretion
• disposing of substances not already in the
filtrate (drugs)
• eliminating undesirable substances that have
been reabsorbed by passive processes (urea
and uric acid)
• ridding the body of excess potassium ions
• By secretion of hydrogen ions for controlling
blood pH.
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18. Composition of Urine
• Water 96%
• Urea 2%
• Uric acid
• Creatinine
• Ammonia
• Sodium
• Potassium 2%
• Chlorides
• Phosphates
• Sulphates
• Oxalates
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19. Renin Angiotensin Aldosterone
System (RAAS)
• The RAAS is a hormonal system.
• Regulate the blood pressure and
fluid balance
• This system involves the kidney,
liver and lungs.
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20. Renin Angiotensin Aldosterone
System (RAAS)
• There are some important factors which
involved in RAAS.
• Renin
• Angiotensinogen
• Angiotensin I
• Angiotensin II
• Aldosteron
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21. Renin Angiotensin Aldosterone System
(RAAS)
• RENIN
• It is released from kidney.
• Hydrolyses angiotensinogen
• Converts the plasma protein
angiotensinogen to angiotensin.
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22. FACTTORS AFFECTING RENIN RELEASE
Increased by:
• Decreased arterial BP.
• Decreased BP in
glomerular vessels.
• Increased loss of sodium
& water.
• Increased sympathetic
activity.
Decreased by:
• Sodium water retention
• Increased BP
• Activation of AT1
receptors
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23. Renin Angiotensin Aldosterone System
(RAAS)
• ANGIOTENSINOGEN
• Produced and released by liver
• Levels increased by corticosteroid,
estrogen and thyroid hormone
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24. Renin Angiotensin Aldosterone System
(RAAS)
• ANGIOTENSIN I :
• Produced in the kidney through
action of renin on angiotensinogen
• Has no biological activity
• Precursor to angiotensin
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25. Renin Angiotensin Aldosterone System
(RAAS)
• ANGIOTESIN II:
• Produced by ACE in lungs
• Main hormone responsible for increase
in blood pressure
• Stimulates Na reabsorption and h+
secretion in proximal tubules of kidney
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26. Renin Angiotensin Aldosterone System (RAAS)
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27. Renin Angiotensin Aldosterone System
(RAAS)
• ANGIOTENSIN III:
• Has 40% activity of angiotensinII
• Has aldosterone producing activity
• Causes increase in mean arterial blood
pressure
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28. Renin Angiotensin Aldosterone System
(RAAS)
• Angiotensin converting enzyme (ACE):
• Acts in the lungs.
• Catalyses conversion of angiotesin1 to
angiotensin2.
• Degrades bradykinin to other vasoactive
peptides.
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29. Renin Angiotensin Aldosterone System (RAAS)
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