1. By: Tengse Kiran A.
(Assistant Professor)
DJPS College of Pharmacy (B. Pharm) Pathri

2. Parts of Urinary System
• 2 kidneys, which secrete urine
• 2 ureters, which convey the urine from the kidneys to
the urinary bladder
• 1 urinary bladder where urine collects and is
temporarily stored
• 1 urethra through which the urine is discharged from
the urinary bladder to the exterior.

3. OVERVIEW OF KIDNEY
FUNCTIONS
 Regulation of blood ionic composition
 Regulation of blood pH
 Regulation of blood volume
 Regulation of blood pressure
 Maintenance of blood osmolarity
 Production of hormones.
 Regulation of blood glucose level
 Excretion of wastes and foreign substances

4. Location & External Anatomy of
Kidneys
Paired reddish, bean shaped organs.
Right kidney is slightly lower than the
 left kidney.
Typical kidney is;
 10-12 cm long
 5-7 cm wide
 3 cm thick
Weight is 135-150 gm
The kidneys are located between the levels of the last thoracic
and third lumbar vertebrae, a position where they are partially
protected by the eleventh and twelfth pairs of ribs

5. Organs Associated with Kideny
Right kidney
 Superiorly— the right adrenal gland
 Anteriorly—the right lobe of the liver, the duodenum
 and the hepatic flexure of the colon
 Posterior—the diaphragm, and muscles of the
 posterior abdominal wall
Left kidney
 Superiorly— the left adrenal gland
 Anteriorly—the spleen, stomach, pancreas, jejunum
 and splenic flexure of the colon
 Posterior—the diaphragm and muscles of the
 posterior abdominal wall

6. External Anatomy of the Kidneys
 The concave medial border of each kidney faces the
vertebral column
 hilus

7. Internal Anatomy of the Kidneys

8. Blood Supply to the kidneys

9. Path of
Blood flow
through
the
Kidney

10. The
Nephron:
Anatomy

11. Nephron
• It is the functional unit of kidneys.
• Each nephron consists of 2 parts.
• Renal corpuscle: Where the blood plasma get filtered
• Renal tubule: Into the filtered fluid passes
Two components of renal corpuscle are the;
Glomerulus (Capillary network)
•
•
• Bowman’s capsule: A double walled epithelial cup that surrounds the
capillary network.
The renal tubule consists of three parts,•
• Proximal convoluted tubule (PCT)
• Loop of Henle (Nephron Loop)
• Distal convoluted tubule (DCT)

12. Types of Nephrons

13. • Cortical nephrons
 ~85% of all nephrons
 Located in the cortex
• Juxtamedullary nephrons
 ~15% of all nephrons
 Located in the medulla

14. Renal corpuscle

15. Renal Corpuscle
• It consists two components:
• Glomerulus: A tuft of capillary loops
• Glomerular (Bowman’s) capsule: It is surrounded by a double
walled cup called as glomerular capsule.
• The blood enters a glomerulus through afferent arteriole and exits
through an efferent arteriole.
• The outer layer of glomerular capsule is called as parietal layer and
inner layer is called as visceral layer. And the space between them is
called as capsular space.
• As blood flows through the glomerular capillaries, water & other
solutes filter into the capsular space.
• Large plasma proteins & formed elements in blood do not normally
passes through it.
• From the capsular space the filtered fluid passes into the renal tubule.

16. Renal tubule
• Proximal convoluted tubule
(PCT)-
• Actively reabsorbs water,
nutrients, plasma proteins & ions
from filtrate
•
• Released into peritubular fluid
Loop of Henle-
• Descending limb
Ascending limb•
• Each limb has a thick and thin
section
• Distal convoluted tubule
(DCT)-
and drugs into filtrate
• Actively secretes ions, toxins,
• Reabsorbs sodium ions from
tubular fluid Collecting tubules- Receive urine
from DCT

17. Nephron –Functional Unit of Kidney

18. Physiology of Urine Formation

20. GLOMERULAR FILTRATION
 Glomerular filtrate
 On average, the daily volume of glomerular filtrate in
adults is 150 liters in females and 180 liters in
males.
 More than 99% of the glomerular filtrate returns to the
bloodstream via tubular reabsorption, so only 1–2 liters
(about 1–2 qt) is excreted as urine.

21.  The Filtration Membrane
 Together, the glomerular capillaries and the
podocytes, which completely encircle the
capillaries, form a leaky barrier known as the
filtration membrane.
1.Glomerular endothelial cells are quite leaky
because they have large fenestrations that
measure 0.07–0.1 micron in diameter.
2. The basal lamina, a layer of acellular
material between the endothelium and the
podocytes, consists of minute collagen fibers and
proteoglycans in a glycoprotein matrix

22.  3.Slit membrane between pedicels: prevents
filtration of medium-sized proteins; it permits the
passage of molecules having a diameter smaller than 0.006–
0.007 micron.
e.g. water, glucose, vitamins, amino acids, very
small plasma proteins, ammonia, urea, and ions

25. The principle of filtration
 Three principles are there
1. capillaries provides a large surface area
2. The filtration membrane is thin and porous : 50
times leakier capillaries than the other tissues
3. Glomerular capillary blood pressure is high :

26. Net Filtration Pressure
 Three main different kinds of pressures exerted in glomerulus and
the bowman's capsule.
1 Glomerular blood hydrostatic pressure (GBHP) is the
blood pressure in glomerular capillaries. 55 mmHg. It promotes
filtration by forcing water and solutes in blood plasma through the
filtration membrane.
2 Capsular hydrostatic pressure (CHP) is the hydrostatic
pressure exerted against the filtration membrane by fluid already in
the capsular space and renal tubule. CHP opposes filtration and
represents a “back pressure” of about 15 mmHg.
3 Blood colloid osmotic pressure (BCOP),
which is due to the presence of proteins such as albumin, globulins,
and fibrinogen in blood plasma, also opposes filtration. The average
BCOP in glomerular capillaries is 30 mmHg.

28. Glomerular Filtration Rate
 The amount of filtrate formed in all the renal
corpuscles of both kidneys each minute is the
glomerular filtration rate (GFR).
In adults male :125 mL/min
and 105 mL/min in females.

29. Control GFR
 Three mechanisms control GFR:
1. Renal autoregulation.
2. Neural regulation: By Sympathetic division-
Vasoconstriction
3. Hormonal regulation:
1. Angiotensin II: vasoconstrictor
2. Atrial Natriuretic Peptide (ANP) :

30. TUBULAR REABSORPTION
AND TUBULAR SECRETION
 Reabsorption
routes:
paracellular
reabsorption
and
transcellular
reabsorption.

31. Reabsorption of
glucose by Na–
glucose
symporters in cells
of the proximal
convoluted tubule
(PCT).
(Normally, all filtered
glucose is reabsorbed
in the PCT.)

32. Actions of
Na+/H+
antiporters in
proximal
convoluted
tubule cells.

33. HCO3
– reabsorption

34.  Passive
reabsorption
of Cl-, K+,
Ca2+, Mg2+,
urea, and
water in the
second half
of the
proximal
convoluted
tubule.

35. Na+K+2Cl- symporter in the thick
ascending limb of the loop of Henle.

36.  Reabsorption
of Na+ and
secretion of
K+ by
principal cells
in the last part
of the distal
convoluted
tubule and in
the collecting
duct

37. Hormonal Regulation of Tubular Reabsorption
and Tubular Secretion
 Renin–Angiotensin–Aldosterone System
 Atrial Natriuretic Peptide
 Parathyroid Hormone
 Antidiuretic hormone

39. URETERS
 The ureters are the tubes that convey urine from the
kidneys to the urinary bladder.
 They are about 25 to 30 cm long with a diameter of about
3 mm.
 It passes downwards through the abdominal cavity,
behind the peritoneum into the pelvic cavity, and passes
obliquely through the posterior wall of the bladder.

41. Structure
The ureters consist of three layers of tissue:
1. outer covering of fibrous tissue, continuous with
the fibrous capsule of the kidney
2. a middle muscular layer consisting of interlacing
smooth muscle fibres
3. an inner layer, the mucosa, lined with transitional
epithelium.
Function
ureters propel the urine from the kidneys into the
bladder by peristaltic contraction of the smooth
muscle

42. URINARY BLADDER

43. Structure

44.  Urine reserviour
 Rugae
 The bladder is distensible but when it contains 300 to
400 ml the awareness of the desire to urinate is
initiated. The total capacity is rarely more than about
600 ml.
 Trigone
 The female urethra is approximately 4 cm long.

45.  Its walls consist of three layers of tissue
1. Mucosa
2. Muscular layer: Detrusor Muscles
3. Outer layer of connective tissues contains blood
vessels, lymphatic vessels and nerves

46. Urethra
 The urethra is a canal extending from the neck of the
bladder.
 Its length differs in the male and in the female.
 Its walls consist of three layers of tissue
1.muscle layer,
2. submucosa
3. mucosa

47. MICTURITION Reflex
 Discharge of urine from the urinary bladder, called
micturition is also known as urination or voiding.
 Micturition occurs via a combination of involuntary and
voluntary muscle contractions.
 Although emptying of the urinary bladder is a reflex, in
early childhood we learn to initiate it and stop it
voluntarily

48. Simple reflex
control of
micturition
when conscious
effort cannot
override the
reflex action

49. Control of micturition
when conscious effort
overrides the reflex
action

50. Role of
RAS in
kidney

51. Role of kidneys in acid base
balance
 Kidney plays an important role in maintenance of
acidbase balance by excreting hydrogen ions and
retaining bicarbonate ions. Normally, urine is acidic in
nature with a pH of 4.5 to 6. Metabolic activities in the
body produce large quantity of acids (with lot of
hydrogen ions), which threaten to push the body
towards acidosis.
 However, kidneys prevent this by two ways:
1. Reabsorption of bicarbonate ions (HCO3–)
2. Secretion of hydrogen ions (H+).

52. Secretion of H+ occurs by two pumps:
i. Sodium-hydrogen antiport pump
ii. ATP-driven proton pump.

53. 1. SODIUM-
HYDROGE
N
ANTIPORT
PUMP

54. Excretion of H+ occurs by three mechanisms:
1. Bicarbonate mechanism
2. Phosphate mechanism
3. Ammonia mechanism.

55. Bicarbonate
mechanism

56. Phosphate Mechanism

57. Ammonia mechanism

58. Composition of Urine
 95% of volume of normal urine is due to Water
Organic Components
 Urea
 Urobilinogen
 Uric acid
 Creatinine
 Amino acids
 Metabolites of harmone
Inorganic Components
Cations: Na+, K+, Ca2+, NH4+
Anions : Cl-, SO4-, HCO3-, HPO4-

59. Disorders of Kideny
Renal Calculi
The crystals of salts present in urine occasionally
precipitate and solidify into insoluble stones called
renal calculi or kidney stones.
 They commonly contain crystals of calcium oxalate,
uric acid, or calcium phosphate
 Conditions leading to calculus formation are:
1. ingestion of excessive calcium,
2. low water intake,
3. abnormally alkaline or acidic urine, and
4. overactivity of the parathyroid glands.
 Shock-wave lithotripsy treatment

60. Glomerulonephritis:
 Inflammatory conditions of the glomerulus
 Effects of glomerulonephritis
Haematuria
Asymptomatic proteinuria
Nephrotic syndrome
Chronic renal failure

61. Urinary Tract Infections
 The term urinary tract infection (UTI) is used to
describe either an infection of a part of the urinary
system or the presence of large numbers of microbes
in urine.
 more common in females due to the shorter length of
the urethra
 Symptoms
painful or burning urination, urgent and frequent
urination, low back pain, and bed wetting
UTIs include -
Urethritis
Cystitis
Pyelonephritis

62.  Renal Failure
 Renal failure is a decrease or cessation of glomerular
filtration.
1.In acute renal failure (ARF), the kidneys abruptly
stop working entirely (or almost entirely).
The main feature of ARF is the suppression of urine
flow, usually characterized either by oliguria -daily
urine output between 50 mL and 250 mL, or by anuria
daily urine output less than 50 mL.
2. Chronic renal failure (CRF) refers to a progressive
and usually irreversible decline in glomerular filtration
rate (GFR).

63. CRF develops in three stages.
1. In the first stage, diminished renal reserve,
nephrons are destroyed until about 75% of the
functioning nephrons are lost.
no signs or symptoms
2. The person enters the second stage once 75% of the
nephrons are lost, called renal insufficiency decrease
GFR and increased blood levels of nitrogen-containing
wastes and creatinine.
3. The final stage, called end-stage renal failure,
occurs when about 90% of the nephrons have been
lost.
need dialysis therapy or kidney transplant
operation

64.  Urinary Bladder Cancer
 About half of all cases occur in people who smoke or
have at some time smoked cigarettes

65. THANK YOU!!!