For D.Pharm students

1. URINARY SYSTEM
• ONE OF THE SYSTEM THAT
CONTRIBUTES HEMOSTASIS
• THIS SYSTEM REGULATES BLOOD
PLASMA COMPOSTION THROUGH
CONTROLLED EXCRETION OF
ORGANIC WASTES, SALTS & WATER

2. COMPONENTS OF URINARY
SYSTEM
• 2 kidneys, which secrete urine
• 2 ureters, which convey the urine from the
kidneys to
• urinary bladder where urine collects and is
temporarily stored
• 1 urethra through which the urine is
discharged from the urinary bladder to the
exterior.

4. KIDNEYS
• Paired, reddish, bean
shaped organ
• Lies on posterior
abdominal wall one
on each side of
vertebral column
• Right kidney is slightly
lower than left
• Each-10-12 cm long,
5-7 cm wide, 3 cm
thick weighs about
1300150 gm

5. External anatomy of kidneys
• Renal Hilum- fissure
• 3 layers of tissue surrounds
1. Renal capsule- immermost, smooth
transparent sheet of dense irregular tissue,
continuous with outer layer of ureters.
2. Adipose capsule- mass of adipose tissue,
surrounding renal capsule. It holds it firmly in
place within abdominal cavity
3. Renal Fascia -outer, thin layer of dense
irregular c.t. It anchors kidneys to surrounding
structures & to abdominal wall

6. Internal Anatomy of Kidney

7. RENAL CORTEX
-Superficial, smooth,
reddish area
-extend from renal
capsule to bases of
renal pyramid
-divided into outer
cortical zone & inner
juxtamedullary zone
-portions that extend
bet. Renal pyramids
called renal column
RENAL MEDULLA
-Deep, Reddish Brown
Region
-Consists Of 8-12 Cone
Shaped Renal
Pyramid
-Apex of pyramid-papilla
• Renal Lobe: Renal
cortex, renal pyramid
& one-half of each
adjacent renal column

8. • The renal pelvis is the funnel-shaped
structure which acts as a receptacle for
the urine formed by the kidney. It has a
number of distal branches called calyces,
each of which surrounds the apex of a
renal pyramid
• Urine formed in the kidney passes through
a papilla at the apex of a pyramid into a
minor calyx, then into a major calyx
before passing through the pelvis into the
ureter.

9. Microscopic Structure of Kidneys
The kidney is
composed of
about 1 million
functional units,
the nephrons,
and a smaller
number of collecting
tubules.

10. NEPHRON
RENAL CORPUSCLE RENAL TUBULE
Glomerulus Glomerular Proximal
(Capillary (Bowman’s Convoluted
Network) Capsule) Tubule
Loop of Henle
Distal
Convoluted
Tubule

11. Cortical Nephrons
(80-85%)
-Renal corpuscles lie in
outer portion of cortex
-have short loop of
Henle & lie mainly in
cortex
-Ascending limb of loop
of Henle has only
thick ascending limb
Juxtamedullary
Nephrons (15-20%)
-Renal corpuscles lie in
the deep cortex, near
to medulla
-have long loop of
Henle that extend into
deepest region of
medulla
-Ascending loop of
Henle has 2 portions:
Thin ascending limb &
Thick ascending limb

12. Histology of Nephron
• Glomerular Capsule:
-Inner visceral layer of modified simple
squamous epithelium-Podocytes- a cell
with thousands foot like projections wrap
endothelial cells of glomerulus.
-Outer parietal layer of simple squamous
epithelium
-Bowman’s / Capsular space: space
between two layers, Fluid filtered from
glomerular capillaries enters this space

14. • Proximal Convoluted Tubule-Simple
cuboidal epithelial cells with microvillus
• Loop of Henle: Descending limb & thin
ascending limb-Simple Squamous
Epithelial cells
• Loop of Henle: Thick ascending limb-
Simple Cuboidal to Columnar epithelial
cells
• Most of Distal convoluted tubule- Simple
Cuboidal epithelial Cells
• Last part of DCT & all of collecting duct-
Simple Cuboidal epithelial cells

15. RENAL PHYSIOLOGY
Formation of Urine- Nephrons & collecting
ducts perform 3 basic processes to
produce urine
1. Golmerular Filtration Renal Capsule
2. Tubular Reabsorption Renal tubule &
3. Tubular Secretion Collecting duct
For any substance ‘S’ excretion rate=
Filtration rate of ‘S’ – Reabsorption rate
of ‘S’ + Secretion rate of ‘S’

16. Golmerular Filtration
On average ,
daily volume of
glomerular
filtrate is 150
liters in female,
180 liters in
male
GFR- the volume of fluid filtered
in all Bowmann Capsules of both
kidneys each minute is GFR
GFR – 125 ml / min in male
105 ml / min in female

17. Tubular Reabsorption
• A process f returning of most of filtered
water & solutes to bloodstream
• About 99% of filtered water is reabsorbed
• Proximal convoluted tubule makes largest
contribution
• Solutes are reabsorbed by both active &
passive processes
• It includes glucose, amino acids, urea &
ions –Na+
,K+
,Ca++
,Cl-
,HCO3
-
, HPO4
--

18. • Some solutes are completely reabsorbed,
unless they are present in blood in
excessive amount. E.g. Glucose
• Reabsorption of some solutes is regulated
by hormones:
-Parathormone & Calcitonin- Calcium &
Phosphate
-ADH- Water
-Aldosterone - Na+
, K+
• Urea & uric acid are reabsorbed only to
slight extent
• Creatinine is not absorbed at all

19. Tubular Secretion
• It is process of transfer of substances from
blood & tubule cells into tubular fluid.
• Process takes place in proximal
convoluted tubule & collecting duct only
• Secreted substances include H+
, K+
,NH4
+
,
Creatinine & certain drugs

20. Kidney controls urine output &
maintain water balance by 3 ways
ANTI-DIURETIC HORMONE
Increased blood osmotic pressure
Osmoreceptors in hypothalamus
Stimulation of post.Pituitary Release of ADH
promotes Reabsorption of water
Reduces loss of water in urine
(reduced blood osmotic pressure)

21. ALDOSTERONE
Decrease in blood volume & pressure
Secretion of Renin by Kidneys
Angiotensinogen Angiotensin I
Angiotensin II Stimulation of Adrenal
Cortex release of aldosterone
Promotes urinary reabsorption of Na+ & Cl- ;
simultaneously increases water reabsorption via
osmosis
Reduces loss of water in urine

22. ATRIAL NATRIURETIC PEPTIDE
Increased blood volume
Secretion of ANP by atria of heart
Reduces Reabsorption of Na+
, Cl-
by
Kidneys Promotes natriuresis,
increased urinary excretion of Na+
, Cl-
Increases loss of water in urine via osmosis

23. Composition of Urine:
Water-96%, Urea-2% & remaining solutes-
2% which includes uric acid, Creatinine, sodium,
potassium, chlorides, phosphates, sulphates,
oxalates, ammonia.
Abnormal constituents of Urine:
Albumin- permeability of glomerulus
Glucose- Dibetes
Ketone bodies-ketoneurea-Diabetes,
starvation, anorexia
RBC- hematuria
Microbes- infection of Urinary Tract

24. Kidney Functions
• Regulation of blood ionic composition:
Kidneys help regulate blood level of
several ions, most importantly Na+
, Ca++
, Cl-
& PO4
—
• Regulation of blood pH: Kidneys excrete
variable amount oh H+
ions into urine and
conserve HCO3 ions, which are buffer for
H+
in blood
• Regulation of blood volume: Kidneys
adjust volume by conserving or eliminating
water in urine

25. • Regulation of blood pressure: Kidneys
help regulate blood pressure by secreting
enzyme renin, which activates RAA
pathway
• Maintenance of blood osmolarity: By
separately regulating loss of solutes in the
urine, kidneys maintain relatively constant
blood osmolarity close to 300 mOsm/L
• Production of hormones: Calcitriol, the
active form of vit. D, helps regulate
calcium and Erythropoetin stimulates
production of red blood cells.

26. • Regulation of blood glucose level: Like
liver, kidneys can use amino acid
glutamine in gluconeogenesis. It release
glucose into blood to help maintain normal
blood glucose level
• Excretion of wastes & foreign
substances: By forming urine, kidneys
excrete wastes- substances that have no
useful function in body. These include
ammonia, urea, bilirubin, creatinine & uric
acid.Foreign substances such as
metabolites of drugs and environmental
toxins are excreted

27. URETERS
• Each ureter is
continuation of renal
pelvis
• 25-30 cm long,
• diameter of about 3 mm
• At the base of
urinary Bladder, ureters
curve medially &
pass obliquely through
wall of bladder

28. As urinary bladder fills with
urine, pressure within it
compresses oblique openings
prevents back flow
-Consists of 3 layers of tissue:
• an outer covering of fibrous
tissue, continuous with the
fibrous capsule of the kidney
• a middle muscular layer
consisting of inner longitudinal &
outer circular smooth muscle
fibers, and an additional outer
longitudinal layer in the lower
third
• an inner layer, the mucosa,
lined with transitional Epithelium
Function-to transport urine from kidneys to urinary bladder

29. URINARY BLADDER
• Hollow, distensible, muscular, pear-
shaped organ, situated in pelvic cavity
In males, directly
anterior to rectum
In females, anterior to
vagina & inferior to
uterus

30. • The bladder wall is composed of three
layers:
• the outer layer of loose connective
tissue, containing blood and lymphatic
vessels and nerves, covered on the upper
surface by the peritoneum
• the middle layer, Muscularis (detrusor
muscle) -consisting of 3 layers of smooth
muscle fibers : inner Longitudinal, middle
Circular & outer Longitudinal
• the mucosa, lined with transitional
epithelium

31. The three orifices in the bladder wall
form a triangle or trigone. The upper
two orifices on the posterior wall are
the openings of the ureters. The lower
orifice is the point of origin of the
urethra.
When the bladder is
empty the inner lining is
arranged in folds, or
rugae, and these
gradually disappear as
the bladder fills.

32. • 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 about600 ml.
• Where the urethra commences is a
thickening of the smooth muscle layer
forming the internal urethral sphincter.
This sphincter is not under voluntary
control.
Functions: 1.Reservoir of Urine
2.Micturition

33. MICTURITION In developed nervous
system, stimulation of
Spinal reflex but
sensory impulse pass
upwards to cerebral
cortex.
There is perception of
desire of Micturition
By conscious effort,
reflex contraction of the
bladder wall and
relaxation of the internal
sphincter can be
inhibited for a limited
period of time

34. URETHRA
• A Canal /tube starting from internal
urethral orifice in urinary bladder to
exterior of body as external urethral orifice
• Female Urethra: length- 4cm, directed
obliquely, inferiorly & anteriorly
External urethral
orifice
located
between clitoris &
vaginal opening

35. Male Urethra: • Length-20cm
• It first passes through
prostate, then through
deep muscles of
perineum finally through
Penis
• External urethral
orifice located in penis

36. Walls of urethra: In both sexes the structure
is the sameIts walls consist of three layers of tissue:
• the muscle layer, continuous with that of the bladder. At
its origin there is the internal urethral sphincter,
consisting mainly of elastic tissue and smooth muscle
fibers, under autonomic nerve control. Slow and
continuous contraction of this sphincter keeps the
urethra closed. In the middle third there is skeletal
muscle surrounding the urethra, under voluntary nerve
control, that forms the external urethral sphincter
• the submucosa, a spongy layer containing blood vessels
and nerves
• the mucosa, which is continuous with that of the bladder
in the upper part. In the lower part the lining consists of
stratified squamous epithelium, continuous externally
with the skin of the vulva.
Function: Discharge of urine. In males, it also discharges semen