2. location
• The kidney occupy the
epigastric, hypochondria,
lumbar and umblical
regions.
• Vertically they extend
from the upper border of
twelfth thoracic vertebrae
to the centre of the body
of third lumbar vertebra.
• The right kidney is slightly
lower than the left.
3. Coverings of the kidney
• THE FIBROUS CAPSULE: this is a thin
membrane which closely invests the
kidney and lines the renal sinus.
• Perinephric fat: this is a layer of adipose
tissue lying outside the fibrous capsule, it
is thickest at the borders of the kidney.
• Renal fascia: attaches to the abdominal
wall.
4. External features
• Each kidney is bean shaped,it has upper and
lower poles. Medial and lateral borders and
anterior and posterior surface
• Two poles of kidney: the upper pole is broad and
the lower pole is pointed.
• Two surfaces: the anterior surface is irregular
and posterior is flat
• Two borders: the lateral border is convex and
medial border is concave the middle part shows
a depression ,the hilum
5. Relations of kidneys
•The upper pole of each kidney is related
to suprarenal gland.
•The medial border of each kidney is
related to suprarenal gland above the
hilus and uretur below the hilus
8. Gross anatomy
• Renal parenchyma
• Two zones
• outer cortex-The cortex is composed of roughly
1.25 million nephrons
• inner medulla-The medulla consists of 6-18
renal pyramids
9. Renal parenchyma
•Renal pyramids-Extensions of cortex
(renal columns) divide medulla into 6 –18
renal pyramids
• Pyramid + overlying cortex = Lobe
• Point of pyramid = Papilla
• Papilla nested in cup (minor calyx)
• 2 – 3 minor calices > Major calyx
• 2 – 3 major calices > Renal pelvis
• Renal pelvis>Ureter
10. Renal sinus
• Surrounded by renal parenchyma
• Contains blood & lymph vessels, nerves,
• Urine-collecting structures
•Hilus
• On concave surface
• Vessels and nerves enter and exit
• Major and minor calyces along with the
pelvis drain urine to the ureters
16. Glomerulus
• The glomerulus is a capillary tuft that
receives its blood supply from an afferent
arteriole of the renal circulation
.
• The glomerular blood pressure provides
the driving force for water and solutes to
be filtered out of the blood and into the
space made by Bowman's capsule
17. Glomerulus
•The remainder of the blood passes
into the efferent arteriole.
• The diameter of efferent arterioles is
smaller than that of afferent
arterioles, increasing the hydrostatic
pressure in the glomerulus.
18. Bowmans capsule
• The Bowman's capsule, also called the
glomerular capsule.
• surrounds the glomerulus.
• It is composed of a visceral inner layer formed
by specialized cells called podocytes.
• Parietal outer layer composed of simple
squamous epithelium.
• Fluids from blood in the glomerulus are filtered
through the visceral layer of podocytes, resulting
in the glomerular filtrate.
19. Renal corpuscle
• Glomerulus plus capsule
• Glomerulus enclosed in two-layered
glomerular capsule
“Bowman’s capsule”
• Fluid filters from glomerular capillaries
“Glomerular filtrate”
• Fluid collects in capsular space
• Fluid flows into renal tubule
20. Renal tubule
• Leads from glomerular capsule
• Ends at tip of medullary pyramid
• 3 cm long
• Four major regions
. Proximal convoluted tubule
. Nephron loop of henle
.Distal convoluted tubule
. Collecting duct
21. Proximal convulated tubule
• Arises from glomerular capsule
• Longest, most coiled region
• lies in cortex
• lined by simple cuboidal epithelium with
brush borders which help to increase the
area of absorption greatly.
• Prominent microvilli
• Function in absorption
22. Loop of henle
•“U” – shaped, distal to PCT
•lies in medulla
•2 parts
• Descending limb of loop of Henle
• Ascending limb of loop of Henle
23. Loop of henle
• The ascending limb of loop of Henle is divided
into 2 segments:
• Lower end of ascending limb is very thin and is
lined by simple squamous epithelium.
• The distal portion of ascending limb is thick and
is lined by simple cuboidal epithelium.
• Thin ascending limb of loop of Henle
• Thick ascending limb of loop of Henle (enters
• cortex and becomes DCT-distal convoluted
tubule.)
24. Distal convoluted tubule (DCT)
• Coiled, distal to nephron loop
• Shorter than PCT
• Less coiled than PCT
• Very few microvilli
• Contacts afferent and efferent arterioles
• Contact with peritubular capillaries
25. Collecting duct
•DCTs of several nephrons empty
into a collecting duct
• Passes into medulla
• Several merge into papillary duct
• Drain into minor calyx
26. classes
• The two general classes of nephrons are
• 1.Cortical nephrons
• 2.juxtamedullary nephrons
which are classified according to the
• length of their Loop of Henle
• location of their renal corpuscle.
27. •All nephrons have their renal
corpuscles in the cortex.
• Cortical nephrons have their Loop of
Henle in the renal medulla near its
junction with the renal cortex,
•Loop of Henle of juxtamedullary
nephrons is located deep in the renal
medulla
28. URETER
• The Ureters are a pair of narrow , thick walled muscular
tubes which convey urine from the kidneys to urinary
bladder.
• Each Ureter is about 25cm (10 inch)long
• The upper half lies in the abdomen and the lower half in
the pelvis.
• It measures 3mm diameter, but it slightly constricted at
three places.
• – At the pelviureteric junction
• – At the brim of lesser pelvis
• – At its passage through the bladder wall
29. • Carry urine from kidneys to urinary
bladder via peristalsis
• Rhythmic contraction of smooth muscle
• Enter bladder from below
• Pressure from full bladder compresses
ureters and prevents backflow
• Small diameter
• Easily obstructed or injured by kidney
stones
30. Blood Supply
• Ureter is supplied by branches of
» Renal artery
» Abdominal aorta
» Gonadal artery
» Common iliac artery
» Internal iliac artery
» Inferior vesical artery
31. Urinary bladder
• • The urinary bladder is a hollow , muscular organ , which
functions as the reservoir for the urine received from the
kidneys and to discharge it out periodically
32. position
• Empty bladder , in the adult situated within the
pelvis . When distended , it rises up to the
abdominal cavity and becomes an
abdominopelvic organ.
• Capacity
The mean capacity of the bladder i 220 ml,
filling beyond 220ml causes a desire to micturate.
Filling upto 500ml may be tolerated, but it
becomes painful.
34. Interior of the bladder
• The mucous membrane is straw colored & is
thrown into folds. When bladder is distended,
these folds disappear.
• The posterior wall shows a smooth triangular
area called trigone. There are no mucous folds in
this region.
• At the upper lateral angles of the trigone are the
ureteric openings.
• At its inferior angle is the internal urethral
orifice
35. urethra
• The urethra is a canal extending from the neck of the
bladder to the exterior , at the external urethral
orifice.
• Male: about 20 cm (8”) long
• Female: 3-4 cm (1.5”) long
• Conveys urine from body
• Internal urethral sphincter
• Retains urine in bladder
• Smooth muscle, involuntary
• External urethral sphincter
• Provides voluntary control over voiding of urine
36. Female urethra
• 3 to 4 cm long
• External urethral orifice
– between vaginal orifice and clitoris
• Internal urethral sphincter
– detrusor muscle thickened, smooth muscle,
involuntary control
• External urethral sphincter
– skeletal muscle, voluntary control
37. Male urethra
• 18 cm long
• Internal urethral sphincter
• External urethral sphincter
• 3 regions
– prostatic urethra
• during orgasm receives semen
– membranous urethra
• passes through pelvic cavity
– penile urethra
