2. location
ā¢ The kidney occupy the
epigastric, hypochondria,
lumbar and umblical
regions.
ā¢ Vertically they extend
from the upper border of
twelfth thoracic vertebrae
to the centre of the body
of third lumbar vertebra.
ā¢ The right kidney is slightly
lower than the left.
3. Coverings of the kidney
ā¢ THE FIBROUS CAPSULE: this is a thin
membrane which closely invests the
kidney and lines the renal sinus.
ā¢ Perinephric fat: this is a layer of adipose
tissue lying outside the fibrous capsule, it
is thickest at the borders of the kidney.
ā¢ Renal fascia: attaches to the abdominal
wall.
4. External features
ā¢ Each kidney is bean shaped,it has upper and
lower poles. Medial and lateral borders and
anterior and posterior surface
ā¢ Two poles of kidney: the upper pole is broad and
the lower pole is pointed.
ā¢ Two surfaces: the anterior surface is irregular
and posterior is flat
ā¢ Two borders: the lateral border is convex and
medial border is concave the middle part shows
a depression ,the hilum
5. Relations of kidneys
ā¢The upper pole of each kidney is related
to suprarenal gland.
ā¢The medial border of each kidney is
related to suprarenal gland above the
hilus and uretur below the hilus
8. Gross anatomy
ā¢ Renal parenchyma
ā¢ Two zones
ā¢ outer cortex-The cortex is composed of roughly
1.25 million nephrons
ā¢ inner medulla-The medulla consists of 6-18
renal pyramids
9. Renal parenchyma
ā¢Renal pyramids-Extensions of cortex
(renal columns) divide medulla into 6 ā18
renal pyramids
ā¢ Pyramid + overlying cortex = Lobe
ā¢ Point of pyramid = Papilla
ā¢ Papilla nested in cup (minor calyx)
ā¢ 2 ā 3 minor calices > Major calyx
ā¢ 2 ā 3 major calices > Renal pelvis
ā¢ Renal pelvis>Ureter
10. Renal sinus
ā¢ Surrounded by renal parenchyma
ā¢ Contains blood & lymph vessels, nerves,
ā¢ Urine-collecting structures
ā¢Hilus
ā¢ On concave surface
ā¢ Vessels and nerves enter and exit
ā¢ Major and minor calyces along with the
pelvis drain urine to the ureters
16. Glomerulus
ā¢ The glomerulus is a capillary tuft that
receives its blood supply from an afferent
arteriole of the renal circulation
.
ā¢ 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
ā¢The remainder of the blood passes
into the efferent arteriole.
ā¢ The diameter of efferent arterioles is
smaller than that of afferent
arterioles, increasing the hydrostatic
pressure in the glomerulus.
18. Bowmans capsule
ā¢ The Bowman's capsule, also called the
glomerular capsule.
ā¢ surrounds the glomerulus.
ā¢ It is composed of a visceral inner layer formed
by specialized cells called podocytes.
ā¢ Parietal outer layer composed of simple
squamous epithelium.
ā¢ Fluids from blood in the glomerulus are filtered
through the visceral layer of podocytes, resulting
in the glomerular filtrate.
19. Renal corpuscle
ā¢ Glomerulus plus capsule
ā¢ Glomerulus enclosed in two-layered
glomerular capsule
āBowmanās capsuleā
ā¢ Fluid filters from glomerular capillaries
āGlomerular filtrateā
ā¢ Fluid collects in capsular space
ā¢ Fluid flows into renal tubule
20. Renal tubule
ā¢ Leads from glomerular capsule
ā¢ Ends at tip of medullary pyramid
ā¢ 3 cm long
ā¢ Four major regions
. Proximal convoluted tubule
. Nephron loop of henle
.Distal convoluted tubule
. Collecting duct
21. Proximal convulated tubule
ā¢ Arises from glomerular capsule
ā¢ Longest, most coiled region
ā¢ lies in cortex
ā¢ lined by simple cuboidal epithelium with
brush borders which help to increase the
area of absorption greatly.
ā¢ Prominent microvilli
ā¢ Function in absorption
22. Loop of henle
ā¢āUā ā shaped, distal to PCT
ā¢lies in medulla
ā¢2 parts
ā¢ Descending limb of loop of Henle
ā¢ Ascending limb of loop of Henle
23. Loop of henle
ā¢ The ascending limb of loop of Henle is divided
into 2 segments:
ā¢ Lower end of ascending limb is very thin and is
lined by simple squamous epithelium.
ā¢ The distal portion of ascending limb is thick and
is lined by simple cuboidal epithelium.
ā¢ Thin ascending limb of loop of Henle
ā¢ Thick ascending limb of loop of Henle (enters
ā¢ cortex and becomes DCT-distal convoluted
tubule.)
24. Distal convoluted tubule (DCT)
ā¢ Coiled, distal to nephron loop
ā¢ Shorter than PCT
ā¢ Less coiled than PCT
ā¢ Very few microvilli
ā¢ Contacts afferent and efferent arterioles
ā¢ Contact with peritubular capillaries
25. Collecting duct
ā¢DCTs of several nephrons empty
into a collecting duct
ā¢ Passes into medulla
ā¢ Several merge into papillary duct
ā¢ Drain into minor calyx
26. classes
ā¢ The two general classes of nephrons are
ā¢ 1.Cortical nephrons
ā¢ 2.juxtamedullary nephrons
which are classified according to the
ā¢ length of their Loop of Henle
ā¢ location of their renal corpuscle.
27. ā¢All nephrons have their renal
corpuscles in the cortex.
ā¢ Cortical nephrons have their Loop of
Henle in the renal medulla near its
junction with the renal cortex,
ā¢Loop of Henle of juxtamedullary
nephrons is located deep in the renal
medulla
28. URETER
ā¢ The Ureters are a pair of narrow , thick walled muscular
tubes which convey urine from the kidneys to urinary
bladder.
ā¢ Each Ureter is about 25cm (10 inch)long
ā¢ The upper half lies in the abdomen and the lower half in
the pelvis.
ā¢ It measures 3mm diameter, but it slightly constricted at
three places.
ā¢ ā At the pelviureteric junction
ā¢ ā At the brim of lesser pelvis
ā¢ ā At its passage through the bladder wall
29. ā¢ Carry urine from kidneys to urinary
bladder via peristalsis
ā¢ Rhythmic contraction of smooth muscle
ā¢ Enter bladder from below
ā¢ Pressure from full bladder compresses
ureters and prevents backflow
ā¢ Small diameter
ā¢ Easily obstructed or injured by kidney
stones
30. Blood Supply
ā¢ Ureter is supplied by branches of
Ā» Renal artery
Ā» Abdominal aorta
Ā» Gonadal artery
Ā» Common iliac artery
Ā» Internal iliac artery
Ā» Inferior vesical artery
31. Urinary bladder
ā¢ ā¢ 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
ā¢ Empty bladder , in the adult situated within the
pelvis . When distended , it rises up to the
abdominal cavity and becomes an
abdominopelvic organ.
ā¢ 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
ā¢ The mucous membrane is straw colored & is
thrown into folds. When bladder is distended,
these folds disappear.
ā¢ The posterior wall shows a smooth triangular
area called trigone. There are no mucous folds in
this region.
ā¢ At the upper lateral angles of the trigone are the
ureteric openings.
ā¢ At its inferior angle is the internal urethral
orifice
35. urethra
ā¢ The urethra is a canal extending from the neck of the
bladder to the exterior , at the external urethral
orifice.
ā¢ Male: about 20 cm (8ā) long
ā¢ Female: 3-4 cm (1.5ā) long
ā¢ Conveys urine from body
ā¢ Internal urethral sphincter
ā¢ Retains urine in bladder
ā¢ Smooth muscle, involuntary
ā¢ External urethral sphincter
ā¢ Provides voluntary control over voiding of urine
36. Female urethra
ā¢ 3 to 4 cm long
ā¢ External urethral orifice
ā between vaginal orifice and clitoris
ā¢ Internal urethral sphincter
ā detrusor muscle thickened, smooth muscle,
involuntary control
ā¢ External urethral sphincter
ā skeletal muscle, voluntary control
37. Male urethra
ā¢ 18 cm long
ā¢ Internal urethral sphincter
ā¢ External urethral sphincter
ā¢ 3 regions
ā prostatic urethra
ā¢ during orgasm receives semen
ā membranous urethra
ā¢ passes through pelvic cavity
ā penile urethra