-Anatomical description of kidney. -Physiological functions of kidney. -Kidney blood supply and its innervation. -Some disease and disorders that affect kidneys and its function.

1. Prepared by
Dr.Ismael I. Surchi

2. The Kidneys/Renes
• Definition
– The kidneys are a pair of excretory organs
situated on the posterior abdominal wall,
one on each side of the vertebral column,
behind the peritoneum.

3. Location
• The kidneys occupies the
epigastric , hypochondriac,
lumbar & umbilical regions.
• Vertically they extends from
upper border of twelfth thoracic
vertebra to the center of the
body of third lumbar vertebra.
• The right kidney is slightly
lower than the left, & the left
kidney is little nearer to the
median plane than the right.

4. The Kidneys- Surface Anatomy
• External Features
– Each kidney is bean shaped.
– It has upper & lower poles,
medial and lateral borders,
and anterior and posterior
surfaces.
– The upper pole is broad & is
in close contact with the
corresponding suprarenal
glands.
– The lower pole is pointed.

5. • The lateral border is
convex.
• The medial border is
concave.
• The middle part of the
medial border is
depressed and is known
as hilum (hilus)
11 cm
3cm
5cm
8

6. Measurements
• Color
• Length
: Reddish Brown
: About 11 cm long( the left
kidney is little longer & narrower than right )
: 6cm broad
: 3cm thick
• Width
• Thickness
• Weight
–Males
–Females
: 150gm
: 135gm
(In fetus the kidney is lobulated & is made up of about 12 lobules.
After birth the lobules fuse , so that in adults the kidney is
uniformly smooth)

7. Surface Marking- Morris Parallelogram
Anterior aspect Posterior aspect

8. Coverings
• It has 3 coverings
1. Innermost fibrous capsule or true capsule
2. Middle fatty capsule / perinephric fat-it is a collection
of fatty tissue. (It acts as a shock absorber & helps to
maintain the kidney in its position)
3. The false capsule – made of renal fascia .It has two
layers-Anterior & Posterior.
(Superiorly the two layers enclose the supra renal gland & then
merge with diaphragmatic fascia, that is why the kidneys move
with respiration)

9. Relations - Anterior

10. Anatomy of Kidney
Macroscopic Structure

11. Renal
Cortex
Renal
Capsule
Renal
Medulla
Renal
Pelvis
Renal
Pyramids
Ureter
Macroscopic Structure
Major
Calyx
Minor
calyces
Papilla

12. • The functional unit of the kidney, the nephron, consists of the
renal corpuscle, Proximal Convoluted Tubule(PCT), loop of
Henle, and Distal Convoluted Tubule (DCT).
• Cortical nephrons have short loops of Henle, whereas
juxtamedullary nephrons have long loops of Henle extending
into the medulla.
• About 15 percent of nephrons are juxtamedullary. The
glomerulus is a capillary bed that filters blood principally based
on particle size.
• The filtrate is captured by Bowman’s capsule and directed to the
PCT.
• A filtration membrane is formed by the fused basement
membranes of the podocytes and the capillary endothelial cells
that they embrace.

13. • Contractile mesangial cells further perform a role in regulating
the rate at which the blood is filtered.
• Specialized cells in the JGA(juxtaglomerular cell) produce
paracrine signals to regulate blood flow and filtration rates of the
glomerulus. Other JGA cells produce the enzyme renin, which
plays a central role in blood pressure regulation.
• The filtrate enters the Proximal Convoluted Tubule(PCT) where
absorption and secretion of several substances occur. The
descending and ascending limbs of the loop of Henle consist of
thick and thin segments.
• Absorption and secretion continue in the Distal Convoluted
Tubule (DCT). but to a lesser extent than in the PCT. Each
collecting duct collects forming urine from several nephrons and
functions to fine tune water recovery.

15. Kidney: Frontal Section
• Minor calyx: cup over papilla collects urine

16. Anatomy of Kidney
• Renal cortex: outer 1 cm
• Renal medulla: renal columns, pyramids - papilla
• Lobe of kidney: pyramid and it’s overlying cortex

17. Microscopic Structure(Histology)
 The kidney may be
regarded as a collection of
millions of uriniferous
tubules.
 Each uriniferous tubule
consists of an excretory
part called nephron and of
a collecting tubule.
 Each kidney contains over
1(1-2 millions) million
nephrons and thousands of
collecting ducts

19. Structure of Nephron

20. Renal Artery
Renal Vein
Nephron

21. vein
artery
efferent
arteriole
afferent
arteriole
glomerulus
peritubular
capillaries
loop of
Henle
Bowman’s
capsule
proximal
convoluted
tubule
distal
convoluted
tubule
collecting
duct

22. urine
blood
filtration
tubular
reabsorption
and secretion
Nephron
Functioning
“refreshed” blood

25. Blood Supply Diagram
Arterial Supply: Renal arteries which
are the direct branches of abdominal
aorta & are large in size.
Venous Drainage: Renal veins, ends
in inferior vena cava. The left renal
vein is longer than the right.
Nerve Supply: Sympathetic fibers
derived from T10,L1 segments and
parasympathetic fibers from vagus
nerve.
Lymphatic drainage: into lateral
aortic nodes.

26. Kidney Functions
• Filters blood plasma, eliminates waste, returns
useful chemicals to blood
• Regulates osmolarity of body fluids
• Endocrine organ –
A-Synthesis of acid protease RENIN –
- enzyme involved in control of blood pressure
and blood volume.
Angiotensinogen Angiotensin I Renin

27. B-Erythropoietin synthesis –
-glycoprotein hormone which regulates RBCs formation
in response to decrease O2 concentration.
- erythropoietin acts on specific receptors expressed on
surface of CFU for erythrocytes in bone marrow.
• Secretes erythropoietin, controls RBC count
• Regulates PCO2 acid base balance
• Detoxifies free radicals and drugs
• Gluconeogenesis

29. Kidney Conditions
• Pyelonephritis (infection of kidney pelvis): Bacteria may
infect the kidney, usually causing back pain and fever. A spread
of bacteria from an untreated bladder infection is the most
common cause of pyelonephritis.
• Glomerulonephritis: An overactive immune system may attack
the kidney, causing inflammation and some damage. Blood and
protein in the urine are common problems that occur with
glomerulonephritis. It can also result in kidney failure.
• Kidney stones (nephrolithiasis): Minerals in urine form
crystals (stones), which may grow large enough to block urine
flow. It's considered one of the most painful conditions. Most
kidney stones pass on their own, but some are too large and need
to be treated.

30. • Nephrotic syndrome: Damage to the kidneys causes them to
spill large amounts of protein into the urine. Leg swelling
(edema) may be a symptom.
• Polycystic kidney disease: A genetic condition resulting in
large cysts in both kidneys that hinder their work.
• Acute renal failure (kidney failure): A sudden worsening in
how well your kidneys work. Dehydration, a blockage in the
urinary tract, or kidney damage can cause acute renal failure,
which may be reversible.
• Chronic renal failure: A permanent partial loss of how well
your kidneys work. Diabetes and high blood pressure are the
most common causes.

31. • Diabetic nephropathy: High blood sugar from diabetes
progressively damages the kidneys, eventually causing chronic
kidney disease. Protein in the urine (nephrotic syndrome) may
also result.
• Hypertensive nephropathy: Kidney damage caused by high
blood pressure. Chronic renal failure may eventually result.
• Kidney cancer: Renal cell carcinoma is the most common
cancer affecting the kidney. Smoking is the most common cause
of kidney cancer.
• Interstitial nephritis: Inflammation of the connective tissue
inside the kidney, often causing acute renal failure. Allergic
reactions and drug side effects are the usual causes.

32. Kidney Tests
• Urinalysis: A routine test of the urine by a machine and often by
a person looking through a microscope. Urinalysis can help
detect infections, inflammation, microscopic bleeding, and
kidney damage.
• Kidney ultrasound: A probe placed on the skin reflects sound
waves off the kidneys, creating images on a screen. Ultrasound
can reveal blockages in urine flow, stones, cysts, or suspicious
masses in the kidneys.
• Computed tomography (CT) scan: A CT scanner takes a
series of X-rays, and a computer creates detailed images of the
kidneys.
• Magnetic resonance imaging (MRI) scan: A scanner uses
radio waves in a magnetic field to make high-resolution images
of the kidneys.

33. • Urine and blood cultures: If an infection is suspected, cultures
of the blood and urine may identify the bacteria responsible.
This can help target antibiotic therapy.
• Ureteroscopy: An endoscope (flexible tube with a camera on its
end) is passed through the urethra into the bladder and ureters.
Ureteroscopy generally cannot reach the kidneys themselves, but
can help treat conditions that also affect the ureters.
• Kidney biopsy: Using a needle inserted into the back, a small
piece of kidney tissue is removed. Examining the kidney tissue
under a microscope may help diagnose a kidney problem.

34. Kidney Treatment
• Antibiotics: Kidney infections caused by bacteria are treated
with antibiotics. Often, cultures of the blood or urine can help
guide the choice of antibiotic therapy.
• Nephrostomy: A tube (catheter) is placed through the skin into
the kidney. Urine then drains directly from the kidney, bypassing
any blockages in urine flow.
• Lithotripsy: Some kidney stones may be shattered into small
pieces that can pass in the urine. Most often, lithotripsy is done
by a machine that projects ultrasound shock waves through the
body.
• Nephrectomy: Surgery to remove a kidney. Nephrectomy is
performed for kidney cancer or severe kidney damage.

35. Kidney Treatment
• Dialysis: Artificial filtering of the blood to replace the work that
damaged kidneys can't do. Hemodialysis is the most common
method of dialysis in the U.S.
• Hemodialysis: A person with complete kidney failure is
connected to a dialysis machine, which filters the blood and
returns it to the body. Hemodialysis is typically done 3 days per
week in people with ESRD.
• Peritoneal dialysis: Placing large amounts of a special fluid in
the abdomen through a catheter allows the body to filter the
blood using the natural membrane lining the abdomen. After a
while, the fluid with the waste is drained and discarded.
• Kidney transplant: Transplanting a kidney into a person with
ESRD can restore kidney function. A kidney may be
transplanted from a living donor, or from a recently deceased
organ donor.