Transcript FUNCTION OF KIDNEY

DVT 1102
TITLE : KIDNEY
NURUL ALIYA BT ROSLAN (D11A030)
HASNA NADIA BT HASAN SAZALLI (D11A009)
JOSEPHIN SUZANA AK JOHN ASIN LOW (D11B013)
NORZUFIKAL BT ZULKIFLY (D11A022)
SYAFFIQ BIN OTHMAN (D11B039)
ANATOMY OF KIDNEY
The Kidney and the Nephron
A.
Renal Vein
B.
Renal Artery
C.
Ureter
D.
Medulla
E.
Renal Pelvis
F.
Cortex
1.
Ascending loop of
Henle
2.
Descending loop of
Henle
3.
Peritubular capillaries
4.
Proximal tubule
5.
Glomerulus
6.
Distal tubule
Efferent Arteriole
Proximal Tubule
Afferent
Arteriole
Distal Tubule
Glomerulus
Bowman’s
Capsule
Collecting Duct
Loop of
Henle
peritubular
capillaries
Structure of kidney
• Renal artery
-takes blood into the kidney
• Renal vein
-this has a large diameter and a thin wall. It carries
blood away from the kidney and back to the right
hand side of the heart.
• Ureter
-it is the tube that carries urine from kidney to the
bladder. It orignates from the base of the kidney and
terminates in the base of the bladder. Consists of
three layers which are the mucosal, muscular and
fibrous.
• Pelvis
-this is the region of the kidney where urine
collects.
• Medulla
-the medulla is the inside part of the kidney.
This is where the amount of salt and water in
your urine is controlled. It consists of billions
of loops of Henlé.
• Cortex
-the cortex is the outer part of the kidney. This
is where blood is filtered. Billions of glomeruli
are found in the cortex.
• Glomerulus and Bowman's Capsule
-a glomerulus is a tiny ball of capillaries. Each
glomerulus is surrounded by a "Bowman's
Capsule“. This is where ultra-filtration takes
place.
• Collecting Duct
-collecting ducts run through the medulla and
are surrounded by loops of Henlé.
• Proximal Convoluted Tubules
-is the coiled up tube near to the Bowman's
capsule. This is the place where all that useful
glucose is re-absorbed from the ultra-filtrate
and put back into the blood.
• Loop of Henlé
-this part of the nephron is where water is
reabsorbed.
• Distal Convoluted Tubules
-end of the nephron from the Bowman's
capsule. This is where most of the salts in the
ultra-filtrate are re-absorbed.
HISTOLOGY OF KIDNEY
Capsule of the Kidney
• A dense collagenous connective tissue envelope.
*Masson’s stain
2
regions
of the
kidney
H&E (100x)
Renal Corpuscle: Glomerulus
• Made up of many parallel capillaries
• Blood flows into these capillaries through a wide
afferent arteriole and leaves through a narrower
efferent arteriole
• The blood entering the afferent arteriole is at very high
pressure already as it from the renal artery
• The pressure actually forces molecules through the
glomerular filtration barrier which is responsible for
selectively filtering the blood, forming the glomerular
filtrate.
• The other component of the glomerulus are the
mesangial cells:
– These give support to the glomerulus
– Maintain glomerular basal lamina
H&E (400x)
•
1. Capsular epithelium 2. Urinary space
3. Glomerulus 4. Macula densa
5. Distal convoluted tubule 6. Proximal convoluted tubule
Renal Corpuscle: Bowmans Capsule
• Surrounds the capillaries of the glomerulus
• Has two layers
– Inner visceral layer - Podocytes
– Outer parietal layer
• It is here where the filtrate is collected before
entering the proximal tubule
H&E 400x
Fenestrated wall of the
capillary
Proximal Convoluted Tubule
• This is the piece of nephron which starts at the
Bowmans capsule and ends in the loop of Henle
• Has a wall of simple cuboidal epithelium
• Has a brush border of densely packed microvilli to
increase surface area
• Only the proximal convoluted tubules has such a
brush border. The other kidney tubules don't
• Here at least 99% of what is present in the filtrate
as it leaves Bowman's space is recovered
Stain: H&E
microvilli
Transmission
Electron Micrograph
Loop of Henle
• The loop of Henle is made of simple squamous
epithelium.
• The loop of Henle basically consists of two
parallel limbs which descend from the cortex into
the medulla.
• They are joined at the bottom and as such the
flow moves down one limb and up the other in
opposite directions.
• This sets up a counter current exchange and
allows the loop of Henle to be the major site of
water reabsorption along the nephron.
H&E (240x)
H&E (400x)
Loop of Henle
Blood capillaries
Distal Convoluted Tubule
• Made of simple cuboidal epithelium
• Consists of two parts
– Straight part - connects the ascending limb of the loop of
Henle to the distal convoluted tubule
– Convoluted part - connects the straight part to the
connecting duct
• No brush border, very few microvilli (difficult to see through
light microscope)
• Characterized by large open lumen with presence of urine.
• The straight portion of the distal tubule contacts the
glomerulus forming the macula densa.
• Its role is to pump sodium ions out of its lumen into the
surrounding intracellular space. It does this by active
transport.
Convoluted part
Macula densa
Straight part
H&E (400x)
Collecting Duct
• This structure links the distal tubule to the area cribosa
of the papilla into the renal pelvis
• Collecting tubules are quite large, with walls formed of
cuboidal epithelium.
• The epithelium of the collecting ducts is sensitive to
antidiuretic hormone (ADH). When ADH levels are
high, the walls become very permeable to water. When
ADH levels are low, the opposite occurs; duct walls are
impermeable to water. Hormonal control of duct
permeability adjusts the final volume and
concentration of urine voided.
H&E
Vasa recta
(blood capillary)
PCT
CD
Loop of Henle
H&E
THANK YOU
Difference of kidney among the animals
Location of the kidney
• Other than pig, right kidney is located further cranial than the
left and its cranial extremity lies in contact with caudate
process of the liver and right hepatic lobe.
• Lies in a fossa of the liver which helps to limit its movement.
• Left kidney not present in the liver.
• In ruminants, considerable size of the rumen pushes the left
kidney towards the right half of the abdomen where it is
suspended by the long and mobile mesonephros caudal to the
right kidney.
Shape of the kidney
• In cat, dog, sheep and dog, the shape of kidney is bean-shape
• Pig-more flatttened
• Horse-right kidney has a valentine heart shape while left
kidney has a bean to pyramidal shape.
• bovine-irregular oval shape and its surface is fissured to divide
the organ into many lobes.
• Other animals kidney has a smooth surface except bovine.
Structure of the kidney
• Ox and pig, medulla and its associated cortex are divided into
pyramidal shaped lobes.
• Ox has multilobar organization of the kidneys is revealed by
the fissure that penetrate the organ between the different
lobes from the surface.
• In dog, horse and sheep, all the lobes fuse finally to form a
single medullary mass with a continuous cortical shell
surrounding it.
Nephron Segment
Renal Corpuscle:
•Glomerulus
•Bowman's Capsule
U-Shaped Tubule
Collecting Duct
Function
Filtration:
Glomerulus filters proteins and
cells from the blood. All other
blood components pass into
Bowman's capsule, then into
the tubule.
Reabsorption and Secretion:
Semipermeable membranes
surrounding the tubule allow
selective passage of particles
back into the blood
(reabsorption), or from the
blood into the tubule
(secretion).
Collection:
Collects all material that has
not returned to the blood
through the tubular
membranes. This material
exits the kidney as urine.