Urinary system Presentation.pdf77996533678

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1. URINARY SYSTEM
Presented to:
Ma’am Madiha
Presented BY:
UsawerMaqsood
MahamKamal
SairaBatool
JaveriaAbid
Toba Abid
SairaJaved
AmnaAshraf

2. URINARY SYSTEM

3. URINARY SYSTEM
FUNCTION:
PARTS:
The chief function of urinary
system is to produce, store and
release urine.
URINE:
A fluid that consists of water and
other types of waste
products(urea, creatinine etc)
▣Pair of kidneys(production of
urine)
▣Pair of ureters(passageway)
▣Urinary bladder(temporarily
stored)
▣Urethra(periodic release from
urethra)

4. PARENCHYMA
OF KIDNEY
NEPHRON
BLOOD SUPPLY OF
KIDNEY:
✔Consists of 1 to 4 million
tubular structures.
✔Chief structural and
functional unit.
✔Long, epithelium lined tube.
✔Consists of 5major
segments:
1)Renal corpuscle
2)Proximal tubule
3)Loop of henle
4)Distal tubule
5)Collecting tubule

5. CLASSIFICATION
OF NEPHRON
Based on location of renal
corpuscles:
1. Superficial cortical(outer
part of renal cortex)
2.Midcotical(middle part of
renal cortex)
3.Juxtamedullary(in the
deepest part of renal cortex)

6. PARTS OF NEPHRON
Renal Corpuscle:
Renal corpuscle are spherical bodies ranging
from 200 to 250nm in diameter.
⮚Vascular pole:
Afferent arterioles enter & efferent arterioles
leave.
⮚Urinary Pole:
Where proximal convulated tubule begins.
Components:
1. Bowman’s Capsule (cup like structure)
2. Glomerulus (tuft of capillaries)
❑Bowman’s Capsule/glomerular capsule:
Having a double layer cup like structure
Layers:
i.Parietal Layer/outer layer/simple
squamous epithilium
ii.Visceral layer/Inner layer/Podocytes
iii.Capsular/urinary/Bowman’s
space(Narrow space Between parietal
and visceral)

7. Podocytes
▣Large, irregular, star shaped cells
▣Share a common basement membrane with endothelial cells of
glomerular capillaries
Pedicels:
from cell body several processes arise( like octopus) give rise to numerous
secondary processes called pedicels or foot processes.
Filtration slits:
Foot process of each podocyte interdigitate with neighbouring podocytes.
These interdigitate processes are separated by narrow gaps called filtartion
slits. 40nm(average width)
Slit diaphragm:
⮚Slit membrane
⮚Important component of filtration membrane
⮚Composed of protein nephrin
⮚Podocalyxin and p cadherin
⮚Allows passage of small molecules( water glucose)
⮚Restricts passage of small molecules(serum albumin)
⮚EM reveals that rough, oval nucleus, cytoplasm exhibits mit, golg, rer
(actin)

8. Gbm
❖The basal lamina of visceral layer of bowman’s capsule that lies b/w
the podocytesand endothelial cells of glomerular capillaries
❖Thickness:150nm in children, 300nm in adults
❖Is intrupled, no gaps or pores
Layers
1. Lamina raraexterna:
✔Adjacent to podocyte
✔Glycosaminoglycan heparansulphate( adhesive glycoprotein)
✔Laminin, fibrinogen help in anchoring the podocyteto basal
membrane
2. Lamina densa:
✔Dense middle layer
✔Collagen 4
✔Sieve like filter(don’t allow large molecules to pass through)
3. Lamina rarainterna
✔Electrons lucent layer bordering on capillary endothyelium
✔Heparin sulphate
✔Repels albumin and other plasma protein

9. Glomerulus
oTuft of fenestrated capillaries > connects
afferent arterioles with efferent arterioles
oAfferent divides to 4 to 5 branches
oLobule formation > anastomosis > then
efferent arterioles
oSize difference to ensure hydrostatic
pressure
oPores in endothelial lining > not covered
by diaphragm
oLuminal surface of endothelium is covered
by glycocalyx coat
Function:
oGlomerular capillaries restrict blood cells
and platelets but allow components of
blood plasma

10. Mesengial cells
▣Each renal corpuscle contains mesengial cells
▣Mesengium:mesengial cells+ extracellular matrix
▣Shape:irregular and enclosed by GBM
▣Their cytoplasm contains actin and myosin
Functions
▣Phagocytosis of unwanted macromolecules
▣Structural support to glomerular capillaries
▣Secretion of cytokines( leukin 1) (prostaglandans –
platelet derived growth factor)
▣Regulation of blood flow through glomerular
capillaries

11. Filtration barrier
Endothelium of glomerular
capillaries:
•Large pores > rapid flow of plasma and
prevents passage of formed elements of blood
Glomerular basement membrane:
•Molecules having size 10nm or large cannot
pass
•Molecules of molecular weight of albumin
(96K Dalton) are restricted
•Has negatively charged heparin
•Restricts negatively charged molecules
(albumin)
Slit diaphragm covering filtration
slits:
•Span the filtration slits b/w interdigitating
pedicles of podocytes
•Porous and allows small molecules only
•Not allow( albumin, gamma, globulin)

12. Proximal Tubule
It comprises of 2 parts:
1. Proximal convoluted tubule:
(coiled,longer)
2. Proximal straight tubule:
(uncoiled, shorter)
Proximal convoluted tubule
(PCT)
i.Location: Renal cortex
ii.Length:14mm , extremely long
covers major portion of renal
cortex)

13. Structure:
●lined by Simple Cuboidal epithelium
❑Central spherical nucleus and abundant mitochondria
Apical domain: (luminal surface)
❑Microvilli forming Brush border
❑Small pits (invagination) called Apical canaliculi
❑Both increase surface area
Junctions:
1. Zonula occludens
2. Zonula adherens
These junctions allow the passage of water.
Basal domain:
❑Invagination of plasmalemma
❑mitochondria aligned in rows
❑basal striations appearance

14. Lateral domain:
✔Not smooth invaginations are present
Functions:
✔Reabsorption of water , electrolytes and organic
nutrients
✔65% reabsorption of water and sodium
Proximal straight tubule
✔Also lined by Cuboidal epithelium with exception of
●Less developed brush border
●Fewer canaliculi and mitochondria

15. Loop of henle( Nephron
loop)
•U shaped structure of nephron
•Location:renal medulla
•Length:variable ( longest in juxtamedullary
nephron)
Parts of loop of Henle
1: Thin descending limb
●Simple squamous epithelium
●Aquaporin channel's
2: Thin ascending Limb
●Simple Squamous epithelium
3: Thick ascending limb
●Simple cuboidal epithelium

16. Distal tubule(continuous with loop of Henle)
1.Distal straight tubule
✔(straight and uncoiled)
✔Continuous with thick ascending limb
✔Simple cuboidal cells
2. Distal convoluted tubule
✔(Coiled and twisted)
✔Joins with collecting duct
✔Simple cuboidal cells

17. Function:
❖Reabsorb sodium ions ,chlorine ions and bicarbonate ion
❖Secret hydrogen and ammonium Ion into Lumen
Collecting tubules
⮚Last part of nephron
⮚Continuous with DCT
⮚Uncoiled tubules
⮚Location :renal cortex
⮚simple columnar epithelium
⮚Special structure: presence of principal cells

18. 1. Collecting ducts of kidney
2. Juxtaglomerular of apparatus
Components:
•Macula densa
•Juxtaglomerular cell
•Extraglomerular cell
3. Renal interstitial tissue
Structure:
▣In medullary rays of renal cortex > connecting tubule(term port of
nephron) > join cortical connecting duct
▣Average size 400 micrometer
▣Lined by simple columnar epithelium
▣Near apex > each renal pyramid > collecting duct merge > duct of
beline(lined by simple cuboidal epithelium)
▣Papillary duct open > at apex > pyramid deliver urine > into minor
calyx

19. Juxtaglomerular apparatus:
Collecting tubules collection
At vascular pole of renal corpuscle > associate> 3 structures
1. Macula densa
2. Juxtaglomerular cell
3. Extraglomerular cell
Macula densa:
Location:
specialized region > distal straight tubule where tubule come in contact with
afferent and efferent arteiole at the vascular pole of the renal corpuscle of its own
nephron.
Cells:
Taller closely packed, nuclei prominent than surrounding so this region of tubule
appear darker than histological section
Function:
Osmoregularity sensor > In dis convoluted tubule. Dec sodium ion conc in
tubular fluid cause sec of chemical with 2 effects and caused by dec in gfr.
Effects:
1. Blood resistance decreases > afferent arteriole > cause glomerular hydrostatic
pressure increase > grf > normal
2. Juxtangluar cell release renin

20. Juxtaglomerular cells:
Location:
Adjacent to macula densa, tunica media contain modify S.M / Called
Justag …cell
Cell Structure:
oLarge, nuclei spherical, cytoplasm contain RER, Golgi complexes,
zymogen granule contain renin
oInternal elastic laminal absent
Secretion:
oIG cell see enzyme renin
oRenin>Hydrolysis>plasma protein antagiotensinogen to
angiotensinogen
oAngiotensinogen 1> II
oBy ACE secreted by lung capillaries Angio II vasoconstriction, inc B.P
Extraglomerular Mesangial cell:
Extraglomerular Mesangial cell (called lacis) form > cushion > b/w afferent
and efferent artery of renal corpuscle
Structure:
These cells resemble the intraglomerular messengial cells > contagious
Function:
Not well understood

21. Ureter
Two muscular tubes ; one connected to kidney ,carry urine from
kidney to bladder
▣25-30cm long , peristalsis movement occur to push urine to
bladder
Coats:
1.Mucosa:
Innermost layer allows ureter to stretch as urine move, contains
layer of connective tissue.
2. Muscularis:
Middle layer arranges in two layers:
❖An inner longitudinal layer
❖Outer circular layer contain smooth muscle fibers and it helps in
contraction that propel urine from kidney to bladder.
3. Adventita :
outermost layer that provides structural support and anchors the
ureter to surrounding tissues and contain blood vessels, lymphatic
vessels and nerves.

22. Urinary bladder
It is a strong reservoir for urine until it is ready to be excreted. And is
located in pelvic cavity behind pelvic bone and lined with transitional
epithelium.
Coats:
1. Mucosa:
Inner layer of bladder that allows to stretch as it fill and contract as it
empties. It contains lamina propia(connective tissue layer) that provides
support or elasticity.
2. Muscularis:
Middle layer composed of smooth muscles called detrousor muscles ,
the contraction allows the bladder to contract and expel urine during
urination.
3. Adventita:
Outer connective tissue layer that provide support to the bladder and
connective tissues in the surroundings , bladder covered with
peritoneum(membrane lining the abdominal cavity)and it is also called
serosa.

23. Urethra
Tube that carry urine from bladder to the outside of the body.
Male urethra
It’s 20 cm long. It serves as a passage for both urine and semen as it
passes through penis and it is divided into 3 parts:
1. Prostatic urethra:
It passes through prostate gland.
2. Membranous urethra:
Shortest portion passing through pelvic floor muscles.
3. Penile urethra:
It’s spongy. The longest part running through penis to external
opening.
Female urethra
✔It’s 4cm long. It runs from bladder to opening above vaginal
opening. It’s shorter than that in males . Females are more
susceptible to urinary tract infections(utis) because of short length.
✔In both sphincters, muscles present at base help to control the
voluntary release of urine.

24. TEAMWORK
▣All the groups members have provided the data for relevant
portions.
UsawerMaqsood (Introduction, Kidney, Nephron)
MahamKamal (Renal Corpuscle, Podocytes, Gbm)
SairaBatool (Glomerulus, mesengialcells, Filtration Barrier)
JaveriaAbid (Proximal tubule)
Toba Abid (Loop of Henle, Distal tube)
SairaJaved (Collecting tubule, Juxtaglomerular apparatus
AmnaAshraf (Ureter,Urinarybladder, Urethra)
Data Compiled (Typed+ Edited in the form of presentation) By:
UsawerMaqsood