Renal System Renal System Anatomy & Anatomy & PHYSIOLOGYPHYSIOLOGY

DR. AMAR UL-ALA BUTTDR. AMAR UL-ALA BUTTCONSULTANT UROLOGISTCONSULTANT UROLOGIST06-R-M-12967 (MOH 88/458)06-R-M-12967 (MOH 88/458)BURAIDAH CENTRAL BURAIDAH CENTRAL HOSPITAL(7/1)HOSPITAL(7/1)

Renal system summaryRenal system summary

Functions:Functions:1. Remove wastes from the body (urine)1. Remove wastes from the body (urine)

2. Regulates fluid balance, maintains homeostasis2. Regulates fluid balance, maintains homeostasis

Structures:Structures: 2 kidneys2 kidneys - filter blood, produce urine- filter blood, produce urine 2 ureters2 ureters - transport urine (kidneys to bladder)- transport urine (kidneys to bladder) bladderbladder - reservoir for urine- reservoir for urine urethraurethra - transport of urine- transport of urine

Renal anatomyRenal anatomy

lies retroperitoneal, on lies retroperitoneal, on posterior abdominal wallposterior abdominal wall

lies from T12-L3 of lies from T12-L3 of vertebral column, next to vertebral column, next to m. psoas majorm. psoas major

superior parts are superior parts are protected by ribs 11, 12protected by ribs 11, 12

tilted: superior poles are tilted: superior poles are closer to midline than closer to midline than inferiorinferior

KIDNEY KIDNEY FEATURES FEATURES

2 Poles2 Poles– UpperUpper– LowerLower

2 Borders2 Borders– LateralLateral– MedialMedial – – has hilumhas hilum

2 Surfaces2 Surfaces– AnteriorAnterior– PosteriorPosterior

RIGHT KIDNEY RIGHT KIDNEY ANTERIOR RELATIONSANTERIOR RELATIONS

Right suprarenal glandRight suprarenal gland

LiverLiver

DuodenumDuodenum

ColonColon

Coils of small intestineCoils of small intestine

LEFT KIDNEYLEFT KIDNEY ANTERIOR RELATIONSANTERIOR RELATIONS

Left suprarenal glandLeft suprarenal gland

Stomach Stomach

Spleen Spleen

Pancreas Pancreas

ColonColon

Coils of small intestineCoils of small intestine

KIDNEYKIDNEY POSTERIOR RELATIONSPOSTERIOR RELATIONS

Diaphragm Psoas

major

Transversus abdominis

Quadratuslumborum

Last ribsIlioinguinal

NIliohypo-gastric N

Rt Lt

Renal anatomyRenal anatomy

R kidney R kidney lowerlower than L than L (due to R lobe of liver)(due to R lobe of liver)

~ 12cm long x 5cm ~ 12cm long x 5cm

wide x 2.5cm thickwide x 2.5cm thick

bean-shaped , bean-shaped , reddish- brown organsreddish- brown organs

renal hilumrenal hilum

kidney levels change kidney levels change during respiration and during respiration and postural changespostural changes

External surface – 3 layers of External surface – 3 layers of tissuetissue

1.1. renal fasciarenal fascia (outer) (outer)– CT attaches kidney to CT attaches kidney to

posterior abdominal wall posterior abdominal wall – flexible, allows kidney – flexible, allows kidney to move with respirationto move with respiration

– covered by layer of fatcovered by layer of fat

2. 2. perirenal fatperirenal fat (middle (middle layer)layer)– protective cushionprotective cushion

3. 3. renal capsulerenal capsule ( (innermost)innermost)– layer of collagen fibres - layer of collagen fibres -

barrier against trauma, barrier against trauma, infection etc.infection etc.

– kidney hangs suspended kidney hangs suspended by collagen fibres and by collagen fibres and packed in soft cushion of packed in soft cushion of adipose tissueadipose tissue

Internal anatomyInternal anatomy

outer outer cortexcortex, inner , inner medullamedulla

6-18 conical 6-18 conical renal renal pyramidspyramids

apex - apex - renal papillarenal papilla projects into the projects into the renal renal sinussinus

renal columnsrenal columns extend from cortex inward extend from cortex inward

to renal sinus between to renal sinus between adjacent renal pyramidsadjacent renal pyramids

granular texture similar to granular texture similar to that of the cortexthat of the cortex

Internal anatomyInternal anatomy

ureter enters renal sinus, it ureter enters renal sinus, it expands to form a chamber expands to form a chamber called - called - renal pelvisrenal pelvis

pelvis branches to form 2-3 pelvis branches to form 2-3 major calycesmajor calyces

branch further to form 6-8 branch further to form 6-8 minor calycesminor calyces

Each minor calyx surrounds Each minor calyx surrounds the papilla of a renal the papilla of a renal pyramidpyramid

ducts within papilla connect ducts within papilla connect to wall of the calyx and to wall of the calyx and discharge urine produced in discharge urine produced in the cortex and medullathe cortex and medulla

Urine passes through the Urine passes through the calyces into the uretercalyces into the ureter

Left kidney: coronal sectionLeft kidney: coronal section

KIDNEY KIDNEY BLOOD SUPPLYBLOOD SUPPLY

IVC

Abdominal aorta

Renal A Renal V

Blood supply to the kidney:Blood supply to the kidney:

Renal arteriesRenal arteries from abdominal aorta enter hilum and branch: from abdominal aorta enter hilum and branch:

1. 1. Interlobar arteriesInterlobar arteries - pass through renal columns and reach - pass through renal columns and reach junction between medulla and cortexjunction between medulla and cortex

2. 2. Arcuate arteriesArcuate arteries run parallel with the base of the pyramids run parallel with the base of the pyramids

3. 3. Interlobular arteriesInterlobular arteries move up into the cortex and branch to move up into the cortex and branch to form the afferent arteriole form the afferent arteriole

The The peritubular capillariesperitubular capillaries unite to form the interlobular unite to form the interlobular veins, arcuate vein, interlobar vein, renal veinveins, arcuate vein, interlobar vein, renal vein

The The renal veinrenal vein exits at hilus and joins the IVC exits at hilus and joins the IVC

Blood supply to kidneyBlood supply to kidney

NephronNephron

= Functional unit of the kidney, ~ 1.2 million nephrons per kidney!= Functional unit of the kidney, ~ 1.2 million nephrons per kidney!

Tubular components:Tubular components:1. 1. Glomerular (Bowman’s) capsuleGlomerular (Bowman’s) capsule – double-walled cup – double-walled cup

– simple squamous epitheliumsimple squamous epithelium

2. 2. Proximal convoluted tubuleProximal convoluted tubule - coiled 1- coiled 1stst section section– simple cuboidal epithelium with microvillisimple cuboidal epithelium with microvilli

3. 3. Loop of HenleLoop of Henle - hair-pin loop - hair-pin loop– thin descending limb, thick ascending limbthin descending limb, thick ascending limb

4. 4. Distal convoluted tubuleDistal convoluted tubule - last section - last section – simple cuboidal epitheliumsimple cuboidal epithelium– specialised region - Juxta glomerular apparatusspecialised region - Juxta glomerular apparatus

Distal convoluted tubule opens into the collecting system Distal convoluted tubule opens into the collecting system collecting ductscollecting ducts papillary ducts papillary ducts minor calyx… minor calyx…

Nephron Nephron

Vascular component of Vascular component of nephronnephron

Made up of blood vessels:Made up of blood vessels:

1. 1. GlomerulusGlomerulus - network of capillaries within Bowman’s - network of capillaries within Bowman’s capsulecapsule

2. 2. Afferent arterioleAfferent arteriole - leading into glomerulus - leading into glomerulus

3. 3. Efferent arterioleEfferent arteriole - leading out of glomerulus - leading out of glomerulus

4. 4. Peritubular capillariesPeritubular capillaries - surrounding tubules - surrounding tubules

5. 5. Vasa rectaVasa recta - specialised loops of blood vessels around - specialised loops of blood vessels around long long Loop of Henle (juxtamedullary Loop of Henle (juxtamedullary nephrons)nephrons)

Nephrons:Nephrons: 85% are cortical, 15% are juxtamedullary 85% are cortical, 15% are juxtamedullary

Renal corpuscleRenal corpuscle

Ureters Ureters Pyelogram (colour-enhanced)Pyelogram (colour-enhanced)

tubes that transport urine from tubes that transport urine from renal pelvis to bladderrenal pelvis to bladder

20-30 cm long20-30 cm long

muscular walls - peristaltic muscular walls - peristaltic waves force urine down to waves force urine down to bladderbladder

retroperitonealretroperitoneal

pressure in the bladder pressure in the bladder compresses ureter, helps compresses ureter, helps prevent backflow of urineprevent backflow of urine

(physiological valve) - still allows (physiological valve) - still allows urine to flow into the bladderurine to flow into the bladder

RIGHT URETER, RIGHT URETER, RELATIONSRELATIONS

– AnteriorlyAnteriorly DuodenumDuodenum Terminal part of ileumTerminal part of ileum Right colic & iliocolic vesselsRight colic & iliocolic vessels Right gonadal vesselsRight gonadal vessels Root of mesentryRoot of mesentry

– PosteriorlyPosteriorly Right psoas major muscleRight psoas major muscle Bifurcation of right common iliac ABifurcation of right common iliac A

LEFT URETER, LEFT URETER, RELATIONSRELATIONS

– AnteriorlyAnteriorly Sigmoid colonSigmoid colon Sigmoid mesocolonSigmoid mesocolon Left colic vesselsLeft colic vessels Left gonadal vesselsLeft gonadal vessels

– PosteriorlyPosteriorly Left psoas major muscleLeft psoas major muscle Bifurcation of left common iliac ABifurcation of left common iliac A

URETER URETER CONSTRICTIONSCONSTRICTIONS

1.1. Where it joins Where it joins

the the renal pelvisrenal pelvis

2.2. Where it crosses Where it crosses

the the pelvic brimpelvic brim

3.3. Where it piercesWhere it pierces

the the bladder wallbladder wall

BladderBladder

hollow muscular organhollow muscular organ retroperitoneal, posterior retroperitoneal, posterior

to pubic symphysisto pubic symphysis

Capacity ~ 300-400 ml Capacity ~ 300-400 ml (max = 1000 ml)(max = 1000 ml)

empty: looks like a empty: looks like a deflated balloon, deflated balloon, rugaerugae

full spherical rises above full spherical rises above abdominal cavityabdominal cavity

Males: anterior to rectum, Males: anterior to rectum, above prostateabove prostate

Females: inferior to Females: inferior to uterus, anterior to vaginauterus, anterior to vagina

URINARY BLADDER URINARY BLADDER FEATURESFEATURES

Apex:Apex: points anteriorly---points anteriorly---median median umbilical lig.umbilical lig.

Base:Base: (posterior surface) (posterior surface)

Superior surfaceSuperior surface

2 Inferiolateral surfaces2 Inferiolateral surfaces

Neck:Neck: rests on rests on prostateprostate

Support of bladderSupport of bladder

superior surfaces - superior surfaces - peritoneumperitoneum

middle umbilical ligamentmiddle umbilical ligament - - superior border to umbilicussuperior border to umbilicus

lateral umbilical ligamentslateral umbilical ligaments - - sides of bladder to umbilicussides of bladder to umbilicus

At base, tough ligamentous At base, tough ligamentous bands anchor bladder to bands anchor bladder to pelvic and pubic bonespelvic and pubic bones

TrigoneTrigone : triangular area : triangular area bounded by openings of bounded by openings of ureters and exit to urethraureters and exit to urethra

cystitis - inflammation of the cystitis - inflammation of the bladder wallbladder wall

Cross section of ureter & Cross section of ureter & bladderbladder

lined by transitional epithelium lined by transitional epithelium to allow for stretch of wallto allow for stretch of wall

lamina proprialamina propria - - mucous membranemucous membrane– elastin fibreselastin fibres

smooth muscle (smooth muscle (m. m. detrusor)detrusor)– inner and outer longitudinalinner and outer longitudinal– middle circularmiddle circular

contraction compresses contraction compresses bladder and expels contents bladder and expels contents into urethrainto urethra

internal sphincter - internal sphincter - involuntary controlinvoluntary control

Urethra Urethra

FemaleFemale ~ 4cm long ~ 4cm long– opens to exterior opens to exterior

between clitoris and between clitoris and vaginal openingvaginal opening

MaleMale ~ 20 cm long~ 20 cm long– passes through prostate passes through prostate

glandgland

– pierces urogenital pierces urogenital diaphragmdiaphragm

– enters penis and enters penis and extends throughout extends throughout lengthlength

– opens at urethral orificeopens at urethral orifice

MALE URETHRA MALE URETHRA PARTSPARTSProstatic part:Prostatic part:

– The widest partThe widest part– About 3 cmAbout 3 cm

Membranous part:Membranous part:– In the urogenital diaphragmIn the urogenital diaphragm– About 1.25 cmAbout 1.25 cm

Penile part:Penile part:– In the penisIn the penis– About 15 – 16 cm longAbout 15 – 16 cm long

FUNCTIONS OF THE FUNCTIONS OF THE KIDNEYKIDNEY

1) Regulate the osmotic pressure (osmolality) 1) Regulate the osmotic pressure (osmolality) of the body fluids by excreting osmotically of the body fluids by excreting osmotically dilute or concentrated urine.dilute or concentrated urine.

2) Regulate the concentrations of numerous 2) Regulate the concentrations of numerous ions in blood plasma, including Na, K, Ca, ions in blood plasma, including Na, K, Ca, Mg, Cl, bicarbonate (HCO3), phosphate, and Mg, Cl, bicarbonate (HCO3), phosphate, and sulfate.sulfate.

3) Play an essential role in acid-base balance 3) Play an essential role in acid-base balance by excreting H, when there is excess acid or by excreting H, when there is excess acid or HCO3, when there is excess base.HCO3, when there is excess base.

FUNCTIONS OF THE FUNCTIONS OF THE KIDNEY KIDNEY 4) Regulate the volume of the ECF by 4) Regulate the volume of the ECF by

controlling Na and water excretion.controlling Na and water excretion.

5) Help to regulate arterial blood pressure by 5) Help to regulate arterial blood pressure by adjusting Na excretion and producing various adjusting Na excretion and producing various substances (e.g.,renin) that can affect blood substances (e.g.,renin) that can affect blood pressure.pressure.

6) Eliminate the waste products of metabolism, 6) Eliminate the waste products of metabolism, including urea (the main nitrogen-containing including urea (the main nitrogen-containing end-product of protein metabolism in end-product of protein metabolism in humans), uric acid (an end-product of purine humans), uric acid (an end-product of purine metabolism), and creatinine (an end-product metabolism), and creatinine (an end-product of muscle metabolism).of muscle metabolism).

FUNCTIONS OF THE FUNCTIONS OF THE KIDNEY KIDNEY 7) Remove many drugs (e.g.penicillin) and 7) Remove many drugs (e.g.penicillin) and

foreign or toxic compounds.foreign or toxic compounds.

8) Are the major production sites of certain 8) Are the major production sites of certain hormones, including erythropoietin and hormones, including erythropoietin and 1,25-dihydroxy vitamin D3 1,25-dihydroxy vitamin D3

9) Degrade several polypeptide hormones, 9) Degrade several polypeptide hormones, including insulin, glucagon, and parathyroid including insulin, glucagon, and parathyroid hormonehormone

10) Synthesize ammonia, which plays a role in 10) Synthesize ammonia, which plays a role in acid-base balance acid-base balance

FUNCTIONS OF THE FUNCTIONS OF THE KIDNEY KIDNEY 11) Synthesize substances that affect renal 11) Synthesize substances that affect renal

blood flow and Na excretion, including blood flow and Na excretion, including arachidonic acid derivatives arachidonic acid derivatives (prostaglandins, thromboxane A2) and (prostaglandins, thromboxane A2) and kallikrein (a proteolytic enzyme that kallikrein (a proteolytic enzyme that results in the production of kinins).results in the production of kinins).

When the kidneys fail, a host of problems When the kidneys fail, a host of problems ensue. Dialysis and kidney transplantation ensue. Dialysis and kidney transplantation are commonly used treatments for are commonly used treatments for advanced (end-stage) renal failureadvanced (end-stage) renal failure

Bone StructureBone Structure

Vitamin DActivation

CalciumBalance

Blood FormationBlood Formation

ErythropoietinSynthesis

Cardiac ActivityCardiac Activity

PotassiumBalance

Regulation of Blood pHRegulation of Blood pH

Recovery ofBicarbonate

Blood PressureBlood Pressure

Water Balance

SodiumRemoval

MetabolicEnd Products

MetabolicEnd Products

Removal of Urea, Creatinine etc.

Functions of the Kidney Functions of the Kidney

Manifold Tasks of the Manifold Tasks of the KidneyKidney

Functions

Healthy Kidney

Functions of the Kidney Functions of the Kidney

Filtration and ReabsorptionFiltration and Reabsorption

1500 lblood per daythrough the renal arteries

180 l filtrate per dayin the glomeruli

60 l urine per dayat the end of the proximal tubules

20 l urine per dayat the beginning of the distal tubules

10 l urine per dayat the end of the distal tubules

1,5 l urine per dayat the end of the collecting ducts

real removal: 1,5 l urine

Healthy Kidney

Micturition reflex:Micturition reflex:

Stretch receptors stimulated when filled Stretch receptors stimulated when filled to ~ 220 mlto ~ 220 ml

afferent fibres to spinal cordafferent fibres to spinal cord motor neurons to sm in bladder wallmotor neurons to sm in bladder wall contracts m. detrusor and increases contracts m. detrusor and increases

pressurepressure

need to relax both internal and need to relax both internal and external sphincter - external under external sphincter - external under voluntary controlvoluntary control

if external sphincter does not relax, if external sphincter does not relax, internal sphincter remains closed & internal sphincter remains closed & sm in bladder wall relaxes againsm in bladder wall relaxes again

Once volume exceeds 500 ml, Once volume exceeds 500 ml, micturition reflex may generate micturition reflex may generate enough P to open internal sphincter enough P to open internal sphincter

leads to reflexive relaxation of leads to reflexive relaxation of external sphincterexternal sphincter

Thank youThank you

All the best with your studiesAll the best with your studies

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