Structure of Kidneys

8/10/2019 Structure of Kidneys

1/36

STRUCTURE AND FUNCTION OF

THE KIDNEYS AND THE LOWER

URINARY TRACT

OBYECTIVES

1.Describe the location of the kidneys and their gross anatomicalfeature.

2.Describe the defferent parts of the nephron and their location

within the cortex and medulla.

3.Identify the components of the glomerulus and the cell types

located in each component.

4.Describe the structur of glomerular capillaries and identify

which structures are filtration barriers to plasma proteins.


2/36

OBYECTIVE

5.Describe the components of the yuxtaglomerular

apparatus and the cells located in each component

6.Describe the bood supply to the kidneys.

7.Describe the innervation of the kidneys.

8.Describe the anatomy and physiology of thelower urinary tract.


3/36

STRUCTURE OF THE KIDNEYS


4/36


5/36


6/36


7/36


8/36


9/36

INNERVATION OF THE BLADDER

Is important in controling urination

Sympathetic hypogastric nerves

Alfa adrenergic receptorprimarily in the bladder

neck and urethra.

Parasympathetic fiber via pelvic nerves (muscarinic)

innervated the bladder bodybladder contraction

Pudendal nervesskeletal muscle fiberexternal

sphinctercontraction


10/36

MICTURATION

IS THE ACT OF EMPTYING THE URINARY

BLADDER : TWO PROCESS

PROGRESSING FILLING OF THE BLADDER

MICTURATION REFLEX TO EMPTIES THE

BLADDER


11/36

GLOMERULAR FILTRATION

AND RENAL BLOOD FLOW

OBJECTIVES1. Describe the concepts of mass balance and clearence

and explain how they are used to analyze renal trnsport

2. Define the three general process by which substances arehandled by the kidneys:glom. Filtration, tub.reabsorb and

tub. Secretion.

3. Explain the use of inulin and creatinine clearence to mea-

sure the GFR.

4. Explain the use of p-aminohippuric acid (PAH) clearence

to measure renal plasma flow(RPF)

5. Describe the composition of theglom.ultrafiltrate, and

identify which molecule are not filtered by the glomerulus.


12/36

OBJECTIVES(cont.)

6. Explain how the los of negative charges on the glom.

capillaries results in proteinuri.7.Describe starling forces involved in the formation of

the glom. Ultrafiltrate , and explain how charges in each

force affect the glom.filtration rate.

8.Explain how the starling force change along the length

of the glom. Capillaries.

9.Describe how changes in the renal plasma flow rate

influence the GFR.

10.Explain autoregulation pf renal blood flow and the GFR

and identify the factors responsible for autoregulation11.Identify the major hormones that influence RBF.

12.Explain how and why hormones influence RBF despite

autoregulation.


13/36


14/36

RENAL CLEARENCE

GLOMERULAR FILTRATION

REABSORBTION

SECRETION

C x= Ux X V

Px

Cx=clearence x

Ux=conc. x in

urine

V= urine flowrate/minute

P= conc. x in

plasma


15/36

MEASUREMENT OF GFR

CLEARENCE OF INULIN

Amount filtered = amount excreted

GFR X Pin = Uin X V

GFR = Uin X V

Pin


16/36

MEASUREMENT OF RENAL PLASMA FLOW

AND RENAL BLOOD FLOW.

RPF= CLEARENCE OF PAH PAH LOW 0,12mg/ml

RPF = Upah X V

P pah

RBF = RPF

1 - HCT


17/36

REQUIREMENTS FOR USE OF A SUBSTANCE

TO MEASURE GFR

1. The substance must be freely filtered by the

glomerulus.

2. The substance must not be reabsorbed or

secreted by the nephron .

3. The substance must not be metabolized or

produce by the kidney.4. The substance must not alter GFR


18/36


19/36


20/36

USING CLEARENCE TO ESTIMATE

TRANSPORT MECHANISM

EXCRETION RATE = FILTERED LOAD

REABSORPTION RATE +

SECRETION RATE

Ux X V = GFR X PxR+S

Note : - if its clearence is less than the inulin clearence , the

substance is reabsorbed by the nephron ( glucose)- if its clearence is greater than the inulin clearence,

the substance is secreted ( e.g. PAH)

- if its clearence equals the inulin clearence , the

substance is only filtered.


21/36


22/36


23/36

RENAL BLOOD FLOW

RBF = 25% CARDIAC OUT PUT (1.25 L/min)

THE IMPORTANT FUCTION OF RBF INCLUDING:

1. Determining the GFR

2. Modifying the rate of solute and water reabsorption by

the proximal tubule.

3. Participating in the concentration and dilution of urine.

4. Delivering oxygen, nutrients and hormones to the nephroncell and returning CO2 and reabsorbed fluid and solute to

general circulation.


24/36

REGULATION OF RENAL BLOOD FLOW

hemorrhage

Arterial blood pressure

Intra renal receptors

Renin secretion

Plasma renin

Plasma angiotensin

Constriction of

Renal arterioles

RBF and GFR

Activity of renal

Symphatic nerves

Carotic sinus andAortic arch reflexs


25/36

REN L TR NSPORT MECH NISM

NaCL AND WATER REABSORPTION ALONG

THE NEPHRONOBJETIVE

1.Explain the three processes involved in the production of urine

a. filtration b. reabsorption c. secretion.

2.Describe the magnitude of the processes of filtration and reab-sorption by the nephron.

3.Describe the composition of normal urine.

4.explain the basic transport mechanisms present in each nephron

segment.5.Describe how water reabsorption is coupled to Na+ reabsorp

tion in the proximal tubule.

6.Explain how solutes, but not water , are reabsorbed by the thick

ascending limb of Henles loop.


26/36

OBJECTIVE - CONT.

7. Describe how Starling forces regulate solute and

water reabsorption across the proximal tubule.

8. Explain glomerulotubular balance and its phy-siological significance .

9. Identify the major hormones that regulate NaCl

and water reabsorption by its nephron segment


27/36

COMPOSITION OF URINE

SUBSTANCE CONCENTRATION

Na+ 50 - 150 meq/l

K+ 20 - 70 meq/l

NH4- 30 - 50 meq/l

Ca++ 5 - 12 meq/lMg++ 2 - 18 meq/l

Cl - 50 - 130 meq/l

PO4 20 - 40 meq/l

Urea 200400 mM

Kreatinin 6 - 20 mM

pH 5 - 7

Osmolality 500 - 800 mOsm/Kg H2O

others 0


28/36

MECHANISMS OF SOLUTETRANSPORT

PASSIVE

Spontaneous , down an electrochemical

gradientno energy requirement.

Diffusion

Facilitated diffusion

ion channel

Uniport

Coupled transport

Antiport

Symport


29/36

MECHANISMS OF SOLUTETRANSPORT (Cont)

ACTIVE

Againstan electrochemical gradient, requires

direct input of energyActive transport

Endocytosis.


30/36

Tubuler fluid

Paracelluler

pathway

Transcelluler

pathway

Tight

junction

Apical cell

membrane

Lateral intercellular space

blood

Na+

K+

Na+

Na+

Basolateral

membrane

Capillary

Basement

membrane

ATP

ATP

ATP


31/36

Tubular fluidblood

Na+

X

Na+H+

HCO3

K+

Na+ATP

X

CO2 + H2O

CA

First half of proximal tubule


32/36

Tubular fluid

blood

NaCl

H2O

Na+

Cl-

orga

nics

H2O

0rganics Na+ Cl-

org

anic Na+ Cl-

organics Na+ Cl-

H2O


33/36

Tubular fluid

CL-

Na+

Na+ Na+ Na+

H+

Hbase

Base

Cl-

Cl-

Na+

Cl-

H base

K+ATP

K+

Cl-

blood

Second half of proximal tubule


34/36

Some organic secreted by the proximal tubule

Endogenous anions Drug

cAMP acetazolamideBile salts chlorothiazide

Hippurate(PAH) furosemide

Oxalate penicillin

Prostaglandins probenecid

Urate salicylate(aspirin)

hidrochlorthiazide

bumetanide


35/36

Some organic cations secreted by the

proximal tubule

Endogenous cations Drugs

Creatinine atropineDopamine isoproterenol

Epinephrine cimetidine

Norepinephrine morphine

quinineamiloride


36/36

Structure of Kidneys

Documents

Transcript of Structure of Kidneys