Physiology of kidney and urinary system compatibility mode

sinh lý thận hay cho sinh viên.tài liệu tiếng anh Physiology of kidney and urinary system compatibility mode sinh lý thận hay cho sinh viên.tài liệu tiếng anh Physiology of kidney and urinary system compatibility mode sinh lý thận hay cho sinh viên.tài liệu tiếng anh Physiology of kidney and urinary system compatibility mode

Kabul Medical University Physiology Department

Physiology of Kidney & Urinary

System

f

Prepared by: Asso Prof Dr Mohammad Amin Frotan

1388

Function of The Kidney

z Control of the level of the substances in the blood

z Filtratiosn of the blood from waste product

z Filtratiosn of the blood from waste product

– Exp: Urea, Createnin, Urinc Acid, Bilirubin, etc

– Drugs, toxin…

z Endocrine Function:

– Renin: Blood Pressure Control

– Erythropoitin: stimulant is mainly hypoxia.

– 1.25 dihydroxyvitD3

z Regulation water and electrolyte balance

z Gluconeogenesis

z Gluconeogenesis

Anatomophysiology of the Urinary System Urinary System Physiology

Kidney Pelvis Ureteropelvic Junction Ureter

Ureterovesical Junction Urinary bladder

Prostate Urethra

Anatomophysiology of the Kidney

Major Calyces Pelvis

Medulla

Ureteropelvic Junction Ureter

Lobe

Renal Blood Flow

– Medullary

z Collecting Duct

THE NEPHRONE

REGIONAL DIFFERENCE IN NEPHRONE

REGIONAL DIFFERENCE IN NEPHRONE STRUCTURE

z Cortical Nephron p

– Short Loop of Henle

– Peritubular capillary network

z Juxtamedullary Nephron (20-30%):

– Long loop of Henle

– Vasa recta

Juxtaglomerular Complex

z Macula Densa

z Juxtaglomerular Cells

z Juxtaglomerular Cells

Mechanism of Function of the Nephron

Filtration

Reabsorption

Excretion

Blood Flow of the Kidneys

Blood Flow of the Kidneys

Diameter of the holes

Glumerolar Membraen and its

Selective Permeability

Diameter of the holes Negativity of the basal memb

Endothelial Epithelium Basal membrane

8 nm

Protein = 1/240

Glumerolar Filtrate and its difference to

Positive Ions 5

No RBC

Plasma

Pressures for Glumerular Filtration

Pressures for Reabsorption in Peritubular Capillaries

Gl l Fil i R

Glomerular Filtration Rate

Amount of glomerular filtrate/min:

Definition:

Blood flow of the kidney

Factors Affect

the GFR: Aff art constriction

Eff art constriction Glomerular Pressure Eff art constriction

Absorption of unnecessary substances Excretion of necessary substances

GFR depends on diameters of afferent and efferent

Angiotensin II blockade

Noradrenaline (Symp

nerves)

R i Angiotensinogen

Renin

Aldosterone

Aldosterone Angiotensi-II

Angiotensin-I

Converting Enzyme

Juxtaglomerular Complex

Mechanism of GFR Regulation:

I: In Case of Hypotension and decrease in GFR

(Stable in 75 - 160mmHg of blood pressure)

GFR

1: Aff art Vasodilator Mechanism:

Tubular flow Na & Cl

absorption Level of Na & Cl

Stimulation of Macula Densa Aff art dilatation

GFR

2: Eff art Vasoconstrictor Mechanism:

Angiotensin Activation

Stimulation of Macula Densa

Aldosterone Eff art Constriction

Na & Fluid

Absorption

GFR by the effect sympathetic is important in cases of acute

Autoregulatory escape disturbances such as brain ischemia or severe hemorrhage

Eff t f Bl d P U i O t t

Effect of Blood Pressure on Urine Out put:

(> 200mmHg ) 7 times of urine Output

1: Pressure Diuresis (> 200mmHg ) 7 times of urine Output

1: Pressure Diuresis

Urine Output 0

2: ( >50mmHg )

Reabsorption & Secretion in the

Sodium Counter-Transport

Massive Pinocytosis

Phagocytosis

Reabsorption Ability of Different Parts of the Tubules

P i i l ll

Aldosterone

Na

Intercaleted (Brown ) cells

Reabsorption of different substances in the Tubules

AA glu AA

Na

Ca

HCoH

Cl

N Aceto acetate

Vitamins Proteins

Urea 50%

50%

125mg/min

T Load

320mg/min Tm

T f S di b ti

Tm for Sodium absorption

Angiotensin

Na 65meq /day

Reabsorption & Secretion in the

Reabsorption & Secretion in the

Inulin (Polysaccharide)

X X

C t l f O l it f th B d Baroreceptors

Control of Osmolarity of the Body

Volume receptors Aldosterone

Salt Apatite Center

Nervous System Factors

ADH Osmoreceptors System

Na 110 – 120meq/lit Death

Osmolality Osmoreceptors ADH

Reabsorption of water

Osmolality(4mosmol) or Threshold for drinking

Thirst Center

2meq.Na Threshold for drinking

Atrial Volume Receptor Reflex Baroreceptors

Factors Affect Blood Volume

Cardiac Disease Cardiac Output GFR Water Absorption

Polycythemia Viscosity & Resistance Blood Return CO

Circulation Capacity

Pregnancy: 15-20%

Varicose Vein (20% )

Mechanism of more Urea excretion against less water excretion Urea Excretion

Mechanism of more Urea excretion against less water excretion

25-30g/day – daily production

P t i E ti Primary Aldosteronism K

Potassium Excretion

Addison K

Aldosteron Na 100meq

27%

100mg 4.5 + 0.3meq (8meq Fibrillation and Cardiac arrest)

Calcium Excretion

Ca

Ca

Metabolic Acidosis Metabolic Alkalosis

Ca

Ca

Phosphate Level Regulation

Protein

1mmol/lit

Overflow 0.8mmol/lit

Threshold level

Tm 0.1mmol/min

P

P

Permanent excretion

Body Fluids and The Kidneys

Total Body Fluids

-Total Body Fluids

- Daily Intake and Loss of water

- Chemical Composition of Body Fluids

- Measurement of Body Fluids

- Edema

Kidney

Intake

Kidney Lung Feces Sweat Skin Plasma3 Lit

Total Body Fluid y (60% of body w or 42lit in 70 kg adult)

Intracellular Fluid

(28 lit)

Extracellular Fluid (14 lit)

Plasma(1/4) (3 lit)

Interstitial Fluid (3/4) (10lit)

Transcellular Fluid (1 2lit)

Total Body Fluid

40 Lit (70Kg) (60% of total body weight) (75% in Newborn) and about 40% in old

Women less: due to more fat

Daily Intake of Water: (2300ml/day)

Ingested Water: (2100ml/day)

Liquid Form (2/3)

In the food eaten (1/3) Synsetized: From oxidation of Carbohydrates

Daily Loss of Water

Normally at atmospheric temperature of 200c:

Urine: 1400ml Sweat: 100ml

Sweat: 100ml Feces: 100ml Insensible:

Skin: 300 – 400ml/day (Diffusion)

(Cholestrol of cornified layer of skin act as a protector so in burn 3 5lit losses)

Respiratory Tract: 300-400ml/day (Vapor)

(Vapor pressure of RT is 47mmHg>Atmospheric air Vapor pressure)

Cold weather decrease the vapor pressure of Atmospheric air so more loss of water and causes dry feeling

in respiratory passage)

Loss of water in Hot Weather and During Exercise g

Hot weather: through

Sweet: occasionally 1-2lit/hour Exercise: Through:

Increase rate of respiration Increases body heat and sweating.

The Body Fluid Compartments

C t l f Fl id i t k d O t t

Control of Fluid intake and Output:

Daily intake and Output of Water (in ml/day)

Output

Insensible skin 350 350 Insensible lungs 350 650 Sweat 100 5000 Feces 100 100 Urine 1400 500 Total Output 2300 6600

Role of the kidneys:

a: water balance:

The urine volume can be as low as 0.5 lit/day or as y high as 20 lit/day according to the fluid intake

b: Electrolyte balance.

Chemical Composition of Extracellular and Intracellular FluidsPlasma Interstitial Intracellular

Chemical Composition of Extracellular and Intracellular Fluids(mOsm/l H2O) (mOsm/L H 2 O) (mOsm/L H2O)

Major cations and anions of the Intracellular and Extracellular Fluids Cations Anions Major cations and anions of the Intracellular and Extracellular Fluids Cations Anions

Chemical Composition of Extracellular and Intracellular Fluids

PhosphoricPotassium

Important constituent of the Extracellular Fluid

-Protein (In Plasma)

Small quantities of:

Important constituent of the Intracellular Fluid

Large quantities of:

large amount of protein (approximately four times as much as in plasma)

Small quantities of:

Na+:

Cl-:

Cl :

Almost no Ca++

Measured Hematocrit : Percentage of RBC in the Blood

In determaining the Hematocrit: 3-8% Plasma entrapped among cells.

Therefore the

True Hematocrit : is about 96% measured Hct.

In Severe Anemia Hct = 10

In Severe Anemia Hct = 10.

In Polycythemia Hct = 65 (Blood Viscous and death)

Body Hematocrit : Average of Hct of large and small vessels

Hct is less in the capillaries, arterioles and other small vessels : Because plasma can easily pass through these vessels

Body Fluids and Other Mass Data

Body Fluid: 50% in (Obese) to 70% of body weight

Measurement of Body Fluid Volume

The Dilution Principle

Quantity of test substance instilled Volume (ml) =

(For measurement of body fluid)

Substance in Syringe A Injected into C t t B

Determination of Volumes of Different Body Fluid

Compartments

Total Body Water:

Radioactive Water contain tritium 3H (3H2O) or heavy water deuterium(H2) or antipyrin (very lipid soluble): These mix with total body water within a few hours after being injected

Extracellular Fluid Volume:

Substances which diffuses into most of the extracellular fluid:

radioactive Sodium (22Na), chloride, bromide, radiothalamate, thiosulfate ion, thiocyanite ion, inulin and Sucrose

30minutes or one hour after injection can the sample be taken.

Calculation of Intracellular Volume:

= Total body water - extracellular fluid volume

Measurement of Plasma Volume:

Substances that attaches strongly to plasma protein can be injected Like: Evans blue dye or y 125 I-albumin (T1824) ( )

Calculation of Interstitial Fluid Volume:

The Plasma Volume subtracted from the extracellular volume

Measurement of Blood Volume:

Radioactively labeled RBC with chromium ( 51Cr) is injected.

Or also can be measured:

Or also can be measured:

Plama volume / (1- hematocrit/100) Example: 3lit / 1- 0.4 = 5 lit

Measurement of RBC Volume:

Measurement of RBC Volume:

by Subtracting Plasma volume from total blood volume

Basic Principles of Osmosis and Osmotic Pressure

To the side of less constituent the chemical potential of water is greater

as a result net diffusion of water molecules will occur which called rate of Osmosis

Osmotic Pressure:

The pressure which opposes the osmosis of water.

19.3 mmHg pressure for 1mosmol/lit.

Osmoles:

Osmoles:

The ability of solutes to cause osmosis and osmotic pressure is measured in terms of “Osmoles”

(The Osmole is the total number of particles)

1 mole = 6.02 x 1023solute particles if it is present in a lit of solution it is called 1osmol/lit.

One gram mole of nonpermeant and non ionizable substance is equal to 1 osmole

If a substance ionizes into two ions (Nacl into Na and Cl ions) then 0.5gram mole of the substance equals to 1 Osmole

Milliosmole = 1/1000 osmole is commonly used

Milliosmole = 1/1000 osmole, is commonly used.

Osmotic effect of Ions:

Nonpermeant Ions effects the osmosis same as nonpermeant molecule does

When a molecules dissociates into two or more ions, each of the ions exerts osmotic

i di id ll pressure individually

Bivalent ion (Ca) exerts no more osmotic pressure than does univalent ion (such as Na)

Relationship of the Molecular Concentration of a Solution to Its Osmotic Pressure:

Each nonpermeant molecule dissolved in water changes the chemical potential of the water

So the osmotic pressure is proportional to the concentration of the nonpermeant molecules

So the osmotic pressure is proportional to the concentration of the nonpermeant molecules regardless of their molecular weight

For instance, one molecule of albumin with a molecular weight of 70,000 has the same

osmotic effect as a molecule of glucose with a molecular weight of 180

Osmolality: (Preferred in very concentrated solution)

The osmole/Kg of water

Osmolarity: (Preferred in very diluted solution of normal human body)

Osmolarity: (Preferred in very diluted solution of normal human body)

The osmole/Lit of solution

Osmolality of the body Fluids:

4/5 of the total osmolality of the extracellular fluid is caused by Na and Cl

Half of the Intracellular osmolality caused by K ions

Corrected Osmolar Activity of the Body Fluids:

Molecules and ions in solution exert either intermolecular attraction from one solute molecule to the next or intermolecular repulsion

These two effects can cause respectively a decrease or an increase in the

These two effects can cause respectively, a decrease or an increase in the

osmotic “activity” of the dissolved substance

body if placed in one side and water at the other, this pressure can be measured:

For Plasma it is 5450 mmHg which is 19 3 times the corrected osmolality of

For Plasma it is 5450 mmHg which is 19.3 times the corrected osmolality of

282.5mOsmol/kg for Plasma

Maintenance of Osmotic Equilibrium

Isotonic Solution (Nacl 0.9% or 5% Glucose

Hypotonic Solution Burst

Hypertonic Solution

Collaps

Edema: Excess fluid in the tissue

I: Intracellular Edema

Causes:

Causes:

1: depression of the metabolic system of the tissue.

2: Lack of adequate nutrition to the cells.

3: Inflammation: Increases the permeability

to sodium & other Ions.

Stop pumping of sodium out of the cells

II: Extracellular Edema

C

Causes:

1: Abnormal leakage of fluid from the plasma.

2: Failure of the lymphatics to return fluid from the interstitium.

Filtration: = Kf x (Pc – Pif – Пc + Пif)

Kf = Capillary filtration coefficient (the permeability and surface area of the capillary)

Pif = Intrastitial fluid hydrostatic pressure

Пc = Capillary plasma colloid osmotic pressure

Пif = Intrstitial fluid colloid osmotic pressure

Causes of Edema:

I: Increased capillary filtration coefficient:

Causes leakage of plasma and proteins As in allergic reaction, infection and toxic substances.

II: Increased capillary hydrostatic pressure: p y y p

As in obstruction of vein or heart failure.

III: Decreased plasma colloid osmotic pressure:

As in liver disease (Cirrhosis), loss of protein in urine (nephrotic syndrome) or loss protein through burned area.

IV: Increased interstitial fluid colloid osmotic pressure:

Causes: lymphatic blockage (Edema can be severe) because once

protein leak into the interstitium have no other way to be returned to plasma.

As in infection of lymphnode, cancer, after surgery etc y p , , g y

Safety Factors That Normally Prevent Edema:

I: The compliance of the tissues is low ( interstitial fluid hydrostatic pressure is in the negative range).

Increase of interstitial fluid volume markedly increases interstitial y hydrostatic pressure which opposes further capillary filtration.

The safety factor for this effect is 3mmHg.

II: Lymph flow can increase 10 to 50 fold:

The safety factor for this effect is 7 mmHg.

III: Washdown of interstitial fluid protein as lymph flow increases:

III: Washdown of interstitial fluid protein as lymph flow increases:

The safety factor is 7mmHg.

Combining all the safety factor is about 17mmHg So capillary pressure should rise 17mmHg before interstitial edema occure g

Relation between interstitial fluid hydrostatic Pressure y and Interstitial Fluid Volume

Lymph Channels of the Body:

- all the tissues have the channels, the exception include the superficial portion of the skin, CNS, the endomysium of muscles and the bones, but they still have prelymphatic channels.

- the total quantity of the lymph is 2-3 lit/day

- 10% of the fluid filtering from the arterial ends of the capillaries returns back to the blood through the lymphatic vessels capillaries returns back to the blood through the lymphatic vessels

Formation of the Lymph: y p

- has almost the same composition as the interstitial fluids

- the protein concentration 2g/dl.

- Lymphatic system of GIT 1-2% fat.

large particles even bacteria can enter

- large particles even bacteria can enter…

Rate of Lymph Flow:

- 100mlit/h flows through the thoracic duct and 20ml through the other channels

through the other channels.

Factors that Determine Lymph Flow:

- the interstitial fluid pressure

- the activities of the lymphatic pump the activities of the lymphatic pump