Download - FISIOLOGI GINJAL

Transcript

dr. Sri Lestari Sulistyo Rini, M.Sc

THE URINARY SYSTEM

The urinary system :

Ginjal menerima + 20% cardiac outputAliran darah ke ginjal 1-1,5 L / mnt

Darah yang difiltrasi 180 L / hr 125 ml/mnt

Ginjal terletak retroperitonealSebuah ginjal 135-150 gr.

Renal Function

1. Elimination of Waste Products 2. Regulation of Fluid Balance3. Regulation of Acid-Base Balance4. Nutrient Balance : - electrolytes : Na+, K+,

Cl-, Ca++,Mg++

- amino acids, glucose, proteins

vitamin5. Elimination, Detoxification of Drug and Toxins6. Endocrine Function : - erytropoietin

- vitamin D metabolism - renin

Nefron Unit fungsional ginjal- Sebuah ginjal terdiri dari + 1 juta nefron- Nefron : - Glomerulus

- Tubulus

Struktur Nefron

Afferent

Arteriole Efferent

Arteriole

The NEPHRON: The Functional Renal Unit

Urine formation

Eliminasi produk sisa metabolik Urea, Kreatinin, Asam urat, Sulfat,

Nitrat, Phosphat, dll.

Proses :1. Filtrasi glomerulus2. Reabsorpsi tubulus3. Sekresi tubulus4. Ekskresi

Ekskresi = Filtrat – reabsorpsi + sekresi

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Steps in Urine Formation

1) Glomerular Filtration

2) Tubular Reabsorption & Secretion

3) Water Reabsorption (Conservation)

How the Kidney Works

Pgc gc Pt

Filtrasi Glomerulus

Filtrasi glomerulus

Filtrasi Glomerulus

Reabsorpsi dan Sekresi Tubulus

Proximal TubulusReabsorpsi 80% air dan garamReabsorpsi semua glukosa, asam aminoReabsorpsi protein, urea, asam urat, bicarbonatSekresi ion Hidrogen, asam-basa organik

ReabsorpsiAktif : glukosa, asam amino, natrium, dllPasif : air dan urea

Transport maximum ( Tm) maksimum substansi yang di reabsorpsi per unit waktu

Transport maximum (Tm)

Reabsorption will return solutes to the blood

Binding sites for transport can become saturated at high levels

Solutes not reabsorped are lost in the urine

Vitamin C is reabsorped unless plasma values are so high that transporters can’t reabsorb any more – then excess vitamin C lost in the urine

Loop of HenleDescending limb permeabel terhadap airAscending limb impermeabel terhadap

air reabsorpsi Na dan Cl

Tubulus DistalReabsorpsi Na, Cl dan airADH mempengaruhi permeabilitas terhadap

airReabsorpsi dan sekresi KaliumAldosteron mempengaruhi reabsorpsi

Natrium dan sekresi Kalium

Mekanisme Countercurrent

Saraf simpatis arteriol aferen & eferen vasokonstriksi, RBF menurun

GFR menurun

Hormonal Renin-Angiotensin Aldosteron ADH Atrial Natriuretic Peptide

Renal Regulation

Duktus kolegentes Reabsorpsi Na dan Cl dipengaruhi ADH

HormonesAldosterone

Acts on distal convoluted tubule cells to stimulate active transport of 3 molecules of Na+ out of tubule (reabsorption) for every 2 molecules of K + brought into tubule (secretion)

Water from tubule lumen follows Na+ by osmosis into blood

Antidiuretic hormone (ADH)Acts to increase the number of aquaporins

(water channels) in the collecting duct membranes

Collecting ducts travel through hyperosmotic medulla

Higher levels of ADH increase the number of aquaporins allowing water to leave the duct and urine volume decreases

antidiuretic hormone (ADH).

Long-Term Effect of Osmolarity on BP

ADH

Distal Tubule

Aldosterone Release: the Renin-Angiotensin Pathway

Factors affecting the release of ADH.

Factors affecting release of Atrial Natriuretic Peptide.

Renal Function Test

Inulin Clearance

MIKSI

Vesika urinaria terisi reseptor regang sensorik N pelvikus (aferen) Medula Spinalis parasimpatis (eferen)

Miksi otot-otot perineum & sphincter uretra externa relaksasi, otot detrusor kontraksi urine melalui uretra

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Conduction of Urine

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Micturition Reflex

MIKSI

Menjaga keseimbangan cairan tubuh homeostasis

keseimbangan -jumlah volume -jumlah zat terlarut -konsentrasinya

Asupan cairan : - larutan/air dalam makanan - hasil metabolisme KH ( tiap individu berbeda, tergantung kebiasaan, aktivitas, cuaca)

Pengeluaran cairan : -insensible water loss tidak dapat diatur dengan tepat, terjadi menerus evaporasi lewat kulit, paru-paru +700ml-keringat + 100ml, dipengaruhi aktivitas, suhu-feses + 100ml, meningkat pada diare-urin dalam pembentukannya terdapat mekanisme untuk menjaga keseimbangan cairan dan elektrolit

KOMPARTEMEN-KOMPARTEMEN CAIRAN TUBUH Cairan ekstraseluler : plasma,cairan interstisial, transeluler ( cairan dalam sinovial, peritonium,perikardium, intraokular, serebrospinal) Cairan intraseluler Prosentase cairan dipengaruhi umur, jenis kelamin, derajat obesitas

Circulating Volume control

Urine pH ~ 6.0

Blood pH = 7.4

Blood [HCO3-] = 24 mM

Blood PCO2 = 40 mmHg

Plasma osmolality = 285 mOsm/kg water

Urine osmolality (depends upon hydration status) = 600 mOsm/kg water (note that this can vary between 50-1200 depending on water intake etc.)

Normal Urine & Blood

Buffer System

RENAL SYSTEM

CARDIOVASCULAR SYSTEM

RESPIRATORY SYSTEM

Acid-base balance

Gas exchange, ACE

Effective circulating volume

control, ECF osmolality, blood

pressure All of these are constantly changing,

trying to maintain HOMEOSTASIS!

Integration Renal – Cardiovascular – Respiratory System

TERIMA KASIH