FISIOLOGI GINJAL
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Transcript of FISIOLOGI GINJAL
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
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
p 904
Steps in Urine Formation
1) Glomerular Filtration
2) Tubular Reabsorption & Secretion
3) Water Reabsorption (Conservation)
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
Saraf simpatis arteriol aferen & eferen vasokonstriksi, RBF menurun
GFR menurun
Hormonal Renin-Angiotensin Aldosteron ADH Atrial Natriuretic Peptide
Renal Regulation
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
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
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
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
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