SISTEM URIN DAN Homeostasis Dr.dr.Zaenal M. Sofro, AIFM, Sport & CIRC. Med. Bagian Ilmu Faal Fak.Kedokteran UGM

NaCl Merangsang penyerapan cairan Meningkatkan rasa Meningkatkan keseimbangan cairan Menjaga keinginan untuk minum Membantu tubuh "hold" ke air Hindari Hiponatremia

Fisiologi Otot Otot Motor Neuron Serat otot Motor Satuan

Homeostasis Sistem kemih mempertahankan homeostasis dalam beberapa cara: Penghapusan urea (limbah nitrogen) dari aliran darah. Pengendalian air dan garam keseimbangan dalam aliran darah. Terlibat dalam regulasi tekanan darah.

Bayi Yang Baru Lahir Laki-laki dewasa Perempuan dewasa

ICF ISF plasma organ tubuh luar lingkungan hidup lingkungan internal Pertukaran dan komunikasi konsep kunci untuk memahami homeostasis fisiologis.

Tubuh Kompartemen Cairan: ICF: 55% ~ 75% 2/3 X 50 ~ 70% berat badan ramping TBW Extravascular Interstitial cairan 3/4 Sebagian besar terkonsentrasi di otot rangka Laki-laki (60%)> perempuan (50%) TBW = 0.6xBW ICF = 0.4xBW ECF = 0.2xBW 1/3 ECF Intravaskular plasma 1/4

Struktur internal Ginjal Lobe ginjal Piramida ginjal Papilla ginjal Kolom ginjal

Ginjal - internal Micro Anatomi Nefron - unit fungsional ginjal Tiga proses fisiologis: 1) filtrasi, 2) reabsorpsi, dan 3) sekresi Ketiga proses bekerja sama untuk mencapai berbagai fungsi ginjal Situs yang berbeda fungsi utama yang berbeda

Renin Renin adalah enzim yang dikeluarkan oleh ginjal sebagai respons terhadap penurunan tekanan darah. Renin mengkatalisis produksi angiotensin, hormon yang menyebabkan arteriol mengerut, meningkatkan tekanan darah. Hal ini juga menyebabkan retensi air. Bagaimana ini mempertahankan homeostasis tekanan darah?

Renal sel darah dan Filtrasi

Umum Tingkat fisiologis Fungsi % 120 100 80 Umum Tingkat fisiologis Fungsi 50 40 20 Orang Aktif Umur, tahun Orang menetap 17

Erythropoietin Respon kedua tekanan darah rendah adalah rilis dari erythropoietin, hormon lain. Erythropoietin perjalanan ke sumsum tulang dan merangsang produksi sel-sel darah baru. Bagaimana ini mempertahankan homeostasis?

Tubulus proksimal Nutrisi (garam, vitamin, dll) dipindahkan dari tubulus melalui transpor aktif. Air mengikuti nutrisi melalui osmosis.

Nefron-Tubular Sistem Proksimal tubulus berbelit-belit Descending lengkung Henle Naik lengkung Henle Distal tubulus berbelit-belit Mengumpulkan saluran

Lengkung Henle Jaringan di sekitar Loop of Henle asin, dari transportasi aktif dan difusi natrium klorida. Kondisi asin memungkinkan air untuk berdifusi keluar dari loop.

Tubulus distal Transpor aktif digunakan untuk memindahkan lebih banyak nutrisi dari urin terkonsentrasi . Beberapa ion, obat, dan racun secara aktif dipompa ke tubulus.

Mengumpulkan Duct Lebih banyak air daun tabung dengan osmosis, karena tabung dikelilingi oleh jaringan asin. Beberapa urea daun melalui difusi, dan dapat bersepeda melalui sistem.

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Minum Air Segera Minum Air Lebih Zona Aman Tidak Dehidrasi Agak terhidrasi Minum Air Lebih Tidak Dehidrasi Sangat Dehidrasi 26

Gambar 25.5

PENGARUH JENIS MINUMAN Terhadap OSMOLARITAS TUBUH aliran urin osmolaritas minum air 1.200 ml aliran urin osmolaritas minum 1200 ml saline isotonik Dua Pengamatan Eksperimental sangat berbeda

Haus

Otak Stem Tingkat pertama Tingkat kedua Tingkat ketiga All of these mechanisms are normally activated by a change in the firing rate of the volume receptors (stretch receptors) in the heart, great vessels and the liver. This input goes to the brain stem and results in an activation of the sympathetic nervous system which then brings about the changes in the body to defend EABV. The input to the hypothalmus that will ultimately have an effect on ADH and thirst is not through sympathetic nerves but through direct nerve tracts between the brain stem and the hypothalmic control centers for thirst and ADH. Minor point of detail. As we will see the effects on ADH and thirst and only brought into play when the depletion of EABV is severe. Whenever there is a reduction in EABV, the first reflex that is triggered involves the first level of response shown in the slide. This results in vasoconstriction of systemic arterioles (except in the heart, lungs and brain) to reduce the size the compartment, and to stimulate the heart to increase heart rate and stroke volume. These two changes bring about the needed change in EABV. You can trigger this reaction in yourself, just by lying down for a few minutes and then standing up. Feel your pulse as you go to the standing position. The kidneys will be added to the system when the reduction in EABV is moderate and persistant. You wouldn’t want this activated every time you stood up! This stimulates the kidney to conserve NaCl and water – nearly isotonic in nature. This aids in returning EABV to normal. Lastly in severe ECV depletion, the input to the brain stem will lead to activation of the hypothalmus to stimulate thirst and ADH. These two mechanisms will lead to the addition of pure water to the body. Because this is triggered by a non-osmotic stimulus i.e. osm was normal when it happened. Body fluid osm will actually decrease as a result causing hyponatiremia. This override of regulation of body fluid osmolality is allowed in the defense of ECV! Rather have your osm less than normal in contrast to dying from circulatory collapse. Tingkat pertama

Terima Kasih I would like to thank Dr. LaPorte and his Supercoures colleagues for providing me with this opportunity to share this lecture with you. I would also like to acknowledge my Iowa Bone Development colleagues for their continual support and insights---Steve Levy (PI), Trudy Burns, Julie Gilmore, Teresa Marshall, Jim Torner, John Warren, and Marcia Willing. Finally, I would like to thank Dr. A. Oliaro, Editor of Minerva Pediatrica, for his invitation to review the literature on this topic. Please contact me at: kathleen-janz@uiowa.edu or http//www.uiowa.edu/~hss/