Ekskresi 2015

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EKSKRESI

Dua proses dasar pembentukan urine :

Ultrafiltrasi Transport aktif (reabsorpsi &

sekresi)

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Organ Ekskresi Vakuola kontraktil (protozoa, sponge) Organ nephridia Kelenjar antenna (crustacea) Tubula malphigi (insekta) Ginjal Vertebrata Insang (crustacea, ikan) Kelenjar rektal (Elasmobranch) Kelenjar garam nasal Hati

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Invertebrate Excretory Structures

Contractile vacuoles are found in protozoans and freshwater sponges. An organ of water balance – expels excess water

gained by osmosis.

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Vakuola Kontraktil Pada Amoeba lacerate fungsi utama adalah

pengaturan osmotic dan volume,

Konsen trasi

Medium Sitoplasm

Vakuola Rasio V./S.

Osmotik (mOsm/l.)Na+ (m mol/l)

K+ (m mol/l)

< 20.20.1

1170,631

5119,94.6

0.4433

0.15

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Invertebrate Excretory Structures

The most common type of invertebrate excretory organ is the nephridium. The simplest

arrangement is the protonephridium of acoelomates and some pseudocoelomates.

Fluid enters through flame cells, moves through the tubules, water and metabolites are recovered and wastes are excreted through pores that open along the body surface.

Highly branched due to lack of circulatory system.

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Invertebrate Excretory Structures The metanephridium is

an open system found in annelids, molluscs, and some smaller phyla. Tubules are open at both

ends. Water enters through

the ciliated, funnel shaped nephrostome.

The metanephridium is surrounded by blood vessels that assist in reclaiming water and valuable solutes.

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Kelenjar Antenna Crustacea

Urine dibentuk melalui filtrasi, reabsorpsi dan sekresi tubula.

Ultrafiltrasi ditunjukkan dengan injeksi inulin yang nampak dalam urine.

Lobster, konsentrasi inulin urine sama dengan darah. Injeksi PAH dan fenol merah, kons.nya dalam urine > dalam darah

Carcinus, mereabsorpsi air, kons. inulin dalam urine > dalam darah. Kons. sodium dalam urine < dalam darah

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Invertebrate Excretory Structures

In arthropods, antennal glands are an advanced form of the nephridial organ. No open

nephrostomes, hydrostatic pressure of the blood forms an ultrafiltrate in the end sac.

In the tubule, selective resorption of some salts and active secretion of others occurs.

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Tubula Malphigi Urine dibentuk tanpa ultrafiltrasi Urine awal dibentuk dengan didahului

transport aktif potasium dan air mengikuti secara pasif.

Proses berikutnya modifikasi urine awal dengan sekresi dan reabsorpsi.

Di hindgut zat terlarut dan air direabsorpsi, asam urat diendapkan untuk dikeluarkan sebagai campuran urine dan feses.

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Invertebrate Excretory Structures

Insects and spiders have Malpighian tubules that are closed and lack an arterial supply.

Salts (especially potassium) are secreted into the tubules from the hemolymph (blood). Water & other solutes

(including uric acid) follow.

Water & potassium are reabsorbed.

Uric acid is expelled in feces.

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Ginjal Mollusca

Urine dibentuk lewat ultrafiltrasi, reabsorpsi dan sekresi aktif.

Ultrafiltrat berisi zat terlarut sama dgn darah, kecuali protein

Reabsoprsi glukosa dan asam amino Dua komponen disekret adl PAH dan fenol

merah Pada Abalone, fungsi dua ginjal tdk identik.

PAH dan fenol merah disekresi oleh ginjal kiri dan reabsorpsi glukosa terjadi pd ginjal kanan.

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Vertebrate Kidneys Kidneys, has six roles homeostasis : ion

balance, osmotic balance, blood pressure, pH balance, excretion and hormone production.

Nephrons and associated blood vessels are the functional unit of the mammalian kidney.

The mammalian excretory system centers on paired kidneys which are also the principal site of water balance and salt regulation.

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Vertebrate Kidneys Each kidney is

supplied with blood by a renal artery and drained by a renal vein.

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Ginjal Mamalia Ginjal Menerima Aliran Darah Kira-Kira 20 – 25 % Dari Total

Output Jantung Unit Fungsional Ginjal Mamalia Adl Nephron. Tiap Ginjal Berisi Sejumlah Besar Nephron Yg Membuang

Isinya Ke Sal. Pengumpul. Setiap Nephron Dimulai Dgn Kapsula Bowman. Sebelah Dlm

Kapsula Ini Terdapat Glomerulus. Glomerulus Bertanggungjawab Untuk Langkah Pertama

Pembentukan Urine Nephron Dpt Dibagi Dlm Tiga Daerah Utama Yi Nephron

Proksimal, Loop Henle Dan Nephron Distal.

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Structure of the nephron

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Dua Tipe Nephron Ditemukan Pada Burung Dan Mamalia :

Juxtamedullary Nephron, Memp Glomerulus Pd Korteks Sebelah Dlm Dan Loop Henle Panjang Masuk Ke Dlm

Medula.Cortical Nephron, Memp. Glomerulus Di Korteks Sebelah Luar

Dan Loop Henle Relatif Pendek Yg Hanya Sedikit Masuk Ke Medula.

Arteri Renal Terbagi Membentuk Arteriola Aferen Pendek Yg Mensuplai Tiap Nephron

Kapiler Glomerulus Bergabung Membentuk Arteriola Eferen.

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General regions of filtration, reabsorption, and secretion

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Filtrasi Glomerulus 15- 25 % air dan solute dikeluarkan dari

plasma Laju ultrafiltrasi 125 ml. min-1 pd ginjal

manusia Tiga faktor penentu utrafiltrasi :

- Perbedaan tekanan hidrostatik diantara lumen kapiler glomerulus dan lumen

kapsula Bowman- Tekanan osmotic koloid plasma darah- Permiabilitas hidraulik jaringan tiga lapis

yang memisahkan dua kompartmen

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Pathway of the Filtrate

From Bowman’s capsule, the filtrate passes through three regions of the nephron: Proximal tubule Loop of Henle Distal tubule

Fluid from several nephrons flows into a collecting duct.

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From Blood Filtrate to Urine: A Closer Look

Filtrate becomes urine as it flows through the mammalian nephron and collecting duct. The composition of the filtrate is modified

through tubular reabsorption and secretion.

Changes in the total osmotic concentration of urine through regulation of water excretion.

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