SISTEM EKSKRESI - WordPress.com

LATIHAN

SISTEM EKSKRESI

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Osmoregulators control water and solute concentrations

– Freshwater fishes gain water by osmosis and tend to lose solutes Osmotic water gain through gills and other parts of body surface Uptake of water and some ions in food

Uptake of salt ions by gills Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Excretion of large amounts of water in dilute urine from kidneys

Many marine fishes lose water by osmosis, drink seawater, and excrete excess salts

Gain of water and salt ions from food and by drinking seawater

Excretion of salt ions from gills


Osmotic water loss through gills and other parts of body surface

Excretion of salt ions and small amounts of water in scanty urine from kidneys

25.9 THE EXCRETORY SYSTEM PLAYS SEVERAL MAJOR ROLES IN HOMEOSTASIS

The excretory system expels wastes regulates water and salt balance

(Inferior vena cava) Renal artery and vein

Kidney

(Aorta) Ureter Bladder Urethra

A. THE EXCRETORY SYSTEM


Renal medulla Renal cortex Renal pelvis

Bowman’s capsule

Nephron tubule

Renal cortex

Renal artery Renal vein

Collecting duct Renal medulla

Ureter To renal pelvis

B. THE KIDNEY


C. ORIENTATION OF A NEPHRON WITHIN THE KIDNEY

Each nephron consists of a folded tubule and associated blood vessels

Bowman’s capsule Arteriole from renal artery

Capillaries

Arteriole from glomerulus Branch of renal vein

– The nephrons extract a filtrate from the blood – They refine the filtrate into a much smaller amount of urine Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

1 Proximal tubule Glomerulus

3 Distal tubule From another nephron Collecting duct

2 Loop of Henle with capillary network

D. DETAILED STRUCTURE OF A NEPHRON

Bowman’s capsule

Proximal tubule NaCl H2O HCO3–

Glucose and amino acids

Distal tubule NaCl

H2O

HCO3–

Blood

Filtrate H2O Salts (NaCl, etc.) HCO3– H+ Urea

Some NH H+ 3 drugs and poisons

K+

H+ Collecting duct

CORTEX MEDULLA

Glucose Amino acids Some drugs

Loop of Henle

NaCl NaCl

H2O

Reabsorption Active transport Passive transport

NaCl

Urea H2O

Secretion (active transport) Urine (to renal pelvis)


Line from artery to apparatus

Pump

Line from apparatus to vein

Tubing made of a selectively permeable membrane

Dialyzing solution

Fresh dialyzing solution


Used dialyzing solution (with urea and excess salts)


