Zoology Chapter 28 Notes
Chapter 28 Cont.
Evolution of the Kidney in Vertebrates * Vertebrates have 2 kidneys * On the back of the abdominal cavity * Kidney has a * Renal capsule * Cortex (towards the outside) * Medulla (towards the central region) * Structure and function of kidneys can differ depending animal type and developmental stage * 3 kinds of vertebrate kidneys * Pronephros * Adult hagfish & (embryos fish and amphibians) * Mesonephros * Adult fish and amphibians & embryos of reptiles, birds, and mammals * Metanephros * Adult mammals , adult reptiles & birds
Marine Fish * Mesonephric kidney * Body fluid has lower ion concentrations * Water tends to leave the fish causing dehydration. * Drinks lots of saltwater, secrete ions through gills and excrete urine concentrated with ions.
Freshwater Fish * Most have a mesonephric kidney * Body fluid h higher ion concentrations * Water tends to enter the fish causing excess hydration. * Ions move out of fish * Do not drink much water, absorb ions through gills and excrete large amounts of dilute urine.
Amphibians
* Similar kidney to freshwater fish * Take up ions and water in what they eat and drink, through skin and through the urinary bladder that balances what is lost by evaporation. * The urinary bladder is a water and ion storage site
Birds, Reptiles, and Mammals * Have a metanephros kidney * Can remove more water than other kidneys * Primary organs for osmoregulation
Metanephric Kidney * The functional unit is the nephron * Begins with the glomerular capsule. * An arteriole enters the glomerular capsule and branches into a network of capillaries called the glomerulus. * Efferent arteriole divides to form pertibular capillaries -> merge into a vein leading out of the kidney. * Proximal
Evolution of the Kidney in Vertebrates * Vertebrates have 2 kidneys * On the back of the abdominal cavity * Kidney has a * Renal capsule * Cortex (towards the outside) * Medulla (towards the central region) * Structure and function of kidneys can differ depending animal type and developmental stage * 3 kinds of vertebrate kidneys * Pronephros * Adult hagfish & (embryos fish and amphibians) * Mesonephros * Adult fish and amphibians & embryos of reptiles, birds, and mammals * Metanephros * Adult mammals , adult reptiles & birds
Marine Fish * Mesonephric kidney * Body fluid has lower ion concentrations * Water tends to leave the fish causing dehydration. * Drinks lots of saltwater, secrete ions through gills and excrete urine concentrated with ions.
Freshwater Fish * Most have a mesonephric kidney * Body fluid h higher ion concentrations * Water tends to enter the fish causing excess hydration. * Ions move out of fish * Do not drink much water, absorb ions through gills and excrete large amounts of dilute urine.
Amphibians
* Similar kidney to freshwater fish * Take up ions and water in what they eat and drink, through skin and through the urinary bladder that balances what is lost by evaporation. * The urinary bladder is a water and ion storage site
Birds, Reptiles, and Mammals * Have a metanephros kidney * Can remove more water than other kidneys * Primary organs for osmoregulation
Metanephric Kidney * The functional unit is the nephron * Begins with the glomerular capsule. * An arteriole enters the glomerular capsule and branches into a network of capillaries called the glomerulus. * Efferent arteriole divides to form pertibular capillaries -> merge into a vein leading out of the kidney. * Proximal