4.2 - Maintaining Water Balance & Waste Disposal

Question 1

when is ammonia released as waste?

Answer 1

when proteins are digested

Question 2

What are the three ways to deal with nitrogenous waste?

Answer 2

1) Dilution of ammonia
2) Production of urea
3) Production of uric acid

Question 3

What is the process of the dilution of ammonia?
Who is it used by?

Answer 3

• NH3 is released as it and not processed
• aquatic animals release it to the surrounding waters
• when NH3 is released, it becomes diluted and does no harm

Question 4

What is the process of the production of urea?
Who is it used by?

Answer 4

• terestrial animals use energy to convert aminoacids to urea which is less toxic
• requires less water then dilution
• used by mammals, most amphibians, and sharks

Question 5

What is the process of the production of uric acid?
Who is it used by?

Answer 5

• urea is further processed to uric acid which is even less toxic and is the most processed form of NH3
• NH3 excreated as a paste with very little water
• used by animals in dry habbitats (ie. birds and reptiles)

Question 6

What are the kidneys responsible for?

Answer 6

• maintain water balance by acting as filter for blood
• blood enters through the renal artery
• waste and water are filtered out, and the “clean” blood leaves through the renal vein
• filtrate is the waste removed from the kidney
• the part in the kidney that filters the blood is called the nephron

Question 7

What is the filtrate?

Answer 7

it is the waste that is taken from the blood in the kidney

Question 8

What are nephrons?
Describe how they work.

Answer 8

• they are tiny systems within each kidney. (there are millions per kidney)
• renal artery branches off into smaller blood vessels leading to the nephron
• it forms a ball shape called a glomerulas
• the shape inscreases pressure in order to remove waste and water
• the filtrate connects to the Bowman’s capsule and moves through the tubes of the nephron

Question 9

What are the “tubes” of the nephron?

Answer 9

• Bowman’s casule
• proximal comvoluted tube (PCT)
• loop of Henle
• distal convoluted tube (DCT)

Question 10

What is the afferent arteriole?

Answer 10

• carries blood that needs to be filtered into glomerous

Question 11

What is the Efferent arteriole?

Answer 11

• contains substances too large to pass through the glomerus
• ex blood cells, proteins

Question 12

What are the peritubualr capilleries?

Answer 12

• a network of capilleries that re-absorbs essientail ions back into the blood from filtrate
• materials that weren’t supposed to be filtered out into the filtrate