Homeostasis + excretory systems

Question 1

In our bodies, the primary nitrogen-containing compound excreted by our kidneys is…

Answer 1

urea

Question 2

Most of our nitrogen-containing waste products are a result of __________.

Answer 2

protein metabolism

Question 3

excretory system unit of annelids (earthworms)

Answer 3

Protonephyridia

-which form a network of dead-end tubules through which interstitial fluid is filtered.

-smallest branches capped by flame bulb

-excrete a dilute fluid

Question 4

excretory system unit of insects + other terrestrial arthropods

Answer 4

Malpighian tubules

-which remove nitrogenous wastes and also function in osmoregulation.

-blind tubes arising from gut

-can conserve water very effectively

Question 5

excretory system unit of vertebrates

Answer 5

kidney

-functions in both osmoregulation and excretion.

-nephrons are function units of vertebrate kidney

-produce urine hypertonic to body fluids ( conserves water )

Question 6

Which of the following substances is generally filtered from the blood by the kidneys?

Glucose

Water

Sodium

Urea

Answer 6

All of the above

Question 7

loop of Henle function

Answer 7

loop of Henle is specialized for water resorption

-critical for desert animals

Question 8

What is the tube that carries urine from the kidneys to the urinary bladder in a mammal?

Answer 8

Ureter

Question 9

The bed of capillaries in a vertebrate kidney where water, urea, and salts are filtered out of the blood is the __________.

Answer 9

Glomerulus

Question 10

Which of the following have an excretory system that functions without a filtration step?

Marine fishes

Insects

Earthworms

Freshwater fishes

Flatworms

Answer 10

Insects

Question 11

Osmoconformers

Answer 11

– Internal solute concentrations match environmental
solute concentrations
– Cells and body fluids isotonic to environment

Question 12

Osmoregulators

Answer 12

– Actively control overall concentration of solutes in
cells and body fluids
– Maintain internal concentration different than
external concentration

Question 13

Ionic regulation

Answer 13

– active control of the
concentration of individual solutes in body
fluids

Organisms can be a sodium conformer, but a calcium regulator

Question 14

Ionic conformers

Answer 14

• maintain same solute
  profile as environment

Organisms can be a sodium conformer, but a calcium regulator

Question 15

Osmoregulation in freshwater fish

Answer 15

+gain water and ions in food
+uptake salt ions by gills
+osmotic gain through gills and body surface

-excretion of salt ions and large amounts of water in dilute urine from kidneys

Question 16

Osmoregulation in a marine fish

Answer 16

+gain of water and ions in food
+gain of water and salt ions from drinking seawater

-excretion of salt ions through gills
-osmotic water loss through gills
-excretion of salt ions and small amounts of water in scanty urine from kidneys

Question 17

Marine Bony Fish

Answer 17

• Marine bony fish are hypotonic to
  environment, so they lose water across gills
• Regain lost water by drinking seawater
• Eliminate excess salts with chloride cells in
  gills

Question 18

Freshwater Bony Fish

Answer 18

• Body fluids and cells are hypertonic to the
  environment, and so gain water across gills
• Produce large quantities of dilute urine
• Beta chloride cells in gills take up Cl- from
  water

Question 19

Key functions of most excretory
systems:

Answer 19

– Filtration
– Reabsorption
– Secretion
– Excretion

Question 20

Filtration:

Answer 20

Filtering of body fluids

Question 21

Reabsorption:

Answer 21

Recovering valuable
solutes

Question 22

Secretion:

Answer 22

Adding nonessential
solutes and wastes to the filtrate

Question 23

Excretion:

Answer 23

Releasing filtrate
(containing nitrogenous wastes) from
the body

Question 24

Metanephridia

Answer 24

– open-ended tubules that collect coelomic fluid and
produce dilute urine
* Function in excretion and osmoregulation
* Found in Mollusca and Annelida
– Each segment of an earthworm has a pair of metanephridia.