Excretion and Osmoregulation

Question 1

What is excretion, and what is often excreted?

Answer 1

elimination from the body of metabolic waste products

CO2, H2O, nitrogen

CO2 is often released through gas exchange

Question 2

What is osmoregulation, and what does it maintain?

Answer 2

regulation of water and ion balance within the body fluids

maintains concentration of body fluids

Question 3

What is nitrogeneous waste, and what is it released as?

Answer 3

excess nitrogen released during deamination of amino acids to build protein

liberated as ammonia that is diluted, eliminated, or converted

Question 4

What are ammonotelic organisms?

Answer 4

aquatic invertebrates releasing nitrogenous waste as ammonia

Question 5

How do ammonotelic invertebrates excrete, and examples?

Answer 5

diffuses easily through fluids and tissues, and lost through body wall

sponges, cnidarians, xenacoelomorphs, and echinoderms lack excretory organs

Question 6

What limits ammonotelic organisms?

Answer 6

limited to aquatic habitat and ammonia production

Question 7

What do terrestric invertebrates convert nitrogenous waste to?

Answer 7

less toxic compounds like urea and uric acid

Question 8

Pros and cons of terrestrial invertebrate nitrogenous conversion

Answer 8

energetically expensive

no dilution by water

can be stored within body

Question 9

What are ureotelic animals?

Answer 9

amphibian, mammals, fish

Question 10

What are uricotellic animals?

Answer 10

terrestrial invertebrates

Question 11

Why is uric acid conversion beneficial?

Answer 11

uric acid is insoluble, and excreted as waste without water loss

Question 12

What is osmoregulation tied to?

Answer 12

environment

Question 13

What state are marine invertebrates in? (2)

Answer 13

isotonic

none are exactly isotonic, and must maintain regulation

Question 14

What state are freshwater invertebrates?

Answer 14

hypertonic, and must prevent influx of water and loss of salts

Question 15

What must terrestrial animals face?

Answer 15

water loss

Question 16

What kind of body walls do aquatic animals have?

Answer 16

modified body wall to reduce permeability

Question 17

WHat are osmoregulators?

Answer 17

maintain internal body fluid; freshwater

Question 18

What are osmoconformers?

Answer 18

allows body fluid change in response to environment (mussels), but must osmoregulate to an extent

Question 19

What are stenohalines?

Answer 19

restricted to a narrow range of salinity

Question 20

What are euryhaline?

Answer 20

tolerate extensive variation of salinity

Question 21

How are all hypotonic organisms similar (2)?

Answer 21

all tends to swell in a hypotonic environment, and excrete excess water
- cells are now in stress and swells, and must release solutes

Question 22

How do terrestrial arthropods and gastropods prevent dessication?

Answer 22

exoskeleton

Question 23

How do small creatures osmoregulate?

Answer 23

diffusion

Question 24

What are water expulsion/ contractile vacuoles? (2)

Answer 24

freshwater sponges/protists method to excrete excess water

accumulates cytoplasmic water and expels it from the cell

Question 25

What is nephridia?

Answer 25

ectodermally derived excretion organ

Question 26

What is protonephridium, and how is it arranged (2)?

Answer 26

simplist nephridium tubular arrangement opening to the outside via nephridiopores and terminating internally in closed unicellular units cap cells (terminal) are folded into cups to create a nephridioduct, into the nephridiopore

Question 27

What are flame bulbs?

Answer 27

protonephridia with cilia

Question 28

What are solenocytes?

Answer 28

protonephridia with one or two flagella

Question 29

What does cilia/ flagella do in a protonephridium (2)?

Answer 29

drives fluids down the duct to create low pressure low pressure draws in fluids and waste

Question 30

What are protonephridium common in>

Answer 30

acoelomates, blastocoelomates, some annelids

Question 31

What is protonephridium important in?

Answer 31

important for osmoregulation than excretion

Question 32

Flaw of protonephridium?

Answer 32

cannot handle large fluid volumes

Question 33

What are metaniphridium?

Answer 33

open internally to the body fluid

Question 34

What kind of metaniphridium do large coelomates have, and what kind do arthropods have?

Answer 34

many have multiple for larger coelomates Arthropods have closed metanephridia

Question 35

What is the structure of metaniphridium?

Answer 35

inner ends bare a nephrostome (ciliated funnel) with an elongated duct

Question 36

What do metanephridium do?

Answer 36

takes in large amounts of body fluid through the open end and asborbs most of the reclaimable components

Question 37

Why would metaniphridium be ineffective in non-coelomates?

Answer 37

ineffective for acoelomates and would drain quickly in blastocoelomates

Question 38

What are coelomoducts?

Answer 38

tubular connections from the coelom extending to the outside via pores

Question 39

What is the structure of coelomoducts? (2)

Answer 39

ciliated for release of gamete fused with nephridia to produce nephromixia

Question 40

What are protonephromixium?

Answer 40

when nephromixia and protonephridium share a common duct

Question 41

What are metanephromixium and mixonephridium, and how do they differ?

Answer 41

when a coelomoduct is united with a metanephridium depends on structural nature

Question 42

Where does nephridia arise from?

Answer 42

nephridia arises from the outer body wall (mesoderm and ectoderm)

Question 43

How do echinoderms and chaetognaths excrete? (3)

Answer 43

no discrete system waste is eliminated across skin surface or gut lining can use ameboid phagocytic cells

Question 44

What are malpighian tubules?

Answer 44

- excretory organs that resemble modified nephridia