respiration 3

Question 1

Understand the range of anatomical adaptations

made by water breathers.

Answer 1

sponges, echinoderms, molluscs, crustaceans, corals, jellyfish, elasmobranchs, jawless fish, teleosts

Question 2

sponges and cnidarians

Answer 2

• cutaneaous respiration and bulk flow
• sponges: unidirectional with flagella moving water through resp system
• cnidarians: tidal ventilation, muscle contractions move water in and out of mouth

Question 3

molluscs

Answer 3

bulk flow at special resp surface, unidirectional and countercurrent flow

Question 4

crustaceans, small or filter

Answer 4

filter feeding ie barnacles or microscopic species lack gills and rely on diffusion

Question 5

crustaceans, big

Answer 5

shrimp, crabs, lobsters have gills at appendages within branchial cavity

• movements of GILL BAILERS propel water out of branchial chanber, negative pressure sucks water in across the gills
• bulk flow, unidirectional, and countercurrent

Question 6

echinoderms

Answer 6

most sea stars and urchins use tube feet for gas exchange

• cutaneaous respiration, countercurrent, non-directional ventilation (external gills absorb oxygen from water
• brittle stars and sea cucumbers have internal invaginations; use cilia to move water in and out of bursae cavity
• cucumbers use contractions of cloaca and resp tree to pump water TIDALLY via anus

Question 7

Jawless fish

Answer 7

hagfish: muscular pump propels water over cavity, unidirectional, countercurrent via rete mirabile: a vessel cluster
lamprey: similar to above when not feeding; when feeding venting is tidal through gill openings

Question 8

elasmobranchs

Answer 8

control valves via mouth and spiracles

• gill slits are passive valves
• buccal cavity acts as a pump, water flow is pulsatile (pulses), blood flow is countercurrent
• water taken in by mouth and spiracles, both close, muscles around buccal cavity contract, forcing water past gills

Question 9

teleost fishes

Answer 9

gills localed at opercular cavity, protected by operculum; use buccal-opercular pump for ventilation
2 valves: mouth and opercular valve
2 force pumps: buccal and opercular cavities
-adv: flow unidirectional and continuous due to coordination of buccal and opercular pumps
-active fish can also use ram ventilation by swimming with mouth open for easier ventilation