Circulation and respiration - Part 2 - 1 Flashcards Preview

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Other than at the gill lamellae, where else does gas exchange occur?

Swim bladder


What type of fish would be typical of using the swim bladder for breathing?

Physostomous fishes


What is an issue with respiration for lungfish?

Blood flow is unidirectional. If lungs are added to the circulation, oxygenated blood will return to the heart from the lungs and deoxygenated blood will come back from the body, potential for mixing.


How do lungfish get around the blood mixing problem?

In lungfish, starting to see a division, not a full one however.
Small division of the ventriclees which functions to keep the two flows separate.


How does oxygen from the skin get to the heart?

Separate side shoot for circulation to the skin. (separate circulatory shunt)
Some of the deoxygenated blood can bypass the gills to the skin to pick up oxygen.


What fish uses the skin a lot for respiration?

Freshwater eels


What is aerial respiration?

Bringing air into contact with a highly vascularized surface to allow gas diffusion.


Describe how some fish can gulp air to breathe.

A number of species gulp air.
Go to surface, gulp air and hold it at a bubble against some part of the mouth of gill chamber that has lots of blood flow.


Describe how carps can gulp air.

Carps have a modified palate (roof of mouth) with lots of blood vessels.
Take mouthful of air and hold it in.


Describe how some pet store fish can breathe from a bubble of air.

Have special chambers within the gill area (branchial chamber). Can hold a physical bubble of air and directly respire from it.


How do snakehead breathe air?

Have highly vascularized mouth and throat.
Throat has modified pockets to hold air with good blood flow.
Keeps air bubbles until they diffuse all the oxygen out of it.


How much oxygen a fish needs will vary by ______.



Describe the three ways in which oxygen consumption will vary with stream velocity/change in activity.

1 - Most pelagic fishes (ex: trout)
- as water flow increases, oxygen consumption increases
- relatively direct relation between stream velocity and oxygen consumption

2 - Sculpin (benthic fish)
- unaffected by stream and oxygen consumption, just sits on the bottom

3 - Daces
- for a while, all gucci then, consumption shoots up


Describe the behaviours for oxygen consumption with increasing stream velocity for gobbies and daces.

Gobies will stick to the bottom and can live in faster flows without worrying or breathing more.

Daces will try to hide to the bottom but, as flow increases, they get dislodged and have to swim


How can oxygen consumption by activity be measured?



Describe a respirometer.

Tube of different sizes that you place a fish in.
Induce flow and measure oxygen in and oxygen out.
Can play with temperature, pH and other gases


Teleosts have a two-pump respiratory system, briefly describe this.

Mouth and opercular chamber work in opposite timings.
Pump water actively over the gills by opening mouth while the operculum was closed and close the mouth and open the operculum, steady flow of water over the gills.


What is the advantage of a two-pump respiratory system?

Don;t need to move to breathe, can sit in one place.


What are the limitations of the two-pump respiratory system?

Limited by how fast the pump can go and how big the pump can be.


What are different ways to modify the two-pump system to increase oxygen exchange?

Open up the mouth chamber using branchiostegal rays to increase the volume of water over the gills.
Can slightly increase rate at which the pump operates - but limited


What fish would be too constrained using the two-pump respiratory system alone?

Very large and active teleosts or fish that aren't teleosts (just don't have it)


What is a solution for very large and metabolically active fish who cannot use the two-pump respiratory system?

Ram ventilation


What is ram ventilation?

just open mouth and swim


Give an example of a fish that uses ram ventilation exclusively



Describe the interplay of the two-pump respiratory system and ram ventilation.

Some teleosts might use pump during normal periods and will switch to ram ventilation when in low oxygen or when migrating.


Do fish on the bottom have this two-pump respiratory system?

for the most part, no.


Describe how the sea lamprey might have difficulty in breathing in some instances.

No jaw, and sucks blood from its prey.
Difficult to breathe when the mouth is blocked.


How does the sea lamprey get over its respiratory dilemma?

Agnathans will have gill slits and branchial pumps.


What are branchial pumps?

Muscles around the gill slits which act as mini pumps to bring water in and out of the gill slits.


Both osteichthyes and chondricthyes have a __-chambered heart.