Circulation and respiration - Part 2 - 1

Question 1

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

Answer 1

Swim bladder
Lungs
Skin

Question 2

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

Answer 2

Physostomous fishes

Question 3

What is an issue with respiration for lungfish?

Answer 3

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.

Question 4

How do lungfish get around the blood mixing problem?

Answer 4

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.

Question 5

How does oxygen from the skin get to the heart?

Answer 5

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.

Question 6

What fish uses the skin a lot for respiration?

Answer 6

Freshwater eels

Question 7

What is aerial respiration?

Answer 7

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

Question 8

Describe how some fish can gulp air to breathe.

Answer 8

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.

Question 9

Describe how carps can gulp air.

Answer 9

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

Question 10

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

Answer 10

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

Question 11

How do snakehead breathe air?

Answer 11

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.

Question 12

How much oxygen a fish needs will vary by ______.

Answer 12

species

Question 13

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

Answer 13

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

Question 14

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

Answer 14

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

Question 15

How can oxygen consumption by activity be measured?

Answer 15

Respirometers.

Question 16

Describe a respirometer.

Answer 16

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

Question 17

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

Answer 17

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.

Question 18

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

Answer 18

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

Question 19

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

Answer 19

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

Question 20

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

Answer 20

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

Question 21

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

Answer 21

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

Question 22

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

Answer 22

Ram ventilation

Question 23

What is ram ventilation?

Answer 23

just open mouth and swim

Question 24

Give an example of a fish that uses ram ventilation exclusively

Answer 24

Tuna

Question 25

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

Answer 25

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

Question 26

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

Answer 26

for the most part, no.

Question 27

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

Answer 27

No jaw, and sucks blood from its prey.

Difficult to breathe when the mouth is blocked.

Question 28

How does the sea lamprey get over its respiratory dilemma?

Answer 28

Agnathans will have gill slits and branchial pumps.

Question 29

What are branchial pumps?

Answer 29

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

Question 30

Both osteichthyes and chondricthyes have a __-chambered heart.

Answer 30

2

Question 31

Both osteichthyes and chondricthyes have an ______ and a ________ composing their heart.

Answer 31

atrium

ventricle

Question 32

Both osteichthyes and chondricthyes have a ______ _______ that takes blood from the head and the body and dumps it into the heart.

Answer 32

sinus venosus

Question 33

Describe the sinus venosus.

Answer 33

Big stretchy vein that takes all the blood from the head and body, dumps it into the atrium.
Stretches until it fills up then delivers lots of blood to the atrium.

Question 34

Between osteichthyes and chondricthyes, who has the most muscular ventricle?

Answer 34

Osteicthyes since almost all the pumping is from the ventricle

Question 35

After leaving the heart, osteicthyes have a ______ ______ and chondricthyes have a ________ ________.

Answer 35

bulbus arteriosus

conus arteriosus

Question 36

What is a bulbus arteriosus?

Answer 36

big stretchy artery that functions to even out the flow of blood by stretching out and more evenly delivering blood to the gills

Question 37

What is the conus arteriosus?

Answer 37

Structure in sharks and rays after the heart that is lined with muscles that acts like a series of pumping stations.
Has a few different chambers with one-way valves.
functions to have blood flow to the gills in a more regular pattern

Question 38

What are pacemaker cells?

Answer 38

Autorhytmic cells that set the heart rate or pace.

Question 39

Where are the pacemaker cells in condricthyes and osteichthyes?

Answer 39

sinus venosus

Question 40

Does the bulbus have contractile muscles?

Answer 40

no