gas exchange in fish

Question 1

what do larger multicellular animals have

Answer 1

specialist gas exchange surfaces

Question 2

what do specialised gas exchange surfaces overcome

Answer 2

they overcome the problem with a low surface are to volume ration and long diffusion distances

Question 3

what do gas exchange surface generally must have

Answer 3

• a large surface area
  -a short diffusion path
  -ventilation mechanisms
  -permeability to gases
  -moist surfaces

Question 4

what must gas exchange surfaces have ventilation mechanisms

Answer 4

for maintaining a concentration gradients

Question 5

why must gas exchange surfaces have moist surfaces

Answer 5

so oxygen can dissolve in the water and diffuse across them

Question 6

what do some animals have to maintain concentration gradients

Answer 6

circulatory systems

Question 7

why do sone animals have a circulatory system to maintain concentration gradients and how dos it do thus

Answer 7

some animals have a circulatory system to maintain concentration gradients by brining oxygenated blood to tissues and removing carbon dioxide

Question 8

what does haemoglobin have and what does it do

Answer 8

haemoglobin has a high affinity for oxygen and transports oxygen

Question 9

what are 2 feature of gas exchange surfaces in all animals

Answer 9

moist and permeable to gases and large surface area and short diffusion paths

Question 10

what 2 features of gas exchange surfaces help to maintain diffusion gradients

Answer 10

circulation of blood and ventilation mechanisms

Question 11

what is the surface of a fish covered in

Answer 11

scales

Question 12

what are scales impermeable to

Answer 12

water and gases

Question 13

how do fish exchange gases

Answer 13

through gills

Question 14

what specific parts of the gills do fish exchange gases

Answer 14

through the gill filaments and the gill plates

Question 15

what are the gills covered by

Answer 15

an operculum

Question 16

why does the operculum open

Answer 16

to let stale water with high carbon dioxide out

Question 17

why does the operculum close

Answer 17

to increase the pressure within the gill cavity during ventilation movements

Question 18

what does each gill cavity contain

Answer 18

4 gills supported on bony gill arches

Question 19

what are the gills and what do they consist of

Answer 19

the gills are a feathery structures consisting of many gill filaments

Question 20

what are the gill filaments covered with

Answer 20

many lamellae/gill plates at right angles to the filaments

Question 21

why do fish have many lamellae/gill plates

Answer 21

as they increase the surface area

Question 22

what do the lamellae provide

Answer 22

a short diffusion path for oxygen and carbon dioxide

Question 23

how do lamellae have a short diffusion path

Answer 23

as lamellae are very think and close to the capillaries which provides a short diffusion path for oxygen and carbon dioxide

Question 24

what do the gill rakers do

Answer 24

they filter large particles out of water to prevent damage to the delicate gill filaments

Question 25

what do the gill rakers prevent

Answer 25

damage to the delicate gill filaments

Question 26

what do the gill filaments have and what does the blood contain

Answer 26

the gill filaments have a rich blood supply the blood contains haemoglobin

Question 27

what is the significance of gill filaments and gill lamella

Answer 27

they provide a large surface area

Question 28

what does ventilation move

Answer 28

it moves the respiratory medium so for fish this means water over the gas exchange surface

Question 29

what does ventilation move over the gas exchange surface

Answer 29

water

Question 30

what does ventilation bring to the gas exchange surface

Answer 30

it brings fresh oxygen to the gas exchange surface

Question 31

what does ventilation remove from the gas exchange surface

Answer 31

it removes carbon dioxide

Question 32

what does ventilation bring oxygen and removing carbon dioxide from the gas exchange surface result in

Answer 32

it results in the diffusion gradient being maintained at the gas exchange surface

Question 33

what type of ventilation is in bony fish

Answer 33

ventilation in boney fish is a positive pressure ventilation

Question 34

what does positive pressure ventilation mean

Answer 34

that water is moved from a high pressure to a low pressure from the buccal cavity to the opercular cavity and out of the operculum

Question 35

in positive pressure ventilation where does the water move from and where does it go to

Answer 35

it moves from the buccal cavity to the opercular cavity and then out of the operculum

Question 36

in order to take oxygenated water in what happens to the mouth and the operculum

Answer 36

the mouth is opened are the operculum is closed

Question 37

what happens to the floor of the buccal cavity and what does this do to the volume and pressure in the cavity when water is taken in

Answer 37

the floor of the buccal cavity is lowered, which increase the volume and decreases the pressure in the cavity

Question 38

why does water flow into the buccal cavity

Answer 38

water flows into the buccal cavity as the water pressure is higher than that in the buccal cavity

Question 39

what happens to the floor of the buccal cavity when the mouth closes

Answer 39

the buccal cavity rises

Question 40

what happens to the volume and pressure inside the cavity when the buccal cavity raises when the mouth closes

Answer 40

the volume inside the cavity decreases and the pressure increases

Question 41

what happens to the water after the volume inside the cavity decrease and the pressure increase

Answer 41

the water then flows across the gill and enters the opercular cavity

Question 42

what does the pressure cause the operculum to do do and what happens to the water

Answer 42

the pressure causes the operculum to open and the water leave the fish through the operculum which forces the water over the gills as the opercular pressure is greater than the external pressure

Question 43

why is water forced over the gills due to the pressure

Answer 43

as the opercular pressure is getter than the external pressure

Question 44

what ventilation do many sharks do

Answer 44

ram ventilation

Question 45

what is ram ventilation

Answer 45

it where the shark swims forward with their mouth open which moves the water into the mouth and out of the gill slits

Question 46

during ram ventilation where does the water move out of

Answer 46

the gill slits

Question 47

what happens during ram ventilation if they stop swimming

Answer 47

they can't get enough oxygen

Question 48

what is the purpose of ventilation

Answer 48

to maintain concentration gradient at the gas exchange surface

Question 49

how does ventilation maintain concentration gradient at the gas exchange surface

Answer 49

as its delivering fresh oxygen in respiratory medium and removing carbon dioxide

Question 50

what does the water have when it enters the shark and what does it have when it comes out

Answer 50

when it enters the shark water contains lots of oxygen when it leaves its oxygen depleted

Question 51

an example of a cartilaginous fish

Answer 51

a shark

Question 52

in cartilaginous fish what do blood and water flow in and across what

Answer 52

blood and water flow in the same direction across the gill plates

Question 53

what is it called when blood and water flow in the same direction

Answer 53

concurrent or parallel flow

Question 54

what happens to the blood with low oxygen and water with high oxygen in parallel flow

Answer 54

blood with low oxygen coming from the body is in contact with water with high oxygen coming in through the mouth

Question 55

where does blood with low oxygen come from

Answer 55

the body

Question 56

where does water with high oxygen come from

Answer 56

in from the mouth

Question 57

oxygen diffuses into the blood until what is reached

Answer 57

oxygen diffuses into the blood until equilibrium is reached

Question 58

in boney fish blood and water flow in what and across what

Answer 58

opposite directions across the gill plates

Question 59

what is blood and water flowing in opposite directions called s

Answer 59

countercurrent flow

Question 60

what is blood with high oxygen come into contact with in countercurrent flow

Answer 60

blood with high oxygen leaving the gill is in contact with water entering the gill from the buccal cavity, which has a higher oxygen content than blood

Question 61

what has a higher oxygen content that blood in countercurrent flow

Answer 61

water entering the gill from the buccal cavity

Question 62

what does blood entering the gill filament have in countercurrent flow

Answer 62

a low oxygen concentration

Question 63

what does blood entering the gill filaments meet with in countercurrent flow

Answer 63

it meets with water as it leaves having had oxygen removed

Question 64

what does water still have a higher oxygen concentration than in counter current flow

Answer 64

blood

Question 65

why is equilibrium never reached in countercurrent flow

Answer 65

as the water has a higher oxygen concentration than the blood across the whole distance of the Gil plate so equilibrium is never reached

Question 66

what does water having a higher oxygen concentration than the blood across the whole distance of the gill plate mean

Answer 66

that equilibrium is never reached

Question 67

how is the concentration gradient maintained over the entire gill

Answer 67

as the water has a higher oxygen concentration that the blood across the whole gill plate

Question 68

what does water having higher oxygen concentration that blood across the whole gill plate mean for diffusion

Answer 68

that diffusion occurs along the entire length of the gill and more oxygen is absorbed