fish and insects quizlet

Question 1

structure of the gills

Answer 1

• on either side of head
• made of gill arches, each attached to 2 stacks of gill filaments
• filaments have lameallae protruding
• lamella = single netweork flattened cell, and network of capillaries underneath
• fragile so covered by operculum

Question 2

flow mechanism

Answer 2

-countercurrent flow
- blood in capillaries flows in opposite direction to water over the gills
- conc gradient maintained over entire length of capillary
- maxes rate of diffusio and vol o2 that diffuses
- tips of gill filaments overlap to slow down water movement ; more time for diffusion to occur

Question 3

ventilation

Answer 3

-fish opens mouth, lowers floor of the buccal cavity,
-the pressure outside of the fish is greater than inside the buccal cavity so water flows in
-the fish raises the floor of the buccal cavity to close their mouth, vol decreases so pressure inside of the buccal cavity increases.
- pressure in buccal cavity greater than in opercular (gill) cavity
- water flows to the gill cavity, from a high pressure to low pressure. over the gills
-causes the operculum valve to be forced open and allow the water to flow through the gills and exit the fish
-the operculum is forced shut when the floor of the buccal cavity is lowered at the start of the next cycle

Question 4

insect why cant they use outer surface

Answer 4

• rigid exoskeleton imperemeable to gases
• prevents water loss

Question 5

spiracle

Answer 5

opening in exoskeleton that allows gas exchange

Question 6

tracheae chitin

Answer 6

• chitin. continuous
• mechanical strength and prevents collapse. impermeable so no gaseous exchange can happen

Question 7

there is a … (tracheoles)

Answer 7

large number
large SA for gas exchange

Question 8

tracheal fluid

Answer 8

withdrawn when the insect isactive, increaes sa of trachele exposed for ge to occur

Question 9

insects ventialtion mechanism

Answer 9

1. spiracles closed. ABDOMINAL MUSCLES PUMP-> abdomen expands, spiracles open, air enters . to let air out, abdoemn contracts and rear spiracles open
2. movement of wings (increase vol, decrease pressure etc)
3. air sacs can be squeezed by the action of flight muscles

Question 10

why insects have tracheal system not blood

Answer 10

1.OPEN CIRCULATION: blood flow not directed to tissues that need it most. sepearte air filled tubes can do this
2. BLOOD FLOW affects by body movements -> unreliable transport of o2
3. TOO SLOW: diffusion liquids slower than gases, diffusion distance too long to supply oxygen by diffusion, mass flow needed.

Question 11

what happens if too much tracheal fluid

Answer 11

• less o2 reaches respirin tissues
• so anaerobic respitation. lactic acid produced. decreases their water potenital.the water moves into the cells by osmosis

Question 12

insect dissection (2)

Answer 12

• cut open exoskeleton to view tracheols
• stain w METHYLENE BLUE

Question 13

LARGE sa gas exchnage system

Answer 13

many branched tubes (tracheae and tracheoles)

Question 14

SMALL insects ge

Answer 14

diffusion at rest supplies sufficien oxygen

Question 15

why cant fish survive out of water

Answer 15

• gills collapse
• small sa exposed to aie
• insufficient GE
• dry out

Question 16

passage of o2 in tracheal system (3)

Answer 16

• air enters through spiracle
• tracheae, tracheole
• diffuses to tracheole fluid + muscle cells

Question 17

2 ways insects increase how much o2 they get

Answer 17

• obdmonial pumping; increase venitlation
• withdraw tracheal fluid, increase SA for exchange

Question 18

how to dissect fish

Answer 18

• remove operculum
• underwater
• use a pencil to hold buccal cavity open. use pins to hold fish