chapter 7

Question 1

why is diffusion alone able to supply a single celled organism enough oxygen (2 reason)

Answer 1

1) has low oxygen demands and low carbon dioxide
production
2) the SA:V is large

Question 2

what requires more oxygen a multicellular organism or single cellular

Answer 2

larger multicellular organisms as their metabolic activity is higher

Question 3

why cant diffusion be the main source of oxygen for multicellular organisms

Answer 3

because the distance between the cells are not close enough for diffusion to take place and its SA:V is low so it would take to long to diffuse the oxygen required

Question 4

what are the 4 main things most multicellular organisms have adapted to their exchange surfaces (4 things)

Answer 4

1) blood supply- the steeper the concentration gradient the
faster the diffusion
2) thin layers- distance the oxygen has to diffuse is shorter
3) high SA:V- provides the area needed for exchange
4) ventilation- helps maintain the concentration gradient

Question 5

why are gaseous exchange systems moist (like the alveoli) and what’s its downside

Answer 5

so the oxygen can diffuse faster by dissolving into the water then diffusing into the blood but it means that water can be lost

Question 6

why do mammals need a specialised exchange system

Answer 6

as they need to regulate their body temperature, the have lots of cells and have a high metabolic rate

Question 7

the nasal cavity’s features (3 features)

Answer 7

1) large surface area with a good blood supply which warms
the air
2) a hairy lining of mucus to catch dust and bacteria ot
allowing it to go into the lungs
3) moist surface to reduce evaporation from surface exchange

Question 8

what is the trachea

Answer 8

the main airway carrying clean moist air from mouth and nose into the lungs

Question 9

what’s the trachea made of

Answer 9

the tube is supported by rings of cartilage to protect it from collapsing

Question 10

what is the trachea lined with

Answer 10

a ciliated epithelium with goblet cells between and below the cells

Question 11

what does the goblet cells do in the trachea

Answer 11

it produces mucus onto the lining of the trachea

Question 12

what does mucus do

Answer 12

trap dust and bacteria which is coughed up or swallowed to be digested

Question 13

what is the bronchus

Answer 13

the trachea divides into two bronchi. it has the same structure

Question 14

what are the bronchioles

Answer 14

the bronchus divides into many bronchioles (1mm diameter) no cartilage rings.

Question 15

what happens in the bronchioles when the smooth muscle contracts

Answer 15

the bronchioles close up this then restricts the air from entering the lungs

Question 16

what happens in the bronchioles when the smooth muscle relaxes

Answer 16

the bronchioles open up this then allows air to enter the lungs

Question 17

what are aveoli

Answer 17

they are tiny air sacs covered by blood vessels. they are the main gas exchange surface and are only in mammals.

Question 18

what are alveoli made from

Answer 18

collagen and and elastic fibres allowing it to stretch. when they go to their resting state its called elastic recoil

Question 19

what are the 3 adaptions an alveoli withhold as a exchanger of gas

Answer 19

1) thin layers
2) good ventilation (from the trachea)
3) good blood supply (from blood vessels on it)

Question 20

explain what the diaphragm is

Answer 20

its a dome shaped muscle which forms the floor of the thorax

Question 21

what’s the external intercostal muscle and the internal intercostal muscle

Answer 21

found between the ribs

Question 22

what is the thorax lined by

Answer 22

the pleural cavity and has lubricant fluid to help the membranes to move around as you breathe

Question 23

what happens when you inhale

Answer 23

the diaphragm contracts and lowers, the external intercostal muscle moves ribs up and out, air is drawn into lungs as the thorax volume increases

Question 24

what happens when you exhale

Answer 24

the diaphragm relaxes and Highers, the external intercostal muscle moves the ribs down and in, the elastic fibres in the alveoli relax, pressure inside thorax is greater than outside so air moves out

Question 25

how can you measure capacity of the lungs (3 ways)

Answer 25

peak flow meter- this measure the most you can exhale vitalographs- exhale quick through a mouthpiece which is put on a graph which shows the volume breathed out and how fast. this volume of air is called forced expiration spirometer- used to measure different aspects of the lung

Question 26

what's tidal volume

Answer 26

the volume of air that moves in the lungs

Question 26

what's vital capacity

Answer 26

strongest exhalation followed by strongest inhalation

Question 26

what's expiratory and inspiratory reserve volume

Answer 26

inspiratory- max volume of air you can breathe in expiratory- extra amount of air you breathe in over and above the tidal volume

Question 26

what's the breathing ate

Answer 26

how many breaths a minute

Question 26

what's residual volume

Answer 26

how much is left in your lungs after max exhale

Question 26

what's total lung capacity

Answer 26

the vital capacity and the residual volume

Question 27

what's the ventilation rate

Answer 27

total volume of air inhaled in a minute

Question 28

what happens to the tidal volume when oxygen needs are high

Answer 28

it increases to as much as 15-50% of the vital capacity

Question 29

what gaseous exchange hard for an insect (3 things)

Answer 29

they have a high metabolic rate they have an exoskeleton which doesnt alow for gaseous exchange to take place dont have blood pigment so cant carry oxygen in the blood

Question 30

How do insects go through gas exchange

Answer 30

they have spiricales which alow for oxygen to be directly delivered to the cells

Question 31

how does the spiricales adapt to lose less water

Answer 31

they have sphincters which close up the spiricles to stop water loss.

Question 32

what hapens to the spiricles when the insect is inactive and whats its benefit

Answer 32

its spiracles close up to prevent water loss. when oygen demands grow or CO2 levels build upthe spiricles start to open up

Question 33

how does O2 travel through the insect

Answer 33

through the piricles in the trachea which then splits into the tracheoles

Question 34

what is the trachea made of and can gas exchange take place

Answer 34

chitin which keeps them open and because chitin is impermeable to gas no gas exchange can take place.

Question 35

where does most of the gas exchange take place inside of an insect and how does it diffuse into cells

Answer 35

through the tracheoles as they are not made of chitin so gas exchange can take place. the O2 dissolves into the tracheal fluid and then diffuses into cells

Question 36

for bigger insects with higher O2 demands what are the two adaptations they have

Answer 36

mechanical ventilation- this is where air is pumped into the system by movements from the thorax bigger air sacs- these act as air resevoirs

Question 37

do fish need to prevent water loss

Answer 37

no because their in the sea

Question 38

why dont fish have lungs

Answer 38

because water is 1000 times denser and more viscous than air and has a much lower O2 content so it would use to much energy

Question 39

why are gills good gas exchangers

Answer 39

thin layers good blood supply large surface area

Question 40

what is the operculum

Answer 40

the flap that covers the gills

Question 41

whats the gill lamellae

Answer 41

these are within the thin layers whcih are close together with good blood supply and large surface area

Question 42

what are gill fillaments

Answer 42

a stack of gill plates

Question 43

how do fish keep a constant water flow over the gills

Answer 43

when they are swimming they just open their mouth and let the water run past the gills but with bony fish they have found a more effcient way

Question 44

how do bony fish keep take in water

Answer 44

the buccal cavity (mouth) lowers increasing the volume and therefore dropping the pressure which alows for water to enter the mouth. and the opercular valve is shut (the gills valve)

Question 45

how do bony fish take water out past the gills

Answer 45

the buccal cavity rises and the opercular valve opens which means the pressure in the mouth is more so water runs over the gills

Question 46

what are the two other things that gills have adapted to for gas exchange

Answer 46

the tips of the gill filaments overlap meaning it slows down the water over the gills a countercurrent exchange system is set up

Question 47

what is a countercurrent exchange system

Answer 47

the water moving over the gills runs opposite to the blood flow. this means there is a steeper concentration gradient is achieved throughout the flow. in a result fish take out 80% of oxygen from the water