Exchange and ratios

Question 1

What factors increase the rate of diffusion?

Answer 1

A higher temperate
A shorter diffusion pathway
A larger concentration gradient
A larger surface area

Question 2

Which 3 factors of increasing the rate of diffusion are exchange surfaces adapted for?

Answer 2

A shorter diffusion pathway
A larger concentration gradient
A larger surface area

Question 3

What is the equation for Ficks Law?

Answer 3

The rate of diffusion is proportional to:
Surface Area x Difference in conc
————————————————
Length of diffusion pathway

Question 4

What is the relationship between SA:V in organisms

Answer 4

The larger the organism, smaller the SA:V ratio

Question 5

How can you reduce heat loss in organisms?

Answer 5

Reducing their contact with surroundings

Question 6

What is another way of reducing heat loss in organisms?

Answer 6

Increasing their surface

Question 7

How are elephants adapted to lose heat?

Answer 7

They have large ears which increase the surface area for heat loss

Question 8

Do elephants have a big or small SA:V

Answer 8

small
it is adapted to lose heat

Question 9

Do shrews have a large or small SA:V

Answer 9

larger SA:V
it is adapted to minimise heat loss

Question 10

How are shrews adapted to minimise heat loss?

Answer 10

They have a high respiration rate to produce heat - high metabolic rate
Shrews have a high metabolic rate so must eat 80-90% of their own body weight in food daily

Question 11

What does the size of an organism surface area define

Answer 11

How quickly they can absorb substances

Question 12

What does the size of an organisms volume define?

Answer 12

How much of a substance they need

Question 13

Why is it harder for larger organisms to exchange substances?

Answer 13

Because larger organisms have smaller SA:V ratios
—> They have evolved specialised exchange surfaces

Question 14

What is ventilation?

Answer 14

Movement of air in and out of the lungs (breathing)

Question 15

What is respiration

Answer 15

Chemical reaction, produced ATP

Question 16

What is gas exchange

Answer 16

Oxygen diffused from alveoli to blood
Carbon dioxide diffuses from blood to alveoli

Question 17

How does deoxygenated blood enter the lungs ?

Answer 17

From the pulmonary artery

Question 18

How does oxygenated blood leave the lungs

Answer 18

from the pulmonary vein

Question 19

How do the intercostal muscles work

Answer 19

They work antagonistically

Question 20

How do the internal intercostal muscles work

Answer 20

They contract to help with forced expiration
(ribs move down and in)

Question 21

How do the external intercostal muscles work?

Answer 21

They contract to help with inspiration (ribs move up and out)

Question 22

What happens when you inhale (inspiration)

Answer 22

Rib cage moved up and outwards
Diaphragm moved downwards (flattens)
Intercostal muscles :
External contract
Internal relax
Volume increases
Pressure decreases

Question 23

What happens when you exhale (expiration)
(opposite to inspiration)

Answer 23

air forces out
ribs move in and down
Diaphragm returns to dome position
Intercostal muscles:
Internal contract
external relax
Volume decreases
Pressure increases

Question 24

What is pulmonary ventilation?

Answer 24

The volume of air moved in and out of the lungs in 1 minute
Unit = dm3min-1

Question 25

What is the equation for pulmonary ventilation?

Answer 25

PV = Tidal Volume x Ventilation Rate PV = TV x VR TV - dm3 VR - min-1

Question 26

What is tidal volume

Answer 26

the volume of air taken in each breath

Question 27

What is ventilation rate ?

Answer 27

The number of breath per minute

Question 28

what is pulmonary ventilation

Answer 28

the volume of air moving into and out of the lungs per minute

Question 29

What is the epithelium

Answer 29

Wall of the alveolus

Question 30

What is the endothelial layer

Answer 30

cell of capillary

Question 31

How is a large surface area achieved for gas exchange

Answer 31

Many small alveoli Many small capillaries

Question 32

How is a short diffusion pathway achieved for gas exchange

Answer 32

Alveolar wall- A single layer of flattened epithelial cells Capillary wall - A single layer of endothelial cells

Question 33

How is a high differential gradient achieved for gas exchange

Answer 33

Movement of air by ventilation Movement of blood

Question 34

What is partial pressure?

Answer 34

If a container is filled with more than 1 gas, each gas exerts a pressure The pressure of any one gas within the container is called its partial pressure Higher concentration -> Higher partial pressure

Question 35

What is the partial pressure of oxygen

Answer 35

The pressure exerted by oxygen within a mixture of gases It is a measure of oxygen concentration

Question 36

How are the lungs adapted for gas exchange ?

Answer 36

Many alveoli - Large SA for diffusion Epithelial cells are thin - Short diffusion pathway The lungs are ventilated so the concentration gradients are maintained Blood is constantly moving through the capillaries so the concentration gradients are maintained

Question 37

What is correlation?

Answer 37

Change in one variable reflected by a change in the other variable

Question 38

What is cause

Answer 38

a factor which directly results in disease

Question 39

What is relative risk

Answer 39

measured by comparing the likelihood of harm occurring in those exposed to a hazard with those who are not exposed to it

Question 40

What is a risk factor

Answer 40

Anything that increases the chance of getting a disease

Question 41

What are some risk factors of lung disease

Answer 41

Smoking Air pollution Infection Genetics