3.1 Exchange surfaces and breathing

Question 1

What are the 2 main reasons why diffusion alone is enough to supply the needs of single celled organisms?

Answer 1

1. the metabolic activity of a single celled organism is usually low so the O demand and CO2 production are relatively low
2. the SA:V of the organism is large

Question 2

What are the characteristic features of effective exchange surfaces?

Answer 2

• increased surface area
• thin layers
• good blood supply
• ventilation to maintain diffusion gradient

Question 3

Where does gas exchange occur in the human body?

Answer 3

The lungs

Question 4

What are the important features of the nasal cavity?

Answer 4

• large surface area
• hairy lining
• moist surfaces

Question 5

What are the important features of the trachea?

Answer 5

• strong flexible cartilage to prevent collapse
• lined with ciliated epithelium
• presence of goblet cells

Question 6

What type of muscle do the bronchioles contain?

Answer 6

smooth muscle

Question 7

What are the alveoli?

Answer 7

Tiny air sacs which are the main gas exchange surfaces of the body

Question 8

What are the main adaptations of the alveoli for effective gas exchange?

Answer 8

• large surface area
• thin layers
• good blood supply
• good ventilation

Question 9

What parts of the body are involved with ventilation?

Answer 9

• rib cage
• diaphragm
• internal and external intercostal muscles
• thorax lined with pleural membranes

Question 10

Is inspiration an energy using or passive process?

Answer 10

energy using

Question 11

Is expiration an energy using or passive process?

Answer 11

passive

Question 12

Do the ribs go up or down during inspiration?

Answer 12

up

Question 13

Does the diaphragm go up or down during expiration?

Answer 13

up

Question 14

Name 3 ways of measuring the capacity of the lungs?

Answer 14

1. Peak flow meter
2. Vitalographs
3. Spirometer

Question 15

What are the 6 different components of lung volume that can be measured?

Answer 15

1. Tidal volume
2. Vital capacity
3. Inspiratory reserve volume
4. Expiratory reserve volume
5. Residual volume
6. Total lung capacity

Question 16

What is the tidal volume?

Answer 16

The volume of air that moves into and out of the lungs with each resting breath

Question 17

What is the vital capacity?

Answer 17

The volume of air that can be breathed in and out when the strongest possible exhalation is followed by the deepest possible intake of breath

Question 18

What is the inspiratory reserve volume?

Answer 18

the maximum volume of air that you can breath in over and above a normal inhalation

Question 19

What is the expiratory reserve volume?

Answer 19

the extra amount of air you can force out of your lungs over and above the normal tidal volume of air you breathe out

Question 20

What is the residual volume?

Answer 20

the volume of air that is left in the lungs when you have exhaled as hard as possible. this cannot be measured directly

Question 21

What is the total lung capacity?

Answer 21

the sum of the vital capacity and the residual volume

Question 22

How is ventilation rate calculated?

Answer 22

ventilation rate = tidal volume x breathing rate

Question 23

How does gaseous exchange take place in insects?

Answer 23

air enters and leaves the system through spiracles which are opened/closed by sphincters it travels through the tracheae lined with chitin, leading to tracheoles which are not lined with chitin so gas can exchange freely

Question 24

How are the gills adapted for efficient gas exchange in bony fish?

Answer 24

• large surface area
• good blood supply
• thin layers
• maintain a continuous flow of water in one direction

Question 25

What is the name of the part of the gill that helps fish to maintain a constant flow of water over the gills even when they stop moving?

Answer 25

Operculum

Question 26

What 2 additional adaptations do gills have?

Answer 26

• the tips of adjacent filaments overlap

- the water flowing over the gills and the blood in the fill filaments move in opposite directions