7 - Exchange Surfaces and Breathing

Question 1

State 3 features of the nasal cavity that improve gas exchange

Answer 1

• moist
• good blood supply
• hairs and mucus

Question 2

Why does good blood supply in the nasal cavity improve gas exchange?

Answer 2

• warms the air
• increased Ek
• greater rate of diffusion when in lungs

Question 3

Why does moisture in the nasal cavity improve gas exchange?

Answer 3

• keeps the air moist

- can dissolve in water when diffusing out of alveloli

Question 4

Why do hairs and mucus in the nasal cavity improve gas exchange?

Answer 4

• trap bacteria and dust

- prevents delicate lung tissue from irritation and infection

Question 5

State 2 features of the trachea that improve gas exchange

Answer 5

• c-shaped rings of cartilage

- lined with ciliated epithelial cells and goblet cells

Question 6

Why are the rings of cartilage in the trachea not full circles

Answer 6

Allows food to easily move down oesophagus behind the trachea

Question 7

Why does the trachea have rings of cartilage?

Answer 7

To protect the trachea from collapsing and trauma

Question 8

What do the ciliated epithelial cells and goblet cells do in the trachea?

Answer 8

Goblet cells, secrete mucus onto the lining of trachea to trap dust and microorganisms

Cilia beat to move mucus and the trapped artefacts away from lungs and to throat where it is swallowed and digested

Question 9

State a feature of the bronchus that improves gas exchange and how it works

Answer 9

-rings of cartilage - provide support, strong yet flexible, prevent from collapse

Question 10

State 2 features of the bronchioles that improve gas exchange

Answer 10

• thin layer of epithelial cells

- smooth muscle

Question 11

Why do the bronchioles have smooth muscle?

Answer 11

Allow the lungs to constrict and dilate

Question 12

Why do the bronchioles have a thin layer of epithelial cells?

Answer 12

Allows some gaseous exchange

Question 13

State 4 features of alveoli that improve gas exchange

Answer 13

Thin
Good blood supply
High SA
Good ventilation

Question 14

Why do alveoli have thin walls?

Answer 14

Short diffusion pathway

MAkes diffusion of oxygen into blood and CO2 out of blood more easy

Question 15

Why do alveoli have good blood supply?

Answer 15

takes O2 away from lungs quickly so maintains a high conc. gradient

Question 16

Why do alveoli have large SA?

Answer 16

Large amounts of oxygen able to diffuse into blood to meet metabolic demand

Question 17

Why do alveoli have good ventilation?

Answer 17

Breathing moves air in and out of lungs

Helps maintain steep conc. gradients

Question 18

Describe inhalation in terms of pressure

Answer 18

Pressure in the atmosphere is greater than the pressure in the lungs, forcing air into the alveoli

Question 19

Describe exhalation in terms of pressure

Answer 19

Pressure in the lungs is greater than the pressure in the atmosphere, forcing air out of the alveoli

Question 20

What happens to the diaphragm during inhalation

Answer 20

contracts and flattens

increases volume fo thorax

Question 21

What happens to the diaphragm during exhalation

Answer 21

relaxes and curves

decreases volume of the thorax

Question 22

What happens to the intercostal muscles during inhalation

Answer 22

external intercostal muscles contract
ribs move up and out
increases volume of the thorax

Question 23

What happens to the intercostal muscles during exhalation

Answer 23

internal intercostal muscles contract
ribs move down and inwards
decreases volume of the thorax

Question 24

What is the tidal volume of the lungs

Answer 24

the volume of air that moves in and out with each resting breath

Question 25

What is the residual volume of the lungs

Answer 25

volume of air left in the lungs when one has exhaled and hard as possible

Question 26

What is vital capacity of the lungs

Answer 26

volume of air that can be breathed in when the strongest exhale is followed by the deepest inhale

Question 27

How do you calculate ventilation rate?

Answer 27

tidal volume x breaths per minute

Question 28

Describe how a spirometer works

Answer 28

The patient breathes in and out of an airtight chamber filled with oxygen thus causing it to move up and down and leave a trace on the graph

Question 29

Describe the structure of spiracles in the insect gaseous exchange system

Answer 29

found along the sides of insects opening of larger tubes called trachea have sphincters to control entry and exit

Question 30

How will the state of spiracles change in an insect depending on metabolic demand

Answer 30

High metabolic demand, O2 demand is high, spiracles open to let oxygen in and CO2 out Low metabolic demand, O2 demand low, spiracles kept closed

Question 31

Describe the structure of tracheas in insect gaseous exchange system

Answer 31

large tubes | lined with chitin rings

Question 32

Describe the structure of tracheoles in insect gaseous exchange system

Answer 32

single, elongated cells no chitin so freely permeable to gas filled with tracheal fluid

Question 33

Describe how gaseous exchange occurs in insects

Answer 33

Low metabolic demand- a small amount of O2 can diffuse from tracheoles High metabolic demand - cells respire anaerobically, produce lactic acid which lowers the water potential of cells. Tracheal fluid diffuses out leaving a moist exchange surface for oxygen to diffuse through

Question 34

What is the difference is the gill structure of bony fish and cartilaginous fish

Answer 34

Bony fish- operculum to cover gills, counter-current exchange system cartilaginous fish- open gill slits, concurrent exchange system, ram ventilation

Question 35

What is the role and structure of the operculum?

Answer 35

Bony plate that covers the gills to protect them from damage

Question 36

What do the gill rakers do?

Answer 36

Clean water for any dirt and bits

Question 37

What does the gill arch do?

Answer 37

Supports the gill plates and carriers the blood supply

Question 38

What are the gill plates made of? (2)

Answer 38

Gill filaments, each filament is made up of hundreds of microscopic lamellae, this is where gaseous exchange occurs

Question 39

Describe how inhalation occurs in fish

Answer 39

Mouth opens Buccal chamber expands (pressure decreases) water flows in

Question 40

Describe how exhalation occurs in fish

Answer 40

Mouth closes Buccal chamber decreases in size (pressure increases) water flows out through gills