Exchange Surfs

Question 1

Why do organisms need exchange surfaces?

Answer 1

To efficiently exchange substances like oxygen, carbon dioxide, and nutrients due to their size and metabolic demands.

Question 2

What features make an exchange surface effective?

Answer 2

Large surface area, thin barrier, good blood supply/ventilation.

Question 3

What is the main gas exchange surface in mammals?

Answer 3

The alveoli in the lungs.

Question 4

How are alveoli adapted for gas exchange?

Answer 4

Large surface area, thin walls, good blood supply, and moist lining.

Question 5

What is the function of the trachea?

Answer 5

Carries air to the bronchi; lined with cilia and mucus to trap particles.

Question 6

What is the role of ciliated epithelial cells in the airways?

Answer 6

Move mucus and trapped particles out of the lungs.

Question 7

What is the role of goblet cells?

Answer 7

Secrete mucus to trap dust and pathogens.

Question 8

What happens during inspiration?

Answer 8

Diaphragm contracts, external intercostal muscles contract, thoracic volume increases, pressure decreases, air enters.

Question 9

What happens during expiration?

Answer 9

Diaphragm and external intercostal muscles relax, thoracic volume decreases, pressure increases, air exits.

Question 10

What is tidal volume?

Answer 10

The volume of air inhaled or exhaled in a normal breath.

Question 11

What is vital capacity?

Answer 11

The maximum volume of air that can be inhaled or exhaled.

Question 12

How do insects carry out gas exchange?

Answer 12

Through a system of tracheae and tracheoles leading directly to cells.

Question 13

What are spiracles in insects?

Answer 13

Openings on the body surface where air enters and exits.

Question 14

How do insects prevent water loss during gas exchange?

Answer 14

They can close their spiracles and have waterproof coverings.

Question 15

Why don’t insects use haemoglobin for gas transport?

Answer 15

They rely on diffusion through their tracheal system.

Question 16

How do fish exchange gases?

Answer 16

Through gills where water flows over lamellae with a countercurrent system.

Question 17

What is the countercurrent flow in fish?

Answer 17

Water and blood flow in opposite directions to maintain a diffusion gradient.

Question 18

What are gill filaments and lamellae?

Answer 18

Structures in fish gills that provide a large surface area for gas exchange.

Question 19

Why is countercurrent flow more efficient than parallel flow?

Answer 19

It maintains a steep concentration gradient along the entire gill surface.

Question 20

What are the common features of good gas exchange systems in all organisms?

Answer 20

Large surface area, short diffusion distance, and concentration gradients maintained.

Question 21

What is the role of exchange surfaces in animals?

Answer 21

To allow efficient movement of gases, nutrients, and waste between the internal and external environments.

Question 22

Why do large multicellular organisms need specialised exchange surfaces?

Answer 22

They have a small surface area to volume ratio and high metabolic demands.

Question 23

What makes a good exchange surface?

Answer 23

Large surface area, thin barrier, good blood supply or ventilation to maintain a steep concentration gradient.

Question 24

What is the structure of the mammalian gas exchange system?

Answer 24

Air enters through the trachea → bronchi → bronchioles → alveoli for gas exchange.

Question 25

How are alveoli adapted for gas exchange?

Answer 25

Thin walls (one cell thick), large surface area, surrounded by capillaries, moist lining, and surfactant to reduce surface tension.

Question 26

What is the function of surfactant in alveoli?

Answer 26

Reduces surface tension to prevent alveoli collapsing.

Question 27

What muscles are involved in ventilation?

Answer 27

Diaphragm, external and internal intercostal muscles.

Question 28

What is the difference between tidal volume and vital capacity?

Answer 28

Tidal volume: normal breath; Vital capacity: max volume inhaled/exhaled in one breath.

Question 29

What are spirometers used for?

Answer 29

To measure lung volumes like tidal volume and vital capacity.

Question 30

What adaptations do insects have for gas exchange?

Answer 30

Tracheae and tracheoles, spiracles, air sacs, and abdominal pumping.

Question 31

What is the role of air sacs in insects?

Answer 31

Act as reservoirs of air to increase air movement in and out of the tracheal system.

Question 32

What is abdominal pumping in insects?

Answer 32

Rhythmic contractions of abdominal muscles to move air in and out of spiracles.

Question 33

How do insects limit water loss during gas exchange?

Answer 33

Close spiracles and have a waxy cuticle.

Question 34

How do fish carry out gas exchange?

Answer 34

Water flows through the mouth, over the gills where gas exchange occurs via lamellae using a countercurrent system.

Question 35

Describe the structure of gills in fish.

Answer 35

Gills are made up of gill arches with gill filaments; each filament has many lamellae for surface area.

Question 36

What are lamellae in fish gills?

Answer 36

Thin, flat structures that contain capillaries and provide a large surface area for gas exchange.

Question 37

Why is the surface of lamellae moist?

Answer 37

To allow oxygen to dissolve before diffusing into the blood.

Question 38

Explain the countercurrent flow mechanism in fish.

Answer 38

Water and blood flow in opposite directions, maintaining a steep oxygen concentration gradient across the gill lamellae.

Question 39

What would happen if fish had parallel flow instead of countercurrent?

Answer 39

Oxygen diffusion would stop once equilibrium is reached, reducing efficiency of gas exchange.

Question 40

Why do fish need an efficient gas exchange system?

Answer 40

Oxygen is less available in water and diffuses slower than in air, so a steep gradient and large surface area are crucial.

Question 41

How does ventilation occur in bony fish?

Answer 41

Fish open their mouths, lowering the buccal cavity floor to draw in water, then close it to force water over the gills and out through the operculum.

Question 42

What is the role of the operculum?

Answer 42

A bony flap that covers and protects the gills and helps to maintain a unidirectional flow of water.

Question 43

Why is the countercurrent system more efficient?

Answer 43

Oxygen is continually diffusing along the entire length of the gill filament due to the maintained gradient.