2.1.3 - The Mammalian Lung

Question 1

Where Are The Lungs Located?

Answer 1

Thorax.

Question 2

What Do The Lungs Provide?

Answer 2

An ideal exchange surface for the diffusion of gases.

Question 3

What Is The Role Of The Lungs?

Answer 3

Maximise gas exchange, while minimising the loss of water across the exchange surface.

Question 4

What Is The Trachea?

Answer 4

Allows air to travel to the lungs.

Question 5

What Does The Trachea Contain?
(4 Points)

Answer 5

~ C-shaped rings of cartilage.

~ Layer of mucus.

~ Cilia.

Question 6

In The Trachea There Are C-Shaped Rings Of Cartilage, What Do They Do?
(3 Points)

Answer 6

~ Ensures the trachea remains open and does not collapse.

~ Prevents any friction from rubbing with the oesophagus.

~ Provides flexibility when swallowing food.

Question 7

In The Trachea There Is A Layer Of Mucus, What Does This Do?

Answer 7

Helps trap dust and pathogens.

Question 8

In The Trachea There Are Cilia, What Do They Do?

Answer 8

Waft mucus towards the top of the trachea, removing trapped particles and pathogens from the airways.

Question 9

How Does The Bronchi Differ From The Trachea?
(2 Points)

Answer 9

~ Have thinner walls and a smaller diameter.

~ Their cartilage rings are full circles.

Question 10

Where Are The Alveoli Located?

Answer 10

Ends of bronchioles.

Question 11

What Does The Alveolar Wall Consist Of?

Answer 11

Epithelium, which is thin and permeable for easy diffusion of gases.

Question 12

What Are The Alveoli Surrounded By & What Does This Allow?

Answer 12

Elastic fibres, allowing them to stretch during inhalation.

Question 13

Which Way Does CO2 Diffuse From The Capillary?

Answer 13

Out the capillaries and into the alveoli to be exhaled.

Question 14

Which Way Does Oxygen Diffuse From The Capillary?

Answer 14

From the alveoli into the capillary to be carried around the body.

Question 15

What Lines The Alveoli?

Answer 15

Layer of moisture, which facilitates the diffusion of gases.

Question 16

What Do The Larger Bronchioles Possess?

Answer 16

Elastic fibres and smooth muscle enabling adjustment of the size of the airway.

Question 17

What Do The Smaller Bronchioles Possess?

Answer 17

Elastic fibres and no smooth muscle.

Question 18

What Are Features Of The Alveoli?
(3 Points)

Answer 18

~ Alveolar wall is one cell thick, short diffusion distance.

~ Has a layer of moisture.

~ Ventilation, creating a steep concentration gradient for CO2 and O2.

Question 19

What Are Features Of The Capillaries?
(2 Points)

Answer 19

~ Wall is one cell thick, short diffusion distance.

~ Good blood supply, creating a steep concentration gradient for CO2 and O2.

Question 20

How Are The Lungs Adapted For Rapid Gas Exchange?
(3 Points)

Answer 20

~ Large surface area due to loads of alveoli.

~ Good supply of blood.

~ Short diffusion distance.