mammalian gas exchange system

Question 1

describe the basic structure of the human gas exchange system

Answer 1

the trachea divides into 2 bronchi (one to each lung) which further divide into bronchioles that branch to the alveoli

Question 2

describe the structure of the trachea

Answer 2

contain C-shaped cartilage rings for support, smooth muscle and elastic tissue

Question 3

what adaptations does the trachea lining have

Answer 3

lined with ciliated epithelial cells and goblet cells

Question 4

what do goblet cells do?

Answer 4

produce mucus

Question 5

what do ciliated epithelial cells do?

Answer 5

move mucus (and trapped particles) up the trachea until it can be swallowed - cilia beat to enable this

Question 6

describe the function of cartilage in the trachea

Answer 6

supported by C-shaped cartilage rings to keep it open/supported so air can move in and out all the time

Question 7

describe the structure of the bronchi

Answer 7

C-shaped cartilage, smooth muscle and elastic tissue from trachea continue into the bronchi

Question 8

describe the structure of the bronchioles

Answer 8

contains bands of smooth muscle with elastic tissue surrounding them

Question 9

describe the function of elastic tissue in the bronchi/bronchioles

Answer 9

allow lungs to recoil back into shape after they expanded during inspiration

Question 10

what are 3 adaptations of alveoli

Answer 10

• large surface area
• rich blood supply to maintain concentration gradient
• thin walls - short diffusion distance

Question 11

what type of cell makes up the capillaries?

Answer 11

endothelial cells

Question 12

what type of cell makes up the alveoli?

Answer 12

epithelial cells (1 cell thick)

Question 13

what is an example of a pressure gradient?

Answer 13

trachea –> alveoli

Question 14

what is an example of a diffusion gradient?

Answer 14

alveoli –> blood

Question 15

describe the process of human ventilation (inspiration)

Answer 15

• external intercostal muscles contract
• ribs move up and out
• diaphragm contracts and flattens
• volume of lungs increases, pressure decreases (lower than atmosphere so air moves in)

Question 16

describe the process of human ventilation (expiration)

Answer 16

• external intercostal muscles relax
• (for forced exhalation): internal intercostal muscles contract
• ribs move down
• diaphragm moves up and relaxes
• volume of lungs decreases, pressure increases (higher than atmosphere so air moves out)

Question 17

what happens during forced expiration?

Answer 17

• internal intercostal muscles contract to pull ribs in hard and fast
• external intercostal muscles further relax

Question 18

what are the intercostal muscles considered?

Answer 18

antagonistic pairs

Question 19

define antagonistic pair + example

Answer 19

a muscle (or pair of something) that opposes the actions of the other
- eg. biceps contract when triceps relax

Question 20

describe the relationship between pressure and volume

Answer 20

pressure is inversely proportional to volume (increase volume = decrease pressure)

Question 21

what process is expiration considered

Answer 21

passive

Question 22

what process is inspiration considered?

Answer 22

active

Question 23

where are intercostal muscles located

Answer 23

between the ribs

Question 24

what is tidal volume

Answer 24

volume of air displaced by the lungs per breath at rest (dm3)

Question 25

what is breathing rate

Answer 25

number of breaths taken each minute (breaths per min)

Question 26

what is FEV1

Answer 26

• forced expiratory volume
• the max volume of air that can be breathed out in 1s

Question 27

what is vital capacity?

Answer 27

maximum volume that can be exhaled after maximum inhalation

Question 28

what does a spirometer measure?

Answer 28

volume and function of the lungs + oxygen uptake

Question 29

how does a spirometer work?

Answer 29

inhalation and exhalation move the lid of the spirometer recorded by a data logger
- Co2 exhaled is absorbed by soda lime, so the volume of O2 can be measured

Question 30

what is the approx. volume of air in each breath in adults

Answer 30

0.4-0.5 dm3

Question 31

what is the average number of breaths per min

Answer 31

15

Question 32

what are 5 examples of lung diseases

Answer 32

• cystic fibrosis
• asthma
• TB
• COVID
• emphacema