3.1.3 tissues in gaseous exchange system

Question 1

cartilage

Answer 1

form of connective tissue

Question 2

ciliated epithelium

Answer 2

layer of cells with many hair-like extensions called cilia

Question 3

elastic fibres

Answer 3

protein fibres which can deform & recoil to original size

Question 4

goblet cells

Answer 4

cells which secrete mucus

Question 5

smooth muscle

Answer 5

involuntary muscle that contracts

Question 6

tissue of alveoli & why

Answer 6

• squamous epithelium = flat/thin for short diffusion distance
• walls contains elastic fibres = stretch in inspiration & recoil to push air out during expiration

Question 7

tissue of airway (trachea, bronchi & bronchioles) & why

Answer 7

• lined with ciliated epithelium = keeps lungs healthy
• cilia^ = move mucus to top of airway & swallowed
• goblet cells in epithelium = release mucus to trap pathogens

Question 8

how are bronchi different to tracheas tissue-wise & why

Answer 8

(still have ciliated epithelium, goblet cells & cilia)
- rings of cartilage = prevent collapse during inspiration & c-shaped to allow flexibility/space for food to pass down oesophagus

Question 9

how are bronchioles different to trachea/bronchi tissue-wise & why

Answer 9

• narrower than bronchi
• larger ones may have cartilage but smaller bronchioles don’t
• wall mainly smooth muscle & elastic fibres

Question 10

what tissues does the trachea have

Answer 10

• large, c-shaped rings of cartilage
• smooth muscle
• elastic fibres
• goblet cells
• ciliated epithelium

Question 11

what tissues does the bronchi have

Answer 11

• smaller pieces of cartilage
• smooth muscle
• elastic fibres
• goblet cells
• ciliated epithelium

Question 12

what tissues does the larger, smaller & smallest bronchiole have

Answer 12

larger:
- smooth muscle, elastic fibres, goblet cells & ciliated epithelium

smaller:
- smooth muscle, elastic fibres & ciliated epithelium

smallest:
- elastic fibres & epithelium (no cilia)

Question 13

what tissues does the alveoli have

Answer 13

• elastic fibres
• epithelium (no cilia) = squamous

Question 14

role of smooth muscle & elastic fibres

Answer 14

smooth muscle:
- can contract = constrict airways
- lumen of airway becomes narrower
- restrict flow of air to/from alveoli
- important if harmful substances in air
- not voluntary eg. allergic reaction
- cannot reverse on own

elastic fibres:
- smooth muscle elongated again by elastic fibres
- muscle contract = deforms elastic fibres

–> acts to dilate airway