4.2 The Lower Respiratory Tract

Question 1

What is typical tidal volume?

Answer 1

500mL

Question 2

Which muscles help during ventilation?

Answer 2

• Diaphragm
• Intercostal Muscles
• Scalene muscles (check: where are these?)

Question 3

What kind of muscle is the diaphragm?

Answer 3

Skeletal muscle

Question 4

Why do we lean over when we are out of breath?

Answer 4

This enables accessory muscles to help increase the size of the thoracic cage during inspiration

Question 5

Which intercostal muscles (internal or external) participate in inspiration vs expiration?

Answer 5

Both in both

Question 6

What is the name of the gap between the visceral and parietal pleura?

Answer 6

Pleural cavity

Question 7

What are the names of the blood vessels and the nerves within the ribs?

Answer 7

Intercostal veins, arteries, and nerves

Question 8

What happens to the pressure in the pleural cavity during inspiration and expiration?

Answer 8

Inspiration: negative
Expiration: positive

Question 9

List the conducting airways

Answer 9

• Trachea
• Main Bronchi
• Bronchi
• Bronchioli
• Terminal bronchioli

Question 10

What do conducting airways do to air?

Answer 10

• Humidification
• Cleaning
• Transport
• Warming

Question 11

How long is the trachea?

Answer 11

10-12cm

Question 12

Why do we have separate rings of cartilage in the trachea, and not one big one?

Answer 12

For mobility

Question 13

If you were to inhale a lego brick, which lung would it end up in? Why?

Answer 13

• Right
• Right main bronchiole is straighter down

Question 14

Which lung has how many lobes?

Answer 14

• Right: 3
• Left: 2 (Because the heart is here)

Question 15

How many segments do both lungs have?

Answer 15

10

Question 16

Why is it important to know about lung segments?

Answer 16

In disease (e.g. cancer), you can remove individual segments without losing the functionality of the lung

Question 17

Why is the parietal pleura larger than the lungs?

Answer 17

When the lungs increase during inspiration, there is room for the lungs to move. Some space remains for fluid to exist.

Question 18

What is the name of the pleura-covered area with no lung?

Answer 18

Costadiaphragmatic recess

Question 19

How does the velocity of air change as we get closer to the alveoli?

Answer 19

Decreases

Question 20

How does the total cross-sectional area change as we get closer to the alveoli?

Answer 20

Increases

Question 21

Recap: what is the function of fibroblasts?

Answer 21

Produce collagen and extracellular matrix of connective tissue