Structures of ventilation

Question 1

What are the 2 types of respiration?

Answer 1

• internal respiration
• external respiration

Question 2

What occurs during internal respiration?

Answer 2

• within a cell
• CO2 produced - glycolysis, Krebs cycle
• O2 consumed - oxidative phosphorylation

Question 3

What occurs during external respiration?

Answer 3

• ventilation
• exchange & transport of gases around the body

Question 4

What is the function of the lungs?

Answer 4

an air pump, allowing exchange of gases with atmosphere. It has a huge surface area for gas exchange, allowing for efficient exchange of gases with the lungs

Question 5

What type of pressure is in the pulmonary system?

Answer 5

low pressure system

Question 6

What type of pressure is in the systemic system?

Answer 6

high pressure system

Question 7

Why do we have control over our respiration?

Answer 7

the body detects the pH & CO2 levels in the blood, adjust accordingly

Question 8

How many levels of branching occurs in the lungs?

Answer 8

23 levels of branching

Question 9

What 2 pathways can branching have?

Answer 9

• conducting zone
• respiratory zone

Question 10

What occurs in the conducting zone?

Answer 10

• doesn’t take part in gas exchange, but useful for getting gas in respiratory zone (first 16 layers)
• bronchi contains cartilage
• bronchioles are a smaller airways - lack cartilage (also can collapse during expiration)

Question 11

What occurs in the respiratory zone?

Answer 11

• where gas exchange takes place
• contains alveoli - site of gas exchange
• lower levels have a huge surface area

Question 12

What parts of the respiratory system are in the conducting zone?

Answer 12

• nose
• nasopharynx
• mouth (oropharynx)
• pharynx
• larynx
• trachea
• bronchial tree

Question 13

What is the purpose in the nose?

Answer 13

conditions the incoming air - filter, warm, humidify & aids in filtering.
- turbulent flow allows particles to stick to mucus.
- warming the air as it travels through the nasal passage (to 37 degrees)
- solubility of gas changes with temperature - gas more soluble in a cold temperature
- warming of the blood therefore prevents bubbles in the blood.
- the air becomes saturated with water, preventing the airways from becoming desiccated (drying out)

Question 14

What is the structure of bronchial wall?

Answer 14

• reinforced with cartilage
• smooth muscle
• mucus glands
• elastic tissues

Question 15

What is in the respiratory epithelium?

Answer 15

• ciliated epithelia
• goblet cells
• sensory nerve endings

Question 16

How large are bronchioles?

Answer 16

less than 1mm diameter

Question 17

Describe the structure of bronchioles

Answer 17

• lack cartilage support
• lined by respiratory epithelium
• proportionately more smooth muscle - used to control diameter of airways
• more smooth muscle in bronchioles than in the bronchi

Question 18

Describe the structure of alveoli

Answer 18

• large surface area
• fed from terminal bronchioles
• thin walled
• alveoli sacks - site of gas exchange

Question 19

What is the air blood barrier?

Answer 19

• a ‘sandwich’ created by flattened cytoplasm of type 1 pneumocyte (epithelial cells) and the capillary wall
• type 2 pneumocyte - involved in surfactant production

Question 20

What is necessary for gas exchange to occur?

Answer 20

gas exchange to take place barriers have to be crossed (large surface are for gas exchange 50-100m^2).
- aquaporin one also helps with gas transfer

Question 21

What are the 2 processes involved in ventilation?

Answer 21

• inspiration
• expiration

Question 22

What are the two types of inspiration & expiration ?

Answer 22

• quiet (at rest)
• forced (when active e.g. during exercise)

Question 23

When does inspiration occur?

Answer 23

Pressure (atmosphere) > Pressure (alveoli)

Question 24

When does expiration occur?

Answer 24

Pressure (atmosphere) < Pressure (alveoli)

Question 25

Describe the physiological effect of quiet inspiration?

Answer 25

involves the primary muscles of inspiration:
- the diaphragm (pulled down)
- external intercoastal muscles

Question 26

What is the effect of the physiological changes during quiet inspiration?

Answer 26

• increase thoracic & lung volume

Question 27

What does it mean that air movement follows the principle of Boyle’s law?

Answer 27

• The increase in volume leads to a reduction in pressure
• air moves into the lungs down the pressure gradient

Question 28

What occurs in forced inspiration?

Answer 28

The accessory (or secondary) muscle of inspiration are used:
- scalenes
- sternocleidomastoids
- neck & back muscles
- upper respiratory tract muscles

Question 29

What occurs in quiet expiration?

Answer 29

quiet expiration is a passive process using elastic recoil.
- no primary muscles of expiration
- relaxation of external inter coastal muscles
- recoil of the lungs (elastic forced returning lungs to the original size)
- diaphragm relaxes

Question 30

What is involved in forced expiration?

Answer 30

• accessory muscles
• abdominal muscles
• internal inter-coastal
• neck & back muscles

Question 31

What is in the pleura?

Answer 31

pleura cavity filled with secretions
- prevents lungs from sticking to chest wall
- enables free expansion and collapse of lungs
- lines the outer part of lungs & inside of ribcage
- pleura membrane
- lungs expand as the chest wall to expand

Question 32

Describe the forces in the lungs & chest at rest

Answer 32

• elastic nature of lungs would tend to cause them collapse inwards
• the chest wall would tend to expand
• at rest, these inward (form the lungs) & outward (from the chest) force balances - as a result the pressure in the intrapleural space is less than atmosphere

Question 33

What is pneumothorax?

Answer 33

(collapsed lung) - usually a puncture in the chest wall
- this allows air into the intrapleural membrane, which leads to a loss of the balance.
- covering of hole will lead to reinflation of lung alongside the forces also coming to equilibrium