L21 Respiratory Physiology 1

Question 1

What are the two types of respiration?

Answer 1

Internal and external respiration

Question 2

What are the stages of internal respiration?

Answer 2

Within the cell,
Glycolysis, Krebs cycle - CO2 produced
Oxidative phosphorylation - O2 consumed

Question 3

What does external respiration do?

Answer 3

1. Ventilation (inhalation and exhalation)
2. Exchange and transport of gases around the body

Question 4

Which major process does respiration rely on?

Answer 4

Diffusion

Question 5

What happens to the time taken for oxygen to diffuse through a solution if the distance increases?

Answer 5

If distance of diffusion increases then the time increases since it takes longer to cross

Question 6

The lungs are separated into two sections. What are they?

Answer 6

Conducting zone
Respiratory zone

Question 7

What happens in the conducting zone of the lungs?

Answer 7

Filter, warm and humidify the incoming air.

Question 8

How does air travel to the lungs?

Answer 8

Trachea —> bronchi —> bronchioles —> alveolar ducts —> alveolar sacs

Question 9

What is involved in the conducting zone?

Answer 9

• Nose
• Nasopharynx
• (Mouth) Oropharynx
• Pharnyx
• Larynx (voice box)
• Trachea (windpipe)
  -Bronchial tree

Question 10

By the time air reaches the respiratory zone, it has undergone significant changes within the conducting zone. What are these changes?

Answer 10

Air has been:
Warmed
Humidified
Filtered
Cleansed

Question 11

What tissue layers are there within the bronchial wall?

Answer 11

Cartilage- provides structural support
Smooth muscle - Controls diameter of airways
Mucous glands - Secrete mucus to trap particles and keep airways moist
Elastic tissue - Allows airways to stretch and recoil during breathing

Question 12

Describe the structure of the respiratory epithelium

Answer 12

Cilitated epithelia - hair like projections called cilia that move mucus and trapped particles upwards towards the pharynx
Goblet cells - secrete mucus to trap inhaled particles
Sensory nerve endings

Question 13

Why do we reinforce the bronchial wall with cartilage?

Answer 13

Prevents the airway from collapsing

Question 14

Describe the structure of the bronchioles

Answer 14

Lack cartilage support (rely on surrounding lung tissue and elastic fibres for structural support)
Lined by respiratory epithelium
Proportionately more smooth muscle (allows for broncho- constriction/dilation)
Less than 1mm diameter

Question 15

Describe the structure of the Alveoli

Answer 15

Large surface area
Terminal bronchiole ( crucial link between bronchi and respiratory zone where gas exchange occurs)
Thin walled

Question 16

What is the air blood barrier?

Answer 16

Also known as the alveolar - capillary membrane, is an incredibly thin interface where the magic of gas exchange happens in the lungs

Question 17

What are the two types of cells that create the air blood barrier?

Answer 17

Type 1 alveolar cells: Extremely thin, flat cells that cover most of the alveolar surface area

Endothelial cells: Cells line the capillaries that surround the alveoli

Question 18

How is the air blood barrier adapted for efficient gas exchange? (4)

Answer 18

• Extreme thinness - minimises distance that gases must travel to diffuse across
• Large surface area - 50-100m^2
• Close proximity to alveoli and capillaries - fresh supply of blood
• Surfactant - Type II alveolar cells, reduces surface tension which prevents alveoli from collapsing, ensuring they remain open for gas exchange

Question 19

Are inspiration and expiration quiet or forced?

Answer 19

Both of these processes can be quiet (at rest) or forced (when active e.g. during exercise)

Question 20

What happens to the pressure during inspiration and expiration?

Answer 20

During inspiration: atmospheric pressure > alveoli pressure so air moves into the lungs
During expiration: Palv> Patmos so air moves out of the lungs

Question 21

What is involved in quiet inspiration?

Answer 21

Diaphragm and external intercostal muscle contractions which increases thoracic cavity volume which decreases pressure within the lungs, relative to atmospheric pressure which allows air to flow in

Question 22

What happens to the diaphragm and external intercostals during inspiration? What is the effect?

Answer 22

Diaphragm contracts so moves down
External intercostals contracts so expands

Effect - increase thoracic and lung volume

Question 23

Which muscles are involved in forced inspiration?

Answer 23

Primary muscles: diaphragm and external intercostal muscles

Accessory muscles: Sternocleodomastoid, scalene muscles, neck and back muscles, upper respiratory tract muscles

Question 24

What is involved in quiet expiration?

Answer 24

Passive process using elastic recoil

Relaxation of external intercostals muscles
Recoil of the lungs (elastic forces returning lungs to original size)
Diaphragm relaxes

Question 25

Which muscles are involved in forced expiration?

Answer 25

Accessory muscles Internal intercostals Abdominal muscles Neck and back muscles

Question 26

What is the function of the pleura?

Answer 26

Pleural cavity filled with secretions Prevents lungs from sticking to the chest wall Enables free expansion and complete collapse of lungs

Question 27

What happens to the elastic nature of lungs at rest?

Answer 27

Elastic nature of lungs would tend to cause them to collapse inwards Chest wall would tend to expand At rest, these opposing forces would balance - resulting the pressure in the intrapleural space to be less than the atmospheric pressure

Question 28

What happens to the chest wall at rest ?

Answer 28

They would tend to expand

Question 29

At rest, why is the counterbalance pressure between lungs and the chest wall at rest important?

Answer 29

The counter forces (inwards of lungs and outwards of chest at rest) results the pressure in the intrapleural space to be less than the atmospheric pressure

Question 30

What happens to a collapse lung ?

Answer 30

Medically known as a pneumothorax, occurs when air leaks into the space between your lungs and chest wall. This buildup of air puts pressure on the lung, preventing it from fully expanding as you inhale