Physiology - Respiration Overview

Question 1

What is internal respiration?

Answer 1

The intracellular mechanisms which consume O2 and produce CO2. Slide 5

Question 2

What is external respiration?

Answer 2

The events that lead to the exchange of O2 and CO2. Slide 6

Question 3

What are the 4 steps of EXTERNAL respiration?

Answer 3

Ventilation
Exchange of O2 and CO2 at alveoli
Transport of O2 and CO2
Exchange of O2 and CO2 at tissues. Slide 7

Question 4

What are the 4 body systems involved in external respiration?

Answer 4

Respiratory, cardiovascular, haematology and nervous system. Slide 9

Question 5

What is Boyles Law?

Answer 5

At any constant temperature the pressure exerted by a gas varies inversely with the volume of the gas. Slide 11

Question 6

How does air flow?

Answer 6

From a area of high pressure to low pressue. Slide 11

Question 7

What are the 2 forces linking the thoracic wall and the lungs close?

Answer 7

Intrapleural fluid cohesiveness - water molecules in the fluid attracted to each other

Negative intrapleural pressure - There is a transmural pressure gradient across lung wall. Slide 12

Question 8

What is the pressure in the alveoli and the pleural cavity in mmHg?

Answer 8

Alveoli is 760 mmHg and the pleural cavity is 756 mmHg. Slide 13

Question 9

What are the 3 pressures most important in ventilation?

Answer 9

Atmospheric, intra-alveolar and the intrapleural. Slide 14

Question 10

What does quiet inspiration rely on to draw air in?

Answer 10

The muscle contraction of external intercostal muscles and the contraction of the diaphragm and is an active process. Slide 15

Question 11

What happens during inspiration?

Answer 11

Lung volume increased so alveolar pressure decreases so air is drawn in down the pressure gradient until its equal again with atmospheric pressure. Slide 16

Question 12

Is normal expiration passive or active?

Answer 12

Passive as it is the relaxation of the muscles. Slide 17

Question 13

What is a pneumothorax?

Answer 13

Air in the pleural space. Slide 19

Question 14

What are ways a pneumothorax can occur?

Answer 14

Spontaneous, traumatic or iatrogenic. Slide 19

Question 15

What are the symptoms of a SMALL pneumothorax?

Answer 15

Shortness of breath and chest pain. Slide 19

Question 16

What are the physical signs of a pneumothorax?

Answer 16

Hyperresonant percussion note and decreased/absent breath sounds. Slide 19

Question 17

What causes the lungs to recoil during expiration?

Answer 17

Elastic connective tissue and the alveolar surface tension. Slide 21

Question 18

What stops alveoli collapsing due to the water molecules attraction and which are more likely to collapse? Large or small alveoli.

Answer 18

Surfactant (lipids and proteins) secreted by alveoli type II lowers the surface tension in SMALL alveoli. Slide 22

Question 19

What is Respiratory Distress Syndrome in a new born baby?

Answer 19

Developing fetal lungs can’t synthesise surfactant until nearly born so premature babies struggle to inflate their lungs due to the high surface tension. Slide 23

Question 20

What is alveolar interdependence?

Answer 20

If an alveolus starts to collapse the surrounding alveoli stretch and recoil pulling the collapsed one open. Slide 24