The Mechanism Of Breathing

Question 1

What is the process of breathing also known as?

Answer 1

Ventilation

Question 2

What is ventilation?

Answer 2

The movement of air in and out of the lungs.

Question 3

What happens when the air pressure of the atmosphere is greater than the air pressure of the lungs?

Answer 3

Air is forced into the lungs.

Question 4

What is inspiration?

Answer 4

Inhalation

Question 5

When does expiration occur?

Answer 5

When the air pressure in the lungs is greater than the air pressure in the atmosphere. This forces air out of the lungs.

Question 6

What is expiration?

Answer 6

Exhalation

Question 7

What 3 muscles bring about pressure changes in the lungs?

Answer 7

Diaphragm
Internal intercostal muscles
External intercostal muscles

Question 8

What is the diaphragm?

Answer 8

This is a sheet of muscle that separates the thorax form the abdomen.

Question 9

What does the diaphragm separate?

Answer 9

The thorax from the abdomen.

Question 10

Where do the intercostal muscles lie?

Answer 10

Between the ribs.

Question 11

The contraction of which intercostal muscles leads to expiration?

Answer 11

The internal intercostal muscles.

Question 12

The contraction of which intercostal muscles leads to inspiration?

Answer 12

The external intercostal muscles.

Question 13

Is breathing in a passive or active process?

Answer 13

It is active.

Question 14

What happens to the internal intercostal muscles during inspiration?

Answer 14

They relax

Question 15

What happens to the external intercostal muscles during inspiration?

Answer 15

They contract.

Question 16

What happens to the volume of the thorax in inspiration?

Answer 16

It increases.

Question 17

What causes the volume of the thorax to increase in inspiration?

Answer 17

The ribs are moved upwards and outwards.

The diaphragm contracts.

Question 18

What happens to the diaphragm when it contracts in inspiration?

Answer 18

It flattens.

Question 19

What does the increased volume in the thorax lead to?

Answer 19

A reduction of pressure in the lungs. This means that the atmospheric pressure is higher than the pulmonary pressure so air is forced into the lungs.

Question 20

Is expiration an active or passive process?

Answer 20

It is largely passive.

Question 21

What happens to the internal intercostal muscles when expiration occurs?

Answer 21

They contract.

Question 22

What happens to the external intercostal muscles during expiration?

Answer 22

They relax.

Question 23

What do the ribs do during expiration?

Answer 23

They move downwards and inwards.

Question 24

What decreases the volume in the thorax?

Answer 24

The movement of the ribs.

The relaxing of the diaphragm.

Question 25

What happens to the diaphragm during expiration?

Answer 25

The diaphragm muscles relax and so it is pushed up again by the contents of the abdomen that were compressed during inspiration.

Question 26

What does the decreased volume in the thorax do to the lungs?

Answer 26

It increases the pressure so air is forced out.

Question 27

What is the main cause of air being forced out during normal breathing?

Answer 27

The recoil of the elastic tissue.

Question 28

What is the pulmonary ventilation rate?

Answer 28

This is the total volume of air that is moved into the lungs during 1 minute.

Question 29

What is the tidal volume?

Answer 29

This is the volume of air that is normally taken in at each breath when the body is at rest.

Question 30

What is the breathing rate?

Answer 30

The number of breaths that is taken in 1 minute.

Question 31

What are the units of pulmonary ventilation rate?

Answer 31

dm^3min^-1

Question 32

What are the units for tidal volume?

Answer 32

dm3

Question 33

What are the units for breathing rate?

Answer 33

Min^-1

Question 34

What is the equation for pulmonary ventilation rate?

Answer 34

Tidal volume X breathing rate.