Spirometry

Movement of air in and out of the lungs is called pulmonary ventilation, and it involves the main structures of the respiratory system

Movement of air in and out of the lungs is called _______ ______, and it involves the main structures of the respiratory system

Gaseous exchange

refers to the transfer of oxygen and carbon dioxide between the air and blood

The walls of the alveoli are only one cell thick

The walls of the _____ are only ___ cell thick

This is also true of the walls of the tiny capillaries surrounding the alveoli (Figure 1) therefore carbon dioxide and oxygen can move by diffusion

This is also true of the walls of the tiny ______ surrounding the alveoli (Figure 1) therefore carbon dioxide and oxygen can move by _______

• When oxygen rich air is breathed in, the oxygen diffuses into the red blood cells (erythrocytes) which deliver the oxygen to all the other cells of the body

• Carbon dioxide, returning from the body in the blood, diffuses from the red blood cells into the alveolar space and is breathed out.

• The capillaries are so tiny that they only allow one blood cell at a time to pass through, slowing the blood flow and allowing time for gaseous exchange

• When oxygen rich air is breathed in, the oxygen diffuses into the _____ blood cells (_____) which deliver the oxygen to all the other _____ of the body

• Carbon dioxide, returning from the body in the blood, diffuses from the red blood cells into the ______ _____ and is breathed ____.

• The capillaries are so ____ that they only allow _____ blood cell at a time to pass through, slowing the blood ____ and allowing time for gaseous ______

capillaries

• tiny that they only allow one blood cell at a time to pass through, slowing the blood flow and allowing time for gaseous exchange

gases diffuse from a region of high concentration to a region of lower concentration (move down their concentration gradient)

An important feature of gaseous exchange

The convention is to use partial pressures when describing the concentration of respiratory gases and the units shown in Figure 1 are millimetres of mercury (mmHg).

The convention is to use ______ pressures when describing the ______ of respiratory gases and the units shown in Figure 1 are millimetres of _____ (mmHg).

partial pressure

 the proportion that gas contributes to atmospheric pressure.

At sea level, the average atmospheric pressure is 760 mmHg – so, if the partial pressure for oxygen at sea level in inspired air is 160 mmHg, then the percentage of oxygen in inspired air can be calculated by dividing 160 mmHg by the atmospheric pressure and multiplying the result by 100:

(partial pressure of the respiratory gas/atmospheric pressure) x 100 = percentage of the gas

(160 mmHg/760 mmHg) x 100 = 21%

The percentage of oxygen in inspired air is 21%

At sea level, the average atmospheric pressure is 760 mmHg – so, if the partial pressure for oxygen at sea level in inspired air is 160 mmHg, then the percentage of oxygen in inspired air can be calculated by dividing 160 mmHg by the _______ pressure and multiplying the result by 100:

(partial pressure of the respiratory gas/atmospheric pressure) x 100 = percentage of the gas

(____ mmHg/_____ mmHg) x 100 = 21%

The percentage of oxygen in inspired air is 21%

when inspiring, ribcage moves upwards and expands outwards as the air enters the lungs

• movement of diaphragm and intercostal muscels acts to expand the size of the thoracic cavity drawing air into the lungs

when inspiring, ribcage moves ______ and expands ______ as the air enters the lungs

• movement of _______ and ______ muscels acts to expand the size of the ______ cavity drawing air into the lungs

in expiration, ribcage moves downwards and retracts inwards as the air leaves your laungs

• relaxation of the intercostal muscles and diaphragm reduces the size of the thoracic cavity. The ribcage, diaphragm and lung tissue itself return by elastic recoil to their original pre inspiratory positions. The consequent retraction of the chest wall forces air out of the lungs

in expiration, ribcage moves ______ and retracts ______ as the air leaves your lungs

• ________ of the intercostal muscles and diaphragm _______ the size of the thoracic cavity. The ribcage, diaphragm and lung tissue itself return by ____ _____ to their original pre inspiratory positions. The consequent _______ of the chest wall forces air ____ of the lungs

• relaxation

• occurs in intercostal muscles and diaphragm reduces the size of the thoracic cavity

• elastic recoil

• The ribcage, diaphragm and lung tissue itself return by what to their original pre inspiratory positions

• The consequent retraction of the chest wall forces air out of the lungs

• The consequent _______ of the chest wall forces air out of the lungs

compliance

The ease with which the lungs and pleura expand and contract, based on changes in pressure is called

Low lung compliance

means that the lungs and alveoli are ‘stiff’, so a higher-than-normal pressure is needed to get the lungs to expand and contract

fibrosis of the lungs

Low lung compliance results to

• asbestos

• tobacco smoke

• indoor cooking smoke

• car exhaust fumes

• coal smoke

ATICC

Low lung compliance results to fibrosis of the lungs due to prolonged inhalation of small particle

chronic bronchitis

Prolonged exposure to tobacco smoke and indoor cooking smoke can cause inflammation of the lungs

emphysema

Prolonged exposure to tobacco smoke and indoor cooking smoke can cause damage to the alveoli called

Chronic Obstructive Pulmonary Disease (COPD)

Prolonged exposure to tobacco smoke and indoor cooking smoke can cause inflammation of the lungs (chronic bronchitis) and damage to the alveoli (emphysema) – a condition called

Chronic Obstructive Pulmonary Disease (COPD).

This makes it more difficult to breathe, reduces the elastic recoil properties of lung tissue and reduces the lung respiratory surface area available for gaseous exchange.

Lung function can be measured using a spirometer – a simple and inexpensive device that measures the flow and volume of expired air

Lung function can be measured using a __________ – a simple and inexpensive device that measures the flow and volume of expired air

spirometer

measures the flow and volume of expired air

forced vital capacity (FVC)

is calculated as the total volume of air that can be forcefully blown out of the lungs in one expiration (one breath).

Peak expiratory flow (PEF)

measures the maximum speed at which air is forcefully expired (litres per second).

forced expiratory volume 1 (FEV1)

is the amount of air that is forcibly blown out within the first second of a forced expiration.

Plotting the FVC and PEF values generates a spirograph, which you will produce when you use the spirometry application.

Plotting the FVC and PEF values generates a ______, which you will produce when you use the spirometry application.

FEV1/FVC ratio (normally expressed as a percentage)

used to evaluate lung function

0.8, meaning that 80% of total volume of air is blown out within the first second.

In healthy individuals, the FEV1/FVC ratio is approximately

A value of less than 70% indicates that lung function is impaired

A value of less than 70% indicates that lung function is _______

Normal lung function is dependent on an individual’s age, height, sex, ethnicity and general fitness

Normal lung function is dependent on an individual’s ___, _____, ___, ______ and general _____