Week 8 Revision Deck:

there are 4 processes that are collectively called respiration, they are:

• pulmonary ventilation (breathing)

• external respiration

• transport of respiratory gases

• internal respiration

what does pulmonary ventilation (breathing) consist of?

• inspiration

• expiration

what happens in external respiration?

• O2 diffuses from lungs to blood

• CO2 diffuses from blood to lungs

what does the cardiovascular system use to transport gases?

blood - as a transporting fluid

what direction does blood transport gases?

• O2 from lungs to tissue cells

• CO2 from tissue cells to lungs

what happens in internal respiration?

• O2 diffuses from blood to tissue cells

• CO2 diffuses from tissue cells to blood

what process of respiration is the respiratory system responsible of?

• pulmonary ventilation (breathing)

• external respiration

what process of respiration is the cardiovascular system responsible of?

• transport of respiratory gases

• internal respiration

what are the structures of the respiratory system?

• nasal cavity

• oral cavity

• pharynx

• epiglottis

• larynx

• trachea

• lungs

• intercostal muscles

• diaphragm

• bronchi

• bronchioles

• alveoli

what structure is the primary entrance of air into the respiratory system?

nose, more specifically nostrils (or nares)

what is the nasal cavity?

a hollow space lined with mucous membranes and cilia

what is the role of the nasal cavity?

filters, warms and humidifies incoming air to enter the respiratory system during breathing

what is another structure that provides a passageway for air into the lungs?

oral cavity

what are the functions of the oral cavity?

• chewing

• swallowing

• speech production

what is another name for the pharynx?

the throat

what is the name of the muscular tube behind the nasal cavity and mouth?

pharynx

what structure serves as the passageway for both air and food?

pharynx

what structure is part of the digestive and respiratory system?

pharynx

what is the name of the flap of cartilage that protects the lower respiratory tract from food or liquid entering into the trachea and lungs while breathing?

epiglottis

what is another name for the larynx?

voice box

where is the larynx located?

at the top of the trachea

what is another name for the trachea?

windpipe

which structure contains vocal cords?

larynx

what do vocal cords do?

vibrate to produce sounds during speech and other vocalisations

what does the larynx do?

acts as a valve to prevent food and liquids from entering the trachea during swallowing

what is the trachea?

a tube-like structure that connects the larynx to the bronci

what does the trachea do?

serves as the main airway for conducting air into and out of the lungs

what is the trachea composed of?

rings of cartilage

what is the purpose of the rings of cartilage in the trachea?

• provides support

• prevents collapse of the airway

what are the primary organs of the respiratory system responsible for gas exchange?

lungs

each lung is enclosed within a _________ cavity

pleural

which lung is composed of 3 lobes?

right lung

• upper

• middle

• lower

which lung is composed of 2 lobes?

left lung

• upper

• lower

where are intercostal muscles located?

between ribs in the thoracic cavity

what is the role of the intercostal muscles?

assist in breathing by expanding and contracting the rib cage during inhalation and exhalation

what is the name of the dome-shaped muscle beneath the rib cage?

diaphragm

what is the role of the diaphragm?

facilitates breathing by contracting and relaxing

what does the trachea divide into?

left and right bronchus that enter into each lung

what are the bronchi lined with?

• ciliated epithelium cells

• mucus-producing goblet cells

what is the role of the ciliated epithelium cells and mucus-producing goblet cells in the lining of the bronchi?

help trap and remove foreign particles, dust and pathogens from the airway

what does the bronchus resemble?

a tree

what are bronchioles?

smaller branches which are extensions of the bronchi

what do bronchioles divide into?

terminal bronchioles

what do terminal bronchioles lead to?

clusters of air sacs called alveoli

what is the primary function of bronchioles?

conduct air deeper into the lungs where gas exchange occurs

what are alveoli?

tiny, grape-like air sacs

what are the primary sites of gas exchange in the respiratory system?

alveoli

which gas diffuses into the alveoli? where from?

• CO2

• from blood in surrounding capillaries

which gas diffuses out of the alveoli? where to?

• O2

• to blood in surrounding capillaries

what is the waste product of cellular metabolism?

carbon dioxide (CO2)

what characteristic of the alveoli allows for optimal gas exchange?

large surface area and thin walls of alveoli

what cells drift through the alveolar lumen?

alveolar macrophages

what is the role of alveolar macrophages?

clearing up debris by phagocytosis

the respiratory system can be separated into __________ and __________ zones

• conducting

• respiratory

what does the conducting zone include?

• nasal cavity

• pharynx

• larynx

• trachea

• bronchi

• bronchioles

• terminal bronchioles

what are the functions of the conducting zone?

• acts as a conduit for the passage of air to reach the respiratory zone

• filter, warm and humidify air

what does the respiratory zone include?

• bronchioles

• alveolar ducts

• alveoli

what are the functions of the respiratory zone?

• facilitating the process of gas exchange

• ensuring O2 is taken by bloodstream to tissues and removing CO2 from bloodstream and body by exhalation

what is the respiratory membrane made up of?

• squamous alveolar epithelial cells

• squamous pulmonary capillary endothelial cells

what are the 2 types of squamous alveolar epithelial cells?

• Type I

• Type II

what is the role of Type I squamous alveolar epithelial cells?

allows for rapid gas diffusion between the air and blood

what percentage of the surface area of the alveolus does Type I squamous alveolar epithelial cells take up?

95%

what percentage of the surface area of the alveolus does Type II squamous alveolar epithelial cells take up?

5%

what are the functions of Type II squamous alveolar epithelial cells?

• to repair the alveolar epithelium when squamous cells are damaged

• to secrete pulmonary surfactant

what is pulmonary surfactant composed of?

• phospholipids

• proteins

what do pulmonary surfactants do?

• coats the alveoli

  • prevents the pressure build up from collapsing the alveoli

what happens if you exhale without pulmonary surfactant?

• walls of deflating alveolus cling together

• makes it very difficult to reinflate them on the next inhalation

what is the surface area of respiratory membranes?

~75m²

what is the diameter of the pulmonary alveolus?

0.2 - 0.5mm

what is the thickness of the respiratory membrane?

0.5µm

how many alveoli do we have altogether?

480 million

what creates a barrier between alveolar air and blood?

respiratory membrane

what is Boyle’s Law?

P1V1=P2V2

what does Boyle’s law state?

the less the volume in a container is, the higher the pressure of the gas contained

as lung volume __________, the pressure inside ________, resulting in a flow of gases into the lungs

• increases

• decreases

what are the steps for inspiration?

• Diaphragm contracts and pulls downwards

• Intercostal muscles also contract and pull upwards and outwards

• Increase in thoracic cavity volume

• lungs expand to fill this cavity

• Lung volume increases

• Pressure inside lungs decrease

• Pressure in lungs is lower than the external atmospheric pressure

• Air pressure gradient is set up for air to move in

• Air moves from higher pressure (external) to lower pressure region (into lungs)

what are the steps for expiration?

• Diaphragm relaxes and moves upwards into the chest cavity

• Intercostal muscles also relax, moving downwards and inwards

• Decrease in thoracic cavity volume

• Lungs recoil

• Lung volume decreases

• Pressure inside the lungs increases

• Pressure in lungs is higher than the external atmospheric pressure

• Air pressure gradient is set up for CO2 to move out

• Air moves from higher pressure (lungs) to lower pressure (external)

what is spirometry?

a measure of airflow in and out of the lungs

what are the axises on the graph of a spirometry?

• x-axis

  • time (sec)

• y-axis

  • volume (mL)

there are 4 divisions of our lung volumes that add up to our maximal lung volume. What are they?

• tidal volume (TV)

• inspiratory reserve volume (IRV)

• expiratory reserve volume (ERV)

• residual volume (RV)

what is tidal volume?

the amount of air inhaled or exhaled with each breath under resting conditions

how much mL is tidal volume usually at?

500mL

what is the inspiratory reserve volume (IRV)?

the amount of air that can be forcefully inhaled after a normal tidal volume inspiration

what is the expiratory reserve volume (ERV)?

the amount of air that can be forcefully exhaled after a normal tidal volume expiration

what is residual volume (RV)?

the amount of air remaining in the lungs after a forceful expiration

when assessing respiratory function, the volumes aren’t assessed alone, but considered in specific groupings called…

lung capacities

what are the 5 lung capacities?

• vital capacity (VC)

• inspiratory capacity (IC)

• functional reserve capacity (FRC)

• total lung capacity (TLC)

• forced vital capacity (FVC)

what is vital capacity (VC)?

the maximum amount of air that can be expired after a maximum inspiratory effort

what is the equation to find vital capacity (VC)?

TV + IRV + ERV

what is the inspiratory capacity (IC)?

the maximum amount of air that can be inspired after a normal tidal volume expiration

what is the equation to find inspiratory capacity (IC)?

TV + IRV

what is the functional reserve capacity (FRC)?

the volume of air remaining in the lungs after a normal tidal volume expiration

what is the equation to find the functional reserve capacity (FRC)?

ERV + RV

what is the total lung capacity (TLC)?

the maximum amount of air contained in lungs after a maximum inspiratory effort

what is the equation to find the total lung capacity (TLC)?

TV + IRV + ERV + RV

what is the forced vital capacity (FVC)?

the gas forcibly expelled after taking a deep breath

results from the spirometry can also be used to assess…

the alveolar ventilation or the amount of air entering the lungs available for gas exchange or ventilation

what does each peak on the graph of a spirometry represent?

one breath

the number of peaks over a minute is…

the number of breaths per minute

what is minute ventilation (MV)?

the total amount of gas flow into or out of the respiratory tract in one minute