Respiratory Tract Flashcards by tommy radford

What are the 2 parts of the respiratory tract?

Upper respiratory tract - nasal cavity, pharynx, larynx

Lower respiratory tract - trachea, bronchi lungs

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Why is it important that air is heated and humidified when it enters the lungs?

The alveolar membrane is not damaged

Moistens the respiratory epithelium to allow gaseous exchange

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What are the concha?

Bony structures in the nose which control airflow to the trachea

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What is the function of concha?

Increase the heating and humidification function of the nose

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What is the function of the nasal cavity?

Olfactory (smell)

Increase humidification and warming of air

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What is the pharynx?

A hole extending from the base of the skull to the border of the cricoid cartilage

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What are the functions of the larynx?

Opens valve to allow air to pass into trachea
Prevents aspiration (substances entering tract accidently)
Speech production

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Explain how the larynx prevents aspiration:

The vocal folds close and epiglottis is pushed back to covers the larynx opening

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Which respiratory tract structure contains the hyoid bone?

Larynx

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What is the function of the C shaped caritlage?

Maintain the rigid structure of trachea

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What is the function of cartilage plates in the bronchi?

Helps to keep the bronchus open to keep air supply to lungs

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What is the function of the trachealis muscle?

Close C shaped cartilage rings during coughing mechanism

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What is the function of smooth muscle in the bronchi?

Regulates diameter of bronchi

Contracts during expiration to help expel air

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Why do the bronchioles have no cartilage?

The smooth muscle in the wall are more dynamic and able to control the flow of air independently

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What are the functions of the trachea?

Maintain rigid structure
Constrict during coughing mechanism
Mucociliary transport

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What is the function of club cells in the bronchioles?

They produce surfactant and enzymes

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What is the function of surfactant in the bronchioles?

Reduces surface tension to allow expansion and collapsation

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Why is there a high concentration of blood vessels in the acinus?

So that alveoli are always close to a blood supply to exchange with

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What makes up the majority of the alveolar lining?

Type 1 pneumocytes, they make up 90% of surface lining

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What are pores of Kohn?

Channels connecting alveoli to other alveoli

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What are channels of Martin?

Channels connecting respiratory bronchioles to other respiratory bronchioles

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What are channels of Lambert?

Channels connecting alveoli to other respiratory bronchioles

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What are type 2 pneumocytes?

Cells in alveoli which produce surfactant to easily inflate the alveoli due to the reduce surface tension

What are the function of pores of Kohn, channels of Martin and channels of Lambert?

They allow gas to find alternative routes to by-pass obstructed airways

What are type 1 pneumocytes?

Thin, squamous cells which allow the exchange of gases

What are the three main ways the lungs defence themselves against the body?

Physical Humoral Cellular

What is the physical defence of the lungs? | what mechanisms are there

``` Filtering at the nasopharynx Swallowing Irritant C-fibre ending nerve endings Cough reflex Mucociliary clearance ```

Explain how the lungs are defended by filtering at the nasopharynx:

Hairs in the nose act as a coarse filter for inhaled particles and mucus in the nose traps particles which are swallowed into the gastrointestinal tract

Explain how the lungs are defended by swallowing:

The larynx protects the lungs from aspiration (food/liquids in the lungs)

Explain why someone with a neurological issue may develop aspiration pneumonia (in relation to the physical defence of the lungs)

The muscles do not co-ordinate in the swallowing and food/liquids can enter the lungs, leading to the development of aspiration pneumonia

Explain how the lungs are defended by irritant C-fibre nerve endings:

These receptors in the bronchi are stimulated and produce a contraction of smooth muscle in the bronchi reducing the damage to the lungs

What is the humoral defence of the lungs? | what mechanisms are there

``` Antimicrobial peptides Surfactant Immunoglobulins Complement proteins Antiproteases ```

Explain how the lungs are defended by antimicrobial peptides:

Short protein structures with antibacterial properties (such as lysosymes) kill bacteria entering the lungs

Explain how the lungs are defended by surfactant production:

Surfactant protein A is hydrophilic which enhances phagocytosis by macrophages in alveoli

Explain how the lungs are defended by immunoglobins:

Present in the mucus and they defend against specific antigens that may enter the lungs

Explain how the lungs are defended by complement proteins:

Propagate the inflammatory response and acts as chemoattractants for neutrophils to the site of injury

Explain how the lungs are defended by antiproteases:

Digest the destructive proteases released by dead bacteria

What is the cellular defence of the lungs? | what mechanisms are there

Alveolar macrophages | Neutrophils

Explain how the lungs are defended by alveolar macrophages:

Ingest microbes through phagocytosis then transport to bronchioles for mucociliary clearance Secretes cytokines to amplify inflammatory response

Explain how the lungs are defended by neutrophils:

Emigrate from intravascular space to alveolar lumen were bacteria are killed through oxidative and non-oxidative mechanisms

What are the predominant cells recruited during the acute inflammatory response?

Neutrophils

What is mucociliary clearance?

A unidirectional movement and removal of deposited particles and gases dissolved in the mucus from the respiratory tract

Describe the structure of the respiratory epithelium in the mucociliary escalator:

A basement membrane contains a 'dip' called the submucosal gland Basement membrane covered by a layer of pseudostratified columnar ciliated epithelium and goblet cells On top of that is the Sol layer and on top of that is the Gel layer

What is the function of goblet cells in the mucociliary escalator?

Secrete mucus

What cell hydrates the Sol layer in the mucociliary escalator?

Pseudostratified columnar ciliated epithelium

Why does the mucociliary escalator have a Sol layer and Gel layer instead of one layer?

The less viscous Sol layer allows the wafting movement of cilia underneath whilst the Gel layer is viscous and sticky to trap particles

Explain how the mucociliary escalator works:

Pseudostratified columnar ciliated epithelium beat synchronously to waft the gel layer unidirectionally

What can inhibit mucociliary clearance?

Tobacco smoke Cold air Drugs / Medication (general anaesthetic)

What pulmonary condition is an example of ineffective mucociliary clearance?

Cystic fibrosis, the mucus is extra sticky so cannot be wafted for clearance

What initiates the coughing mechanism?

Cytokines, Histamine, Foreign bodys, cancers... detected by receptors in the mucosa area then delivered to the medulla via the vagus nerve

What efferent and afferent nerves are involved in the coughing mechanism?

Efferent: Phrenic, Spinomotor, Recruitment Larangeal Afferent: Vagus nerve

What effector muscles are involved in the coughing mechanism that are activated by the efferent nerves?

Respiratory muscle Laryngeal muscle Bronchial smooth muscle

What happens during the inspiratory phase of the coughing mechanism?

We take a large breath in which stretches expiratory muscles and increases pressure inside the lungs

What happens during the compression phase of the coughing mechanism?

Glottis closes an respiratory muscles contract which dramatically increases pressure in lungs

What happens during the expiratory phase of the coughing mechanism?

Glottis opens and the air is pushed out sharply due to the high pressure inside the lungs

Place the following parts of the coughing mechanism in order: ``` Inspiratory phase Detection Expiratory phase Medulla Efferent nerves Compression phase Afferent nerve ```

``` Detection Afferent nerve Medulla Efferent nerves Inspiratory phase Compression phase Expiratory phase ```