Lab 7: Respiratory Air Flow and Volume Lab

What is spirometry

It is the study of the principles of how the integration of the flow signal gives a volume

What will you examine regarding lung volumes and capacities

You will examine the respiratory cycle and measure changes in flow and volume

What parameters will you measure in pulmonary function tests

You will measure parameters of forced expiration that are used in evaluating pulmonary function

What will you simulate in the exercise on simulating an airway obstruction

You will simulate an airway obstruction

What primary function does the respiratory system serve

The primary function of the respiratory system is to furnish oxygen for use by body tissues and to accomplish this, it must also clear carbon dioxide

What are the four processes of respiration

Pulmonary ventilation, external respiration, transport of respiratory gases, and internal respiration

What is pulmonary ventilation

It is the movement of air into (inspiration) and out of (expiration) the lungs so that the gases in the air sacs (alveoli) are constantly refreshed with new supplies of oxygen and removal of the air (respiratory system waste product, carbon dioxide)

Where does external respiration occur

It involves gas exchange between the blood and the air-filled chambers of the lungs

What happens to oxygen during external respiration

Oxygen diffuses from the lungs to the blood

What happens to carbon dioxide during external respiration

Carbon dioxide diffuses from the blood to the lungs

What is the transport of respiratory gases

It is accomplished by the cardiovascular system

What does the blood transport during the transport of respiratory gases

It transports oxygen from the lungs to the body cells and carbon dioxide from the body cells to the lungs

What is internal respiration

It involves gas exchange between the systemic blood and the body cells

What happens to oxygen during internal respiration

Oxygen diffuses from the blood to the body cells

What happens to carbon dioxide during internal respiration

Carbon dioxide diffuses from the body cells to the blood

What is the conducting zone of the respiratory system made up of

It consists of the structures from the nose (by way of the nostrils) to the respiratory bronchioles

What does the conducting zone provide

It provides a fairly rigid conduit for air to reach the gas-exchanging sites

What do the walls of the conducting zone contain

They contain cilia and secrete mucus (by goblet cells)

What is the function of mucus in the conducting zone

It traps bacteria, dust, and other debris

What is the function of cilia in the conducting zone

They propel the mucus-containing debris away from the lungs and toward the throat, where it can be swallowed or spat out

What else does the conducting zone do to the air

It cleanses, humidifies, and warms the incoming air

Where does the respiratory zone begin

It begins where the terminal bronchioles feed into the respiratory bronchioles

What structures are included in the respiratory zone

Respiratory bronchioles, alveolar ducts, and alveoli

What occurs in the alveoli

Gas exchange

What is the function of the nasal cavity

It provides an airway for respiration, moistens and warms the entering air, filters and cleans inspired air, serves as a resonating chamber for speech, and houses the olfactory receptors

What are the nasal conchae

They are scroll-like mucosa-covered projections into the nasal cavity

What is the function of the nasal conchae

They increase the mucosal surface area exposed to the air and enhance air turbulence in the nasal cavity

What is the pharynx

It is the throat

What are the three parts of the pharynx

The nasopharynx, oropharynx, and laryngopharynx

What passes through the nasopharynx

Only air

What passes through the oropharynx

Both swallowed food and inhaled air

What passes through the laryngopharynx

Both swallowed food and inhaled air

What is the larynx

It is the voice box

Where is the larynx located

It is situated inferior to the pharynx and superior to the trachea

What are the three functions of the larynx

To provide a patent airway, to act as a switching mechanism to route air and food into the proper channels, and to function in voice production

What is the epiglottis

It is a flap of elastic cartilage at the base of the tongue

What is the function of the epiglottis during swallowing

It covers the laryngeal inlet, preventing food from entering the trachea

What are the vocal folds

They are folds within the larynx that vibrate to produce sound

What is the glottis

It is the opening between the vocal folds

What is the trachea

It is the windpipe

Where is the trachea located

It descends from the larynx through the neck and into the mediastinum

What are the walls of the trachea reinforced with

C-shaped cartilaginous rings

What is the function of the cartilaginous rings in the trachea

They prevent the trachea from collapsing during pressure changes that occur during breathing

What is the carina

It is the last tracheal cartilage that projects posteriorly into the trachea

What is the significance of the carina

It is highly sensitive to inhaled irritants and triggers a forceful cough reflex

What does the trachea branch into

The right and left main (primary) bronchi

Where do the main bronchi enter the lungs

At the hilum

What do the main bronchi subdivide into

Lobar (secondary) bronchi

How many lobar bronchi are in the right lung

Three

How many lobar bronchi are in the left lung

Two

What do the lobar bronchi subdivide into

Segmental (tertiary) bronchi

What do the segmental bronchi further divide into

Smaller and smaller bronchi

What are bronchioles

They are smaller than 1 mm in diameter

What are terminal bronchioles

They are the smallest of the conducting passageways

What do terminal bronchioles subdivide into

Respiratory bronchioles

What do respiratory bronchioles lead to

Alveolar ducts

What are alveolar ducts

They are winding alveolar sacs

What are alveolar sacs

They are clusters of alveoli

What are alveoli

They are thin-walled air sacs where gas exchange occurs

What type of epithelium are the walls of the alveoli primarily composed of

A single layer of squamous epithelial cells called type I alveolar cells

What are type II alveolar cells

They are cuboidal alveolar cells scattered among the type I alveolar cells

What do type II alveolar cells secrete

Surfactant

What is surfactant

It is a detergent-like complex of lipids and proteins that reduces surface tension in the alveoli

What are alveolar pores

They connect adjacent alveoli

What is the function of alveolar pores

They equalize air pressure throughout the lungs and provide alternate routes for air to reach alveoli whose bronchioles have collapsed due to disease

What are alveolar macrophages

They are also called dust cells

What is the function of alveolar macrophages

They crawl freely along the internal alveolar surfaces, consuming bacteria, dust, and other debris

What is the respiratory membrane

It is the blood-air barrier that consists of the alveolar and capillary walls along with their fused basement membranes

What is the pleura

It is a double-layered serous membrane surrounding each lung

What is the parietal pleura

It lines the thoracic cavity

What is the visceral pleura

It covers the external lung surface

What is the pleural cavity

It is the slit-like potential space between the parietal and visceral pleurae

What does the pleural cavity contain

A thin film of pleural fluid

What is the function of pleural fluid

It lubricates the surfaces of the pleurae, allowing the lungs to glide easily over the thoracic wall during breathing

What is pleurisy

It is inflammation of the pleura, often resulting from pneumonia

What is Boyle's law

It states that at a constant temperature, the pressure of a gas varies inversely with its volume

What happens to the diaphragm and external intercostals during inspiration

They contract

What is the result of the contraction of the diaphragm and external intercostals

The thoracic volume increases

What happens to the intrapleural pressure during inspiration

It becomes more negative

What happens to the intrapulmonary pressure during inspiration

It decreases to slightly below atmospheric pressure

What is the pressure gradient that causes air to flow into the lungs

The difference between atmospheric pressure and intrapulmonary pressure

What happens to the diaphragm and external intercostals during expiration

They relax

What is the result of the relaxation of the diaphragm and external intercostals

The thoracic volume decreases

What happens to the intrapleural pressure during expiration

It returns toward its preinspiratory value

What happens to the intrapulmonary pressure during expiration

It rises to slightly above atmospheric pressure

What is the pressure gradient that causes air to flow out of the lungs

The difference between intrapulmonary pressure and atmospheric pressure

What are the accessory muscles of inspiration

Sternocleidomastoid, scalenes, pectoralis minor

When are the accessory muscles of inspiration used

During forced inspiration

What are the accessory muscles of expiration

Abdominal wall muscles (external and internal obliques, transversus abdominis, and rectus abdominis) and internal intercostals

When are the accessory muscles of expiration used

During forced expiration

What is tidal volume (TV)

It is the amount of air inhaled or exhaled with each breath under resting conditions (approximately 500 ml)

What is inspiratory reserve volume (IRV)

It is the amount of air that can be forcefully inhaled after a normal tidal volume inhalation (approximately 1900-3100 ml)

What is expiratory reserve volume (ERV)

It is the amount of air that can be forcefully exhaled after a normal tidal volume exhalation (approximately 700-1200 ml)

What is residual volume (RV)

It is the amount of air that remains in the lungs even after a forceful exhalation (approximately 1100-1200 ml)

What is inspiratory capacity (IC)

It is the sum of tidal volume and inspiratory reserve volume (TV + IRV)

What is functional residual capacity (FRC)

It is the sum of residual volume and expiratory reserve volume (RV + ERV)

What is vital capacity (VC)

It is the sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume (TV + IRV + ERV)

What is total lung capacity (TLC)

It is the sum of tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume (TV + IRV + ERV + RV)

What is forced vital capacity (FVC)

It is the total volume of air that can be forcibly and rapidly expelled from the lungs after a maximal inspiration

What is forced expiratory volume in 1 second (FEV1)

It is the volume of air that can be expelled from the lungs in the first second of a forced exhalation