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Respiration involves both
the respiratory and the circulatory systems
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What are the 4 processes that supply the body O2 and dispose of CO2
- Pulmonary ventilation
- External ventilation
- Transport of O2 and CO2 in the blood
- Internal respiration
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Pulmonary ventilation is
breathing, movement of air in and out of the lungs.
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External respiration is
O2 and CO2 exchange between the lungs and the blood
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What is internal respiration?
O2 and CO2 exchange between systemic blood vessels and tissues.
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What are the 9 major organs of the respiratory system?
- Nose, nasal cavity, and paranasal sinuses
- Pharynx
- Larynx
- Trachea
- Bronchi and their branches
- Lungs and alveoli
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The site of gas exchange is called the
respiratory zone
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The respiratory zone includes
Microscopic structures: respiratory bronchioles, alveolar ducts, and alveoli
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What are the conduits to gas exchange sites called?
Conducting zone
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What are the functions of the nose?
- Provides an airway for respiration
- Moistens and warms the entering air
- Filters and cleans inspired air
- Serves as a resonating chamber for speech
- Houses olfactory receptors
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The nasal cavity superior to the nostrils is called_______________ it has _________________
- Vestibule
- Vibrissae (nose hairs) that filter coarse particles from inspired air.
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What lines the superior nasal cavity and contains smell receptors?
Olfactory mucosa
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Respiratory mucosa contain
- Mucous and serous secretions
- Cilia
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Cilia in the nasal cavity move
contaminated mucus posteriorly to throat
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Mucous and serous secretions contain
lysozyme and defensins
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The nasal cavity has three grooves called
Superior, middle and inferior nasal conchae
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Three aspects of nasal conchae
- Protrude from the lateral walls
- Increase mucosal area
- Enhance air turbulance
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What are the two functions of the nasal mucosa and conchae?
During inhalation_________________
During exhalation___________________
- Filter, heat and moisten air
- Reclaim heat and moisture
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Functions of the paranasal sinuses
Lighten the skull and help to warm and moiten the air
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Name of the muscular tube that connects to the nasal cavity and mouth superiorly
Pharynx (throat)
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The ____________ and _______________ close the nasopharynx during swallowing
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The _________________ is the passageway for food and air from the level of the soft palate to the epiglottis
Oropharynx
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_____________ attaches to the hyoid bone and opens into the laryngopharynx
The larynx
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What are the 3 functions of the larynx?
- Provides a patent airway
- Routes air and food into proper channels
- Voice production
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Larynx contains ___________ that contain elastic fibers.
vocal ligaments
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The opening between the vocal ligaments is called the _____________. Folds vibrate to produce sound as air rushes up from the lungs
glottis
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Vestibular folds of the larynx are called _______________. They are superior to the vocal cords. They play __________-. help to ________________
- false vocal cords
- no part in sound production
- close the glottis during swallowing.
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The trachea is also called _______. It extends from the _________________
- windpipe
- larynx into the mediastinum
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The trachae wall is composed of 3 layers called
- Mucosa
- Submucosa
- Adventitia
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Mucosa layer of trachea has
ciliated pseudostratified epithelium with goblet cells
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The adventitia is
outermost layer of trachea made of connective tissue that encases the C-shaped rings of hyaline cartilage
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Trachealis muscle connects _______________ and contracts during _________________-
- posterior parts of cartilage rings
- coughing to expel mucus
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Air passages undergo ____ orders of branching
23
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Branching patterns of of bronchi are called the
bronchial (respiratory) tree
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Right main bronchus is ____________________________ than the left
wider, shorter and more verticle
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Each lobar bronchus branches into
segmental (tertiary) bronchi
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_____________- are the smallest bronchioles, less than 0.5 mm diameter
terminal bronchioles
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Respiratory zone includes
bronchioles, alveolar ducts, alveolar sacs (clusters of alveoli)
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Respiratory membrane is composed of
alveolar and capillary walls and their fused basements membranes
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Alveoli are surrounded by
fine elastic fibers
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Alveoli contain ______________ that connect ______________, allow _________________
- open pores
- adjacent alveoli
- air pressure throughout the lung to be equalized
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Alveoli house
alveolar macrophages that keep alveolar surfaces sterile
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What is Boyle's Law?
Pressure (P) varies inversely with volume (V)
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Pulmonary ventilation constists of what two phases?
- 1. Inspiration: gases flow into the lungs
- 2. Expiration: gases exit the lungs
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Atmospheric pressure is
- the pressure exerted by the air surrounding the body
- 760 mm Hg at sea level
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Respiratory pressures are described relative to atmospheric pressure
- Negative respiratory pressure is less than PatmPositive respiratory pressure is greater than PatmZero respiratory pressure = Patm
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Intrapulmonary (intra-alveolar)pressure is pressure __________. It fluctuates with ___________ and always ____________-
- in the alveoli
- breathing
- eventually equalizes with Patm
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Intrapleural pressure is _____________. It ______________ and is always _________-
- pressure in the pleural cavity
- fluctuates with breathing
- a negative pressure
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Negative intrapleural pressure is caused by
opposing forces
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What are the two inward forces that promote lung collapse?
- Elastic recoil of lungs decreases lung size
- Surface tension of alveolar fluid reduces alveolar size
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What is the one outward force that tends to enlarge the lungs?
Elasticity of the chest wall pulls the thorax outward
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When volume changes
pressure changes
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When pressure changes
gases flow to equalize pressure
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List factors of the inspiration processes
- Inspiratory muscles contract
- thoracic volume increases
- lungs are stretched and intrapulmonary volume increases
- Air flows into the lungs down its pressure gradient
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List factors of the expiration process
- Inspiritory muscles relax
- thoracic cavity volume decreases
- elastic lungs recoil and intrapulmonary volume decreases
- pulmonary ventilation rises
- Air flows out of the lungs down its pressure gradient
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Forced expiration is an ______________: it uses ___________________--
- active process
- abdominal and internal intercostal mucles
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What are the 3 physical factors influencing pulmonary ventilation?
- Airway resistance
- Alveolar surface tension
- Lung compliance
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Friction is the major
nonelastic source of resistance to gas flow
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Resitance is usually _______ because of ____________- in the first part of the conducting zone and _________________ of airways as they get smaller, increasing the total cross-sectional area
- insignificant
- large airway diameters
- progressive branching
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As airway resistance rises
breathing movements become more strenuous
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Severly constricting or obstruction of bronchioles can prevent ______________________ and can occur during _________________-
- life-sustaining ventilation
- acute asthma attacks and stop ventilation
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Alveolar surface tension attracts _______________ and resists ________________
- liquid molecules to one another at a gas-liquid interface
- any force that tends to increase the surface area of the liquid
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Lungs secrete _________ a deterdent like lipid and protein complex produced by type II alveolar cells
surfactant
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Surfactant reduces
surface tension of alveolar fluid and discourages alveolar collapse
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Insuficient quantities of ________ in premature infants causes respiratory distress syndrome
surfactant
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______________ is a measure of the change of lung volume that occurs with a given change in transpulmonary pressure
Lung compliance
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Lung compliance is normally high due to
- distensibility of the lung tissue
- Alveolar surface tension
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Lung compliance is diminished by
- Nonelastic scar tissue (fibrosis)
- Reduced production of surfactant
- Decreased flexability of the thoracic cage
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Four factors used to assess a person's respiratory status
- Tidal volume
- Inspiratory reserve volume
- Expiratory reserve volume
- Residual volume
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List the 4 respiratory capacity assessment values
- Inspirational capacity
- Functional residual capacity
- Vital capacity
- Total lung capacity
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Some inspired air never contributes to gas exchange describes
Dead space
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Anatomical dead space is
volume of the conducting zone conuits
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Alveoli dead space
alveoli that cease to act in gas exchange due to collapse or obstruction
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Total dead space is the sum of
anatomical dead space and alveolar dead space
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A spirometer is
an instrument used to measure respiratory volumes and capacity
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Spirometry can distinguish between
- obstructive pulmonary disease - increased airway resistance (bronchitis)
- resitrictive disorders - reduction in total lung capacity due to structural or functional lung changes (fibrosis or TB)
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Increases in TLC, FRC, and RV may occur as a result of
obstructive disease
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Reduction in VC, TLC, FRC, and RV result from
restrictive disease
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The alveolar ventilation rate (AV) is
flow of gases into and out of the alveoli during a particular
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To consider external and internal respiration processes, first consider
- Physical properties of gases
- Composition of alveolar gas
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Dead space is normally
constant
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Rapid, shallow breathing decreases
alveolar ventilation (AVR)
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The partial pressure of each gas is
directly proportional to its percentage in the mixture
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What is Dalton's Law of partial pressures?
Total pressure exerted by a mixture of gases is the sum of the pressures exerted by each gas
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What are the 4 gases in alveoli (in order from greatest percentage to least)?
N2, O2, CO2 and H2O
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is in contact with a liquid, each gas will dossolve in the liquid in
proportion to its partial pressure
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At equalibrium
the partial pressures in the two phases will be equal
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The amount of gas that will dissolve in a liquid also depends on
its solubility
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CO2is 20 times more soluble than
oxygen
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Very little ________ dissolves in water
N2
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Alveoli contain more CO2 and water vapro that atmospheric air, due to
- Gas exchanges in the lungs
- Humidification of air
- Mixing of alveolar gas that occurs with each breath
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Exchange of O2 and CO2 across the respiratory membrane describes
external respiration
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External respiration is influenced by
- partial pressure gradients and gas solubilities
- Ventilation profusion coupling
- Structural characteristics of the respiratory membrane
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Partial pressure gradient for O2 in the lungs is
steep
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Ventilation is
the amount of gas reaching thhe alveoli
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Perfusion is
blood flow reaching the alveoli
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Ventilation and profusion must be ________ for sufficient gas exchange
matched (coupled)
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Changes in Po2 (partial pressure gradient) in the alveoli cause
changes in the diameters of the bronchioles
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Where alveolar CO2 is high
bronchioles dilate
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Where alveolar CO2 is low
bronchioles constrict
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What is the thickness and surface area of the respiratory membrane?
- .05 to 1 um thick
- Total surface area (40 times that of one's skin)
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Capillary gas exchange in body tissues describes
Internal respiration
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Partial pressures and diffusion gradients are reversed compared to
external respiration
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Po2 in tissue is always
lower than in systemic arterial blood
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Po2 of venous blood is ____________ and Pco2 is ______________
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