Respiratory System Flashcards
Breathing is formally called
Respiration
For complete exchange of oxygen (O2)
and carbon dioxide (CO2) in respiration, four steps occur simultaneously:
Ventilation
External Respiration
Gas Transport
Internal Respiration
This is what most of us think of as breathing.
Ventilation
It is the movements of the thorax and certain muscles that cause air to go into and out of our lungs.
Ventilation
Oxygen enters the blood in the lungs and CO2 exits the blood in the lungs.
External Respiration
Carbon dioxide and O2 are circulated in the blood to and from tissues.
Gas Transport
Gas exchange with the tissues involves the exit of O2 from blood to move into the tissues, while CO2 exits the tissues to enter the blood.
Internal Respiration
The respiratory system performs
the following functions:
Regulation of blood pH
Production of chemical mediators
Voice Production
Olfaction
Protection
The respiratory system can alter
blood pH by changing blood CO2 levels.
Regulation of blood pH
The lungs produce an enzyme called angiotensin-converting enzyme (ACE), which is an important component of blood pressure regulation
Production of chemical mediators
Air moving past the vocal folds makes
sound and speech possible.
Voice Production
The sensation of smell occurs when airborne molecules are drawn into the nasal cavity
Olfaction
The respiratory system provides protection against some microorganisms by preventing them from entering the body and removing them from respiratory surfaces.
Protection
There are seven structures that make up the respiratory system:
- External Nose
- Nasal cavity
- Pharynx
- Larynx
- Trachea
- Bronchi
- Lungs
The upper respiratory tract consists of the
External Nose
Nasal Cavity
Pharynx and its associated structures
Larynx
Lower respiratory tract consists of the
Trachea
Bronchi and smaller bronchioles
Lungs
The respiratory system can be classified in two ways:
Structurally and functionally
Structurally, the respiratory system is divided into the
Upper Respiratory Tract
Lower Respiratory Tract.
Functionally, the respiratory system is divided into two regions.
Conducting Zone
Respiratory Zone
is exclusively for air movement and extends from the nose to the bronchioles.
Conducting Zone
is within the lungs and is where gas exchange between air and blood takes place.
Respiratory Zone
The conduction zone structures are well adapted for the
Movement
Cleaning
Warming
Humidification of air
or nasus, consists of the external nose and the nasal cavity.
Nose
is the visible structure that forms a
prominent feature of the face.
External Nose
The largest part of the external nose
is composed of
Hyaline Cartilage Plates
The nasal bones plus extensions of the frontal and maxillary bones constitute
the _____ of the nose, which is where eyeglasses would rest.
Bridge
is the open chamber inside the nose where air first enters the respiratory system.
Nasal Cavity
Nasal cavity extends from the anterior structures called the (1) ______ to the posterior structures called (2) ______
(1) Nares or nostrils
(2) Choanae
are the external openings of the nasal cavity.
Nares
Just inside each naris, in the anterior part of the nasal cavity, is the region called the
Vestibule
The _________ is lined with stratified squamous epithelium, which is continuous with the stratified squamous
epithelium of the skin.
Vestibule
in the posterior part of the nasal cavity are the openings into the pharynx.
Choanae
is the anterior portion of the roof of the mouth.
Hard Palate
The hard palate is formed by the
palatine process of the
maxillae and the palatine bone
It separates the nasal cavity from the oral cavity.
Hard Palate
The nasal cavity is divided into right and left halves by a partition called the
Nasal Septum
The anterior part of the nasal septum is composed of
Cartilage
The posterior part of the nasal septum consists of the
Vomer bone
Perpendicular plate of the ethmoid bone
There are three lateral bony ridges called ______ on each side of the nasal cavity
Conchae
The conchae used to be named the ____________ because they act as
“wind turbines,” helping the air churn through the nasal cavity.
Turbinate bones
The air passes through tunnels beneath each concha. Each of these tunnels is called a
Meatus
Within the superior and middle meatuses are openings from the various
Paranasal Sinuses
Each inferior meatus also contains the opening of a ______________ for tear
drainage from the surface of the eye
Nasolacrimal duct
The five functions of the
nasal cavity are the following:
Serves as a passageway for air
Cleans the air
Humidifies and warms the air
Contains olfactory epithelium
Helps determine voice sound
is lined with hairs, which trap
some of the large particles of dust in the air.
Vestibule
Mucous membrane consists of pseudostratified ciliated columnar epithelium with ______ cells.
Goblet
secrete mucus, which traps debris in the air.
Goblet Cells
The olfactory epithelium, the sensory organ for smell, is located in the _____________ of the nasal cavity
Most Superior Part
are resonating chambers for speech
Nasal Cavity
Paranasal Sinuses
is the common opening of both
the digestive and the respiratory systems.
Pharynx (Throat)
is inflammation of sinus mucous
membranes, especially those of the paranasal sinuses.
Sinusitis
Inferiorly, the pharynx is connected to the respiratory system at the _______ and to the digestive system at the esophagus.
Larynx
From superior to inferior, there are three regions of the pharynx:
Nasopharynx
Oropharynx
Laryngopharynx
is immediately posterior to
the nasal cavity.
Nasopharynx
it is posterior to the choanae and superior to the soft palate.
Nasopharynx
is an incomplete partition composed of muscle and connective tissue.
Soft Palate
It separates the nasopharynx from the oropharynx.
Soft Palate
The posterior extension of the soft
palate is called the
Uvula
The soft palate blocks swallowed materials away from the nasopharynx and nasal cavity toward the back of the
Pharynx
The posterior wall of the nasopharynx houses the _____________,
or adenoids, which helps defend the body against infection
Pharyngeal tonsil
The nasopharynx is continuous with the
Oropharynx
The oropharynx is the ________ portion of the pharynx.
Middle
It is immediately posterior to the mouth and begins at the soft palate. From there, it descends to the superior portion of the larynx.
Oropharynx
A region called the ______ joins the mouth’s oral cavity and the oropharynx.
Fauces
Thus, air, food, and drink all pass through the
Oropharynx
Two sets of tonsils
Palatine Tonsils
Lingual Tonsils
spans the posterior length of the larynx: from the most superior larynx structure, the epiglottis, to the esophagus.
Laryngopharynx
pass through the
laryngopharynx to the esophagus.
Food and drink
is located in the anterior part of the laryngopharynx and extends
from the base of the tongue to the trachea
Larynx
The largest of the cartilages is the single thyroid cartilage, or
Adam’s Apple
The base of the larynx is formed by the single ___________, the most inferior cartilage of the larynx.
Cricoid cartilage
The third single cartilage is the
Epiglottis
It is attached to the thyroid cartilage and projects superiorly as a free flap toward the tongue.
Epiglottis
The paired _____________
articulate with the posterior, superior border of the cricoid cartilage
Arytenoid cartilages
The paired _______________ are attached to the superior tips of the arytenoid cartilages.
Corniculate cartilages
The paired _____________ are contained in a mucous membrane anterior to the corniculate cartilages
Cuneiform Cartilage
extend from the anterior surface of the arytenoid cartilages to the posterior surface of the thyroid cartilage.
Two pairs of ligaments
The superior ligaments are covered by a mucous membrane and are called the
Vestibular folds or false vocal cords
The inferior ligaments are covered by a mucous membrane and are called the
Vocal folds or true vocal cords
is the combination of the vocal folds and the opening between them
Glottis
The vestibular folds and the vocal folds are lined with
Stratified Squamous Epithelium
The remainder of the larynx is lined with
Pseudostratified ciliated columnar epithelium
An inflammation of the vocal folds is called
Laryngitis
are the primary source of sound production.
Vocal Folds
The pseudostratified ciliated columnar epithelium lining the larynx produces _______, which traps debris in air.
Mucus
move the mucus and debris into the pharynx.
Cilia
or windpipe, allows air to flow into the
lungs.
Trachea
Trachea is a membranous tube attached to the
larynx
Trachea consists of dense regular
Connective tissue and smooth muscle
Reinforcing the trachea are 15–20 C-shaped pieces of
Hyaline Cartilage
or the Heimlich maneuver, are designed to force an object out of the air passage by the sudden application of pressure to the
abdomen.
Abdominal Thrusts
a tube is passed through the mouth or nose into the pharynx and then through the larynx to the trachea.
Intubation
The preferred point of entry in emergency cases is through the membrane between the cricoid and thyroid cartilages, a procedure called a
Cricothyrotomy
is an operation performed to make an opening into the trachea, commonly between the second and third cartilage rings.
Tracheostomy
refers to the actual cutting into the trachea
Tracheotomy
has an inside diameter of 12 mm and a length of 10–12 cm, descending from the larynx to the level of the fifth thoracic
vertebra
Trachea
The trachea divides to form two smaller
tubes called ___________, each of which extends to a lung.
Main bronchi or primary bronchi
The tracheal cartilage separating the openings into the main bronchi forms a ridge called the
Carina
consists of the trachea and all other respiratory passageways in the lungs
Tracheobronchial Tree
The trachea divides to form a __________, each of which divides to form smaller and smaller bronchi.
Left and right bronchus
is larger in diameter and more directly
in line with the trachea than the left main bronchus.
Right main bronchus
Within each lung the main bronchi divide into
Lobar bronchi or secondary bronchi
There are two lobar bronchi in the
Left Lung
There are three lobar bronchi in the
Right Lung
The lobar bronchi, in turn, give rise to
Segmental bronchi or tertiary bronchi
The bronchi continue to branch, finally giving rise to ____________, which are less than 1 mm in diameter.
Bronchioles
The bronchioles also subdivide several times to become even smaller
Terminal bronchioles
Approximately ___ generations of branching occur from the trachea to the terminal bronchioles.
16
have no cartilage, and
the smooth muscle layer is prominent.
Terminal Bronchioles
occurs when the smooth muscle relaxes, making the bronchiole diameter larger.
Bronchodilation
occurs when the smooth muscle contracts,
making the bronchiole diameter smaller.
Bronchoconstriction
During an ___________, bronchoconstriction decreases the diameter of the airways, which increases resistance to airflow and
greatly reduces air movement.
Asthma attack
are small, air-filled chambers
where the air and the blood come into close contact with each other.
Alveoli
Terminal bronchioles divide to form _______________, which have a few attached alveoli
Respiratory bronchioles
As the respiratory bronchioles divide to form smaller respiratory bronchioles, the number of attached alveoli
Increases
The respiratory bronchioles give
rise to ____________, which are like long, branching hallways with many open doorways.
Alveolar ducts
The alveolar ducts end as two or
three ___________, which are chambers connected to two or more
alveoli
Alveolar Sacs
Approximately ____ generations of branch-
ing occur from the terminal bronchioles to the alveolar ducts
7
The tissue surrounding the alveoli contains _________, which allow the alveoli to expand during inspiration and recoil during
expiration
Elastic Fibers
or pertussis, is a serious bacterial infection of the tracheobronchial tree, caused by the
bacterium Bordetella pertussis
Whooping cough
B. pertussis affects both the respiratory
and the immune systems simultaneously in
two major ways:
(1) by directly attacking the ciliated epithelium in the tracheobronchial tree
(2) by avoiding the effects of complement
Approximately _________ alveoli are in the two lungs.
300 million
The average diameter of an _________ is approximately 250 μm, and its
wall is extremely thin.
Alveolus
Two types of cells form the alveolar wall
Type I pneumocytes
Type II pneumocytes
are thin squamous epithelial cells that form 90% of the alveolar surface. Most of the gas exchange between alveolar air and the blood takes place through these cells.
Type I pneumocytes
are round or cube-shaped secretory cells that produce surfactant, which makes it easier for the alveoli to expand during inspiration
Type II pneumocytes
in the lungs is where O2 enters the
blood and CO2 exits the blood. It is formed mainly by the alveolar walls and surrounding pulmonary capillaries.
Respiratory Membrane
are the principal organs of respiration, and on a volume basis they are among the largest organs of the body.
Lungs
Each lung is _______ in shape, with its base resting on the diaphragm and its apex
extending to a point approximately 2.5 cm superior to the clavicle.
Conical
The _______ is larger than the left and weighs an average of 620 g, whereas the left lung weighs an average of 560 g.
Right lung
is a region on the medial surface of the lung
where structures, such as the main bronchus, blood vessels, nerves, and lymphatic vessels, enter or exit the lung.
Hilum
All the structures passing through the hilum are referred to as the ____ of the lung.
Root
The left lung also has an indentation called the
Cardiac Notch
The lung lobes are separated by deep, prominent ________ on the surface of the lung.
Fissures
Each lung lobe is supplied by a
Lobar bronchus
The lung lobes are further subdivided into
________________, each of which is supplied by the segmental bronchi.
Bronchopulmonary segments
There are 9 bronchopulmonary segments in the
Left lung
There are 10 bronchopulmonary segments in the
Right lung
The bronchopulmonary segments are even further subdivided into _______ by partial walls
of connective tissue.
Lobules
The __________ supply the lobules.
Bronchioles
consists of the thoracic vertebrae, ribs, costal
cartilages, sternum, and associated muscles.
Thoracic wall
is the space enclosed by the thoracic wall and the diaphragm
Thoracic cavity
is a sheet of skeletal muscle separating the thoracic cavity from the abdominal cavity.
Diaphragm
The diaphragm and other skeletal muscles associated with the thoracic wall are responsible for
Ventilation
There are several muscles of _________ that increase thoracic volume.
Inspiration
The remaining muscles of inspiration include the
External Intercostals
Pectoralis Minor
Scalene Muscles
The muscles of __________ are the muscles that decrease thoracic volume by depressing the ribs and sternum.
Expiration
are most active during expiration
Internal intercostals
Transverse thoracis
are most active during inspiration
External intercostals
The diaphragm is __________, and the base of the dome attaches to the inner circumference of the inferior thoracic cage.
Dome-shaped
The top of the dome is a flat sheet of connective tissue called the
Central Tendon
during quiet breathing is a passive process.
Expiration
The lungs are contained within the thoracic cavity, but each lung is contained within its own _____________ formed by the pleural serous membrane
Pleural Cavity
Separating the two pleural cavities is a central
region called the
Mediastinum
covers the inner thoracic wall, the superior surface of the diaphragm, and the mediastinum.
Parietal pleura
At the hilum, the parietal pleura is continuous with the ___________, which covers the surface of the lung.
Visceral Pleura
The pleural fluid has two functions:
(1) It acts as a lubricant, allowing the parietal and visceral pleural membranes to slide past each other during ventilation
(2) it causes the parietal pleura to cling to the visceral pleural around the lungs.
Blood that has passed through the lungs and picked up O2 is called
Oxygenated blood
Blood that has passed through the
tissues and released some of its O2 is called
Deoxygenated Blood
The lungs have two lymphatic supplies.
Superficial Lymphatic Vessels
Deep Lymphatic Vessels
are deep to the visceral pleura; they drain
lymph from the superficial lung tissue and the visceral pleura.
Superficial Lymphatic Vessels
follow the bronchi; they drain lymph from the bronchi and associated connective tissues.
Deep Lymphatic Vessels
No lymphatic vessels are located in the walls of the
Alveoli
Both the superficial and deep lymphatic vessels exit the lung at the
Hilum
The pressure of a gas in a container at a constant temperature follows
Boyle’s Law: P=k/V
P
Gas pressure
k
a constant for a given temperature
V
Volume of the container
states that, in a container, such as the thoracic cavity or an alveolus, pressure is inversely proportional to volume.
Boyle’s Law
The partial pressure of a gas in a mixture of gases is the percentage of the gas in the mixture.
Dalton’s Law
The concentration of a gas dissolved in a liquid is equal to the partial pressure of the gas times the solubility coefficient of the gas.
Henry’s Law
the resistance to airflow is proportional to the diameter (D) of a tube.
Poiseuille’s law
which is simply atmospheric air pressure outside the body, is designated as zero.
Barometric air pressure (PB)
is the air pressure inside an alveolus.
intra-alveolar pressure (Palv)
barometric air pressure and intra-alveolar pressure are equal. Therefore, no air moves into or out of the lungs.
End of expiration
contraction of inspiratory muscles increases thoracic volume, which results in expansion of the lungs and an increase in alveolar volume
During inspiration
the thorax stops expanding, the alveoli stop expanding, and intra-alveolar pressure becomes equal to barometric air pressure because of airflow into the lungs.
End of inspiration
the volume of the thorax decreases as the diaphragm relaxes, and the thorax and lungs recoil.
During expiration
It is important to understand that lung recoil and changes in pleural pressure cause changes in
Alveolar volume
This is the tendency for the lungs to decrease in size after they are stretched.
Lung recoil
A molecule called _________ forms a one molecule-thick layer over the alveolar fluid,
which reduces the surface tension in the alveoli.
Surfactant
mixture of lipoprotein molecules produced by the type II pneumocytes of the alveolar epithelium.
Surfactant
With surfactant, the force produced by surface tension is approximately
3 mm Hg
Without surfactant, the force can be as high as
30 mm Hg
do not produce enough surfactant.
Premature infants
is common in premature infants, especially those with a gestation age of less than 7 months.
Infants Respiratory Distress Syndrome
is the difference between intra-alveolar pressure and pleural pressure.
Transpulmonary pressure
When pleural pressure is lower than intra-alveolar pressure, the alveoli tend to
Expand
This pleural pressure increase is called a
Pneumothorax
A pneumothorax has two major possible causes:
Penetrating Trauma
Nonpenetrating Trauma
Types of penetrating traumas include
Being stabbed
Getting shot by a gun
Breaking a rib
Types of nonpenetrating traumas include
A blow to the chest
A medical procedure, such as insertion of a catheter to withdraw pleural fluid
Disease, such as an infection or emphysema
Severe, spastic coughing
The most common symptoms of a pneumothorax are
Chest pain
Shortness of breath
the pressure within the pleural cavity is always higher than barometric air pressure.
Tension pneumothorax
is a measure of the ease with which the lungs and thorax expand.
Compliance
For a normal person the compliance
of the lungs and thorax is
0.18 L/mm Hg
is the process of measuring volumes of air that move into and out of the respiratory system
Spirometry
is the device used to measure these pulmonary volumes.
Spirometer
The four pulmonary volumes and representative values for a young adult male
Tidal Volume
Inspiratory Reserve Volume
Expiratory Reserve Volume
Residual Volume
is the normal volume of air inspired and
expired with each breath.
Tidal volume
At rest, quiet breathing results in a tidal volume of approximately
500 mL
is the amount of air that can be inspired forcefully after a normal inspiration (approximately 3000 mL at rest)
Inspiratory reserve volume
is the amount of air that can be forcefully expired after a normal expiration (approximately 1100 mL at rest)
Expiratory reserve volume
is the volume of air still remaining in the
respiratory passages and lungs after the most forceful expiration (approximately 1200 mL).
Residual Volume
The tidal volume increases when a person is more
Active
are the sum of two or more pulmonary
volumes
Pulmonary capacities
Some pulmonary capacities follow:
Inspiratory Capacity
Functional Residual Capacity
Vital Capacity
Total Lung Capacity
is the tidal volume plus the inspiratory
reserve volume.
Inspiratory Capacity
Inspiratory capacity is the amount of air a person can inspire maximally after a normal expiration
Approximately 3500 mL at rest
is the expiratory reserve volume plus the residual volume.
Functional Residual Capacity
Functional Residual Capacity is the amount of air remaining in the lungs at the end of a normal expiration
Approximately 2300 mL at rest
is the sum of the inspiratory reserve volume,
the tidal volume, and the expiratory reserve volume.
Vital Capacity
Vital Capacity is the maximum volume of air a person can expel from the respiratory tract after a maximum inspiration
Approximately 4600 mL
is the sum of the inspiratory and expiratory reserve volumes plus the tidal volume and the residual volume (approximately 5800 mL).
Total Lung Capacity
is a simple and clinically important pulmonary test.
Forced expiratory vital capacity
A more accurate measure of the amount of air available for gas exchange per minute is
Alveolar Ventilation
In order to calculate alveolar ventilation, we must first account for a parameter called the
Dead space
The structures of the respiratory system where gas exchange does not take place are collectively called the dead space:
Anatomical dead space
Physiological dead space
is generally about 1 mL of dead space per pound of an individual’s “ideal” body weight.
Anatomical dead space
Anatomical dead space includes the
Nasal cavity
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Terminal Bronchioles
is the anatomical dead space plus the volume of any alveoli in which gas exchange is less than normal.
Physiological dead space
the total pressure of a gas is the sum of the
individual pressures of each gas.
Dalton’s Law
CO2 is approximately 24 times more ________ in water than O2 is.
Soluble
The most common cause of increased respiratory membrane thickness is an accumulation of fluid in the alveoli, known as
Pulmonary edema
is a measure of how easily a gas diffuses
into and out of a liquid or tissue.
Diffusion coefficient
The alveoli supplied with air (alveolar ventilation) also have an ample blood supply,
referred to as
Pulmonary capillary perfusion.
Blood that is not completely oxygenated is called
Shunted blood
results when deoxygenated blood from the
bronchi and bronchioles mixes with blood in the pulmonary veins
Anatomical shunt
The combination of these two
shunts is called the
Physiological shunt
Normally, ____ of cardiac output makes up the physiological shunt.
1-2%
describes the percent saturation of hemoglobin in the blood at different blood Po2 values.
Oxygen-hemoglobin dissociation
curve
This effect of pH on the oxygen-hemoglobin dissociation curve is called the _________,
after its discoverer, Christian Bohr.
Bohr effect
Within red blood cells, an enzyme called ______________ catalyzes a reversible reaction that results in carbonic acid formation when CO2 and H2O mix.
Carbonic anhydrase
The medullary respiratory center in the medulla oblongata consists of two (1) _______________ and two (2) ________________
(1) Dorsal Respiratory Groups
(2) Ventral Respiratory Groups
Each forming a longitudinal column of cells located bilaterally in the dorsal part of the
medulla oblongata
Dorsal Respiratory Groups
Each forming a longitudinal column of cells located bilaterally in the ventral part of the medulla oblongata
Ventral Respiratory Groups
is believed to establish the basic rhythm of respiration.
pre-Bötzinger complex
formerly called the pneumotaxic center, is a collection of neurons in the pons.
Pontine respiratory group
is the absence of breathing.
Apnea
are specialized neurons that detect changes in the concentration of specific chemicals.
Chemoreceptors
are located bilaterally and ventrally in the chemo sensitive area of the medulla oblongata, and they are connected to the respiratory center.
Central Chemoreceptors
are found in the carotid and aortic
bodies.
Peripheral Chemoreceptors
The respiratory center is connected to the carotid body chemo receptors through the (1) ______________ and to the aortic body chemoreceptors by the (2) _______________
(1) Glossopharyngeal nerve (IX)
(2) Vagus nerve (X)
A greater than normal amount of CO2 in the blood is called
Hypercapnia
A lower than normal CO2 level, called
_____________, results in periods when breathing rate is reduced or does not occur at all.
Hypocapnia
limits the depth of inspiration and prevents overinflation of the lungs
Hering-Breuer Reflex
The highest level of exercise that can be performed without causing a significant change in blood pH is called the
Anaerobic Threshold
