Transcript The RESPIRATORY System

The RESPIRATORY System
Respiration
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The exchange of gases between the
atmosphere, blood, and cells
Pulmonary Ventilation - the exchange of air
between the atmosphere and lungs
External (Pulmonary) Respiration - gas
exchange between the lungs and blood
Internal (Tissue) Respiration - gas exchange
between the blood and cells
Functions of the
Respiratory System
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Provides structures and mechanisms for
gas exchange
– Intake of O2
– Elimination of CO2
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Helps maintains body’s pH
Sense of smell
Speech and sound production
Organs of the
Respiratory System
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Nose
Pharynx
Larynx
Trachea
Bronchi
Lungs
Respiratory System
Respiratory Structures
Nose
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External Portion
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Supporting bony framework
Cartilage
- Skin
Mucous membranes
Nostrils or external nares
Internal Portion - large cavity within the skull
– Connects the external nose to the pharynx through
two openings (Internal Nares)
External Nose Structures
Nose
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Nasal Cavity - large cavity that contains
both the external and internal nose
cavities
divided into the right and left sides by
the NASAL SEPTUM
Internal Nose Structures
Functions of the Nose
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Warming, moisturizing and filtering
incoming air
Smell (reception of olfactory stimulus)
Resonating chamber for speech
Pharynx
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Funnel-shaped tube about 13 cm long
Extends from the internal nares down to the
cricoid cartilage of the larynx
Walls composed of skeletal muscle lined with
a mucous membrane
Divided into three areas
– Nasopharynx
– Oropharynx
– Laryngopharynx
Regions of the Pharynx
Functions of the Pharynx
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Passageway for food and air
Resonating chamber for speech
Larynx
(Voice Box)
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A short passageway that connects the
pharynx with the trachea
Walls of the larynx is composed of 9
pieces if cartilage
– Three single pieces of cartilage
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epiglottic cartilage (Epiglottis)
thyroid cartilage (Adam’s Apple)
cricoid cartilage
(attaches the Larynx to the Trachea)
– Three paired pieces of cartilage
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arytenoid - corniculate - cuneiform
Larynx Structures
Trachea
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Tubular passageway about 12 cm long and
2.54 cm in diameter
Anterior to the esophagus
Extends from the larynx to about the 5th
thoracic vertebrae
Composed of 16 - 20 C-shaped cartilage rings
stacked upon one another
– Hyaline cartilage rings
– Covers the anterior and lateral walls
Trachea and Esophagus
Trachea
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Non-cartilaginous posterior softer
portion of the trachea allows for
expansion of the esophagus during
swallowing
Lined with ciliated epithelium
The point where the trachea bifurcates
is called the carina
– About the 5th thoracic vertebrae
Bronchi
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Tubes that branch off of the trachea at the
carina and extend into the lungs
Left Primary Bronchus
(Left Mainstem Bronchus)
Right Primary Bronchus
(Right Mainstem Bronchus)
– Shorter and more vertical
– Swallowed objects more likely to lodge in the
right primary bronchus than the left
Bronchi
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Also composed of cartilaginous rings
Continue branching as they enter the
lungs into a structure called the
bronchial tree
– Trachea
-Mainstem (Primary) Bronchi
- Secondary (Lobar) Bronchi
- Segmental (Tertiary) Bronchi
- Terminal Bronchioles
- Respiratory Bronchioles
- Alveolar Ducts
Bronchial Tree
Bronchioles
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Bronchioles are smaller air passages
which branch from the bronchi.
Bronchioles are small, muscular tubes
with a narrow diameter. Changes in
the size of the bronchioles help direct
the flow of air to various parts of the
lungs.
Alveolar Ducts
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Alveolar ducts are enlarged chambers
found at the end of the bronchioles.
These very fine passageways end at the
alveolar sacs and connect to the alveoli.
Alveoli
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A cup shaped out pouching of
epithelial tissue
Place where external respiration occurs
(gas exchange between the lungs and
the blood)
Lungs contain 300 - 500 million alveoli
– Surface area of about 750 sq. ft.
– The size of a Tennis Court
Alveoli
Pharynx
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Funnel-shaped tube about 13 cm long
Extends from the internal nares down to the
cricoid cartilage of the larynx
Walls composed of skeletal muscle lined with
a mucous membrane
Divided into three areas
– Nasopharynx
– Oropharynx
– Laryngopharynx
Structures of the Larynx
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Epiglottis
Glottis
Hyoid Bone
Thyroid Cartilage
Cricoid Cartilage
True and False Vocal Cords
Epiglottis
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Large leaf-shaped piece of cartilage lying on
top of the larynx
– The stem of the epiglottic cartilage is attached to
the thyroid cartilage
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Leaf portion of the cartilage is unattached and
acts like a trap door covering the opening to
the trachea which is called the glottis.
– Dependent upon breathing or swallowing
Epiglottis
Glottis
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The opening from the pharynx to the
larynx that contains the vocal cords
– Vocal Cords - mucous membrane folds that
extend across the glottis in two layers
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upper layer or folds - false vocal folds
lower layer or folds - true vocal folds
Sounds originate from vibration of
these true vocal cords
Glottis and Vocal Cords
Hyoid Bone
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Is located in the neck between the lower
jaw and the larynx.
It does not articulate with any other
bones.
It serves as the posterior attachment for
the tongue and helps in swallowing.
Thyroid Cartilage
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The thyroid cartilage is the largest
cartilage of the larynx.
It give the larynx its characteristic
triangular shape.
Nicknamed the Adam’s Apple because
of its enlarged size due to the influence
of testosterone.
Cricoid Cartilage
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The most inferior cartilage of the larynx.
Used as a landmark to perform a
tracheotomy.
True Vocal Cords
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The most inferior of the horizontal folds
in the larynx.
Contain elastic fiber which vibrate to
create sound.
False Vocal Cords
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The most superior of the folds in the
larynx.
Help the glottis close during
swallowing to prevent food from
entering the lower respiratory passages.
Lungs
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Paired - cone shaped organs that
occupy most of the thoracic cavity
Separated from each other by the heart
and other structures of the
mediastinum
Surrounded by a double layered serous
membrane called the pleural membrane
Features of the Lungs
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Apex - the pointed, superior portion of
the lungs.
Base – the broad, inferior surface of the
lungs which rests on the diaphragm.
Lungs
Left Lung
Pleural Membrane
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Parietal Pleura - outer layer of the pleural
membrane
– Attached to the thoracic wall
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Visceral Pleura - inner layer of the pleural
membrane
– Attached to the lungs themselves
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Between the parietal pleura and the visceral
pleura is a potential space called the pleural
cavity
– Contains pleural (serous) fluid (reduces friction)
Gross Anatomy of the Lungs
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Extend from the diaphragm to an area
about 2.54 cm above the clavicles on
both sides of the thoracic cavity
Base
Apex
Hilus
Lobes
Lobes and Fissures
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Each lung is divided into lobes by one
or more fissures
There are three lobes in the right lung
and two lobes in the left lung.
Pleural Cavity
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The mediastinum divides the thoracic
cavity into two pleural cavities, each of
which contains one lung.
Gas Exchange
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Gas exchange occurs in the alveoli due
to the difference in the partial pressures
of oxygen and carbon dioxide in the
capillary blood and the alveoli.
Since the concentration of oxygen is
greater in the alveoli, it diffuses into the
capillary blood.
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Since the level of carbon dioxide is
higher in the capillary blood than in the
alveoli, carbon dioxide diffuses out of
the blood and into the alveoli.
Lung Parameters
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Tidal Volume (TV) - 500 ml - volume of
air moved in and out of the lungs
during breathing
Vital Capacity (VC) - 4500 ml maximum volume of air that can be
exhaled after taking the deepest
possible inhalation
VC - TV + IRV + ERV
Spirometry
Physiology of Ventilation
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Ventilation - the process of inhaling and
exhaling air in and out of the lungs
Pulmonary Ventilation - the process by
which air flows between the lungs and
the external environment
Due to a change in pressure between
the atmosphere and the air in the lungs
Physiology of Ventilation
Inspiration (Inhalation)
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Bringing air into the lungs from the
external environment
The lungs themselves contain no
muscles and thus depend upon the
relationship with the muscles of the
walls of the thoracic cavity to alter lung
volumes
Ventilation
Muscles of Ventilation
Expiration (Exhalation)
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Movement of air from the lungs to the
external environment
Normally a passive process (no energy
or muscular contractions required)
Dependent upon muscle and lung
elasticity
May become active during high levels
of physical activity
– Most people require ventilation rates above
55% - 65% of their vital capacity for
expiration to become active
Physiology of Respiration
Respiratory Center
Chemical Stimuli
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Determines how fast and how deeply
an individual breathes
Very sensitive to the levels of CO2 and
H+ ion concentration in the blood
Monitored by chemoreceptors at:
– carotid arteries, aorta, and the medulla
oblongata.
Ventilatory
Homeostasis
RESPIRATORY
DISORDERS AND
HOMEOSTATIC
IMBALANCES
Bronchiogenic Carcinoma
(Lung Cancer)
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Most fatal cancer in the U.S.
Highly metastatic
Usually linked with cigarette smoking
Starts in the walls of the bronchi due to
irritation of the bronchiole epithelium
Common irritants include smoking,
pollution, dust particles
20 times more prevalent in smokers
than non- smokers
Emphysema
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“Blown up or full of air”
A condition where the alveolar walls lose
their elasticity and remain filled with air
during expiration
Alveoli become damaged and eventually
merge together to form large air sacs with
reduced overall volume
Patients often develop a barrel chest
Generally caused by cigarettes, pollution,
industrial dust particles
Influenza
•Caused by one of many viruses
• Antibiotics cannot help
• Medications used to treat the symptoms
– sneezing
– congestion
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- coughing
- rhinorrhea
May result in rhinitis: inflammation of
the nasal mucosa
Commonly known as the flu
Pneumonia
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Acute infection or inflammation of the alveoli
of the lungs
Most common infectious cause of death in the
U.S.
Alveolar sacs fill with fluid and dead white
blood cells reducing the amount of functional
surface area of the lungs
Most commonly caused by bacterium
– Streptococcus pneumoniae
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Affects those in poor health or compromised
immune system
Sudden Infant Death
Syndrome (SIDS)
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10,000 infant deaths per year in the U.S.
Cause is not known but thought to be
caused by an infectious agent or
compressed carotid artery
Most deaths occur in the fall or winter
Over 50% of SIDS death children had an
upper respiratory infection within the
past two weeks
May also be caused by improper
positioning for sleeping in the crib
Tuberculosis (Tb)
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Caused by a bacterium
– Mycobacterium tuberculosis
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An infectious communicable disease
that destroys the lung tissue and pleura
Replaced by fibrous connective tissue
called tubercles
Disease is spread by inhalation of the
bacterium