Download The Respiratory System

THE RESPIRATORY SYSTEM
THE RESPIRATORY SYSTEM
In this chapter, you will learn:
• The upper respiratory tract filters, warms, and moistens oxygencontaining air, and channels it into the lungs.
• The lower respiratory tract is made up of specialized structures
that exchange oxygen for carbon dioxide in the bloodstream.
• Humans ventilate their lungs by the mechanism of breathing,
which involves inspiration and expiration.
• The volume of air that is taken into the lungs can increase if the
need for oxygen increases, such as during exercise.
• External respiration takes place in the lungs, between the air in the
alveoli and the blood in the capillaries.
THE RESPIRATORY SYSTEM
In this chapter, you will learn:
• Internal respiration takes place between the blood in the capillaries
and tissue cells.
• Gas exchange occurs through the processes of simple diffusion and
facilitated diffusion.
• Some disorders are specific to the respiratory system. Technologies
are available to treat respiratory disorders, but they may not be
able to restore the respiratory system to optimal health.
• Smoking causes respiratory diseases. Technologies can help some
symptoms of smoking, but many symptoms are untreatable.
STRUCTURES OF THE RESPIRATORY SYSTEM
In this section, you will:
• identify the principal structures of the respiratory system
• identify the principal functions of the respiratory system
• observe and identify the major respiratory structures
RESPIRATORY STRUCTURES
Breathing involves two basic processes: inspiration (breathing in, or
inhaling) and expiration (breathing out, or exhaling). Inspiration
moves air from the external environment to the lungs inside the
body. Expiration moves air from the lungs back to the external
environment.
•
External respiration is the exchange of oxygen and carbon dioxide between the
air and the blood.
•
Internal respiration is the exchange of oxygen and carbon dioxide
between the body’s tissue cells and the blood.
•
Cellular respiration is the series of energy-releasing chemical
reactions that take place inside the cells. Cellular respiration is the
final stage in respiration. It is the sole means of providing energy for
all cellular activities, and it helps the body maintain homeostasis.
•
ANATOMY
https://www.youtube.com/watch?v=o2OcGgJbiUk
THE RESPIRATORY TRACT
• The respiratory tract is what brings air from
the atmosphere to the lungs
• Your body needs oxygen in the air to undergo
aerobic cellular respiration to create energy
• There is an upper and lower respiratory tract
RESPIRATORY STRUCTURES
• Air enters via the nasal cavities and mouth
• The nasal cavities contain hairs and mucus that traps
particles and keeps cells moist
• At the same time, the large number of blood vessels inside
the nose also warm the incoming air
• The air then travels through the pharynx, which separates
the trachea (windpipe) and the esophagus
• When eating, an enlarged flap of
cartilage called the epiglottis covers
the trachea to prevent food from
entering
• Food and drink that enter the
trachea stimulates cilia that lines
the respiratory tract, producing a
cough
• Beyond the pharynx is the larynx, which is composed of thin
sheets of elastic ligaments
• When air passes past the larynx, sounds are produced (these are
the vocal cords)
• During speech, muscles contract and move these cords closer
together
• Males have thicker vocal cords, which results in a deeper voice
NASAL CAVITY- UPPER RESPIRATORY TRACT
• Turbinate bones increase SA in nasal cavity
• Air cleaned warmed and moistened before passing to lungs
• Well supplied with blood, moisture from secretions of epithelial
tissues moisten air and together with small hairs (cilia) trap dust
EUSTACHIAN TUBEUPPER RESPIRATORY TRACT
• Connects nasopharynx to middle ear
PHARYNX- UPPER
RESPIRATORY TRACT
• Common passageway
for air and food
• Nasopharynx contains
ciliated epithelial cells
LARYNX- UPPER RESPIRATORY TRACT
• Voice box - located at opening to trachea - formed by several pairs of
cartilage
• Contains vocal cords
• When you speak the muscles around the
larynx contract drawing the vocal cords together
[♂ voice change due to
enlargement of larynx]
https://www.youtube.com/watch?v=Z_ZGqn1tZn8
VOCAL CORDSUPPER RESPIRATORY TRACT
• Two folds of tissue stretched across the
larynx
• Air in larynx, pharynx and mouth
vibrated to produce sound - change in
tension gives change in pitch
[inflamed vocal cords thicken &
produce husky voice or
laryngitis]
TRACHEA- UPPER RESPIRATORY
TRACT
• Major air tube of respiratory system
(12 cm long)
• Loosely attached to esophagus
• Composed of smooth muscle and held
open by cartilage rings cartilage
prevents the trachea from collapsing
• Lined with mucus producing cells that
are ciliated & sweep toward the
pharynx
https://www.youtube.com/watch?v=d_5eKkwnIRs
BRONCHI- LOWER RESPIRATORY TRACT
• Trachea spits into 2 smaller pathways
called bronchi
• These bronchi lead to the left and right
lungs
• Once they reach the lungs the bronchi
split into even smaller tubes called
bronchioles
• Both Bronchi and bronchioles are lined
with cilia and mucus-producing cells
BRONCHIOLES- LOWER RESPIRATORY TRACT
• Each bronchus divided into many smaller passages
without cartilage ("respiratory tree")
ALVEOLAR DUCTS
• Smaller ducts leading into alveolus
ALVEOLILOWER RESPIRATORY TRACT
• “Grape-like" clusters of tiny sacs in
which air exchange takes place
• Each is about 0.1 - 0.2 mm
diameter and is surrounded by
capillaries
[about 300 million alveoli in 2 adult lungs]
• Walls of capillaries and alveolus
consist of single layer of epithelial
cells which allows diffusion of gases
to occur
EACH BRONCHIOLE ENDS IN SEVERAL CLUSTERS OF ALVEOLI. SURROUNDING
EACH ALVEOLUS IS A FINE NETWORK OF CAPILLARIES FROM THE CIRCULATORY
SYSTEM. GAS EXCHANGE OCCURS BETWEEN THE BLOOD IN THE CAPILLARIES
AND THE AIR IN THE ALVEOLUS, SO THAT BLOOD LEAVING THE LUNGS HAS A
HIGH OXYGEN CONTENT.
https://www.youtube.com/watch?v=XTMYSGXhJ4E
PLEURA- LOWER RESPIRATORY TRACT
• Two membranous sacs which surround lungs
• Parietal - lines inner surface of chest wall & top of diaphragm
• Visceral - adheres to surface of lungs
• Film of fluid between two pleura serves as lubricant and to pull lung as chest wall expands
[glass slide analogy]
[pleurisy - inflammation of pleura caused by pneumonia, influenza or
tuberculosis - breathing becomes painful]
[collapsed lung - seal between the pleura is broken, air is eventually
taken up by tissue and seal re-established]
https://www.youtube.com/watch?v=cWQ14x1URXo
LUNGS- LOWER RESPIRATORY TRACT
• Left lung has 2 lobes
(leaves room for heart),
right lung has 3 lobes
(larger than left)
https://www.youtube.com/watch?v=CUUq7fLMruM
https://www.youtube.com/watch?v=I40Qr9bOLOY
RIBS
• Move up and
down as
intercostal
muscles contract
and relax
RIBS
DIAPHRAGM
• Thin, dome shaped sheet
of muscle stretched
across the bottom of the
thoracic cavity
• Separates thoracic from
abdominal cavity
https://www.youtube.com/watch?v=hp-gCvW8PRY
THE MECHANISM OF BREATHING
https://www.youtube.com/watch?v=hc1YtXc_84A
BREATHING RATE
• The breathing rate is the number of times you need to breathe
in each minute
• This rate is controlled by the amount of carbon dioxide in the
blood not the amount of oxygen
• If the carbon dioxide is high because of increased exercise, your
breathing rate will speed up in order to get rid of the excess
carbon dioxide
RATE OF BREATHING
• The normal breathing rate is between 12-20 times per minute
depending on the body size
• Physical activity increases the breathing rate because of the
increased build up of Carbon dioxide
• However, athletes at rest tend to use oxygen more effectively and have
more developed lung capacity, which causes their respiration rate to be
lower than normal
• Children breathe twice as fast as adults because their lungs have less
surface area for gas exchange
BREATHING AND RESPIRATION
• Air will flow if there is a pressure difference between
the alveoli and the atmosphere
https://www.youtube.com/watch?v=sKY6FXo3g-0
• Air needs help to flow in and out of the lungs
• The diaphragm and the intercostal (chest) muscles
work together during inhalation and exhalation
• They control the air pressure in the lungs
https://www.youtube.com/watch?v=SWJHSTAWTCk
THE MECHANICS OF BREATHING
Fig. 7.5
INHALATION
• Inspiration is an active process of muscles contracting
• Increase in volume of thoracic cavity results in a pressure differential 
decreases the air pressure around the lungs
• The lungs are drawn outwards and the air pressure in the lungs decreases
• Air moves from an area of high pressure to low pressure so moves from the
environment to the lungs
i diaphragm - on inspiration pulls downward, flattening shape -> pressure
falls which draws air in
ii intercostal muscles - contract moving ribs upward and outward
[ about 500 mL enter respiratory tract (350 mL to lung & 150 mL to upper
respiratory tract)]
EXHALATION
• The intercostal muscles and the diaphragm
relax which makes the space in thoracic cavity
smaller
• This causes the lungs size to decrease which
increases the air pressure inside the lungs
• The pressure is now greater inside the lungs
than in the environment so the air wants to
move out
NOW FOR THE QUESTION THAT YOU HAVE
ALL BEEN ASKING…. AND THEN MAKING UP
RANDOM STUFF TO EXPLAIN
• The muscles that control breathing are controlled and
regulated by the nervous system. Sometimes nerves misfire
and cause irregular contractions of the diaphragm. This
interrupts the normal rhythm of breathing and causes air to
rush in to the lungs unexpectedly.
• The brain immediately tries to correct this by causing the
epiglottis to snap shut and close off the trachea
• Air hits this closed opening, which is near the vocal cords,
resulting in the “hic” sound of the hiccup
YOUR TASK
GAS EXCHANGE AND RESPIRATION
• Respiration is a combination of external and internal
respiration
• External Respiration: happens in the lungs where gases
are exchanged between the alveoli and the blood in
capillaries
• Internal Respiration: occurs between the blood and
tissue cells in our body
• Most oxygen in the blood is carried by
hemoglobin which is only found in red blood
cells When oxygen dissolves into the
plasma, hemoglobin forms a weak bond with
the oxygen molecule to form oxyhemoglobin
• Very little carbon dioxide, 23%, is carried by
hemoglobin
• Most carbon dioxide is carried in the blood as
bicarbonate ion (HCO3-), 70%
• The final 7% is carried by plasma
REGULATION OF BREATHING MOVEMENTS
• Breathing movements are controlled by nerves from
the medulla oblongata in the brain
• Information about the accumulation of carbon dioxide
and acids and the need for oxygen is detected by
chemoreceptors
• Two different types of receptors are:
• Oxygen chemoreceptors
• Carbon dioxide, or acid chemoreceptors (most sensitive and are
the main regulators of breathing movements)
REGULATION OF BREATHING MOVEMENTS
• Carbon dioxide dissolves in the blood to form an acid
• Carbon dioxide accumulates and chemoreceptors in the medulla
oblongata relay message to the intercostal muscles and diaphragm to
increase breathing movements
• Accelerated breathing rate decreases the levels of Carbon dioxide in
the blood
• Once Carbon dioxide levels fall, chemoreceptors become inactive
• Breathing returns to normal
REGULATION OF BREATHING MOVEMENTS
• A second monitoring system, relies on chemoreceptors
sensitive to oxygen found in the carotid and aortic arteries
• Specialized receptors are responsible for detecting low
levels of oxygen
• When stimulated they send a nerve impulses to the
intercostal muscles and diaphragm to increase breathing
movements.
• Increased ventilation increases blood oxygen
LUNG CAPACITY
• 14 - 20 breaths/minute for a healthy adult
TIDAL VOLUME
• Amount of air moved by an individual at rest
EXPIRATORY RESERVE VOLUME
• Air left in lungs after normal exhalation
INSPIRATORY RESERVE VOLUME
• Air which can be added to lungs after normal inhalation
VITAL CAPACITY
• 3 volumes added together
[varies according to age, size, and physical condition]
RESIDUAL AIR CAPACITY
• Air which cannot be forced
from lungs
A TYPICAL SPIROGRAPH
Fig. 7.6
YOUR TASK
• Practice Questions Page 288 #1 and 2  you will need to
use the graph on the side of the page
• Practice Questions Page 291 #2, 3, 5
• Explain Carbon monoxide poisoning page 293
• Practice Questions Page 297 # 1, 2, 4, 5
UPPER RESPIRATORY TRACT INFECTIONS - TONSILLITIS
 Infection of the tonsils (located in the pharynx)
 A viral infection is the common cause of tonsillitis
UPPER RESPIRATORY TRACT INFECTIONS - TONSILLITIS
 Can be removed surgically if the infections are frequent
and breathing is impaired.
[In the past, many children had their tonsils removed as a precaution, but surgery is no
longer as common.]
 Tonsils help to prevent bacteria and foreign pathogens
from entering the body, so removing them can increase
the number of infections later in life.
UPPER RESPIRATORY TRACT INFECTIONS - LARYNGITIS
 Inflammation of the larynx - vocal cords
are not able to vibrate normally
 Symptoms of laryngitis include a sore
throat and hoarseness
 Most common cause of laryngitis is a
viral infection; allergies and overstraining
of the voice
LOWER RESPIRATORY TRACT DISORDERS
Fig. 7.8
LOWER RESPIRATORY TRACT INFECTIONS - BRONCHITIS
 Causes the bronchi to become inflamed and filled with mucus,
which is expelled by coughing
LOWER RESPIRATORY TRACT INFECTIONS - PNEUMONIA
 Alveoli in the lungs become inflamed and fill with liquids interfering with
gas exchange -> body becomes starved for oxygen
LOWER RESPIRATORY TRACT INFECTIONS - PLEURISY
 A lung disorder that is caused by the swelling and irritation of
the pleura, the membranes that surround the lungs
LOWER RESPIRATORY TRACT INFECTIONS - EMPHYSEMA
 Is an obstructive respiratory disorder in which the walls of the alveoli
break down and lose their elasticity
 Reduces the SA for gas exchange
and causes hypoxia in the tissues.
LOWER RESPIRATORY TRACT INFECTIONS - CYSTIC FIBROSIS
 Serious genetic condition affecting the lungs
 An abnormal gene disrupts the function of the cells lining the
passageways of the lungs
LOWER RESPIRATORY TRACT INFECTIONS - ASTHMA
 Chronic obstructive lung disease that affects the bronchi and
bronchioles
 Making breathing difficult or impossible because of reduced
air flow.
LOWER RESPIRATORY TRACT INFECTIONS - LUNG CANCER
 Uncontrolled and invasive
growth of abnormal cells in
the lungs
 Leading cause of cancer
deaths for men and women
in Canada.
NORMAL LUNGS VS. DISEASED LUNGS
A. normal lungs have healthy red tissue. (The heart is visible near the lower centre.)
B. diseased lungs have black tissue caused by heavy smoking & white
tumors, or carcinomas.
CARCINOMA OF THE LUNG
The large ball of cells in the centre of the image is a carcinoma that has developed
from the interior surface cells of the human lung. The carcinoma continues to grow
and invade surrounding tissues, including the lymphatic and blood vessels in the
lung. The lymphatic and blood vessels circulate through the body and carry the
cancerous cells, or metastatic cells, to new locations where they can grow and
invade new tissues.
SUPERFICIAL REASONS NOT TO SMOKE
REASONS NOT TO “CHEW”
• Chewing tobacco is every bit as dangerous as
smoking
• Cancer - lips, tongue, the floor of the mouth,
the roof of the mouth, the cheeks, gums, lining
of your stomach, your esophagus, and into
your bladder
THE BENDS
• The blood and tissues of divers absorb extra amounts of gases because of the
increased pressure under water.
• This is not a problem unless the individual comes to the surface too quickly
• If this happens, the gases will bubble in the tissue which can cause dizziness,
nausea as well as muscle and joint pain.
• In extreme cases it can be fatal
TUBERCULOSIS
• Communicable disease among humans and animals that is caused by bacteria
• Manifests in the lungs, bones, urinary tract, brain and other parts of the body
• Affects the pulmonary system the most
• Can cause mental illness and has a high infant death rate
• Tuberculosis kills more people than all other communicable diseases
combined
• Symptoms include: fatigue, abnormal sound in the lungs, afternoon fevers,
buildup of blood in the lungs
• Treatment includes collapsing the lung in order to rest it or surgically removing
infected area
CONCEPT ORGANIZER
CHAPTER SUMMARY
• Respiration enables the body to take oxygen from the external environment
and process it for delivery to the cells and, at the same time, rid itself of carbon
dioxide.
• O2 is delivered to the cells and CO2 is removed from the cells and the body in a
number of exchanges.
• Inspiration and expiration (breathing) exchange air between the environment
and the lungs.
• External respiration exchanges oxygen and carbon dioxide between the air in
the lungs and the blood.
• Internal respiration exchanges oxygen and carbon dioxide between the blood
and the body’s tissue cells.
• Cellular respiration is the final step, when the oxygen delivered to the cells is
used to provide the energy for all cellular activities.
CHAPTER SUMMARY
• The respiratory tract is the passageway for air to move from the external
environment to the lungs.
• The upper respiratory tract begins at the nostrils and includes the nasal
passages, pharynx, larynx, and trachea.
• These passageways all clean and warm the air as it passes through.
• Infections of the upper respiratory tract, such as tonsillitis and laryngitis are
short term infections that do not obstruct breathing.
• The lower respiratory tract consists of two bronchi that each lead to a lung.
• Within the lungs are small, fine tubes called bronchioles, where the air
continues to be cleaned and warmed.
• The exchange of gases takes place in a cluster of tiny sacs at the end of each
bronchiole, called alveoli, where the oxygen diffuses through the
membranes of the alveoli into the capillaries of the circulatory system.
CHAPTER SUMMARY
• Disorders of the lower respiratory tract can impair the delivery of
oxygen to the cells
• Examples include: bronchitis, pneumonia, pleurisy, emphysema,
cystic fibrosis, asthma, and lung cancer.
YOUR TASK