Transcript File

Human Respiratory System
A system that provides a large surface
area for the diffusion of O2 into the
blood, and the diffusion of CO2 out of
the blood in order to maintain
homeostasis.
Human Respiratory System and
Homeostasis
• Responsible for
– Obtaining oxygen for cells
– Ridding the body of waste (carbon dioxide)
Requirements for Respiration
• 2 requirements
• Humans require a surface for gas exchange
that is big enough for exchange of oxygen
and carbon dioxide at a rate to meet
organisms metabolic rate.
• Take place in a moist environment so that
oxygen and carbon dioxide are dissolved
Parts of the Respiratory System
Two Main Sections of Respiratory System
• Upper Respiratory
– Nasal cavity
– Pharynx
– Epiglottis
– Larynx
– Trachea
• Lower Respiratory
– Bronchii
– Bronchioles
– Alveoli/Lungs
– Diaphragm
Oral and Nasal Cavities
• Structure - openings through which air
enters the system. Nasal cavity is the
chamber behind the nose. It contains hairs,
cilia, and mucus.
• Function - the nose and nasal cavities have
the following functions:
• (A) air is cleansed by the mucus, cilia, and
hair
Oral and Nasal Cavities
• (B) air is heated by blood passing through a large
number of capillaries just below the mucus
membranes. Must be at 37 degrees for optimal
performance
• (C) mucus membranes moisten the air
• The cleansing, heating, and moistening of the air
prevents damage to the delicate lung tissue.
Pharynx
• Structure - cavity behind the nasal cavity
that is common to the respiratory and
digestive systems. It contains two lymph
glands: adenoids and tonsils.
• Function - transports air between the nasal
cavity/mouth and the trachea.
Larynx (Voice Box)
• Structure - consists of several pieces of cartilage.
Located inside is elastic tissue known as vocal
cords.
• Function - When you breathe there is a gap
between cords.
• When you speak gap closes the vocal cords vibrate
as air goes through them producing sound.
• The pitch of the sound produced depends on the
length of the vocal cords. Long length produces
low sound, while shorter cord produces a higher
sound
Trachea
• Structure - a tube about 10 to 17 cm long containing rings
of cartilage which prevent the tube from collapsing. At the
top is located the epiglottis. It is lined with mucus
membrane that is ciliated. connects pharynx to the bronchii
• Function - a connecting tube that leads air to and from the
lung by passing through the pharynx to the bronchii.
• *Epiglottis - prevents liquids or solids from entering the
lungs.
• *Mucus membrane - produces mucus that traps foreign
materials that are then swept out of the trachea by the cilia.
This material is carried away by food passing down the
esophagus.
Bronchii
• Structure - tubes which branch from the
trachea leading into the two lungs.
• Function - a connecting tube that leads air
to and from the lung.
Bronchials
• Structure - small tubes that branch from the
bronchi inside the lungs. Lined with ciliated
mucous membrane
• Function - connecting tubes that lead from
the bronchi to the bronchioles.
Bronchioles
• Structure - yet smaller tubes that branch
from the bronchials inside the lung.
• Function - connecting tubes that lead from
the bronchials to the alveoli. Brings air deep
into the lungs
Lungs
• Structure:
• Protected by the ribs, sternum, and spine.
• Surrounded by two membranes called pleura.
The pleura isolates the lungs and protects the
delicate tissue. A lubricating fluid is found
between the two layers allowing the lungs to
move freely in the chest cavity during breathing.
• Function - contain a variety of tubes and
chambers where gases are exchanged between the
lungs and the blood.
• Humans have 2 lungs
– Left has 2 lobes and the right has 3 lobes
– Left lung has 2 lobes making it slightly smaller
than right to make room for the heart
• Contains thousands of alveoli that inflate
with air
• Surface of as typical lung can cover a
Tennis court
Lung Systems
• Vary from species to species, but they all
have 3 basic elements:
– One or two lungs that have a moist respiratory
surface
– Means of forcibly bringing air in contact with
lung surface
– Circulatory system to carry gases between
lungs and the other cells of the body
Diaphragm
• Structure - sheet of muscle that separates
the thorax (chest) and abdomen cavities.
• Function - its movement is responsible for
breathing.
• Inspiration (inhale) - diaphragm contracts
• Expiration (exhale) - diaphragm relaxes
Alveoli
• Structure - millions per lung, giving the lungs a
very large surface area for gas exchange. They
are found at the ends of the bronchioles and are a
cluster of microscopic, one cell thick, grape-like
air sacs. They are moist and surrounded by
capillaries.
• Function - site of gas exchange between the air in
the lungs and the blood in the capillaries. Gas
exchange takes place through simple diffusion
but 30%occurs through facilitated diffusion
Alveoli of the Lungs
Steps in Gas exchange in Alveolus
• Oxygen is bought to the surface of an alveolus by
inhaling air
• Oxygen diffuses across the alveolar membrane via
concentration gradient and into a capillary. Water is
needed at the surface between the alveolus and the
capillary to facilitate the diffusion of gases(oxygen and
carbon dioxide).
• At the same time carbon dioxide in the blood diffuses
across the membrane and into the alveolus. This happens
in the opposite direction to oxygen
• The carbon dioxide is then sent back up the airway to be
Process of Breathing
• Definition - breathing is a mechanical process where
gases are exchanged between the lungs and the
atmosphere. Breathing is the first step in
respiration.
• Breathing occurs due to changes in the pressure in
the thorax or chest cavity of the body. This pressure
is controlled by changing the size of the thorax.
Two structures responsible for changing the size of
the thorax are:  ribs and rib muscles (intercostal muscle)
 diaphragm
Inhalation (Inspiration)
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Definition - air enters the lungs
Process - there are six steps to the process:
(1) rib muscle and diaphragm contract
(2) ribs move up and out
(3) diaphragm moves down
(4) thorax increases in size or volume
(5) pressure decreases in the thorax due to increase in
volume. The result is lower pressure inside the thorax
than outside.
• (6) air rushes into the lungs
• When the above happens it increases the
volume of the chest cavity. This creates a
low pressure inside the chest. The pressure
inside the chest is less than the pressure
outside the body.
• Air rushes into the lungs from the outside
• The lungs inflate
Exhalation (Expiration)
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Definition - air leaves the lungs
Process - there are six steps to the process:
(1) rib muscle and diaphragm relax
(2) ribs move down and in
(3) diaphragm moves up
(4) thorax decreases in size or volume
(5) pressure increases in the thorax due to decrease in
volume. The result is a higher pressure inside the
thorax than outside.
• (6) air rushes out of the lungs
• When this happens it decreases the volume
of the chest cavity. This creates a high
pressure inside the chest. The pressure
inside the chest is greater than the pressure
outside the body
• Air is forced out of the lungs
• The lungs deflate
Rate of Breathing
• Breathing is an involuntary response controlled
by a section of the brain called the medulla
oblongata.
• This structure sends impulses to the intercostal
muscles of the ribs and diaphragm, causing them
to contract which produces inspiration.
• When this impulse stops, the intercostal muscle
and diaphragm relax producing expiration.
• The amount of CO2 in the blood determines the
rate of breathing.
• Two sensors located in the circulatory
system measure the CO2 content of the
blood:
 carotid artery in the neck
 aorta leading from the left
ventricle of the heart
CO2 Level
Rate of Breathing
High
Fast
Low
Slow
* Breathing rates vary with age
and activity.
Stages of Respiration
1. Breathing
(previously discussed)
2. External Respiration
• Definition - exchange of gases between the
alveoli of the lungs and the blood.
• Process - occurs by diffusion
• O2 goes into the blood from the alveoli
• CO2 goes into the alveoli from the blood
3. Gas Transport
• Definition - transportation of gas between the lungs and
body cells.
• Process - the gases enter the blood and combine with
the protein hemoglobin found on the red blood cell
(RBC)
• lung ----> body cells : O2 enters the bloodstream and
combines with the hemoglobin forming oxyhemoglobin
• body cells ----> lung : CO2 enters the bloodstream and
combines with the hemoglobin forming
carboxyhemoglobin
* CO2 also combines with water on
the RBC and in the plasma, this
forms carbonic acid.
Gas Exchange
4. Internal Respiration
• Definition - exchange of gases between the
blood and the cells of the body.
• Process - occurs by diffusion
• O2 goes into the body cells from the blood
• CO2 goes into the blood from the body cells
5. Cellular Respiration
• Definition and Process both covered
previously.
Lung Capacity
• What's the difference between normal breathing and a deep
breath?
• Normal breathing does not use up the full capacity of your lungs.
– Tidal Volume; the volume of air inhaled and exhaled in a normal
breathing movement. About 500mL
– Inspiratory reserve volume: is the additional volume of air that can be
taken in beyond a regular or tidal inhalation. About 2000mL
– Expiratory reserve volume: is the additional volume that can be forced
out of the lungs beyond a regular or tidal exhalation. About 1500mL
– Vital Capacity is the total volume of gas that can be moved in or out of the
lungs. It can be calculated as tidal volume + inspiratory reserve volume+
expiratory reserve volume = vital capacity. About 4L
– Residual volume: is the amount of gas that remains in the lungs and the
passageways of the respiratory system even after a full exhalation. This
volume never leaves the respiratory system, if it did the lungs would
collapse. About 1500mL
Diseases of the Respiratory System
Bronchitis
• Definition - inflammation of the bronchial passages. Two
forms:
• Acute - severe form which involves an infection of the air
passages.
• Chronic - less severe form which involves an irritation of
the air passages.
• Symptoms - fever, chest pain, severe coughing and often
the secretion of sputum.
• Causes: infection from coughs and colds
– Smoking
• Treatments: Antibiotics
– Stop smoking
Asthma
• Caused by the constriction of bronchial passages and
swelling of their mucus linings.
• It is triggered by a hypersensitivity to various agents
within an individual’s environment.
• Can develop at any age
• Affects can be mild or extremely severe
• Leading cause of childhood hospitalization in Canada
• Symptoms – occur in episodes, attack begins with
pressure in the chest, feeling of suffocation, with severe
bouts of uncontrollable coughing and the secretion of a
thick mucous sputum.
What happens during an asthma attack?
– Airway swells
– Bronchial muscles tighten
– Increased mucous is secreted in the airway
• Common triggers are:
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colds and chest infections,
exercise and sports,
exposure to pollen,
flowers, grass, plants, trees,
exposure to tobacco,
dust,
cold air,
pets mould and mildew
How to manage Asthma
– Through lifestyle changes and medications
– Reduce contact with triggers
– Test for allergens
– Keep asthma diary
– Use medications
• Types of meds used:
– anti-inflammatory agents: which help prevent attacks
by delaying or interrupting inflammation, and they
help end attacks
– Bronchodilators: relax bronchial muscles and open up
airways
Causes of pneumonia
• Infection by
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bacteria,
viruses,
mycoplasma,
fungi and
other infectious agents
and some chemicals
Types
• Bacterial pneumonia
– occurs in lobar pneumonia
– is caused by an invasion of streptococcus pneumonia.
– Can get a vaccination to provide long term
protection
• Viruses
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usually attacks upper respiratory,
but they also cause many forms of pneumonia.
Is less serious then other forms and
last for long periods of time
• Mycoplasma pneumonia: Walking Pneumonia
– caused by small free living agents of disease in humans.
– Have characteristics of both bacteria and viruses.
– Patients require a long recovery period and can be weak
for a long time
• Symptoms - fever, pain in the chest while breathing,
cough, and sshortness of breath, shivering, chills, headache,
delirium (confusion), severe bad breath, muscle pain,
weakness, blue lips and nail beds from lack of oxygen in
the blood
Treatments
• The best approach to treating pneumonia depends on a
number of factors, including your age and general health,
the organism or organisms involved, and the setting —
community or health care — where the infection
developed.
• Medication
Antibiotics are used to treat bacterial pneumonia.
• Antivirals
• Fever reducers
• Cough medicine
• Hospital admission
Cancer
• Cancer is the uncontrollable
multiplication of cells. Cancer may
occur in any part of the body, and
therefore in any part of the
respiratory system.
Lung Cancer
• Uncontrolled and invasive growth of abnormal cells in
lungs and is the leading cancer killer of both men and
women in North America
• Carcinoma
– Malignant tumour
– grows abnormal cells that continue to multiply and
take over healthy cells.
• Death is caused by
– difficulty in breathing,
– or cancer moving out of lungs And into brain or other
body parts
• Causes
– 87% of lung cancer is due to smoking(Carcinogens)
– Another cause is exposure to radon an element used in
radiotherapy(12%)
• symptoms
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Chronic cough,
coughing up blood,
weigh loss
los of appetite,
shortness of breath
chest pain
and fever without cause
• Effects of Lung Cancer
– Death but not by difficulty breathing. Death is
normally caused by the cancer moving out of
lungs an into other body parts such as the brain
• Treatments
– Radiation and chemotherapy if not too far
advanced
Emphysema
• A progressive disease in which the tissues of the
lungs lose their elasticity, and therefore the volume
of air that the lungs are able to handle continually
decreases.
• Alveoli are distended and their walls are so damaged
that the surface available for gas exchange is reduced
and less oxygen is available to the brain and tissues
• The deterioration in the lungs is permanent and
irreversible.
• Symptoms - severe coughing, shortness of breath,
and wheezing; developing into difficulty in
breathing. It sometimes results in disability and
death.
• Treatments:
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reduce or eliminate smoking
exercise,
some drugs help to keep alveoli working
and supplemental oxygen
Influenza
• A viral infection of the respiratory tract,
especially the trachea. Commonly called flu.
Reduces a person’s resistance making them
susceptible to further infections such as
pneumonia.
• Symptoms - sore throat, nasal discharge, fever,
chills, headache, aching of muscles and joints,
upset stomach
• Treatments:
– Treat symptoms — .
– Rest until the flu is fully resolved, especially if the
illness has been severe
– Fluids — Drink enough fluids so that you do not
become dehydrated.
– Acetaminophen (such as Tylenol® and other brands)
can relieve fever, headache, and muscle aches.
– Cough medicines are not usually helpful; cough usually
resolves without treatment.
Common Cold
• A viral infection of the upper respiratory
tract.
• Symptoms - sneezing, headaches, sore
throat, nasal discharge
Pleurisy
• Inflammation of the pleura membranes that
surrounds the lungs. Most cases are due to
infections, and many are associated with
pneumonia.
• Symptoms - sharp pain brought on by
breathing and coughing. Patient breaths
shallowly.
Treatments
• Use an anti-inflammatory medicine, such as
ibuprofen (Motrin) or aspirin, to reduce the pain
and inflammation.
• You may have less pain if you lie on the side that
hurts.
• Avoid exerting yourself or doing anything that
would cause you to breathe hard.
• Call your doctor or go to your hospital's emergency
department if you can't breathe deeply or cough
because of severe pain
Carbon Monoxide Poisoning
• Definition - Carbon monoxide is a chemical
compound consisting of one atom of carbon
and one atom of oxygen (CO). It is an
odorless and tasteless gas.
• Source - It is produced when organic
compounds are burned with an insufficient
air supply.
• Effects - When inhaled, it combines with
the hemoglobin on the RBC, preventing
absorption of oxygen.
• Symptoms - symptoms are normally mild
and include nausea, headache, or fatigue.
Excessive inhalation can be more serious,
even fatal.
• Treatment - remove the individual from the
source of CO. Perform mouth to mouth
resuscitation if necessary.
Emphysema
• The swelling and scarring of alveoli in the lung resulting in
loss of elasticity( cannot inflate and deflate) of the alveoli.
This causes some of them to burst resulting in decrease of
surface area for gas exchange
• Difficulty in breathing
• Causes of emphysema
– Smoking
– Other agents
• Treatments for emphysema
– Stop smoking
– Drugs to make alveoli work
– Extra oxygen