Respiration Notes

Unit 3 Transportation & Respiration

The Respiratory
System


Gas Exchange
All animals need food, water,
and air to survive. The
respiratory system of each
animal is what handles these
needs. Oxygen is taken from
outside and exchanged with
carbon dioxide in the lungs. That
exchange is called respiration,
and is composed of five basic
events.


Gas Exchange


• 1. Pulmonary Ventilation
Air inside the lungs is exchanged with fresh air on
the outside.
• 2. External Respiration
Fresh air in the lungs is moved into the blood, and
used air in the blood is moved into the lungs to be
removed.
• 3. Respiratory Gas Transport
The circulatory system pumps the blood, into
which the fresh air has been moved, throughout
the body.
• 4. Internal Respiration
The cells of your body remove air from your red
blood cell and move the carbon dioxide into them.
 5. Cellular Respiration
The process by which cells obtain energy from
food.


External Respiration
 During the trip that air takes
through the conducting zone, it is
humidified, cleaned, and warmed
so that it does not harm any of
delicate organs that it passes
through. When the air finally
reaches the alveoli, it is closer to
the air in the tropics, which is the
kind of air that your lungs prefer.


 Gas exchange in an alveolus takes place
by diffusion across the moist membrane
of the alveolus and the capillary walls.
About 18% to 20% of the air is oxygen,
which is a much higher concentration of
oxygen than that found in the blood. Due
to these differences in concentration, the
oxygen diffuses from the alveoli to the
blood in the capillaries. At the same time,
waste carbon dioxide diffuses from the
blood into the alveoli due to a higher
concentration of carbon dioxide in the
blood than in the air in the alveoli.


 Gas exchange in an alveolus takes
place by diffusion across the moist
membrane of the alveolus and the
capillary walls. About 18% to 20% of the
air is oxygen, which is a much higher
concentration of oxygen than that found in
the blood. Due to these differences in
concentration, the oxygen diffuses from
the alveoli to the blood in the
capillaries. At the same time, waste
carbon dioxide diffuses from the blood
into the alveoli due to a higher
concentration of carbon dioxide in the
blood than in the air in the alveoli.


Internal Respiration
 As the oxygen laden blood
passes through the body into the
capillaries adjacent to the body
cells, the reverse action takes
place. This process is called
internal respiration.
 Because of the oxidation of food
nutrients constantly going on
within the cells (cellular
respiration), the cells' supply of
oxygen is quickly depleted while
the by-product of food oxidation,
carbon dioxide, builds up.


Internal Respiration
 This condition causes the oxygen to
diffuse from the bloodstream into the
cells, while the carbon dioxide leaves
the cells and enters the bloodstream.
 Oxygen must constantly be
replenished in the body cells through
the respiratory and circulatory
systems as it cannot be stored by the
body. Oxygen is absolutely essential
in the cells, where it combines with
food molecules, producing the energy
needed to maintain the body
functions.


Internal
Respiration
& External
Respiration


Cellular Respiration
 Cellular Respiration or aerobic
respiration involves the use of oxygen
to break down glucose and produce
energy in the cell. This process
occurs in the mitochondria of cells.
Cellular respiration is a series of
chemical reactions that converts the
chemical energy of foods into energy
that can be used by cells (ATP).
Carbohydrates, usually in the form of
glucose, are the most useable source
of energy.


Cellular Respiration
 The Chemical Equation for Cellular Respiration:

C6H12O6 + 6O2 ----> 6H2O + 6CO2 + Energy (ATP)
Glucose Oxygen Water Carbon Dioxide


Structures of the Respiratory System


Meet the Lung!


The Conducting Zone
The subsystem that removes carbon dioxide from
the lungs and moves in fresh air from outside is
made up of the:
• nasal cavity (nose )
• the pharynx
• the larynx
• the trachea
• the bronchi (and all the
smaller branches of the
bronchi)


The Respiration Zone
This subsystem consists of:
the bronchioles (not the large bronchi)
the alveolar ducts
air sacs, or alveoli
(all of which basically make up the lungs.
This is where the oxygen and carbon dioxide
are exchanged)


Nasal Cavity
 The nose is the first and last organ that
air passes through.
 The nasal cavity is separated from the
oral cavity by the hard palate.
 Turbinate bones extend into the nasal
cavity - which increases the surface area
in the nose.
 As part of the conducting zone, it cleans
the air of dust and other impurities,
warms the air if it is too cool, and
moistens the air if it is dry.
 Cilia help trap dust and dirt.
 Moisture is supplied from secretions of
the epithelial tissue.


Pharynx
 The pharynx, most commonly
known as the throat, serves duel
purposes. Not only does it move
the air into your lungs, but it also
moves food into your stomach.
 The pharynx is separated into
distinct regions, chosen by location
and function: the nasopharynx and
the oropharynx.


Pharynx


Pharynx
The nasopharynx is located above
the part of the pharynx that food
enters and as a result must be
blocked when swallowing to prevent
food from entering.
The nasopharnyx is covered with
ciliated epithelial cells that trap dust.
They contain the tonsils and
adenoids.
The oropharynx lies behind the
mouth cavity and is a passageway
for both food and air.


Larynx

 Also known as the voice box, the larynx
is what allows you to speak. It is made
up of cartilage; thyroid cartilage, epiglottis
and glottis.
 The larynx is located at the opening of
the respiratory passageway.
 The larynx has an inlet at the top that
allows substances to pass through it or
not. When food is being swallowed, the
inlet is closed, forcing food into the
stomach. When air is being breathed, the
inlet is wide open so that air can enter
your lungs.


Pharynx &
Larynx


Trachea
 The trachea, or windpipe
connects the larynx to the
bronchi.
 The trachea is made up of
between 16 and 20 cartilage
rings in the shape of a "C".
 The trachea is made up of
smooth muscle.
 The trachea is lined with mucous
and cilia that help carry any
foreign substances up to be
swallowed.


Bronchi
 The trachea branches off into
two main bronchi, your left
and right primary bronchi,
which lead to the left and right
lung respectively.
 Each bronchi enters its lung
and begins on a series of
branches, called the bronchial
or respiratory tree.
 The final branches are called
the terminal bronchioles.


Alveolar Ducts and Alveoli
 Respiration begins when the
terminal bronchioles lead into
the respiratory bronchioles.
 These bronchioles are
covered with thin-skinned air
sacs that allow for gasses to
pass through them. These
sacs, which contain alveoli,
are called alveolar sacs, and
are at the end of alveolar
ducts.


Alveolar Ducts and Alveoli

 The alveoli are covered in
inter linking capillaries
through which blood flows.
 Your lungs rely simply on
diffusion to exchange the
gasses, and that moves
enough gas to have a steady
supply of oxygen in your
body.


Pleura
 The Pleurae is a thin, double-layered
tissue which lines the walls of the lungs
and heart.
 The outer membrane is called the
parietal pleura and it lines the inner
surface of the chest wall and covers the
diaphragm.
 The pulmonary pleura adheres to the
lungs.
 The intrapleural fluid separates the two
membranes.
 The pleura help isolate each lung and
act as a lubricant, reducing friction.


Pleura


Mechanics of Breathing


 Breathing consists of two phases,
inspiration and expiration.
 During inspiration, the diaphragm
and the intercostal muscles
contract. The diaphragm moves
downwards increasing the volume
of the thoracic (chest) cavity, and
the intercostal muscles pull the
ribs up expanding the rib cage and
further increasing this volume.


 This increase of volume lowers the
air pressure in the alveoli to below
atmospheric pressure. Because air
always flows from a region of high
pressure to a region of lower
pressure, it rushes in through the
respiratory tract and into the alveoli.
 During expiration the diaphragm and
intercostal muscles relax. This
returns the thoracic cavity to it's
original volume, increasing the air
pressure in the lungs, and forcing
the air out.

air air

rib cage rib cage

Rib cage moves Rib cage moves
up and out. down and in.

external internal
intercostal muscles intercostal muscles

Diaphragm contracts Diaphragm relaxes
and moves down. and moves up.

Pressure in lungs Pressure in lungs
decreases, and air increases, and air is
comes rushing in. pushed out.

pleural
membranes

a. Inspiration diaphragm b. Expiration diaphragm

air

rib cage

Rib cage moves
up and out.

external
intercostal muscles

air

rib cage

Rib cage moves
up and out.

external
intercostal muscles

Diaphragm contracts
and moves down.

air

rib cage

Rib cage moves
up and out.

external
intercostal muscles

Diaphragm contracts
and moves down.

Pressure in lungs
decreases, and air
comes rushing in.

pleural
membranes

a. Inspiration diaphragm

air air

rib cage rib cage


external internal

Diaphragm contracts
and moves down.

Pressure in lungs
decreases, and air
comes rushing in.

pleural
membranes


air air

rib cage rib cage


external internal

Diaphragm contracts Diaphragm relaxes
and moves down. and moves up.

Pressure in lungs
decreases, and air
comes rushing in.

pleural
membranes



Respiratory Volumes
• There are totally about 700 million
alveoli in the two lungs of an adult
human being. This increases the
surface area enormously. The total
surface area of the lungs is 70
square metres which is almost the
size of the tennis court. It is nearly
100 times the surface of the human
body (skin). Thus, the lungs can
hold a lot of air, about 6000 ml. This
lung capacity is defined as the
maximum air which can be held in
the two lungs at any given time.


Vital capacity


Respiratory Volumes
• Tidal volume
• Amount of air moving in and out
with each breath
• Average is 500 ml
• Vital capacity
• Maximum volume moved in and
moved out in a breath
• Illness can affect vital capacity
• Inspiratory reserve volume
• Forced inhalation
• Amount of air brought in above
tidal volume
• Normally about 2,900 ml


Respiratory Volumes
• Expiratory reserve volume
• Forced exhalation
• Air exhaled beyond tidal volume
• Residual volume
• Amount of air always remaining in
lungs
• Not useful for gas exchange
• Oxygen depleted
• The vital capacity is tidal volume +
inspiratory reserve volume + expiratory
reserve volume


Regulation of Breathing

 Breathing movements are
controlled by the diaphragm and
intercostal muscles. These
muscles are stimulated by nerve
impulses from the brain. This
system of brain, nerves, lungs,
and muscles constitutes one of
the many negative feedback
mechanisms that maintain
homeostasis in the human body.



 The respiratory center is located
in the medulla oblongata of the
brain (located at the back of the
brain). The medulla is connected
to the respiratory muscles
(diaphragm and intercostal
muscles) by motor neurons. A set
of sensory neurons conducts
impulses from the lungs to the
respiratory center.


 During inspiration, the respiratory
center sends a nervous impulse to
the respiratory muscles that
causes them to contract. This
inflates the lungs.
 The expansion of the lungs
initiates impulses in the sensory
neurons that extend from the
lungs to the brain. These impulses
inhibit the breathing center, which
then ceases to send impulses to
the respiratory muscles.


 No longer stimulated, these
muscles relax, and the lungs
deflate in an expiration. The
deflated lungs stop stimulating the
sensory neurons which then stop
sending impulses to the
respiratory center of the brain.
 No longer inhibited, the respiratory
center once again sends out
nerve impulses that stimulate the
respiratory muscles, and the
process repeats.


Control of Breathing Rate
 Normal breathing usually supplies
enough oxygen to meet the body’s
needs and removes carbon dioxide
as fast as it is formed.
 Occasionally, however, carbon
dioxide may begin to accumulate in
the blood or oxygen concentration
may fall -- two changes that often
occur simultaneously. Either of
these conditions increases the rate
and/or the depth of breathing.


 It should be noted that the body
is more sensitive to the carbon
dioxide concentration in the
blood than to the oxygen
concentration.


 Recall, breathing rate is mainly
controlled by the respiratory
center in the brain. The
respiratory centre monitors the
carbon dioxide level in the blood.
 Oxygen levels are monitored by
chemoreceptors in the aorta and
the carotid arteries.


 When carbon dioxide is dissolved in the blood, it
reacts with water to form carbonic acid, which
then ionizes to form a bicarbonate ion and a
hydrogen ion:

CO2 + H2O → H2CO3

H2CO3 → HCO3- + H+


 As more carbon dioxide enters the
blood, the hydrogen ion
concentration rises. The high
concentration of hydrogen ions
rather than the dissolved carbon
dioxide gas stimulates breathing.
 The high hydrogen ion
concentration in the blood
stimulates the respiratory center in
the brain, which then sends
impulses to the respiratory muscles
and the breathing rate is increased.


 Neurons with endings
(chemoreceptors) in the aorta and
the carotid arteries are sensitive to
oxygen concentration. These
neurons monitor the blood
continuously, and when the oxygen
concentration begins to fall, they
also stimulate the respiratory
center in the brain.


Respiratory Diaphragm and
Center intercostal
muscles
contract

Blood pH Breathing rate
is lowered increases and
CO2 is released

Exercise

Blood pH
returns to
normal


Respiratory
Disorders


What is Asthma?
• Asthma is a chronic lung condition. It
is characterized by difficulty in
breathing. People with asthma have
extra sensitive or hyper responsive
airways. The airways react by
narrowing or obstructing when they
become irritated. This makes it
difficult for the air to move in and out.
This narrowing or obstruction can
cause one or a combination of
wheezing, coughing, shortness of
breath, chest tightness


What is Asthma?


Factors Provoking Asthma?
• This narrowing or obstruction is
caused by airway inflammation
(meaning that the airways in the
lungs become red, swollen and
narrow) and bronchoconstriction
(meaning that the muscles that
encircle the airways tighten or go
into spasm)
• Two factors provoke asthma:
a) Triggers
b) Causes or Inducers


Triggers
• Triggers irritate the airways and result in
bronchoconstriction although they do not
cause inflammation and therefore do not
cause asthma. The symptoms and
bronchoconstriction caused by triggers
tend to be immediate, short-lived, and
rapidly reversible. The airways will react
more quickly to triggers if inflammation
is already present in the airways.
• Common triggers of bronchoconstriction
include everyday stimuli such as:
cold air, dust, strong fumes, exercise,
inhaled irritants, emotional upsets,
and smoke.


Inducers
• In contrast to triggers, inducers cause
both airway inflammation and airway
hyper responsiveness and are
recognized as causes of asthma.
Inducers result in symptoms which
may last longer, are delayed and less
easily reversible than those caused by
triggers.
• The most common inducers are
allergens and respiratory viral
infections.
• Allergens
• Respiratory Viral Infections


Diagnosing Asthma
• Making a correct diagnosis is
extremely important: if asthma is
correctly diagnosed it can be
treated appropriately.
• The diagnosis of asthma involves
the following:
• Detailed history
• Physical examination


Managing Asthma
• The consensus of asthma
specialists is that the best way to
manage asthma is to have the
individual actively involved in his or
her own treatment.
• This includes:
• Education
• Environmental Control
• Medications


What is pneumonia?
• Pneumonia is an inflammation of the
lungs caused by bacteria, viruses, or
chemical irritants.
• It is a serious infection or
inflammation in which the air sacs fill
with pus and other liquid.


Symptoms of Pneumonia
• shaking chills
• chattering teeth
• severe chest pain
• cough that produces rust-colored or
greenish mucus
• high temperature
• heavy perspiring
• rapid pulse
• rapid breathing
• bluish color to lips and nailbeds
• confused mental state or delirium


Treatment for Pneumonia
• Treatment may include antibiotics
for bacterial pneumonia.
• There is no clearly effective
treatment for viral pneumonia, which
usually heals on its own.
• Other treatment may include
appropriate diet, oxygen therapy,
pain medication, and medication for
cough.


What is chronic bronchitis?
• Chronic bronchitis is a long-term
inflammation of the bronchi, which
results in increased production of
mucous, as well as other other
changes.
• To be classified as chronic bronchitis:
cough and expectoration must occur
most days for at least three months per
year, for two years in a row.
• In acute bronchitis, bacteria or viruses
may be the cause, but in chronic
bronchitis there is no specific organism
recognized as the cause of the
disease.


Symptoms of Chronic Bronchitis
• Symptoms may include:
• cough
• expectoration (spitting out) of
mucus
• frequent and severe respiratory
infections
• narrowing and plugging of the
breathing tubes (bronchi)
• difficult breathing


Treatment for chronic bronchitis

• oral medications
• bronchodilators for inhaled
medications
• oxygen supplementation from
portable containers
• lung reduction surgery to remove
damaged area of lung
• lung transplantation


What is Emphysema?
• Emphysema is a chronic lung condition
in which alveoli, or air sacs, may be:
destroyed, narrowed, collapsed,
stretched, over-inflated
• Emphysema occurs when a breakdown
in the chemical balance that protects
the lungs against the destruction of the
elastic fibers occurs.
• There are a number of reasons for the
breakdown in chemical balance:
smoking, exposure to air pollution,
irritating fumes and dusts on the job


What is Emphysema?


Symptoms of Emphysema
• Early symptoms of pulmonary
emphysema may include:
shortness of breath
cough
• Other symptoms may include:
fatigue
anxiety
sleep problems
heart problems
weight loss
depression


Treatment for Emphysema:
• The goal of treatment for people with pulmonary
emphysema is to live more comfortably with the
disease by providing relief of symptoms and
preventing progression of the disease with a
minimum of side effects. Treatment may
include:
• quitting smoking - the single most important factor
for maintaining healthy lungs
• antibiotics for bacterial infections
• oral medications
• bronchodilators and other inhaled medications
• exercise
• oxygen supplementation from portable containers
• lung reduction surgery to remove damaged area
of the lung
• lung transplantation


What is lung cancer?
• Lung cancer is cancer that usually
starts in the lining of the bronchi, but
can also begin in other areas of the
respiratory system, including the
trachea, bronchioles, or alveoli.


Symptoms of lung cancer:
• Lung cancer usually does not cause
symptoms when it first develops, but they
often become present after the tumor
begins growing. A cough is the most
common symptom of lung cancer. Other
symptoms include:
• constant chest pain
• shortness of breath
• wheezing
• recurring lung infections, such as
pneumonia or bronchitis
• hoarseness
• fever for unknown reason


Treatment for lung cancer:
• Surgery, radiation therapy, and
chemotherapy may be used in the
treatment of lung cancer.


Normal lung versus cancerous lung


Gas Exchange in the Lungs

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