Transcript The Respiratory System

The Respiratory System
continued
The Process of Gas Exchange
• The exchange of oxygen gas
and carbon dioxide gas occurs
at the alveoli. This area has a
rich supply of capillaries that
allow for the exchange of
oxygen and carbon dioxide
between the circulatory
system and the respiratory
system. Air that enters the
bronchial tubes is rich in
oxygen and therefore is
needed by the cells of the
body. The oxygen diffuses
from the alveoli into the
capillary. The capillaries
contain red blood cells that
contain the iron rich protein
hemoglobin.
• Hemoglobin transports
oxygen to the cells of the
body via the blood
vessels. Oxygenated
blood appears red and
deoxygenated blood
appears blue. Carbon
dioxide, produced in the
cells as a waste product,
also binds to hemoglobin
and is transported to the
alveoli for removal.
Carbon dioxide diffuses
out of the blood and into
the alveoli. From there,
the carbon dioxide is
expelled from the body
through exhalation.
The diagram above summarizes the human respiratory system
and the process of internal gas exchange.
Breathing
• Breathing is an involuntary process. The medulla
oblongata, which is located in the brain, ultimately
controls the breathing rate.
• You can alter your breathing rate by temporarily
holding your breath or breathing faster. However,
your brain will ultimately take over the process if the
body becomes stressed.
• Breathing is a physical
process of inhaling air
that will move from an
area of high pressure to
an area of low pressure.
• There are two main
muscles that are
involved in breathing,
the intercostal muscles
of the rib cage and the
diaphragm.
• The diaphragm is a thin
layer that separates the
lungs from the stomach.
• The next diagram illustrates the physical process of
inhalation and exhalation.
• In inhalation, the intercostal muscles contract and force
the chest cavity to move out and up.
• At the same time the diaphragm contracts and moves
downward.
• This movement increases the volume of the chest cavity.
• As a result, the internal pressure of the lungs decreases
and air moves into the lungs.
• In exhalation, the intercostal muscles relax and the chest
cavity moves down and inwards.
• The diaphragm relaxes and moves upwards.
• The volume of the chest cavity decreases. The internal
pressure of the lungs increases and air moves out.
Try this at home!
• http://athome.harvard.edu/programs/hse/vid
eo/hse2_5_frame.html?module
• Many factors can influence the breathing rate.
These include air quality, altitude, pulmonary
diseases and medications.
• When the breathing rate is altered, the level of
oxygen and carbon dioxide within the body may
fluctuate from normal levels.
• The flow chart (next slide) illustrates the negative
feedback loop that is used to regulate the
concentration of oxygen and carbon dioxide gas.
• You may be surprised to learn that carbon dioxide
plays a bigger role in regulating the breathing rate
than oxygen.
• When oxygen levels are lowered, the body will
immediately increase the breathing rate to
increase the amount of oxygen available to
the cells.
• In addition, the body will also increase the
production of red blood cells.
• Remember, it is hemoglobin found within red
blood cells that transports both oxygen and
carbon dioxide throughout the body.
Breathing Animation
• http://www.nhlbi.nih.gov/health/dci/Diseases
/hlw/hlw_when.html
Questions
1. How does exercise affect the breathing rate?
2. The XIX Olympic Games were held in Mexico City amongst
much opposition because of its high altitude. The air in
Mexico City contains 30% less oxygen than at sea level.
(a) What effects may an athlete feel when arriving in
Mexico City?
(b) What advice would you give to an athlete who is
competing at a higher altitude?
(c) Is there any benefit to training at a higher altitude
prior to a competition at sea level?
Answers
1. When a person exercises, they require energy in
the form of ATP. ATP is generated through the
process of cellular respiration. Cellular
respiration involves the breakdown of glucose in
the presence of oxygen. One of the products
produced is carbon dioxide. An increase in
cellular respiration increases the amount of ATP
available and also increases the concentration of
carbon dioxide in the blood. Therefore, an
increase in carbon dioxide will trigger the body
to increase the breathing rate.
2. (a) An athlete may feel tired, light headed, nausea, and
shortness of breath.
(b) An athlete who will perform at high altitudes should
arrive a couple of weeks prior to their competition. This will
allow the body to adjust to the low levels of oxygen and
produce more red blood cells. A diet rich in protein or an
iron supplement will help the body construct the protein
hemoglobin needed to transport oxygen gas.
(c) Being at high altitudes causes your body to produce
more red blood cells. More red blood cells will increase the
delivery of oxygen to the cells. This will increase the rate of
cellular respiration and therefore provide the cells of the
body with more energy (ATP). However, once the athlete
returns to sea level, the body will adjust and the red blood
cells production will decrease.
Task
• All living things must be able to acquire oxygen from their
external environment and eliminate carbon dioxide waste
produced during cellular respiration. However, the
respiratory systems of animals vary greatly. Some animals
use diffusion while others require a system that is
composed of specialized organs, tissues and cells.
• Research the respiratory systems of the following
organisms. Describe and explain how each respiratory
system meets the needs for the specific organism. You may
include illustrations or images in your explanations.
• Bacteria
• Grasshopper
• Earthworm
• Fish