Respiratory System
By Ben K, Sam W, and Aaron W
Getting to the lungs
The diaphragm is a sheet of muscle that runs below
the rib cage and is the main muscle in the respiration
process.
● When it contracts it increases the volume of the
chest cavity, decreasing the pressure, and due to
the pressure gradient air is drawn into the lungs(1).
The sinuses are hollow spaces in
the bones of the head and they
help regulate the temperature and
humidity of air breathed in. Small
openings connect them to the
nose.
● There are two entrances for the air to enter
your body. The nose and the mouth. The
nose is preferred as the hairs with in it help
clean the air.
Getting to the lungs cont.
● After the air enters through the mouth and or nose
it is travels down the Larynx, and into the
Trachea, otherwise known as the windpipe.
● The Trachea is the passage leading from the
larynx to the lungs, like the Larynx it too is made of
cartilage.
● The trachea then divides into the right and left
BRONCHIAL TUBE (or Bronchus), one for each
lung,
● These bronchial tubes are lined with cilia that carry
mucus upward into the throat.
Asthma actually causes the
airways of the throat and
trachea to swell up and become
more narrow; this is why
asthmatics often suffer from
wheezing, shortness of breath,
chest tightness, and coughing.
(3)
The Lungs:
The Bronchial Tubes divide into the lobes of the lung.
The left lung is
slightly smaller as
it has the
“Cardiac notch”
which allows
room in your
chest for the
heart.
The right lung is divided into three lobes, or sections. The
(barely) smaller left lung is divided into only two lobes.
Inside the lungs, the Bronchial Tubes divide further and
further, branching out in the lungs
The smallest component of bronchial tubes are called
Bronchioles,
At the end of each bronchiole are a group of Alveoli,
microscopic air sacs.
Alveoli are where the actual gas exchange takes place. (2)
Gas Exchange:
Gas Exchange in the respiratory system is the diffusion of
oxygen and Carbon Dioxide in opposite directions across a
membrane.
Gas Exchange is simple (non-facilitated) diffusion across a membrane, and
thus a pressure (concentration) gradient drives it.
Most of the Gas Exchange in the body occurs in the in the lungs, and takes
place between the Alveoli and the Capillaries which surround them.
The (O2) hypertonic air inside the alveoli diffuses
That is why things like smoking, which
can gradually damage the alveolar, lead to
Oxygen molecules into the hypotonic blood cells
shortness of breath because less space
for oxygen diffusion into the blood means
While the (CO2) hypertonic blood cells diffuse
oxygen is needed more rapidly to fuel the
body.
Alveoli:
The alveoli have a structure specialised for efficient
gas exchange:
● Alveoli have thin walls which allow gas to easily diffuse
across them.
There are about
600 million alveoli
● They are spherically in order to maximize surface area and
thus maximize the available space for gas exchange.
in your lungs and if
● The alveoli share a membrane with the capillaries
surrounding it, allowing the Oxygen in the Alveoli to and the
Carbon DIoxide in the Blood cells to easily diffuse into one
another.
out, they would
● These membranes are also fluid lined, allowing gas to
dissolve making it easier for it to diffuse across the
you stretched them
cover an entire
tennis court.
Main Components of Blood
● Platelets- Fragments of cytoplasm who stop bleeding by causing clots.
● White Blood Cells- Cells of the immune system
● Red Blood Cells- The component specifically related to gas exchange,
they carry oxygen and carbon dioxide across the body.
Main Components of Red Blood Cells
● Haemoglobin is the thing in red blood
cells that the Oxygen molecules and
carbon Dioxide molecules bind to.
● The reaction that binds Oxygen and
Carbon Dioxide to the Haemoglobin is
catalysed by the carbonic anhydrase
enzyme in red blood cells. (4)
A red blood cell can make a
complete circuit of your body
in 30 seconds!
(Dailymail.co.uk)
Relation to Circulatory System
Gas Exchange Diagram
There are 10 billion
capillaries in your body!
The largest capillary is
just 0.2 mm wide —
thinner than a hair!
● Capillaries, part of the circulatory system
are so narrow that they force blood cells to
line up single file, making it easier for the
Oxygen in the Alveoli to diffuse into each red
blood cell, and the Carbon Dioxide to diffuse
out of each red blood cell.
● Once the red blood cells gain oxygen and
lose carbon dioxide while in the lungs they
become oxygen rich. They then travels
through the circulatory system throughout
the entire body (4)
References
1. "The Respiratory System." Body by Design. Gale, 2007. Science in Context. Web. 17 Nov. 2014.
2. "Lungs." World of Anatomy and Physiology. Gale, 2007. Science in Context. Web. 17 Nov. 2014.
3. "Respiratory diseases." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda
Wilmoth Lerner. 5th ed. Farmington Hills, MI: Gale, 2014. Science in Context. Web. 17 Nov.
2014.
4. “Circulatory system." World of Anatomy and Physiology. Gale, 2002. Science in Context. Web.
17 Nov. 2014.