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Mr. Vallee’s
Student Handout for the Respiratory System
http://www.brainpop.com
http://www.innerbody.com/anim/lungs.html
I. The Respiratory System is the process of taking in oxygen and giving off
carbon dioxide. It includes the lungs, the pathways connecting the lungs to
the outside environment, and structures in the chest involved with moving
air in and out of the lungs.
A. How we breathe/Journey to the Lungs:
1. Air enters the nose or mouth and travels down the trachea. Tiny hairs
line the inside of the nose.
2. At the end of the trachea (windpipe), there are two branching tunnels,
each leads to one of the two lungs.
3. These tunnels are called bronchial tubes, and these tubes are further
divided into even smaller tunnels. These tunnels look like upside
down trees.
4. These upside down trees are called the “bronchial tree”. The trunk of
the tree is called the trachea and the main branches are called
bronchial tubes. The smaller branches or twigs are called
bronchioles. The smallest twigs of the bronchial tree end inside the
lungs.
B. Inside the lungs:
1. At the end of the bronchial tube is a spongy lung tissue made of
many sacs filled with air. The walls of the sacs are very thin.
2. Filled with air tubes, air sacs, and blood vessels.
3. Air tubes and blood vessels in the lungs divide until they are very
small.
4. Alveoli – air sacs at the end of tiny tubes in the lungs, surrounded
by capillaries. Puts oxygen into the blood and takes carbon dioxide
out. Walls of alveoli have capillaries where the exchange of
oxygen and carbon dioxide takes place. When you exhale, you
breath out air containing carbon dioxide.
C. Outside of the lungs:
1. Lungs are located in a large chest cavity called the thorax
2. The sides are made of thick bands of muscle/bone called
ribs/protect you from injury.
3. When you breath, the walls of the thorax move in and out
4. At the bottom of the thorax is another wall of muscle –
diaphragm, which separates the chest cavity from the abdominal
cavity.
5. One lung is on right side, one is on the left.
6. Lungs look different. Right one has 3 divisions/lobes. Left one has
2 divisions/lobes.
D. Lungs (An Overview)
Air, which is inhaled through the mouth and nasal passages, travels
through the windpipe or "trachea" into two main air passages. These
divide into smaller branches, which separate into even smaller "twigs"
like an upside-down tree.
1. The little air sacs at the end of the twigs comprise the fruit of the tree,
and through its thin walls gasses pass into and out of the blood.
2. The respiratory system is mainly contained in two lungs.
3. The right lung is made up of three compartments, each of which contain a
branch and each of which stems off into smaller "twigs," which hold the air
sacs (or "fruit" of the tree) that process the oxygen in the air to be released
into the blood and expel carbon dioxide, which is exhaled through the nose
and mouth.
4. The left lung cavity contains only two sections (each with its own
branches, twigs and fruit) and encloses the heart, which processes the
oxygenated blood and returns deoxygenated blood into the lungs for
exhalation.
5. Breathing is an automatic process which comes from the brain stem and is
so strong a force that the involuntary reflexes will not allow us to stop
breathing for any length of time. The passageways in the respiratory system
are lined with various types of epithelia to prepare the air properly for
utilization and with hair-like fibers called cilia that move in a wave-like
motion to sweep debris out of the lungs for expulsion.
Air enters the body through the nose, is warmed, filtered, and passed through
the nasal cavity. Air passes the pharynx (which has the epiglottis that
prevents food from entering the trachea). The upper part of the trachea
contains the larynx. The vocal cords are two bands of tissue that extend
across the opening of the larynx. After passing the larynx, the air moves into
the bronchi that carry air in and out of the lungs.