Download Unit Notes on The Respiratory System

Biology 11 - Ms. Bowie
The Respiratory System
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The
Respiratory
System
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Biology 11 - Ms. Bowie
The Respiratory System
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The Respiratory System
What is does:
The job of your respiratory system is very simple: To bring oxygen into your body, and remove the
carbon dioxide from your body. Your body needs oxygen to survive.
Why does your body need oxygen?
Oxygen is used by your cells as it carries out the functions of life. As your body uses oxygen, your
cells produce another gas known as carbon dioxide. Too much carbon dioxide can be toxic, even
deadly. For this reason, it is important that your body have a way to get rid of it.
What are the parts of the respiratory system?
The main organs in your
respiratory system are your
lungs. As you breathe in, you fill
the lungs with fresh oxygen-rich
air. Your heart pumps blood into
the walls of your lungs where it
absorbs oxygen and releases
carbon dioxide. As you exhale, or
breathe out, you release the
carbon dioxide-rich air into the
space around you. With each
breath, you are taking oxygen in,
and putting carbon dioxide out.
From your lungs, blood returns
back into your heart where it is
pumped out to the rest of your
body, carrying oxygen along with
it.
Biology 11 - Ms. Bowie
The Respiratory System
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Let’s follow a breath of air through the system:
Air enters the respiratory system through the mouth
or nose. Sometimes we call these the oral (mouth)
and nasal (nose) cavities.
The nose has tiny hairs inside it that help catch dirt
and other substances in the air. The mucus (which
we sometimes call “snot”) acts like a glue to catch
the bad stuff in the air. We can then blow our nose
to remove the bad stuff before it makes its way to
our delicate lungs.
The nose also helps to warn the air before it reaches
the lungs. Have you ever noticed that it hurts to
breathe really cold air into your lungs on a very cold
winter day?
The mouth is also another way air can enter the respiratory system. This entrance is much larger
and let’s a lot more air into the system. This is very helpful when you need a lot of air, like when
you are exercising.
Q1.
At night when you are calm and relaxed in bed, do you tend to breathe through your nose
or your mouth? Why do you think you do this?
Q2.
During gym class or a sports activity (like basketball or jogging) do you tend to breathe
through your mouth or nose? Why do you think this is the case?
Try this:
Sit quietly for 5 minutes; try to breathe through your nose. Count how many breaths you make during 1 minute.
Now run in one spot as fast as you can for 2 minutes. Stop and count your breaths for 1 minute. How did your
breathing rate change? How did the method (nose or mouth) of breathing change?
Biology 11 - Ms. Bowie
The Respiratory System
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The air pathway continued
Once the air has entered your body (either by the
mouth or nose), it moves into your throat. The
throat is also known as the pharynx. It travels down
the throat and passes the larynx. The larynx is a
fancy name for your vocal cords. As air passes over
the larynx, it allows us to make sounds and to
speak. It produces the sound of our voice.
The air is then ready to enter into the tube to the
lungs. To get into this tube, the air passes the
epiglottis. The epiglottis is just a flap of skin that
stops food from accidently getting into your lungs.
Have you ever started coughing because “food went
down the wrong way”? This just means that the
epiglottis was open when you tried to swallow your food so a little slipped past into the air way.
Laughing or talking during eating can cause this to happen; another reason why you should not
talk with your mouth full.
Now the air is in your wind pipe, also known as the trachea. The trachea is bumpy. You can feel it
if you rub the front of your neck. It feels a little like a vacuum cleaner hose.
Down in your chest, your trachea splits into two smaller branches that lead to each of your lungs.
These are called the bronchi (bronchus is what we call just one of them). Just like a tree branches,
so do the bronchi. They branch into smaller tubes
called bronchioles.
At the end of the bronchioles are many, many tiny
sacs called alveoli. It is here at the end of the
pathway that oxygen from the air passes into the
blood (held in the tiny blood vessels called
capillaries) and carbon dioxide, a poisonous gas,
passes out of the blood and into the alveoli (of the
lungs) to reverse the path of the air and leave the
body.
The muscle called the diaphragm at the bottom of your rib cage helps to inflate and deflate your
lungs.
Biology 11 - Ms. Bowie
The Respiratory System
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Try this:
Label the diagram of the respiratory system below:
Diaphragm
Trachea
Nose
Left Bronchus
Mouth
Right Lung
Larynx
Right Bronchus
Pharynx
Bronchioles
Alveoli
Vocal cords
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The Respiratory System
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What is cellular respiration?
Cellular respiration is a set of chemical reactions that take place in each and every one of your
trillions of cells in your body. The goal of these reactions is to release the energy that is locked up
in the foods we eat so we can use that energy to do other jobs needed inside our cells.
Oxygen is brought into the body in the respiratory system.
Food, which is broken down into the simplest sugar know as glucose, is brought into the body by
the digestive system.
The circulatory system brings the oxygen and the glucose to each of the cells of the body. Inside
the cells, the oxygen breaks the glucose and releases the stored energy. The energy is captured
in tiny packages, called ATP.
The waste created during that reaction is carbon dioxide and water.
Here is the formula for the reaction:
Glucose + Oxygen → Carbon dioxide + Water + ATP (energy)
Biology 11 - Ms. Bowie
The Respiratory System
Respiratory System
Test your knowledge
Name_________________________________________
Date___________________
1.
Draw a picture of the trachea, bronchi, bronchioles, and lungs below. Label each part clearly.
2.
What round structure is at the end of every bronchiole? What happens there?
3.
People who have asthma sometimes have “asthma attacks”, which means their bronchioles swell up and
close. Why do you think an asthma attack makes it difficult to breathe?
4.
Smoking cigarettes makes your alveoli less elastic (or “stretchy”), so they can’t expand as much.
Explain why people who smoke often may have trouble breathing.
5.
Explain one way that the circulatory system (blood system) is important to the respiratory system.
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Biology 11 - Ms. Bowie
The Respiratory System
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Complete the following sentences about the respiratory system:
1)
Air can enter the respiratory system through your mouth or your n____________________________.
2)
Your nose has tiny h________________________ that help to clean dirt our of the air so it doesn’t get into your
lungs.
3)
Another name for the back of the throat is the p____________________________.
4)
Another name for your vocal cords is your l________________________________.
5)
The e___________________________________ is a flap of skin that helps to keep food out of your wind pipe.
6)
Another name for your windpipe is the t____________________________________.
7)
The t_________________ is a bumpy tube that feels like a vacuum cleaner hose at the front of your neck.
8)
The trachea splits into two b___________________________ which lead to each of your lungs.
9)
At the very end of all the branches in your lungs are tiny sacs called a____________________________.
10)
Oxygen passes out of the alveoli and into the tiny blood vessels called c___________________________.
11) What is the job of the respiratory system?
12) What is cellular respiration? How is it different from breathing?
13) What is the chemical formula for cellular respiration?
Biology 11 - Ms. Bowie
The Respiratory System
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Respiratory System Labelling Test
Name: ________________________________________________
Date: __________________________
Label the following diagram without using your notes. Include the words in the box in your diagram.
Diaphragm
Nose
Mouth
Larynx
Pharynx
Alveoli
Trachea
Left Bronchus
Right Lung
Right Bronchus
Bronchioles
Vocal cords
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9
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The Respiratory System
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To Recap
 Air enters through one of two cavities:
o Nasal Cavity: Air enters, while tiny hairs act as a filter system, preventing the entrance of debris
into the body.
o Oral Cavity: Air also enters here, especially in people who have a mouth breathing habit, or who
have obstructed nasal passages (i.e. from a cold)
 Air then enters into the “throat region”, known as the pharynx.
o The pharynx splits into two tubes:
 The esophagus, which carries food to the stomach
 The epiglottis prevents food from entering the trachea during ingestion
 The trachea (or windpipe), which transports air to the lungs. The trachea is lined in mucus-producing
cells, which catch debris before it enters the lungs
 Debris is swept back up into the pharynx by cilia which line the trachea
 The trachea contains cartilaginous rings that keep it open.
 Air travels from the pharynx into the larynx, also known as the voice box.
o The larynx is located at the upper end of the trachea
 The trachea splits into two bronchi (singular: bronchus), which travel into either the left or right lung.
The bronchi contain cartilaginous rings that keep them open.
 These bronchi further split into smaller airways known as bronchioles.
o The bronchioles do not contain cartilaginous rings, and have rings of smooth muscles in their
walls. If they become obstructed at all (by a disease etc), breathing becomes difficult.
 At the end of the bronchioles are tiny air sacs called alveoli (singular: alveolus). It is here that gas
exchange happens with the circulatory system. The alveoli are adapted for this, as they have thin cell
walls and capillary beds within them. Oxygen and Carbon Dioxide move from areas of higher
concentration to lower concentration. This means that oxygen is enters the blood stream upon
inhaling, and carbon dioxide exits the blood stream, and the body, upon exhaling.
 The diaphragm is the sheet of muscle, separating the chest cavity from the abdominal cavity. It
works to facilitate breathing. During inhaling, the diaphragm muscles contracts, moving downwards,
and allowing for air to enter into the body. During exhalation, the diaphragm relaxes, and helps to
push air out of the lungs.
 The ribcage is the collection of bones that surrounds the chest cavity. This protects the respiratory
system, moving to a limited degree, allowing the lungs to inflate and deflate.