Download The Respiratory System

The Respiratory System
Function of the Respiratory System
2 Functions:
 To move oxygen from the outside environment into the
body
 To remove carbon dioxide and water from the body
 Q: Why do we need oxygen?
 Answer: because every cell in your body needs oxygen
for cellular respiration
 Q: Why do we need to get rid of carbon dioxide?
 Answer: If carbon dioxide builds up in cells, they can’t
perform their functions
The Path of Air - Organs Involved
Mouth & Nose
Pharynx
larynx
Vocal cords
trachea
The Path of Air - Organs Involved
(continued)
bronchi
bronchioles
alveoli
“Respiration” vs. “Breathing”
BREATHING
Refers to the
movement of air
into and out of the
lungs
RESPIRATION
Refers to the chemical
reactions inside the
cells. Also known
as “cellular
respiration”
The Nose

Air enters through nostrils where the following
functions are performed:
 Air
is warmed- blood vessels line the nasal cavities
and the warm blood warms the air.
 Air is filtered - hairs and sticky mucus trap dirt and
dust
 Mucus
is then swept by the CILIA into the throat so you can
swallow it.
 Air
is moistened – mucus also adds moisture to the air
along with goblet cells
The Pharynx



Air enters here from
nasal cavities
ONLY part of
respiratory system that
is shared with another
system…the digestive
system.
Epiglottis – prevents
food from entering
trachea
The Larynx

Houses the VOCAL
CORDS – flaps of
tissue that vibrate and
produce sound

https://www.youtube.com/watch?v=
D6mLc9gOgVA
The Trachea






Also called the “windpipe”
Can feel it if you run your fingers gently down
center of neck
Lined with mucus which continues to moisten the air
Lined with cilia which sweep the mucus up into the
trachea where it goes to stomach
When trachea is irritated, you cough which sends
particles out of body
Sealed by epiglottis when you swallow food
How do the cilia and goblet cells
function?




They they line the respiratory tract and move in
waves to sweep particles up and out of the
respiratory tract.
https://www.youtube.com/watch?v=Uvs5cOJYw7U
&list=PL-A8SZnIEPDFp32rDpgrriYP1u08miZJH
Goblet cells also line the respiratory tract along
with the cilia. Goblet cells secret mucus to moisten
the air.
https://www.youtube.com/watch?v=miEEluVlemQ
Bronchi and Lungs




Lungs – main organs of the respiratory system
Bronchi are the passages that direct air into the
lungs (single: bronchus)
Inside lungs, bronchi divide into smaller and smaller
tubes like branches of a tree
Alveoli – at the end of the smallest tubes.
Specialized lung tissue for movement of gases
between air and blood. Each alveolus is surrounded
by capillaries where gas exchange takes place.
Gas Exchange


After air enters an alveolus, oxygen passes through
the wall of the alveolus and then through the
capillary wall into the blood.
Carbon dioxide and water pass from the blood
into the alveoli
Page 561, Fig. 2






Q: What do the red and blue lines surrounding the
alveoli in the second picture represent?
A: Those are capillaries – tiny blood vessels that carry
oxygen AWAY from the lungs and carbon dioxide TO the
lungs
How thick are the walls of the alveoli and the
capillaries?
A: They are only one cell thick
Q: What is leaving the alveoli and entering the
blood?
A: oxygen
Page 561, Fig. 2 (continued)




Q: What is leaving the blood and entering the
alveoli?
A: carbon dioxide
Q: Through what process are these gasses
“exchanging?”
A: Diffusion – The gases are moving from areas
where they are highly concentrated to areas where
they have low concentrations.
How does gas exchange work?

https://www.youtube.com/watch?v=AJpur6XUiq4

https://www.youtube.com/watch?v=5LjLFrmKTSA
Understand inhalation and
exhalation



To understand how these two things happen, you
must understand 2 things:
1. Because air is a GAS, it behaves according to
Boyle’s law of gases
2. Gases always move from areas of high
pressure to areas of low pressure
BOYLE’S LAW OF GASES

With GASES, there is an INVERSE RELATIONSHIP
between VOLUME AND PRESSURE (as one goes up, the other
goes down)






As VOLUME INCREASES gas PRESSURE DECREASES
As VOLUME DECREASES gas PRESSURE INCREASES
Q: When the volume inside the chest cavity INCREASES
what happens to air pressure inside the chest cavity?
A: Because VOLUME INCREASES, PRESSURE DECREASES
Q: When the volume inside the chest cavity DECREASES,
what happens to air pressure inside the chest cavity?
A: Because VOLUME DECREASES, PRESSURE INCREASES
How does the volume of the chest
cavity increase or decrease?




VOLUME INCREASES:
1. diaphragm contracts
and MOVES DOWN
2. Intercostal muscles
contract and move rib
cage up and out
(this increase in volume
causes the air pressure in
the chest cavity to decrease
so higher pressure in the
outside environment moves
into the lungs)




VOLUME DECREASES:
1. diaphragm relaxes
and MOVES BACK UP
2. intercostal muscles
relax and rib cage moves
down and back in
(this decrease in volume
causes the air pressure in
the chest cavity to increase
so higher pressure air in the
lungs moves out into the
outside environment)