The document discusses the respiratory and digestive systems and their roles in obtaining energy from nutrients. The respiratory system works with the digestive system to transform nutrients into energy. It obtains oxygen needed for cellular respiration to release energy from nutrients and expels the resulting carbon dioxide waste. The respiratory system consists of the airways and lungs. In the lungs, gas exchange occurs via diffusion - oxygen diffuses from the alveoli into the blood while carbon dioxide diffuses from the blood into the alveoli to be exhaled.

1. THE NUTRITION FUNCTION I.
The respiratory system.

2. Obtaining energy.
We have just studied the DIGESTIVE SYSTEM.
Its function is to get nutrients from food.
To transform NUTRIENTS INTO ENERGY, in the
mitochondria, our cells NEED OXYGEN.
These molecules are essential for cellular
respiration: the process through we obtain
energy.

3. Expeling waste substances.
In respiration, oxygen is consumed to
release energy (ATP) from nutrients,
and carbon dioxide is produced.
The respiratory system is also in charge
of expelling that carbon dioxide that we
don’t need.

4. Parts of the respiratory system
https://www.youtube.com/
watch?v=hc1YtXc_84A

5. Parts of the respiratory system.
Our respiratory systems consists on:
 The AIRWAYS or RESPIRATORY TRACT: The air
passes through this tube or pipe. They are:
 Nasal cavity
 Pharynx (shared with digestive system)
 Larynx
 Trachea
 Bronchi
 Bronchioles
 The LUNGS: Organs that contain bronchi,
bronchioles, pulmonary alveoles and capillaries.

6. Transport and modification of
air.
 Nasal cavity: In here air is
 Filtered by cilia and mucus. The nasal cavity is
covered with a respiratory mucosa lined with a
ciliated columnar epithelium.
 Warmed by capillaries in that tissue.
 Moistened.
Is in this part of our body where sense of smell
resides.
 Pharynx: Tract shared with digestive system.
Communicates nasal and oral cavity. Here we
find tonsils, that produce white blood cells.

7.  Larynx. Separated from the oesophagus by the
epiglottis. Here we find the vocal cords.

9.  Trachea. Tube surrounded by rings of cartilage that
keep it open. It is also covered by mucus, that traps
foreign particles, and force them out.

10. Mechanics of breathing.
Inspiration and expiration.
https://www.youtube.com/watch?v=SWJHSTAWTC
k
Lungs model. Pulmonary ventilation.
https://www.youtube.com/watch?v=DAR9Ne57Cl4

11. Inside the lungs.
Lungs are formed by lobes. The right one is formed by
3 lobes, and the left one by two. As we have our
heart is pointed slightly to the left in our chest, the
left lung is smaller that the right one.
Lungs are
surrounded by
pleura, two
membranes
separated by a
fluid (to slide
smoothly).

12. Inside the lungs.
Once the air enter
the lungs, it passes
through the
bronchi,
bronchioles and
alveoli, where
GAS EXCHANGE
takes place.
This gas exchange is
produced through
a DIFFUSION
process.

13. Diffusion

14. What is diffusion through the
membrane?
Diffusion is a form of transportation of certain
substances through the cell membrane.

15. Inside Outside
Cell
membrane
HIGHER
concentration
LOWER
concentration
Inside
Outside
Cell
membrane
HIGHER
concentration
LOWER
concentration
Diffusion through the membrane
Diffusion is the process where substances pass from one side of a membrane where
the concentration is higher to the other side where the concentration is lower.
If the concentration of a substance is higher on
the outside, the substance enters.
If the concentration of the substance is higher on
the inside, the substance leaves.

16. After inhalation, the concentration of O2 in the alveoli is higher than in the
capillaries. The O2 therefore passes by diffusion from the alveoli into the blood.
Inside the alveolus
Membrane of the
alveolus
Diffusion of O2 during gaseous exchange
Blood
O2
HIGHER concentration
of O2
LOWER concentration
of O2
Oxygen (O2) is transported by diffusion from the alveoli into the
blood.
* Blood does not
only transport
oxygen, but
also carbon
dioxide. So…

17. The blood that goes to the lungs has a higher concentration of CO2
than that outside the alveoli. Therefore, the CO2 passes into the
alveolus.
Diffusion of CO2 during gaseous exchange
CO2
Membrane of the alveolus
LOWER concentration
of CO2
HIGHER concentration
of CO2
Inside the alveolus Blood
The carbon dioxide (CO2) is transported by diffusion from the
blood to the inside of the alveoli.

18. Diffusion inside the lungs.
https://www.youtube.com/watch?v=d-f3RL0KiUg