Download Respiratory System Unit 1: Anatomy and Physiology

The Respiratory System
The role of the respiratory system
The respiratory system helps the body obtain oxygen for respiration
and remove the waste product carbon dioxide.
As we breathe, oxygen moves through
the surface of the lungs into the body.
It is then absorbed by the blood cells
and transported around the body via
the blood vessels.
The respiratory system is adapted for
efficient exchange of gases between the
lungs and the blood.
The respiratory system
The passage of air from nose/mouth to lungs
Click the
mouse to
follow the
passage of
air from the
nose/mouth
to the lungs
Nose
Air enters the
respiratory
system through
the nose and
mouth.
It is here that the air
is warmed,
filtered (by tiny
hairs), and
moistened.
From the nose, the
air passes
through the
throat (the
pharynx).
Pharynx
The pharynx lies
behind the nose
and mouth and
both cavities
open into it.
Both food and air
pass through the
pharynx, the
food is then
directed to the
oesophagus.
Larynx (Voice box)
The cavity of the
larynx is
separated
from the
pharynx by a
flap known as
the epiglottis.
This prevents
food from
entering the
windpipe
(trachea), into
the lungs.
Trachea (Windpipe)
The trachea is
approximately
10-12cm long
and is kept open
by a series of
rings of cartilage.
It contains cells
which remove
foreign particles
from the air.
Bronchi
The trachea
divides into two
bronchi, one
leading to each
lung.
Each bronchi then
breaks up into
smaller tubes
known as
bronchioles.
Bronchioles
The bronchial
tubes further
divide into
smaller tubes
called
bronchioles
before
terminating in
clusters of air
sacs known as
alveoli.
Alveoli
Alveoli look like
bunches of
grapes.
There are millions of
alveoli in each
lung and it is here
that gaseous
exchange takes
place.
They have large
surface areas,
thin walls and are
surrounded by a
network of
pulmonary
capillaries.
Gas exchange at the alveoli
The alveoli are bunches of tiny
air sacks inside the lungs.
Each individual sack is called an
alveolus.
When you breathe in, they fill
with air.
The alveoli are covered in tiny capillaries (blood vessels).
Gases can pass through the thin walls of each alveolus and capillary,
and into the bloodstream.
Gases can also pass from the bloodstream into the alveolus.
Gas exchange at the alveoli: describe in
your own words what is happening
Gaseous exchange
• Oxygen passes into the body and carbon dioxide
leaves the body through the process called
gaseous exchange.
• For this process to work we must control the
amount of each gas on each side of a semipermeable membrane (a wall one cell thick that
lets some things through but not others).
• A gas will always move from an area of high
concentration (or pressure) to an area of low
concentration (or pressure).
Continued
• When we breathe in there will be a high concentration
of oxygen in the lungs and a low concentration in the
blood. Therefore the oxygen will pass from the lungs
into the blood capillaries surrounding the alveoli.
• This highly oxygenated blood now transports the oxygen
to the muscle capillaries, which have a low
concentration of oxygen, thus allowing the oxygen to
pass into the muscle where it will be used to release
energy.
• Carbon dioxide is diffused from the muscles into the
bloodstream where it is transported to the lungs and
diffused out into the alveoli.
The flow of air
1 .Air containing oxygen is inhaled and taken to the
2 alveoli in the lungs, where the oxygen diffuses into the
3 . blood and is taken to the heart to be pumped around the
4 . body to the muscles. At the same time
5 .carbon dioxide produced by the muscles is taken to the ..
6 .heart to be pumped to the ...
7 .lungs, where it diffuses out of the blood and into the ...
8 . alveoli to be exhaled.
Lungs
Situated in the thoracic cavity, there are 2 lungs.
The Right lung is made up of 3 sections called
lobes. Where the left only has 2.
Why do you think this is?
What organ do you know is situated towards the
left side of the chest?
The Heart
The lungs have 2 protective coverings called the
PLEURAL MEMBRANES.
The visceral membrane is closest to the lungs and the
parietal membrane is the one that’s furthest away
from the lungs
These are 2 layers that have a gap in between them.
This gap is called the PLEURAL CAVITY.
This gap is filled with pleural fluid.
The membranes, cavity and fluid all work to protect
the lungs and reduces friction between the lungs
and the ribcage
Mechanisms of breathing – inspiration
When you breathe in:
Intercostal muscles
pull ribs up and out
the intercostal muscles between the
ribs contract, pulling the chest walls
up and out.
the diaphragm muscle
below the lungs contracts and
flattens, increasing the size of the
chest.
the lungs increase in size, so the
pressure inside them falls. This causes
air to rush in through the nose or
mouth.
Diaphragm
contracts and
moves down
Mechanisms of breathing – inspiration
During Exercise (Inhalation)
• During exercise the diaphragm and the
intercostal muscles contract which makes the
ribs moves upwards and outwards and results
in more air being taken in
Mechanisms of breathing – expiration
Ribs move in
and down
When you breathe out:
the intercostal muscles between
the ribs relax so that the chest walls
move in and down.
the diaphragm muscle below the
lungs relaxes and bulges up,
reducing the size of the chest.
Diaphragm
relaxes and
bulges up
the lungs decrease in size, so the
pressure inside increases and air is
pushed up the trachea and out
through the nose or mouth.
Mechanisms of breathing – expiration
During exercise (Exhalation)
• During exercise the intercostal muscles relax
to help decrease the size of the thoracic cavity,
which means that more air can be forced out.