3. Introduction
Respiration is one of the characteristics processes of life.
Definition: It is the release of energy from food substances (like
glucose) in all living cells 24/7 (in the mitochondria).
Word equation: oxygen + glucose water + carbon dioxide +
energy
Oxygen needed for respiration comes from inhaled air.
The human breathing system consists of a system of tubes that
bring oxygen-rich air to the lungs and remove air rich in carbon
dioxide from the lungs.
Air moves into nose and mouth pharynx larynx trachea
bronchus (2 bronchi) bronchioles alveolus (many
alveoli) blood capillaries cells
8. BREATHING SYSTEM
Part Function
Nasal
cavity
Warms, moistens and cleans the air we breathe in.
Pharyn
x
Point where the breathing and the alimentary pathways
cross.
Epiglott
is
Flap which closes over the trachea during swallowing and
opens during breathing.
Larynx Contains vocal cords which makes sounds.
Trachea Tube by which air passes to and from the lungs.
9. BREATHING SYSTEM
Part Function
Bronchi Tubes into which the trachea divides to transport air
to and from left and right lungs.
Bronchioles Narrow tubes into which bronchi divide after
entering the lungs, and end alveoli through which
gases diffuse through.
Alveoli Gaseous exchange surfaces in the lungs.
Lungs 2 large, cone-shaped organs, made of almost only
alveoli
Rib cage Consist of ribs and intercostal muscles. Protects
lungs and heart.
Diaphragm Dome-shaped muscle between the chest and
abdomen.
12. Pharynx and epiglottis
Here the air and food passages cross.
The epiglottis ensure that food go down the oesophagus
and air move into the trachea.
trach
phar
ynx
oesoph
agus
13. Larynx (voice box):
Situated at the upper part of the
trachea and contains vocal cords.
When exhaling – the vocal cords can be
made to vibrate which produce sounds.
The epiglottis closes over the larynx when
food is swallowed (prevents food from
entering the trachea).
During breathing; epiglottis opens; air
continues from the larynx to the trachea.
15. Its a wall made of muscle tissue, but it is held open
by a series of C-shaped cartilage ring prevent the
trachea from collapsing.
16. The trachea is lined with ciliated cells (microscopic
hair-like structures) that help sweep dust particles and
pathogens out the airways.
17. Bronchus (plural bronchi) (note left and right)
Trachea divides into 2 bronchi which transport air to and
from left and right lungs.
Have the same structure as the trachea.
18. Bronchioles
Inside the lungs, the bronchi branch into several
smaller air passages called the bronchioles.
The smallest have no cartilage in their walls and end in
elastic air sacs called alveoli through which gases
diffuse through.
19. Lungs (note left and right)
2 large, cone-shaped organs.
Fill most of the chest cavity.
Made of almost only alveoli.
Protected by ribcage.
Base of each lung rests on diaphragm.
Right lung – 3 lobes.
Left lung – 2 lobes, makes space for heart.
Lined with pleura.
20. Pleura
Thin membrane that lines the outside of each lung and
the inside of the ribcage.
The space between these layers are filled with pleural
fluid, which reduce friction during breathing movements.
21. Collapsed lung
A collapsed lung occurs when
air escapes from the lung.
The air then fills the space outside
of the lung (between lung and
chest wall).
This build up of air puts pressure
on the lung, so it cannot expand
as much as it normally does when
you take a breath.
22. Alveolus (plural alveoli)
At the end of each bronchioles we
find air sacs called alveoli.
The walls of alveoli are made of a
singer layer of flattened epithelial
cells.
Each alveolus is surrounded by a
network of capillaries (thin blood
vessels) (see. p106).
The walls of the capillaries are
only a single layer thick.
23. Thin walls allows inhaled oxygen to diffuse easily into
the blood capillaries.
Similarly; carbon dioxide easily diffuses out of the
blood into the alveoli, to be exhaled.
It has an enormous surface area where gaseous
exchange, between oxygen (O ) and carbon dioxide
₂
(CO ), takes place.
₂
24. Rib cage
Protects lungs and heart.
Intercostal muscles run between each rib.
27. The airways
Air moves into the body through the nose and mouth
pharynx larynx trachea bronchus (2
bronchi) bronchioles alveolus (many alveoli)
Blood capillaries Tissue (cells)
By the time the air reaches the lungs it is:
warmed to body temperature (37°C),
moist and
filtered to be free of dust particles.
30. The air passages adaptations for breathing:
Trachea: has rings of cartilage to prevent it from
collapsing under pressure.
Lined with mucus membranes: secrete mucus,
which trap dust particles and pathogens, making the
air clean before it reaches the lungs.
Cilia: for sweeping out mucus containing trapped
particles and pathogens.
Epiglottis: keep the trachea open during breathing
and prevents food from entering into the trachea
during swallowing.
33. THE BREATHING SYSTEM
Gaseous exchange:
occurs at the alveoli and at the body cells.
The diffusion of oxygen from alveoli to blood
capillaries to body cells and
the diffusion of carbon dioxide from the body cells to
blood capillaries to alveoli.
In other words: It is the continuous supply of oxygen to the body
and removal of carbon dioxide from the body cells
36. THE BREATHING SYSTEM
For efficient gaseous exchange to take place:
the exchange surface has to be moist and thin.
It should be rich in blood supply
have a large surface area and
be well ventilated.
Gaseous exchange is vital to the body’s functioning:
the system for gaseous exchange should be well protected.
37. THE BREATHING SYSTEM
Gaseous exchange at the alveoli.
https://www.youtube.com/watch?v=WzrN6sJ1i_g
https://www.youtube.com/watch?v=mZvzl8KH6iI
38. GASEOUS EXCHANGE AT THE AVEOLI
INHALE
Volume of the chest cavity increases
Air flow through the airways into the alveoli of the
lungs
39. GASEOUS EXCHANGE AT THE AVEOLI
EXALE
Volume of the chest cavity decreases
The air in the alveoli which is now rich in carbon
dioxide is pushed out of the lungs and is carried
out of the body along the airways.
40. GASEOUS EXCHANGE AT THE AVEOLI
Air inside the alveoli:
High concentration of oxygen
Low concentration of carbon dioxide
Blood in the capillaries:
Low concentration of oxygen
High concentration of
carbon dioxide
42. Gaseous exchange at the alveoli
The heart pumps deoxygenated blood from the rest
of the body to the lungs. The blood is rich in carbon
dioxide.
The carbon dioxide diffuses out of the blood into the
alveolus, down the concentration gradient. It crosses
over two layers of cells because the walls of the
alveolus and the blood capillary are one cell layer
thick
43. Gaseous exchange at the alveoli
Oxygen dissolves in the moist lining of the alveolus.
From here it crosses over two layers of cells into the
blood.
In the capillary, the oxygen binds the red blood cells.
This oxygenated blood is transported to the rest of
the body via the heart
44. Gaseous exchange at the alveoli
Test your knowledge
The heart pumps ______________ from the rest of
the body to the _______. The blood is rich in carbon
dioxide.
The _____________ diffuses out of the blood into
the ____________, down the concentration gradient.
It crosses over __________because the walls of the
alveolus and the blood capillary are one cell layer thick
45. Gaseous exchange at the alveoli
__________dissolves in the moist lining of the
alveolus. From here it crosses over two layers of cells
into the blood.
In the capillary, the oxygen binds the
___________cells. This ____________blood is
transported to the rest of the body via the heart
46. Features of the alveoli for gaseous exchange
For efficient gaseous exchange to take place:
47. Features of the alveoli for gaseous exchange
Approximately 30 million alveoli; which increase
the surface area for faster gaseous exchange.
Thin walls of both alveoli and capillary (one cell
layer) which give a shorter distance for diffusion.
48. Features of the alveoli for gaseous exchange
Network of blood capillaries offers a rich
blood supply, which ensures continuous transport
of oxygen and carbon dioxide.
49. Features of the alveoli for gaseous exchange
Breathing keeps the surface well ventilated and
maintain concentration gradients between the
alveoli and capillaries.
Layer of moisture for gasses to dissolve in for
faster diffusion.
51. BREATHING SYSTEM
Cellular respiration keeps us alive.
To sustain cellular respiration:
The human breathing system consists
of a system of tubes that bring oxygen-
rich air to the lungs and remove air
rich in carbon dioxide from the lungs.
52. BREATHING SYSTEM
The muscular mechanism which is
applied to transport air containing
oxygen from the external atmosphere
to the lungs (inhalation) and air
containing carbon dioxide from the
lungs to the external atmosphere.
(exhalation).
53. MECHANISMS OF BREATHING
Inhalation:
Sucking air into the lungs brought
about by the chest expanding.
Exhalation:
Forcing air out of the lungs brought
about by the chest relaxing.
55. MECHANISMS OF BREATHING
Inhalation (breathing in) Exhalation (breathing out)
External intercostal muscles ? Internal intercostal muscles ?
Rib cage moves? Rib cage moves ?
Diaphragm ? Diaphragm?
Volume in thorax ? Volume of air in thorax ?
Atmospheric pressure ? Pressure ?
56. Inspiration Expiration
Intercostal muscles
contract.
Intercostal muscles
relax.
Rib-cage moves up and
out.
Rib-cage moves down
and in.
Diaphragm contract
and flattens out.
Diaphragm muscle relax
(dome shaped).
Volume in chest cavity
increase, and internal
pressure decreases.
Volume in chest cavity
decreases, and internal
pressure increases.
Air flows into the
lungs (air pressure
outside higher than
inside the lungs).
Air flows out of the lungs
(Air pressure inside the
lungs are higer that
outside).
57. Inspiration:
1. Intercostal muscles contract.
2. Rib-cage moves upwards and
outwards.
3. Diaphragm contract and moves
downwards and flattens.
4. Volume in chest cavity increases
and pressure falls.
5. Atmospheric pressure forces air
into lungs.
58. Expiration:
1. Intercostal muscles relax.
2. Rib-cage moves downwards and
inwards.
3. Diaphragm relax and move
upwards and become dome-
shaped.
4. Volume of air in chest cavity
decreases, pressure increase.
5. Pressure in chest cavity forces air
out of the lungs.
59. Tuberculosis (TB)
An infectious disease that affects the lungs.
People with a weaker immune system (HIV-positive) are more likely to become
infected with the bacteria.
Spreading of TB:
Through droplets from infected person’s cough or sneeze.
The bacteria move quickly through the nose and mouth, travelling all the way to
the alveoli.
Symptoms of TB:
severe coughing
coughing up blood
chest pain
fatigue
fever
60. EFFECTS OF PHYSICAL ACTIVITY ON THE BREATHING SYSTEM
Increased physical activity:
increase the pulse rate and
increase the breathing rate.
This ensures sufficient supply of oxygen
and nutrients to the body cells.
61. EFFECTS OF PHYSICAL ACTIVITY ON THE BREATHING SYSTEM
With exercise
Breathing rate
Oxygen supply
Respiration
energy to active muscles
removal of carbon dioxide
62. HOMEWORK
Topic 6B The human body: The breathing system
Homework:
Label the breathing system on your notes
Pg. 110 no. 1, 4 & 5
65. HOMEWORK
Topic 6B The human body: The breathing system
Pg. 110 no. 1, 4 & 5
1.
a) The diffusion of oxygen from alveoli to blood capillaries to body
cells and the diffusion of carbon dioxide from the body cells to
blood capillaries to alveoli.
b) Inspiration is the process whereby air is taken into the lungs.
c) Aerobic is a term used to describe any process that requires
oxygen.
66. HOMEWORK
Topic 6B The human body: The breathing system
Pg. 110 no. 2, 3, 4, 5
4.
Breathing is the driving force behind respiration and gaseous exchange. It is the
process whereby air containing oxygen is inhaled into the lungs and carbon
dioxide is exhaled out of the lungs.
Gaseous exchange is the exchange of oxygen and carbon dioxide at a cellular level
between lungs and blood, as well as blood and body cells.
Respiration is the process during which oxygen is used to generate energy in cells
and carbon dioxide is produced as a waste product.
All three processes are linked: respiration is a life process, breathing is essential
for gaseous exchange and gaseous exchange is crucial for respiration.
67. HOMEWORK
Topic 6B The human body: The breathing system
Pg. 110 no. 2, 3, 4, 5
5.
a) Inhaled air is rich in oxygen whereas exhaled air is poor in
oxygen (but rich in carbon dioxide).
b) Oxygen diffuses down a concentration gradient from a high
concentration (in the lungs), to a low concentration (the blood
in capillaries).
Carbon dioxide diffuses down a concentration gradient from a
high concentration (blood in capillaries), to a low concentration
(in the lungs).
68. Homework: For the next period bring to school
Practical:
Choose a group of 4 learners in a group.
Each group need to bring the following to class:
plastic 2 bottle
scissors
2 straws
2 balloons
masking tape
elastic band
sheet of flexible plastic (groceries bag is fine.)
The practical can only be completed during the specific period).
Ensure that you understand the breathing system.
Do questions on page 109 in your books
70. Practical Pg. 108 & 109
Practical:
Choose a group of 4 learners in a group.
Each group need to bring the following to class:
plastic 2 bottle
scissors
2 straws
2 balloons
masking tape
elastic band
sheet of flexible plastic (groceries bag is fine.)
The practical can only be completed during the specific period).
Ensure that you understand the breathing system.
Do questions on page 109 in your books
72. 1.
The balloons inflate when the sheet of plastic is
pulled downwards and the balloons deflate when the
sheet of plastic returns to its original position.
73. 2.
a) Straws = airways
b) balloons = lungs
c) plastic sheet = diaphragm
d) plastic bottle = chest cavity
74. 3.
When the diaphragm (plastic sheet) moves downwards,
an increase in the volume of the chest cavity (bottle) is
created, which decreases the pressure in the chest
cavity.
Since the air pressure outside the lungs (balloons) is
now greater than the air pressure inside the lungs, air
flows into the balloons.
When the diaphragm (plastic sheet) returns to its
original position, the volume of the chest cavity (bottle)
decreases and this forces the air to flow out of the lungs
(balloons).
77. Respiration:
The continuous release of energy from food
substances in the mitochondria of all living cells.
Respiration occurs continuously in every cell of the
body.
It is a chemical reaction that breaks down glucose to
release energy.
The energy keep the cells working.
Because oxygen is needed for this reaction, it is called
aerobic respiration.
Carbon dioxide and water are formed as waste
products.
79. Gaseous exchange:
The diffusion of oxygen from alveoli to blood capillaries to
body cells and the diffusion of carbon dioxide from the body
cells to blood capillaries to alveoli.
A continuous supply of oxygen is needed for respiration to
take place.
Carbon dioxide also has to be removed from the cell
continuously because it is a waste product.
Oxygen diffuses from the blood into the body cells.
At the same time, carbon dioxide diffuses out of the body
cells into the blood.
80. Breathing:
Breathing and respiration are NOT the same process!
Breathing: The movement of air in and out of the lungs
brought about by the rib cage, the intercostal muscles and
the diaphragm muscle.
Breathing is the driving force behind respiration and
gaseous exchange.
Inhaling brings air rich in oxygen into the lungs
Exhaling removes air full of carbon dioxide from the lungs.
81. IMPORTANT!!!!!!
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intended group of learners of Gobabis Gymnasium
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