RESPIRATION
Chapter 1
LEARNING OUTCOMES
1.1
1.2
The Human Respiratory
System
Gas Exchange
1.1
The Human
Respiratory
System
Respiration
A series of chemical reactions that
happens inside every living cell
Produces energy
Aerobic respiration
•
•
•
The type of respiration that usually occurs
inside our cells
Aerobic = uses oxygen
Cells produce carbon dioxide as a waste
product
Aerobic respiration
•
•
•
•
•
Breathe → air goes into lungs
Some oxygen from air enters blood
Blood delivers oxygen to cells → respiration
Cells produce carbon dioxide
Blood delivers carbon dioxide back to lungs
Human Respiratory System
Pathway of Air into Lungs
1)
2)
3)
4)
5)
6)
Entrance to nose/mouth
Larynx (voicebox)
Trachea (windpipe)
Bronchus
Bronchiole
Alveoli (air sacs)
Emily
Loves
To
Bake
Brownies
Always
Larynx (voicebox)
•
•
•
•
Contains vocal cords
Vocal cords: bands of
muscle that stretch
across larynx
When vocal cords vibrate
→ produce sound
Like guitar strings
Trachea (windpipe)
Nose and mouth
connect to trachea
• Has strong rings of
cartilage around it
• Rings of cartilage:
➢ Keep trachea open and
preventing it from
collapsing → air can
keep moving in and
out of body
•
Bronchus
•
•
•
•
•
Plural: bronchi
Has cartilage to
provide support
One bronchus goes to
each lung
Carries air deep into
lungs
Divides into smaller
tubes: bronchioles
Bronchioles & Alveoli (air sacs)
Bronchioles: allow air
to reach deeper into
lungs
• Branch into alveoli
(air sacs)
• Alveoli (air sacs):
➢ Where oxygen goes
into blood
➢ Where carbon dioxide
comes out
•
1.2
Gas
Exchange
Structure of Alveoli (air sacs)
Air sacs = alveoli
Singular: alveolus
Tiny blood vessels
wrapped around alveoli
→ capillaries
• Wall of air sacs and
capillaries are made up
of one layer of cells
•
•
•
Lung under microscope
Structure of an Alveolus
Gas Exchange in Alveolus
•
•
•
Gas exchange: oxygen from
air goes into blood, carbon
dioxide from blood goes into
air
Gas exchange occurs through
diffusion
Diffusion: movement of
particles from an area of
higher concentration to
lower concentration
Gas Exchange in Alveolus
Alveolus
•
High oxygen
•
Low carbon dioxide
•
•
•
•
Blood in capillary
•
Low oxygen
•
High carbon dioxide
Blood in capillary comes from
organs in the body
Organs contain cells that
undergo respiration → use up
oxygen and produce carbon
dioxide
Blood in capillary contains
little oxygen but a lot of
carbon dioxide
Air in alveolus contains a lot
of oxygen but little carbon
dioxide
Gas Exchange in Alveolus
Alveolus
•
High oxygen
•
Low carbon dioxide
•
•
•
•
Blood in capillary
•
Low oxygen
•
High carbon dioxide
Diffusion: movement of
particles from an area of
higher concentration to
lower concentration
There are only 2 very thin
cells between air and blood
Oxygen moves easily from air
→ thin-walled cells → blood
(diffusion)
Oxygen particles move from
where there are a lot of them
(air) to where there are fewer
of them (blood)
Gas Exchange in Alveolus
Alveolus
•
High oxygen
•
Low carbon dioxide
Blood in capillary
•
Low oxygen
•
High carbon dioxide
•
Oxygen dissolves when it gets
into blood → goes into red
blood cells → combines with
haemoglobin
•
Carbon dioxide diffuses from
the blood into the alveolus
THE END.
Questions?