Structure of the Respiratory and
System
• Nose  hairs and mucus filter air. Air is
warmed
• Pharynx  Food and air pass through. At the
bottom of the pharynx air is directed through
the larynx (food down the oesophagus)
• Larynx  The opening is covered by the
epiglottis (made of cartilage) which prevents
food from entering the lungs.
Structure of the Respiratory and
System
• Trachea  kept open and protected by C-shaped
pieces of cartilage. Lined with mucus-secreting
and ciliated cells. These cells remove foreign
particles by pushing them back up towards the
larynx.
• Bronchi  Enter the lungs (one in each).
Reinforced with cartilage.
• Bronchioles  contain smooth muscle. If this
muscle contracts (as it does during an asthma
attack), it can cause severe breathing difficulties.
Structure of the Respiratory and
System
• Alveoli  approx. 300 million, which provide
a surface area similar to that of a tennis court.
– Walls are extremely thin, aiding efficient gas
exchange
– Surrounded by capillaries
– Surface are moist to aid diffusion and disolve
oxygen
I know that lungs are specialised
organs where oxygen from the air
enters the blood and carbon dioxide in
the blood passes into the alveoli.
I know how the alveoli provide a
large surface area for gas
exchange.
I know the mechanism of
breathing.
Keywords: Inhalation, Exhalation, Inter-coastal Muscles, Diaphragm, Alveoli, Diffusion,
Structure of the Respiratory System
Cartilage (rings
to prevent
collapse)
Cilia
(Hair like
structures help
move mucus)
Mucus
secreting cells
Smooth muscle
Trachea
Yes
Yes
Yes
Yes
Bronchus
Yes
Yes
Yes
Yes
Large
Bronchioles
No
Yes
Yes
Yes
Alveolus
No
No
No
No
Keywords: Inhalation, Exhalation, Inter-coastal Muscles, Diaphragm, Alveoli, Diffusion,
I know the
mechanism
of brethg.
Keywords: Inhalation, Exhalation, Inter-coastal Muscles, Diaphragm,
Alveoli,
Diffusion,
Task 1: Complete the following table for breathing in only!
Breathing IN
External Intercostal
muscles move
Ribs move
Volume of lungs
Diaphragm
Contract
Move OUT and UP
Increases
Contracts and moves
DOWN
Breathing OUT
Keywords: Inhalation, Exhalation, Inter-coastal Muscles, Diaphragm, Alveoli, Diffusion,
Keywords: Inhalation, Exhalation, Inter-coastal Muscles, Diaphragm, Alveoli, Diffusion,
Task 2: Complete the following table for breathing OUT.
Breathing IN
Intercostals muscle
move
Ribs move
Volume of lungs
Diaphragm
Contract
Breathing OUT
Relax
Move OUT and UP
Move IN and DOWN
Increases
Decreases
Contracts and moves
DOWN
Relaxes and moves UP
Complete the following table:
Muscles
Contracting or
relaxing?
Muscles involved
Inspiration at
rest
Expiration at
rest
Inspiration
during exercise
Expiration during
exercise
Use page 31 of your text book to help.
Changes
occurring to size
and pressure
Muscles
Contracting or
relaxing?
Inspiration at
rest
Contracting
Expiration at
rest
Relaxing (muscles
are passive)
Inspiration
during exercise
Expiration during
exercise
Muscles involved
Changes
occurring to size
and pressure
External
intercostals,
diaphragm
Volume of thoracic
cavity increases,
Pressure decreases
External
intercostals,
diaphragm
Volume of thoracic
cavity decreases,
Pressure increases
Muscles
Contracting or
relaxing?
Muscles involved
Changes
occurring to size
and pressure
Inspiration at
rest
Expiration at
rest
Inspiration
during exercise
Expiration during
exercise
Contracting
Diaphragm, External Volume of thoracic
intercostals,
cavity increases,
Scalenes,
Pressure decreases
sternocleidomastoid
and pectoralis
minor.
• Strenocleidomastoid lifts the sternum
• Scalenes and pectoralis minor lift the ribs
further
Complete the following table:
Muscles
contracting or
relaxing?
Muscles involved
Changes
occurring to size
and pressure
Contracting
Abdominals,
Internal
intercostals;
Diaphragm
External
intercostals
Volume of thoracic
cavity decreases,
Pressure increases.
Inspiration at
rest
Expiration at
rest
Inspiration
during exercise
Expiration during
exercise
Relaxing
External Respiration
• The process of gas exchange between the
lungs and the blood. Oxygen diffuses into the
blood, while CO2 diffuses from the blood into
the lungs.
Internal Respiration
• The process of gas exchange between the
blood, the fluids surrounding the cells, and
the cells. Inside the cell, cellular respiration
generates energy (ATP), using O2 and glucose
and producing waste CO2.