Gas exchange
UNIT 10
4Y - Biology for I.G.C.S.E
Prof.: Gonzalo Ortiz
Name: ………………………………………………………………………………………………………………….
EXERCISE 1
On the diagram label the following parts:
Lungs, diaphragm, external intercostal muscles, internal intercostal muscle, larynx,
trachea, bronchus, bronchiole, alveoli
EXERCISE 2
The trachea is the tube that connects your lungs to the outside world. Complete the
sentences below describing how the trachea is adapted for its function (i.e. how its
structure and shape make it good at its job). Use the words below:
pressure, mucus, cilia, pathogens, cartilage, swallowed, dust, ciliated epithelial,
goblet, breathe
If your trachea becomes squashed or folded, you won’t be
able to __________________________. Fortunately your trachea
is strengthened by solid rings of
__________________________ that run all the way down it.
This material is very strong and resists
__________________________. When you breathe in air, you
also breathe in lots of __________________________ and
__________________________ which can be harmful to the
body. Specialcells in the trachea called
__________________________ cells produce
__________________________, which traps this harmful material.
Specialhair-like pieces called __________________________ are
found on __________________________
__________________________ cells, which cover the inside of the
trachea. This hair-like things sway backwards and forwards
to move mucus (and the materials trapped in it) up
and out of the trachea, where it can be
__________________________ (or spat out, if you’re a bit
gross about it).
EXERCISE 3
Make a simple drawing of one alveolus with a single capillary surrounding it. Include
the following feature/details:
• A one-cell thick lining of the alveolus
• A one-cell thick lining of the capillary
• a red blood cell
• A labeled arrow indicating the direction of oxygen diffusion
• A labelled arrow indicating the direct of carbon dioxide diffusion red blood cells,
oxygen transfer, carbon dioxide transfer
EXERCISE 4
Explain how the gas exchange surface is adapted to its function. Use the subheadings
to help you:
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Surface area> ________________________________________
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________________________________________ <Thin surface
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Good blood ________________________________________
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supply>
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________________________________________ <Good ventilation
with air
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EXERCISE 5
Describe how you would perform an experiment using lime water to investigate the
differences in composition between inspired and expired air.
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EXERCISE 6
Complete the following table about inspired and expired air composition
Oxygen Carbon dioxide Nitrogen Water vapor
Inspired air
Expired air
EXERCISE 7
Read the following statement about inhaled (breathed in) and exhaled (breathed out)
air. For each one, put a tick if it is correct, or a cross if it is not correct.
The air we inhale contains the same things we exhale, in the same amounts
The air we exhale contains more carbon dioxide and more oxygen than the air
we inhale.
The air we exhale contains more carbon dioxide but less oxygen than the air we
inhale.
The air we exhale contains more carbon dioxide and more oxygen than the air
we inhale.
The air we inhale contains more water vapour than the air we exhale
EXERCISE 8
Explain how intercostal muscles help with breathing. In your answer, include the
following words: external, internal, intercostal, contract, relax, volume, pressure
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EXERCISE 9
Read the following statement about the diaphragm. For each one, put a tick (✔) if it
is correct, or a cross (✗) if it is not correct.
The diaphragm is a sheet of muscle
When the diaphragm contracts, it moves down.
When the diaphragm relaxes, it moves down
When the diaphragm moves down, pressure is increased inside the thorax
When the diaphragm moves down, it forces more carbon dioxide out of the
lungs.
EXERCISE 10
Complete the following diagrams about inhalation and exhalation
Inhalation
Inhalation
EXERCISE 10
State the function of cartilage in the trachea
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EXERCISE 10
In your own words, define the following phrases:
Breathing rate:
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Depth of breathing:
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EXERCISE 11
State what changes occur in your breathing when you undergo strenuous exercise
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EXERCISE 12
A class of students measured their breathing rate and depth. Chart A shows Mike’s
breathing when he is relaxed and at rest. Compare the breathing patterns in graphs B
and C with that of graph A.
The depth of breathing remains
constant (The amount that is
breathed in and out doesn’t change)
The rate of breathing (the amount
of breaths per minute) also stays
constant
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EXERCISE 13
Which of the graphs, B or C, represent Mike’s breathing during strenuous exercise.
Explain your answer
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