Biology 1.1 - 1.4
1.1 - The respiratory system
In this section you will answer:
● What is the path that air takes when you breathe in and out?
● Why is it better to breathe in through your nose?
● Why you should not talk while you’re eating?
You can breathe through your nose and through your
mouth. If you breathe, air enters your body through the
nasal cavity or oral cavity. Then it goes through the
pharynx and the larynx into the windpipe (also called
trachea). The windpipe split into two tubes called bronchi.
Then air enters the lungs. The bronchi branches out and
the air enters the many tiny tubes called bronchioles.
They end in small air sacs called alveoli.
The temperature of the air that enters your nose must be
warmed up. If the air is cold, it can dry out the mucus
lining. This can make you ill. The air is warmed up by
blood, running through tiny blood vessels in the walls of the nasal cavity.
Air contains all kinds of dust particles. Therefore, nose hairs filter the large
particles out of the air you inhale. The smaller particles get trapped by mucus in
the nasal lining. This mucus is then swept to your pharynx by ciliated cells. The
olfactory cells high up in your nasal cavity checking the air. Then the air passes
your pharynx. The pharynx diverges into your trachea and your oesophagus. The
air must go down the trachea and food and liquids down the oesophagus.
When you swallow a plate of cartilage, called the epiglottis, closes the trachea.
This means you can’t swallow and speak at the same time. Another small flap,
called the uvula, closes the nasal cavity when you swallow.
, After passing the pharynx, air enters your larynx. There are your vocal folds or
vocal cords: two elastic folds that stretch across the trachea. When you exhale
you can produce sounds because the passing air causes the vocal cords to
vibrate. The larynx is also called the voice box. The faster the vocal folds vibrate,
the higher the note, or pitch. The loudness of your voice is also called amplitude.
After the larynx, the air enters the trachea. The trachea is a tube-like organ and
contains C-shaped cartilage rings, which prevent the trachea from collapsing.
The windpipe branches out into two tubes called bronchi which then divide into
many tiny tubes called bronchioles. At the end of the bronchioles you find tiny
air sacs called alveoli (singular: alveolus).
1.2 - Gas exchange and respiration
In this section you will answer:
● What is air?
● What happens during gas exchange?
● What is diffusion?
Air is a mixture of gases. It contains nitrogen, oxygen, carbon dioxide and water
vapour.
When you burn fuel with the help of oxygen, you produce energy, carbon
dioxide and water vapour. When this happens inside your cells it’s called cellular
respiration: the process where cells break down glucose to get energy.
We use energy for:
1.1 - The respiratory system
In this section you will answer:
● What is the path that air takes when you breathe in and out?
● Why is it better to breathe in through your nose?
● Why you should not talk while you’re eating?
You can breathe through your nose and through your
mouth. If you breathe, air enters your body through the
nasal cavity or oral cavity. Then it goes through the
pharynx and the larynx into the windpipe (also called
trachea). The windpipe split into two tubes called bronchi.
Then air enters the lungs. The bronchi branches out and
the air enters the many tiny tubes called bronchioles.
They end in small air sacs called alveoli.
The temperature of the air that enters your nose must be
warmed up. If the air is cold, it can dry out the mucus
lining. This can make you ill. The air is warmed up by
blood, running through tiny blood vessels in the walls of the nasal cavity.
Air contains all kinds of dust particles. Therefore, nose hairs filter the large
particles out of the air you inhale. The smaller particles get trapped by mucus in
the nasal lining. This mucus is then swept to your pharynx by ciliated cells. The
olfactory cells high up in your nasal cavity checking the air. Then the air passes
your pharynx. The pharynx diverges into your trachea and your oesophagus. The
air must go down the trachea and food and liquids down the oesophagus.
When you swallow a plate of cartilage, called the epiglottis, closes the trachea.
This means you can’t swallow and speak at the same time. Another small flap,
called the uvula, closes the nasal cavity when you swallow.
, After passing the pharynx, air enters your larynx. There are your vocal folds or
vocal cords: two elastic folds that stretch across the trachea. When you exhale
you can produce sounds because the passing air causes the vocal cords to
vibrate. The larynx is also called the voice box. The faster the vocal folds vibrate,
the higher the note, or pitch. The loudness of your voice is also called amplitude.
After the larynx, the air enters the trachea. The trachea is a tube-like organ and
contains C-shaped cartilage rings, which prevent the trachea from collapsing.
The windpipe branches out into two tubes called bronchi which then divide into
many tiny tubes called bronchioles. At the end of the bronchioles you find tiny
air sacs called alveoli (singular: alveolus).
1.2 - Gas exchange and respiration
In this section you will answer:
● What is air?
● What happens during gas exchange?
● What is diffusion?
Air is a mixture of gases. It contains nitrogen, oxygen, carbon dioxide and water
vapour.
When you burn fuel with the help of oxygen, you produce energy, carbon
dioxide and water vapour. When this happens inside your cells it’s called cellular
respiration: the process where cells break down glucose to get energy.
We use energy for:
