CHAPTER 1.5 BLOOD : RED BLOOD CELLS
Nasal cavity
Mouth
Voicebox (larynx)
Trachea (Windpipe)
Lungs
bronchi
diaphragm
bronchiole
alveolus
Blood from
heart
Oxygen
Carbon
dioxide
Blood
flow
towards
the heart
Blood capillary
Wall of blood
capillary
Wall of air sac
Diffusion
of carbon
dioxide
Diffusion
of oxygen
Breathing in happens when:
•The diaphragm contracts and moves down, increasing the volume in our chest.
•The ribcage moves up and out, helping make even more space.
•This makes the pressure inside the chest decrease and air comes rushing into our
lungs.
Breathing out happens when:
•The diaphragm relaxes and moves up decreasing volume in our chest.
•The ribcage moves down and in, making less space in our chest.
•This increases the pressure inside the chest and air gets pushed out of our lungs.
Red Blood Cells
• Red blood cells are specialised cells found in the blood.
• Main function is to transport oxygen from the lungs to all parts of the body.
Structure of Red Blood Cells
•Biconcave shape (disc-shaped with a dip in the middle)
→ Increases surface area for oxygen to diffuse in and out
•No nucleus
→ More space for haemoglobin
•Flexible
→ Can squeeze through narrow capillaries
•Contain haemoglobin
→ A red protein that carries oxygen
Textbook pg33
Haemoglobin
Haemoglobin is a red protein found inside red blood cells.
Functions of Haemoglobin:
•Binds with oxygen in the lungs
•Transports oxygen around the body
•Releases oxygen to body cells for respiration
Haemoglobin contains iron, which gives blood its red colour and
allows oxygen to bind.
Oxyhaemoglobin
When haemoglobin combines with oxygen, it forms
oxyhaemoglobin.
Word equation:
Haemoglobin + Oxygen ⇌ Oxyhaemoglobin
•This reaction is reversible
•It happens in different directions depending on oxygen levels
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ALL QUESTIONS
PAGE 38-39