This is a presentation regarding Human System topic for Year 7 Stage 8.

1. Illustration by Smart-Servier Medical Art
Human
Blood
General Science Year 7 – AY 2023/2024
→

2. Each cell gets its energy through respiration.
2
Aerobic (need oxygen) respiration happens inside cell mitochondria.
● The reactants are glucose and oxygen.
● The products are carbon dioxide and water.
● The delivery of reactants and removal of products is done by the blood.
→
←

3. Illustration by Smart-Servier Medical Art 3
What is blood?
→
←
White blood cells are a lot
bigger than red blood cells
in size.
Blood looks red because most
of the cells in blood are red
blood cells.

4. Activity : let us find the odd one!
4
→
←
4
Use the microscope at the back to see a few samples of cell. Please seek
help if you have difficulties regarding the focus.
Search
Analyze the characteristics for each cell through the microscope. Draw
the image of the cell that you see and describe their main characteristic
(shape, color, etc).
Observe
Based on the image and characteristic, single out one cell that you
think it might be a different type cell comparing to the other. Relate
your findings with the blood component from the previous slide.
Find
01
02
03

5. 5
Discussion
→
←

6. 6
Blood Plasma
● Liquid part of blood and mostly consists of water.
● Has many other different substance dissolved in it (example:
nutrients like glucose, wastes, gas, ions, etc).
● From respiration and gas exchange, carbon dioxide is being carried
away by blood plasma instead of red blood cells.
→
←

7. 7
Red Blood Cell
● Large surface area
● Biconcave shape
● Do not have mitochondria
● Do not have any nucleus to
make more room for
carrying oxygen
● Full of a red pigment called
haemoglobin to carry
oxygen
→
←

8. 8
Red Blood Cell
● From alveoli in the lungs, oxygen diffuses into the red blood cells.
● Then oxygen combines with haemoglobin (oxyhaemoglobin)
● When the blood passes cells, the oxyhaemoglobin gives its oxygen to the cells.
→
←

9. 9
White Blood Cell
● Have nucleus
● Have so many types that varies in
size, shape, and function
● Most of them larger than red blood
cells
● Help to defend us against
pathogens
→
←
What is
pathogen?

10. 10
White Blood Cell
● Have nucleus
● Some kinds larger than red blood cells
● Help to defend us against pathogens by two mechanisms:
→
←
 Change shape to capture a pathogen inside their cell, then digest the
pathogen
 Produce chemicals called by antibodies that stick onto the pathogen and kill it
directly

11. 11
Mechanism of defense
Change shape to capture a
pathogen inside their cell,
then digest the pathogen
Produce chemicals called by
antibodies that stick onto the
pathogen and kill it directly
→
←
1 2
White Blood Cell