Download Grade 10 Academic Science – Biology

Grade 10 Academic Science – Biology
Eyewitness DVD – Human Machine (Body Zone)
Teacher Resource Centre DVD 8303
No machine is as complex as the human body. It is light, flexible and strong. It is made up of
billions of cells…very tiny cells, and each cell carries out ALL the processes of life…allowing you
and I to live and grow. As we know, similar cells group together to form tissues (e.g., muscle
tissues, bone tissue, nerve tissue), and group of tissue form organs (e.g., lungs, heart, brain).
Lastly, organs group to form organ systems (e.g., digestive system, respiratory system and
nervous system). The highest level of organization is the whole organism: a living human being.
How do these separate systems work together?
The circulatory system delivers oxygen and nutrients to the cells, removes waste from the cells,
relays information via hormones and carries disease-fighting white blood cells of the immune
system. The circulatory system includes three organs:
 Blood
 Heart
 Blood vessels (i.e., arteries, veins and capillaries). NOTE: Recall the question in your
textbook about the shape of blood vessels. Arteries were thick walled since blood is
pumped through them under pressure, capillaries are one cell thick to permit diffuse
across the cell membrane and veins are thin-walled with “doorways” to only permit blood
flow in one direction.
The respiratory system includes the lungs and other organs. Oxygen enters the body through
lung tissues called alveoli. As well, the waste by-product of cellular respiration, carbon dioxide, is
removed (…exhaled).
How does the circulatory system work with the respiratory system?
Our immune system stands guard to protect us from microscopic disease and infection-causing
germs. Disease causing micro-organisms (…or pathogens…) include viruses, bacteria, some
fungi and some protozoa. These pathogens enter our bodies through openings (e.g., eye, nose,
mouth). To prevent invasions, the immune system has three lines of defense: (1) barriers (e.g.,
skin), (2) secretions (e.g., mucus, gastric juices) that wash away, expel or kill invaders and (3)
prevention via that white blood cells that prevent pathogen activity.
The digestive system breaks down food (…chemically and physically…) so the body can absorb
and use the energy. The system includes many organs including the mouth, teeth, stomach,
small intestine, liver, pancreas and large intestine.
The nervous system is the body’s command centre. It includes the brain, spinal cord and billion
of nerve cells. All other systems rely on messages sent via the nervous system. The body’s
functions are maintained by electrochemical signals. Messages travel along special nerve cells
called neurons. The brain is the body’s most complex organ. The brain maintains the capacity
for thinking, reasoning, memory and decision-making.
Do all messages start in the brain?
TASK
Watch the DVD and answer the following questions.
1. What is the primary function of the lungs?
2. Why are tears important?
3. What are rods and cones? How do they work?
4. How many bones comprise the human body?
5. How many muscles comprise the human body?
6. Why is human blood red?
7. How does the brain organize memories?
8. Which sense is most important? Explain your choice.
9. Good nutrition is important to health. How could you improve your nutrition? Provide
three ideas.
10. Sanitation has saved more lives worldwide than all the medicines and medical treatment.
How has the development of sanitation methods saved lives?