THE
HUMAN BODY
All living things share two characteristics:
ü They are made up of cells. They can be unicellular (made up of a single cell)
or multicellular (made up of many
cells).
ü They carry out the three basic life processes:
o
Nutrition: Cells obtain nutrients and energy from food.
o
Sensitivity: Cells react to what they perceive around them.
o
Reproduction: Cells divide and produce two new identical cells.
Cells are the basic units of life. Human beings are made of millions of
cells. That is why they are considered multicellular living things.
Tissues: In multicellular living things groups of the same
type of cells join together to form tissues.
Organs: Tissues join together to form organs. All the
tissues in an organ work together to perform a common function.
Systems: Organs join together to form systems. Organs within
systems work together to perform a common function.
Organism: Finally, all the different types of systems in our
body work together to form a human being.
Bone cells Bone tissue Bone Skeleton system Human body
The locomotor
system consists of the skeletal system and the muscular system.
The skeletal
system: In gives our body its shape and protects delicate organs. There are
over 200 bones in the human body.
The muscular
system: There are about 240 muscles in our body. Muscles are joined to
bones by tendons.
The muscles in the locomotor system receive orders
from the brain and work with the bones to make the body move.
When a muscle receive an order, it contracts and pulls
the bones attached to it. Once the order is performed, the muscle relaxes and
the bones return to their original position.
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