introduction to cells, tissues, organs and 8/science 8 unit 4 life... · pdf...
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Introduction to Cells, Tissues,
Organs and Systems
304-7 Explain structural and functional relationships
between and among cells, tissues, organs and
systems in the human body
110-2 Compare the early idea that living organisms
were made of air, fire and water with the modern cell
In previous grades when you have studied living things, you have not broken them down into their smallest units, cells. However, this year, you get to learn about the cell in great detail.
We will explore how the cell is important to life and we will explore the human body to see how cells make tissues, tissues make organs, organs make systems and the systems make the body.
A long time ago
A couple thousand years ago, people
could not study Biology like we do today.
They did not have the technology that we
have, but they were smart for their time.
Aristotle (born in 384 B.C.), a philosopher
and scientist of the ancient times thought
that all substances were compounds of
four elements: earth, water, air and fire.
He thought for instance that humans were
made of earth, which gave material
strength and weight; fire, which provided
warmth; water, which accounted for blood
and other bodily fluids; and air, which filled
the lungs and provided the breath of life.
Of course, some people were more
earthly, fiery, airy, or watery than others.
This is a neat idea and we can see why he
may have thought these things.
What do you think we are made of?
Now with the technology that we have, we
can break matter down smaller than in the
ancient times and we now know that living
things are made of cells.
This is called Cell Theory the idea that
cells are the basic unit of structure of
every living thing.
Red Blood Cells
White Blood Cells
Nerve Cells Generalized Cell
Cells are the smallest independent units of
life, and all life depends on the many
activities of that cells perform.
Some basic functions of cells include:
growth, metabolism, and reproduction.
Cells range from 5 micrometers (sperm) to
more than a meter (some nerve cells).
In the cell
The cell is like its own little body that has mini-organs that keep it alive. These include:
Cytosol water, proteins, nutrients, waste products, glycogen granules and lipid droplets
Ribosomes RNA and proteins
Mitochondria proteins and lipids
* These are only some examples
Tissues are made up of many similar cells
that perform a specific function. Tissues
are divided into four groups: epithelial
(skin, linings, protective), connective
(bones and tendons, connects and
supports body), muscle (skeletal, smooth
and cardiac, produces movement) and
nervous (brain, spinal cord and nerves,
responds to stimuli and transmits signals).
Organs are a collection of two or more kinds of
tissues that work together to perform a certain
Epithelial tissue lines the stomach to protect it
Smooth muscle tissue churns food
Nervous tissue transmits nerve impulses that
coordinate muscle contractions
Connective tissue holds all other tissues together
A group of organs that work together to
perform a major function.
Example: The respiratory system contains several organs that provide a mechanism
for exchange of oxygen and carbon dioxide between
the outside the body and the blood inside
Cardiovascular (heart, blood, blood vessels)
Endocrine (ductless glands)
Nervous (brain, spinal cord,
peripheral nerves, sensory organs)
Muscular (skeletal, smooth,
Integumentary (skin, hair, nails,
sweat and oil glands)
Skeletal (bones and cartilage)
Respiratory (airways, lungs)
Digestive (stomach, intestines,
other digestive structures)
Excretory (kidneys, ureters,
urinary bladder, urethra)
Reproductive (ovaries, testes, reproductive
cells, accessory glands and ducts)
Lymphatic (glands, lymph nodes,
lymph, lymphatic vessels)
What are the common structures that make up
all living things?
What do you think are the basic materials
involved in the metabolism of all cells?
Food, Oxygen, Carbon Dioxide and Water
What do you think happens when cells use up their food and oxygen before there is time to replenish it?
The cells can not function death.
The "strongest" human muscle
Since three factors affect muscular strength simultaneously and muscles
never work individually, it is misleading to compare strength in individual
muscles, and state that one is the "strongest".
1. lifting a weight - the jaw muscle is the strongest.
2. If "strength" refers to the force exerted by the muscle itself - the
quadriceps femoris or the gluteus maximus.
3. A shorter muscle will be stronger "pound for pound" (i.e., by weight) than
a longer muscle - during childbirth, the uterus exerts 100 to 400 N (25 to
100 lbf) of downward force with each contraction.
4. The external muscles of the eye are large and strong in relation to the
small size and weight of the eyeball. It is frequently said that they are "the
strongest muscles for the job they have to do" and are sometimes claimed
to be "100 times stronger than they need to be."
The statement that "the tongue is the strongest muscle in the body"
appears frequently in lists of surprising facts, but it is difficult to find any
definition of "strength" that would make this statement true. Note that the
tongue consists of eight muscles, not one.
5. The heart has a claim to being the muscle that performs the largest
quantity of physical work in the course of a lifetime.http://en.wikipedia.org/wiki/Jawhttp://en.wikipedia.org/wiki/Quadricepshttp://en.wikipedia.org/wiki/Gluteus_maximushttp://en.wikipedia.org/wiki/Masshttp://en.wikipedia.org/wiki/Human_eyeballhttp://en.wikipedia.org/wiki/Tonguehttp://en.wikipedia.org/wiki/Heart