Content Benchmark L.8.B.4
Students know cells combine to form tissues that combine to form organs and organ systems that
are specialized to perform life functions. E/S
The smallest unit of life is a single cell. A single-celled organism must perform all of the
functions of life independently of other cells. In contrast, multicellular organisms have
differentiated cells that perform specific tasks that collectively perform all of the functions of
life.
Figure 1. Example of a unicellular organism.
This one-celled paramecium must perform
all of the functions of life. (From
http://biology.clc.uc.edu/mansfield/protisttest
.html)
Figure 2. Example of multicellular tissue.
A leaf has many types of cells working
together to perform function of life. (From
http://www.deltapix.dk/biomedical.htm)
Levels of Organization
Multicellular organisms exhibit many levels of organization starting with cells. Cells are
differentiated, meaning that not all cells are identical within an organism. Each cell has the same
genetic code (DNA) but not all genes are active within a cell. For example, a skin cell has a
different structure and function than a liver cell. Therefore, these cells look different and
perform a different task.
One type of cells working together to perform a specific function is called a tissue. Examples of
tissue are muscle (Figure 3), nerve (Figure 4), epithelial (Figure 5), and connective tissues.
These tissues are made of many cells performing a function together. Muscle tissues have the
ability to contract and relax performing movement, nerve tissue responds to stimuli and conducts
impulses, epithelial cells provide a continuous protective barrier between the body and the
environment, and connective tissue supports and binds other tissues.
Figure 3. Smooth cardiac muscle. (From
http://www.uoguelph.ca/zoology/devobio/2
10labs/muscle1.html)
Figure 4. Nerve Tissue. (From
http://www.okc.cc.ok.us/biologyla
bs/Documents/Cells%20Membran
es/Nervous_tissue.htm)
Figure 5. Cheek cells are an example
of epithelial. (From
http://www.washington.uwc.edu/about
/faculty/schaefer_w/TISSUES/cheek_
cells2.jpg
The heart is an example of an organ. It is made up of several types of tissues like muscle, nerve,
and connective tissues working together to move blood around the body.
Figure 6. The heart.
(From http://www.gwc.maricopa.edu/class/bio202/cyberheart/hartbak.htm)
The next level of hierarchy is the organ system. An organ system is composed of several organs
working together to perform a specific function. The heart is part of the circulatory system
which heart works together with the veins, arteries, blood, and capillaries to transport oxygen
and nutrients to all of the cells in an organism and carry away metabolic wastes.
Figure 7. The human circulatory system.
(From. http://www.imcpl.org/kids/guides/health/circulatorysystem.html)
Finally, several organ systems working collectively comprise the whole organism. Each system
depends on the others to complete the activities of life. For example, the circulatory system is
responsible for delivery of materials, including oxygen, around the body. Therefore, the
circulatory system is linked with the respiratory system which absorbs oxygen from the air and
transfers it to the bloodstream.
Figure 8. The whole human body.
(From http://americanhistory.si.edu/anatomy/collection/nma03_collection_human.html)
To review, multicellular organisms have multiple levels of organization. An organism is made
up of several organ systems. Each organ system is made up of several organs that work together.
Each organ is made up of several tissues working together. Finally, each tissue is made up of
similar cells working together. Figure 9 illustrates this hierarchy within a frog starting with a
muscle cell. This muscle cell works with other muscle cells to form smooth muscle tissue. The
muscle tissue works with other tissues to form a heart which combines with other organs to form
the circulatory system. Finally, the respiratory system works with other organ systems to form
the frog.
a
.
b
c
d
e
.
.
.
.
.
.
.
.
Figure 9. Levels of Hierarchy within an Organism.
a. Organism = Frog (From http://sos.georgia.gov/state_symbols/state_amphibian.html)
b. Organ System = Circulatory System (From
http://slohs.slcusd.org/pages/teachers/bsmith/ZZ%20%20Folder/Ron's%20Biology%20Web%20Page/Biology/Frog%
20Dissection/respiratory%20system.htm)
c. Organ = Heart (From
http://slohs.slcusd.org/pages/teachers/bsmith/ZZ%20%20Folder/Ron's%20Biology%20Web%20Page/Biology/Frog%
20Dissection/respiratory%20system.htm)
d. Tissue = Smooth Muscle (From http://www.ihcworld.com/imagegallery/displayimage.php?album=3&pos=4)
e. Cell = Muscle Cell (From http://www.udel.edu/biology/Wags/histopage/modelspage/smooth_muscle_fiber.GIF)
Human Organ Systems
There are several organ systems that comprise the human body. Each organ system performs a
function necessary for survival. However, organ systems do not work in isolation. The organ
systems must interact with each other to complete whole organism activities necessary to remain
alive. For example, the circulatory system functions to transports materials to body cells and
remove metabolic wastes. These transported materials may have origins in the respiratory
system (oxygen, carbon dioxide), endocrine system (hormones), digestive system (nutrients),
immune system (white blood cells), and the excretory system (metabolic wastes).
The following table summaries the structure and function of the major organ systems of the
human body.
Table 1. Summary of the Major Organ Systems of the Human Body
Organ system
Organs
Function
Circulatory
Heart, arteries, veins, blood
Transports oxygen, hormones, and nutrients
to cells and removes metabolic wastes
Digestive
Mouth, esophagus, stomach,
Breaks down food and absorbs nutrients
intestines, liver, pancreas
Endocrine
Pituitary, adrenal, thyroid,
Coordinates the activities of the body
hypothalamus, and others
including growth and metabolism
Immune
Lymph, lymph nodes and
Removes foreign bodies from the bloodstream
vessels, white blood cells
Integumentary
Skin hair, nails, sweat glands
Provides barrier between body and outside
Muscular
Respiratory
Skeletal muscle, cardiac muscle,
smooth muscle
Nerves, sense organs, brain,
spinal cord
Testes, ovaries, associated
reproductive structures
Lungs, nose, trachea
Skeletal
Bones, cartilage, ligaments
Urinary
Kidneys, bladder, urethra
Nervous
Reproductive
environment
Produces body movement
Relay electrical signals throughout the body,
directs behavior and movement
Carries out reproduction
Captures oxygen and exchanges gasses
Provides protection and provides support for
movement
Removes metabolic wastes from the
bloodstream and excrete from the body
For further detail on organ systems visit TIPS Benchmark L.12.B.2
Content Benchmark L.8.B.4
Students know cells combine to form tissues that combine to form organs and organ systems that
are specialized to perform life functions. E/S
Common misconceptions associated with this benchmark
1. Students incorrectly believe that digestion is the process that releases usable energy
from food.
Students confuse digestion with cellular respiration. It is difficult for students to understand
that digestion is only the breakdown of food, both mechanically and chemically, into
absorbable substances necessary for growth and maintenance. Digestion begins in the mouth
with chewing and the enzyme activity of saliva. Acid and different enzymes in the stomach
continue the breakdown of macromolecules. The majority of digestion and absorption
actually takes place in the small intestine. Nutrients pass through the wall of the small
intestine and enter the blood stream. The large intestine absorbs water and stores feces for
elimination from the body. Carbohydrates in the bloodstream are broken down into glucose
and delivered to every cell in the body. Energy is derived from the glucose at the cellular
level through the process of respiration.
For more information on digestion visit http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/
For more information on cellular respiration visit
http://www.phschool.com/science/biology_place/biocoach/cellresp/intro.html
2. Students incorrectly believe that respiration is synonymous with breathing.
Breathing refers to the process that brings about an exchange of gases between the organism
and its environment. Respiratory tissue absorbs oxygen and expels carbon dioxide. On the
other hand, respiration refers to the process that releases energy from food substances in
living cells. At the primary level, students do not make the distinction between breathing as a
physical process and respiration as a chemical process.
For further explanation of this misconception visit
http://www.ied.edu.hk/apfslt/v8_issue1/boohk/boohk3.htm
For more information on cellular respiration visit
http://www.biology.iupui.edu/biocourses/N100/2k4ch7respirationnotes.html
For more information on the process of breathing visit
http://yucky.discovery.com/flash/body/pg000138.html
3. Students incorrectly believe that organ systems work independently of each other.
Students usually learn the body systems in isolation and memorize the parts and function of
each organ, but lack understanding of how the systems work together. For example, the
circulatory system functions to transports materials to body cells and remove metabolic
wastes. These transported materials may have origins in the respiratory system (oxygen,
carbon dioxide), endocrine system (hormones), digestive system (nutrients), immune system
(white blood cells), and the excretory system (metabolic wastes).
For information on how the body systems interact with the nervous system visit
http://faculty.washington.edu/chudler/organ.html
An article on how organ systems communicate can be found at
http://www.merck.com/mmhe/sec01/ch001/ch001d.html
4. Students incorrectly think muscles are only used for voluntary physical actions like
walking, running, or throwing.
“Skeletal muscles are probably most familiar to middle school students even though other
types of muscles, cardiac and smooth, are essential for life functions. The heart muscle is
composed of a different type of muscle cell (cardiac muscle cells) and beats to move blood
throughout the body. Smooth muscle cells line blood vessels and the intestinal tract to help
move blood or food through those passages. The tongue is made up of muscle cells that
enable us to speak and is also an important part of the digestive system.”
An article on misconceptions associated with the muscular system can be found at
http://science.education.nih.gov/supplements/nih6/Bone/guide/info_musculo_skin-a.htm
5. Students incorrectly think that muscles turn to fat if you quit exercising.
Students believe that if they stop exercising their muscles will turn into fat. Students must
understand that muscle cells cannot change into adipose (fat) cells and understand the
definition of a tissue. Cells are differentiated. This means that cells may differ from one
another in structure and function but they retain that same function through out the life of the
cell. Muscles cells and fat cells may increase or decrease in volume or quantity due to
changes in nutrition and activity, but the cells do not convert from one form to another.
The following link provides and explanation of different types of human body cells
http://www.cancerhelp.org.uk/help/default.asp?page=98
6. Students do not relate the concept of tissues, organs, and organ systems to plants.
Students can easily identify roots, stems, and leaves in a plant but do not understand that
plants are also made of cells organized into tissues, organs, and organ systems. For example,
vascular plants have a circulatory system composed of xylem (transports water from the roots
to the leaves) and phloem (transports sugars from the leaves to the rest of the plant) tissues
that work together to circulate materials around a plant. Xylem is made up of two main types
of cells: tracheids and vessel elements. Xylem also contains other kinds of cells, such as
parenchyma, that function in structure and storage. Phloem is made up of sieve tube cells
and companion cells, as well as parenchyma cells. Therefore, together xylem and phloem
comprise the circulatory system of a vascular plant.
For more information on the vascular system of plants visit
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPLANTANAT.html
Content Benchmark L.8.B.4
Students know cells combine to form tissues that combine to form organs and organ systems that
are specialized to perform life functions. E/S
Sample Test Questions
1. Respiration is the process of
a. taking oxygen into our bodies and releasing carbon dioxide.
b. taking carbon dioxide into our bodies and releasing oxygen.
c. converting glucose into energy using oxygen
d. converting glucose into energy using carbon dioxide
2. Which of the following best explains the interaction between the circulatory system and the
respiratory system?
a. The respiratory system adds nutrients to the bloodstream which are delivered to the
cells.
b. The respiratory system adds oxygen to the bloodstream which is delivered to the cells.
c. The bloodstream delivers oxygen to the lungs to be exhaled from the body.
d. The bloodstream delivers nutrients to the lungs to be converted to carbon dioxide.
3. Which organ system is responsible for providing a barrier between the organism and the
environment?
a. Respiratory
b. Nervous
c. Digestive
d. Integumentary
4. Which human body system controls production of the hormones that regulate body
functions?
a. Digestive
b. Endocrine
c. Respiratory
d. Skeletal
From Leaves
From Roots
Figure 10: Figure modified from free clip art website
http://school.discoveryeducation.com/clipart/category/scie.html
5. Which organ system in humans performs the same function as shown in the plant in Figure
10?
a. Circulatory
b. Respiration
c. Digestion
d. Excretory
6. Which of the following is the correct ranking of organizational hierarchy of organisms
from simplest to most complex?
a. cells, organs, tissues, organ systems, organisms
b. cells, tissues, organs, organ systems, organisms
c. tissues, cells, organs, organ systems, organisms
d. tissues, organs, cells, organ systems, organisms
7. Which two body systems work together to produce movement?
a. circulation and skeletal
b. muscular and excretory
c. respiration and endocrine
d. skeletal and muscular
Content Benchmark L.8.B.4
Students know cells combine to form tissues that combine to form organs and organ systems that
are specialized to perform life functions. E/S
Answers to Sample Test Questions
1. (c)
2. (b)
3. (d)
4. (b)
5. (a)
6. (b)
7. (d)
Content Benchmark L.8.B.4
Students know cells combine to form tissues that combine to form organs and organ systems that
are specialized to perform life functions. E/S
Intervention Strategies and Resources
The following is a list of intervention strategies and resources that will facilitate student
understanding of this benchmark.
1. Online research/writing activity
This lesson asks students to “use the internet and library resources to find out more about the
effects of zero gravity and space travel on body systems. Then create a brochure that explains
some of the technologies that allow people to live for extended periods of time in space. This
is a good chance to have students write. They need to express an understanding of organ
systems and explain the effects that space travel would have on those systems. The hook for
this activity is students’ natural curiosity of space.
You can access this activity at http://go.hrw.com/resources/go_sc/hst/ia/hstl22.htm
2. Online organ system game is appropriate for middle school and English Language
Learners
“This practice lesson introduces students to several organ systems through an interactive
online experience. The objective of the lesson is for students to understand that there are
different systems within the body and that they work independently and together to form a
functioning human body. Through the use of an online interactive activity, students learn
about the concept of separate components working together to build a body system. In
addition, this lesson focuses on activities to help students learn that body systems work
together to build the functioning human body. This lesson could be used in conjunction with
instruction on the human body and/or systems.” http://ohiorc.org/record/3572.aspx
You can access the lesson plan page through the following link
http://www.sciencenetlinks.com/lessons.cfm?BenchmarkID=11&DocID=385
You can directly access the game at
http://www.sciencenetlinks.com/interactives/systems.html
3. Discover Kids Website “Yucky, Gross, and Cool Body”
Nothing motivates a middle school student more than an explanation of belches, snot, and ear
wax. This website lets students “find out all about the human body with Wendell the Worm,
Yucky's Ace Reporter.” The website allows students to choose a body function or a body
system to investigate. The reading level is appropriate for middle school students and the
explanations are grounded in science.
You can access this site at http://yucky.discovery.com/flash/body/index.html
4. Neuroscience for Kids
“Discover the exciting world of the brain, spinal cord, neurons, and the senses. Use the
experiments activities and games to help you learn about the nervous system. There are
plenty of links to other web sites for you to explore.” This is a great website written for
middle aged students to investigate the nervous system. Parts of the website are available in
Spanish and other languages.
You can access this website at http://faculty.washington.edu/chudler/neurok.html
5. Welcome to the Organ Systems
“This "Organ Systems" module has five units of instruction that focus on the main classes of
functions that a body must perform. Rather than just naming organs of the body and what
they do, we present a perspective on the body as a coordinated group of systems that must do
certain things correctly in order to survive and thrive.”
This is a great website for average to above average middle school students. It has five
modules including: Bodily Defenses, Digestion, Detoxification, Gas Exchange, and
Coordination and Control. Each module starts with an introduction with module objectives.
Then each module covers why each system is important, how we learned about each
system’s structure and function, historical perspective, and common hazards. Each module
also contains several activities that teachers can use to reinforce the concepts presented.
Lastly, each module contains a “Self-Study Game”. A plug-in must be downloaded to run
the Self-Study Game.
There is also a teacher companion site. An account must be activated to use the teacher
pages.
You can access this website at
http://peer.tamu.edu/curriculum_modules/OrganSystems/index.htm