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SUBJECT
GRADE
LEARNING UNIT
SCIENCE
SCIENCE 9TH GRADE
What is everything around us made of?
TITLE OF LEARNING
OBJECT
How does your body defend itself from the attack of pathogens?
CURRICULAR AXIS
STANDARD
COMPETENCIES
Science and technology
Curricular Horizon
LEARNING OBJECTIVES
 To identify the basic concepts of pathogenicity and immunity associated to the
generation of infections by pathogenic agents such as viruses and bacteria.
 To describe the principal forms of immunological protection in vertebrates.
 To distinguish how the different cells of the immune system differentiate and act in
the production of the so-called immune response.
 To recognize how the mechanism of action of vaccines in the human body is.
SKILLS/ KNOWLEDGE
LEARNING FLOW
 To identify and explaining how the immune system responds to allergies and cancer.
SKILL 1: Understand the concept of pathogenicity.
SKILL 2: Identify some viruses and pathogenic bacteria.
SKILL 3: Illustrate the principal forms of protection from diseases in vertebrates.
SKILL 4: Explain how nonspecific defenses work.
SKILL 5: Differentiate the cells that participate in the immune response.
SKILL 6: Investigate the mechanism of action of vaccines.
SKILL 7: Explain that allergies are badly directed immune responses.
SKILL 8: Explain how cancer evades the immune response.
Introduction
Objetives
Activities
Activity 1. The concepts of pathogenicity and immunity
ASSESSMENT
GUIDELINE
Activity 2. Forms of immunological protection in vertebrates
Activity 3. The cells of the immune system
Activity 4. Action of vaccines in the human body
Activity 5. Immune system in response to allergies and cancer
Abstract
Homework
Glossary
This learning object seeks to help the teacher guide his teaching practice and achieve that
his students understand in the best way the basic function of the immune system. It is
focused specially in the human body and its ability to defend itself from pathogenic
organisms. To achieve this comprehension, students must complete the different activities
which will help them learn and understand the subject better.
Stage
Learning flow
Teaching/Learning Activities
Introduction
Introduction
The teacher gives a brief explanation to his students, starting with everyday
situations that are related to the immune system and to how it is capable
of defending us from different pathogenic microorganisms that may cause
diseases.
Once he/she is done, it may good for him/her to reflect on this subject with
the students and relate it to different topics that have to do with the immune
system, like, for example, stress and cancer.
The teacher can complement these subjects with the following reading:
Content
The teacher
presents
the topic
http://search.proquest.com/openview/4e809c2eb636f8833d56c2052d110
d5b/1?pq-origsite=gscholar
First Activity
Nowadays people talk about two public health issues associated to a same
transmitting agent: the Aedes aegypti mosquito, which transmits the
Chikungunya and Zika viruses. These viruses generate events of
Recommended
Resources
Animation
resource for
the
introduction.
pathogenicity in human beings, and there isn’t a cure for either of them.
Only people who have been infected have generated immunity from them.
Activity 1
Exercise
Carry out a survey with your classmates about the concepts of immunity
and pathogenicity. Also, ask them what they know about Chikungunya and
Zika.
Did you know that…?
Currently, scientists are developing preclinical tests for a possible vaccine
against the Zika virus. These tests had a strong and long-lasting result in
mice. Tests on humans are expected to be carried out before this year
(2016) ends.
Second Activity
As said before, pathogenicity is a microorganism’s capacity to cause a
disease. Nowadays, there are several examples of infectious diseases
caused especially by microbiological pathogenic agents like viruses and
bacteria.
Exercise
Make a crossword puzzle that includes all the following terms for infectious
pathologies:
Diseases caused by viruses:






aids
flu
Ebola
chickenpox
measles
Chikungunya
 Zika
Diseases caused by bacteria:







tuberculosis
syphilis
tetanus
gingivitis
cholera
dengue fever
leprosy
Third Activity
The fundamental role of the immune system is the body’s defense against
a great variety of pathogenic agents, capable of generating diseases
(pathogenicity) in the affected individual. This system has gone through
evolutionary changes throughout history, which have made it more
specialized and highly efficient, as it is today, producing immunity in the
favored organism.
Learning activity
In groups, reflect upon the immunological mechanism that the individuals
from the animal kingdom apparently benefit exclusively from.
Additionally, think about and investigate how a person who was infected by
some type of disease and who wasn’t previously vaccinated, suffers from
that disease and survives, but never gets it again (consider especially the
term “immunity” to address this topic).
Content development as a conclusion
Throughout this activity, we’ve been learning that the event of generation
of any type of disease is known by the term of pathogenicity.
Also, we have seen that there are mechanisms that allow to resist such
microbiological invasion, through a specialized defense system known as
immune system. This system brings immunity and is present in all
individuals of the animal kingdom, but is known with greater depth in human
beings.
First Activity
Humans as well as animals benefit from a specialized immune system which
we don’t see in action every day. Even though we can only see this when
we get sick, we must remember that the defense mechanisms (specific and
nonspecific) are always active and in the defense process.
Activity 2
Exercise
Complete, in pairs, the following comparative chart. To do this, you must
investigate and look further into the characteristics of the innate and
adaptive immunities:
Characteristics
Specificity
Diversity
Memory
Components
Physical and chemical
barriers
Blood proteins
Cells
Did you know that…?
Innate Immunity
Adaptive
Immunity
In five liters of blood, the white blood cells represent only 1%. And even
though this seems a small amount, in every microliter of blood there are
between 5,000 and 10,000 leucocytes.
Second Activity
The fact that human beings belong to the group of vertebrates, allows them
to have a very specialized and evolved immune system, with direct and
indirect protection mechanisms.
Exercise
Next, groups of three students will organize and do a crossword puzzle,
using the following information:
Down
1. Direct action immune mechanism (Specific).
2. Type of immunity that acts as a first line of defense (Innate).
3. Process that some specialized cells carry out, which consists on “eating”
strange particles that have been previously recognized (Phagocytize).
4. Barrier of a non-immunological type (Epithelium).
5. Mechanism of adaptive immunity which is generated as a response to
infection after repeated exposure to one same microorganism (cellular
memory).
Across
1. Indirect action immune mechanism (Nonspecific)
2. Type of immunity that is generated as a response to infection
(Acquired).
3. Pathogenic agents that cause a great number of diseases
(Microorganisms).
4. Barrier of a non-immunological type (Mucosae).
5. Type of animals that benefit from a more evolved immune system
(Vertebrates).
Third Activity
The specialized defense mechanisms of vertebrates have generated
effective processes of immune response. When immunity is generated in an
individual, after a process of recognition and response, it becomes
“immunized” and will not fall again in the same infectious process generated
by the same microorganism.
Learning Activity
There are many words associated to immune response, and for this reason
sometimes this topic isn’t very clear. Individually investigate, from the point
of view of immunity, the functional meaning of each one of the following
terms, with respect to microorganisms:





Specificity
Diversity
Cellular memory
Specialization
Auto limitation
Content development as a conclusion
Throughout the activities that we’ve carried out, we’ve seen in a general
way how the different strategies and mechanisms in the immune system of
vertebrates are, especially in the human body. Their purpose is to help us
not get sick, despite of all of the microbiological threats that surround us.
First Activity
The evolution of the immune system brings with it the molecular and cell
specialization of such system. For this reason, we can find other types of
cells capable of complementing the specific immune response towards all
pathogens capable of generating infections.
Exercise
Elaborating a diagram that shows and identifies the origin or lineage of the
five types of cells that make part of the white blood cells or leucocytes
(neutrophils, lymphocytes, monocytes, eosinophils and basophils).
Did you know that..?
The cells called phagocytes (monocytes), are filled with lysosomes, which,
upon entering a pathogenic agent, secrete the totality of their enzymes and
this way degrade the invasive agent.
Activity 3
Second Activity
The main cells that generate the specific defense mechanism are called
lymphocytes, which divide into T and B lymphocytes depending on their
function and specificity. These cells are responsible for the immune
response in the human body and have been affected by evolutionary
processes which have implied a production of a marked functionality and
efficacy in the immune processes.
Exercise
Solve, individually, the following ten statements, which refer to specialized
cells in the immune system. Choose if each statement is True or False. For
this, it is important for you to read the previous information.
True/False questions
( F ) Lymphocytes are specific cells that don’t recognize nor differentiate
antigens.
( T ) Phagocytes are in charge of phagocytizing previously recognized
strange particles.
( T ) T and B lymphocytes are the only cells that participate in the specific
corresponding immune response.
( F ) Only B lymphocytes originate in the bone marrow.
( F) B lymphocytes intervene in the so-called immune response through
adaptive immunity.
( T ) The cells that stand out for being the only capable of producing
antibodies are B lymphocytes.
( F ) The cells in charge of presenting the corresponding antigen, for its
posterior recognition, are B lymphocytes.
( F ) T lymphocytes are cells that generate and produce cellular memory.
( T ) Both T and B lymphocytes are in charge of coordinating and mediating
the immune response.
( T ) White blood cells are also called leucocytes.
Third Activity
There are other types of cells in the immune system that complement, in
one way or another, the work of immune response. These cells are known
as granulocytes and are also present in the bloodstream.
Exercise
In pairs, investigate the function that the rest of the cells (granulocytes) of
the immune system have in the body. These cells are the following:
 Neutrophils
 Basophils
 Eosinophils
Content development as a conclusion
The main cells of the immune system are lymphocytes, which generate the
immune response, which is the defense response that these cells carry out
and which makes the mechanism to be divided in two parts:


The innate response, which is represented by the antibodies produced
by B lymphocytes.
The cellular response, provided by the T lymphocytes.
First Activity
The effectiveness of vaccination is very important, since through this
technique some of the worst infectious diseases have been eradicated
almost by 100%. These diseases, years ago, caused high death rates at a
global level.
Exercise
Working in pairs, investigate what the following diseases, which were
eradicated thanks to the good use of vaccination, consisted in:




Smallpox
Poliomyelitis
Pertussis
Diphtheria
Did you know that…?
Currently, there are investigations that actively look for new types of
vaccines, like the ones called DNA vaccines, made by a fragment of DNA,
capable of codifying a protein antigen of the microorganism. The DNA enters
the cells and induces the production of the protein which immunizes the
vaccinated person.
Second Activity
Activity 4
Currently, there are several types of vaccines that meet their task of
inducing immunity to those who receive them. They have been created
through different tests and medical-scientific strategies.
Exercise
This next chart shows the types of vaccines that exist today. Write, in front
of each type, two examples that still exist.
Type of vaccine
Dead or live attenuated
bacteria
Live attenuated virus
Subunit vaccines
Conjugate vaccines
Synthetic vaccines
Viral vectors
DNA vaccines
Examples
Content development as a conclusion
Even though in these times many great prevention and health promotion
campaigns have been carried out, as well as restrictions to inadequate use
of antibiotics and promotion of a larger awareness of the importance of
vaccination, infectious diseases continue to be an important cause of
sicknesses and deaths in the entire world.
First Activity
Allergies can happen to any individual, reacting to different environmental
agents like pollen and bee stings or to some antibiotics. All of these
disorders are related to the activation of certain cells of the immune system,
as a reaction to an antigen, which triggers the disease immediately.
Exercise
Taking into account that asthma is an allergy that produces breathing
difficulties, investigate how inhalers and bronchodilators work to help
control this disease. This investigation must be carried out in pairs.
Did you know that…?
The earliest description of cancer was found in an Egyptian papyrus which
is approximately from the year 3000 B.C.
Second Activity
Exercise
Write a reflection on the importance of the breast self-exam, as a breast
cancer prevention method, taking the following reading (Profamilia, 2016)
as a reference:
Activity 5
BREAST CANCER
What is breast cancer?
Breast cancer is a malignant tumor that originates in the cells of the breast.
A malignant tumor is a group of cancer cells that can grow, penetrating
(invading) the surrounding tissue, or that can spread (metastasize) to
distant areas of the body. This disease occurs almost exclusively in women,
but men can also get it.
Types of breast cancer: Breast cancer can be divided into different types,
according to how the shapes of the cancer cells look from a microscope.
Most of the breast cancers are carcinomas, a type of cancer that starts in
the cells that coat the organs and tissues (epithelial cells), like the breast.
In fact, breast cancers are often a type of carcinoma called adenocarcinoma,
which is the carcinoma that starts in glandular tissue. Other types of cancer
can also occur in the breast, like sarcomas, which start in the cells of
muscles, fat and connective tissue.
Symptoms: The first recognizable symptom of breast cancer is usually a
lump that feels different than the rest of the breast tissue.
Prevention and early detection: A way to detect breast cancer early is
through the breast self-exam, which consists of an examination that women
make of their own breasts to detect if they have any abnormalities.
The self-exam must be made as a part of the integral self-care of each
woman. She can do it herself once a month, from five to seven days after
her period, when there’s less tension in the breast. This must be done to
prevent or detect breast cancer on time.
Third Activity
Exercise
Working in pairs, do a word search puzzle which includes the following
terms, associated to pathologies related to allergies and cancer:
 allergy
 basophil
 mast cell
 antigen
 rhinitis
 cancer
 immunosuppressant
 allergen
 pollen
 immunoglobulins
 mutation
 mitosis
 tumors
 immunovigilance
Abstract
Abstract
Content development as a conclusion
Cancer and its appropriate comprehension have been studied for many
years. The main alteration caused by this disease is the uncontrolled
proliferation of cancer cells and the great risk of metastasis (propagation of
cancer cells to different parts of the body). Nowadays the topic is well
known, but a definitive cure to treat this pathology hasn’t been found.
The immune system is a group of specialized cells and molecular structures
(antibodies) that use organized processes to defend the body from external
pathogens. These pathogens can cause damage or disease in the individual.
Pathogenicity is a microorganism’s ability to cause a disease. In its turn, the
disease causes a strong imbalance in the affected individual; it generates
physiological problems, producing symptoms and characteristics that are
representative of the associated pathology.
In nature, there’s a great diversity of beings that have the characteristic of
being microbiological pathogenic agents. The most well-known are: viruses,
bacteria, fungi and parasites.
In vertebrates, we speak mainly of two defense mechanisms: specific and
nonspecific. The specific includes two methods of defense or protection from
some diseases: innate and adaptive immunity.
Innate immunity is the first line of defense against microorganisms (skin
and some specialized cells that phagocytize). Adaptive immunity is
generated as a response to infection, after repeated exposure to the same
microorganisms (cellular memory).
On the other hand, there’s the nonspecific defense mechanism, which acts
indirectly as a barrier against any type of external invasion, without
specifically attacking any pathogen coming from outside. The most relevant
defense is that of: skin, mucosae and their corresponding secretions (of
acid), cilia and saliva.
The cells that participate in the specific immune response are specially the
so-called T and B lymphocytes. T lymphocytes are cells that mediate the
immune response by presenting the antigen, while B lymphocytes are
capable of producing antibodies and possess cellular memory.
Vaccination is a method to provide immunity from some infections to
individuals, in order to prevent certain types of disease. Vaccines provide
immunity through the stimulation of effector and memory cells. The majority
of the vaccines bring about adaptive immunity, since the event happens as
a response to the infection.
Allergies are badly directed immune responses, since they promote the
activation of specialized cells, induced by a specific antigen which generates
the disease. Among the most common pathologies are asthma, rhinitis and
hives.
Homework
Homework
Cancer evades the immune response through several specialized
mechanisms: regulating the expression of molecules, selecting cells so that
they don’t express tumor antigens and producing immunosuppressive
substances that generate tolerance to the antigens that are formed in the
cells.
In groups of six students, make a creative and illustrative video to present
to the other classmates. The video must show, in detail, the work carried
out by the immune system.
The content of the unit must be taken into account, as well as the goals
mentioned in the beginning, to explain and clarify the following to the rest
of the class:
1. The concept of immunity and the danger of being infected by virus and
bacteria.
2. The specialized forms of immune protection in the human being.
3. How the immune response works, through the action of different types
of cells.
4. How vaccines act in the human body.
5. How the immune system acts when allergies and cancer arise.
This activity can be graded and must meet the five points written above.
Students can use the following links as guides, since they can give them
further information about these topics:
http://www.medigraphic.com/pdfs/revmexneu/rmn-2006/rmn061f.pdf
http://www.ucm.es/BUCM/revistasBUC/portal/modulos.php?name=Revista
s2&id=RCCV&col=1
Evaluation
Evaluation
http://www.academia.edu/18429840/El_Sistema_Inmune_Innato_II_la_p
rimera_respuesta_frente_a_la_infecci%C3%B3n
The following is a test which means to evaluate the student’s performance
in relation to the studied unit, through 15 basic questions. This test includes
different types of questions. First, there are true/false questions, then
multiple choice and finally a matching exercise.
For this test, students must understand all the content presented in this
learning object.
I. CHOOSE TRUE (T) OR FALSE (F), DEPENDING ON THE CASE.
1. Pathogenicity is the microorganism’s ability to cause a disease.
A. True
B. False
Answer key: A
Feedback: This is the most appropriate definition referring to this term.
2. Two examples of pathogenic agents in nature are bacteria and viruses:
A. True
B. False
Answer key: A
Feedback: Yes. However, there are also fungi and parasites, which can
cause pathogenicity as well.
3. The immune response in vertebrates is mediated mainly by two types of
immunity: innate and natural.
A. True
B. False
Answer key: B
Feedback: No, since there are also nonspecific defenses, like mucosae and
skin, which help as an indirect immunological mechanism.
4. The great majority of vaccines induce adaptive immunity in the human
body.
A. True
B. False
Answer key: A
Feedback: Vaccines always generate this type of immunity.
5. In allergies like asthma and diseases like cancer, the immune response
that is generated is the same.
A. True
B. False
Answer key: B
Feedback: The response is different since allergies cause immediate
hypersensitivity that generates antibodies, while in cancer we’re dealing
with adaptive immunity.
II. CHOOSE
QUESTIONS:
THE
CORRECT
ANSWER
FOR
THE
FOLLOWING
6. Which of the following diseases is produced by a bacteria as the
pathological agent?
A. zika
B. aids
C. chikungunya
D. cholera
Answer key: D
Feedback: Cholera is a disease generated by the Vibrio cholerae bacteria.
7. Nonspecific defenses act indirectly to protect the human body. Of the
following options, which make part of this defense system?
A. secretions
B. T lymphocytes
C. antibodies
D. B lymphocytes
Answer key: A
Feedback: Secretions are indirect methods of immunity, which don’t
depend on the action of cells like lymphocytes, nor on antibodies.
8. Which of the following cells are present in the immune system?
A. red blood cells
B. osteocytes
C. white blood cells
D. antibodies
Answer key: C
Feedback: White blood cells or leucocytes are the only cells in the immune
system, including neutrophils, basophils, eosinophils, monocytes, and
lymphocytes.
9. Through which immunity do the great majority of vaccines act?
A. natural
B. adaptive
C. nonspecific
D. innate
Answer key: B
Feedback: Vaccines generate protection through the stimulation of the
development of cells that provide cellular memory.
10. Allergies are badly directed immune responses, since they promote the
activation of certain specialized cells, induced by a specific antigen that
generates the disease. What is this antigen called?
A. T lymphocyte
B. antibody
C. allergen
D. B lymphocyte
Answer key: C
Feedback: The allergen is a specific antigen that produces antibodies.
11. Immunovigilance is a process that is carried out, mainly, to prevent the
production of cells that can contain some type of mutation. Of the following
diseases, which one is most linked to this concept of immunovigilance?
A. aids
B. asthma
C. cholera
D. cancer
Answer key: D
Feedback: This is an early recognition of potential cells that may form
tumors eventually.
III. MATCH. PLACE THE LETTER THAT CORRESPONDS INSIDE THE
PARENTHESES.
A. Innate immunity
B. Polio
C. Acquired immunity
D. Antigen
Glossary
antibody( D )
skin
(A)
lymphocytes ( C )
vaccine ( B )
Answer key:
Innate immunity is related to the skin since it acts as a barrier method.
Polio is a vaccine given to children, which prevents poliomyelitis.
Acquired immunity works exclusively with T and B lymphocytes.
Antigens form antibodies.
Acquired Immunity: Mechanism that is generated as a response to Multimedia
Glossary
infection.
Active immunoprotection: Lasting effect after being vaccinated.
Allergens: Specific antigens, which generate diseases immediately.
Allergy: Immediate hypersensitivity responses.
Antibody: Molecule that is responsible for immunity.
Antigens: Chemical structures that form antibodies.
Asthma: Allergy that produces airway obstruction.
B lymphocytes: Cells that are capable of producing antibodies and
generate cellular memory.
Bacteria: Unicellular
pathologies.
prokaryotic
microorganisms
that
cause
many
Basophils: Specialized cells of the immune system that appear in greater
quantities in inflammation processes.
Cancer: Pathology associated to a high cellular proliferation, which is
caused by a mutation that makes cells “immortal”. This uncontrolled process
can generate metastasis. Cancer produces tumors in the zones where it
appears.
Cell: Morphological and physiological unit of all living beings.
Cellular memory: Mechanism supplied by adaptive immunity, which
generates the capacity of having available information about a past event
of infection.
Cilia: Specialized structures of cellular movement and protection.
Cytotoxic T lymphocytes: They are in charge of destroying the infected
cells.
Disease: Pathology that causes imbalance in an organism.
Fungi: Unicellular or multicellular eukaryotic organisms that are known for
being opportunist. They also cause certain fungal pathologies.
Granulocytes: Blood cells that belong to white blood cells (neutrophils,
eosinophils, basophils).
Hives: Skin disease that is caused by contact with an irritating agent.
Homeostasis: The organisms’ capacity to maintain a balanced internal
condition.
Host: Organism that hosts another inside.
Immune response: Coordinated response to an event of infection.
Immune system: Organized group of molecular and cell structures, which
uses specialized processes to help defend anorganism from pathogenic
agents.
Immunity: Protection from infectious diseases.
Immunoglobulins:
antibodies.
Specialized
chemical
molecules
that
produce
Immunovigilance: Process that is carried out to avoid the production of
certain types of cancer cells.
Innate immunity:
microorganisms.
First
line
of
defense
against
the
action
of
Leucocytes: Specialized cells of the immune system, better known as white
blood cells.
Major histocompatibility complex: Genes whose products are in charge
of distinguishing what belongs to the human body and what is external.
Mast cells: Specialized cells that act in allergic or inflammatory processes.
Metabolism: Group of chemical reactions that happen in the organism or
in one cell.
Monocytes: Type of white blood cells that specialize in phagocytizing.
Parasites: Individuals that live at the expense of other organisms.
Pathogenic agents: Microorganisms or molecules that cause diseases.
Pathogenicity: An organism’s ability to cause diseases.
Pathology: Biomedical science that studies diseases.
Phagocytes: Cells that specialize in phagocytizing.
Phagocytosis: Process in which a cell “eats” or phagocytizes particles of
the external environment.
Red blood cells: Specialized cells that transport oxygen and carbon dioxide
in the blood. They are also known as erythrocytes.
Rhinitis: Allergic and inflammatory process of the mucous membrane inside
the nose.
T lymphocytes: Cells that mediate the immune response, since they
present the corresponding antigen.
Thymus: A gland of the human body, where T lymphocytes mature.
Toxins: Molecules that can cause diseases in individuals.
Vaccines: Substances that provide protection against some infections. They
are given before the organism is attacked by the corresponding pathogenic
microorganism.
Virus: Obligate intracellular parasites that exist in RNA and DNA types. They
cause many infectious/contagious diseases.