SC.6.L.14.5:
Identify and investigate the general functions of
the major systems of the human body (digestive,
respiratory, circulatory, reproductive, excretory,
immune, nervous, and musculoskeletal) and
describe ways these systems interact with each
other to maintain homeostasis.
Immune System
To be immune means to be protected. The body system that
helps fight off sickness is called the immune system. The
immune system is made up of a network of cells, tissues, and
organs that work together to protect the body.
Immune System Movie
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Identify the invaders
Call for help
Tag the invaders
Destroy the invaders
Remember the invaders
Quiz
Matching Activity
Review the Lymphatic System
Pathogen
A pathogen is an organism, virus, or
particle that can make you sick.
Fungal
Meningitis
Can you name some pathogens?
Photo Credit: Cynthia Goldsmith,
Centers for Disease Control and
Prevention
Flu virus
Photo Credit: Centers for Disease
Control and Prevention
Photo Credit: Janice Haney Carr,
Centers for Disease Control and
Prevention
Trichinella Parasite
Photo Credit: Centers for Disease
Control and Prevention
Bacteria blood
infection
External Defenses
What are your external defenses against
pathogens?
• Tears and saliva
• tears and saliva both contain enzymes that destroy
invaders.
• Skin
• Skin provides both a physical and a chemical
barrier against the outside world.
• Mucus membranes
• Mucous membranes produce mucus in the nose.
Structures called cilia line the body's airways and
constantly wave foreign particles and mucus away
from the lungs to where they can be swallowed
safely.
Images courtesy of Microsoft
office clip art
Imagine! Think-Pair-Share
If you were a pathogen, what external defenses of
the host’s body would you have to get past?
Choose one external defense and describe your
journey into the body.
Images courtesy of Microsoft
office clip art
Internal Defenses
Inflammation
• Blood rushes to the cut where the pathogen entered.
Platelets seal the open wound to prevent more
invaders from entering.
Fever
• The body increases its internal temperature which
slows down the growth of bacteria and some other
pathogens.
White Blood cells
• Specialized cells made in the bone marrow that fight
disease are produced to fight diseases.
Images courtesy of Microsoft
office clip art
Activity: Compare/Contrast Defenses
Internal
External
How do our defenses help us maintain homeostasis?
• Homeostasis is the ability to maintain a constant internal environment.
• The nervous and endocrine systems control homeostasis in the body through
feedback mechanisms involving various organs and organ systems.
• Examples of homeostatic processes in the body include temperature control,
pH balance, water and electrolyte balance, blood pressure, and respiration.
• The Immune system is also involved with maintaining Homeostasis by using the
thymus gland to send chemical messages to the white blood cells to attack
invaders.
Do you remember?
1.Name 4 types of pathogens.
2.Where are white blood cells
produced?
3.How does having a Fever help your
body defend against pathogens?
Types of White Blood Cells
The granulocytes attack any invaders in
large numbers, and "eat" until they die. The
pus in an infected wound consists chiefly of
dead granulocytes
The macrophages are “big eaters” of
invaders. They are larger, live longer, and
alert the rest of the immune system of
invaders.
• Video 1
• Video 2
The dendritic cells are also "eater" cells and
devour intruders. And like the
macrophages, the dendritic cells help with
the activation of the rest of the immune
system. They filter body fluids to clear
them of foreign organisms and particles.
Images credited to: "The Immune System - in More Detail".
Nobelprize.org. Nobel Media AB 2013. Web. 16 Feb 2014.
<http://www.nobelprize.org/educational/medicine/immunity/immun
e-detail.html>
White Blood Cells (Lymphocytes)
• White blood cells called lymphocytes originate
in the bone marrow but migrate to parts of the
lymphatic system such as the lymph nodes,
spleen, and thymus.
• Antigen: Invading particle
• Antibody: A large Y shaped protein that is
produced by the immune system to mark
invaders.
• Each lymphocyte cell is made to “match” up to
a specific type of antigen. Think of puzzle
pieces.
• Video
• Simulation
Images courtesy of
Microsoft office clip art
Lymphocytes (T cells)
• T cells are produced in the bone marrow and move to the
Thymus gland (part of the lymphatic system) when they
mature.
• Helper T cells are the main regulators of the immune
defense. Their primary task is to activate B cells and killer T
cells. The helper T cells are activated when a macrophage or
dendritic cell, which has eaten an invader, travels to the
nearest lymph node to present information about the
captured pathogen.
• Killer T cells are specialized for attacking cells infected by
viruses and bacteria. It also attacks cancer cells. The killer T
cell has receptors that are used to search each cell that it
meets. If a cell is infected, it is swiftly killed.
Lymphocytes (B-cells)
• The B lymphocyte cell searches for antigens matching its
receptors. If it finds such antigen it connects to it, and inside the B
cell a triggering signal is set off.
• The plasma cell (created by a “triggered” B cell) is specialized in
producing an antibody, that matches an invader. Plasma cells
produce antibodies at an amazing rate and can release tens of
thousands of antibodies per second.
• The Memory Cells are a cell type produced by the division of B
cells. These cells have a prolonged life span and can thereby
"remember" specific intruders. T cells can also produce memory
cells with an even longer life span than B memory cells. The
second time an intruder tries to invade the body, B and T memory
cells help the immune system to activate much faster. The
invaders are wiped out before the infected human feels any
symptoms. The body has achieved immunity against the invader.
Illustrations of your Immune system in
action
Antigen Presentation, Killer T-Cell
and Memory Cells
Immune Platoon
Images courtesy of Microsoft
office clip art
Thumbs up/Thumbs down
1. An antigen is one of our body’s defense cells.
2. A macrophage is a white blood cell that lives longer
than other cells and is called a “big eater”.
3. T cells mature to make plasma cells and memory cells.
4. White Blood cells originate in our bone marrow.
5. Helper T cells are found in the Thymus gland and they
activate the immune response.
6. Antibodies are Y shaped proteins produced by the
immune system to attach to antigens.
7. Lymphocyte cells can match up to many different
antigens.
Vaccine
How does a vaccine work?
Images courtesy of Microsoft
office clip art
A Vaccine is prepared using a dead or weakened pathogen
and is given as a shot.
The immune system responds by making T cells, B cells,
and Memory cells.
If the pathogen enters the body after the vaccination,
Memory cells identify it and T cells and B cells begin to
attack the invader.
Video
Challenges to the Immune System
Allergies: the immune system reacts to foreign particles
that are not dangerous to most people. When you have
allergies, the immune system overreacts and tries to
"fight" ordinary things like grass, pollen, certain foods, or
medicine. This causes the sneezing, itching, and other
reactions that you get with allergies.
Cancer: Cancer happens when cells that are not normal
grow and spread very fast. Normal body cells grow and
divide and know to stop growing. Over time, they also die.
Unlike these normal cells, cancer cells just continue to
grow and divide out of control and don't die when they're
supposed to.
Images
courtesy of
Microsoft
office clip art
Challenges to the Immune System
Immune Deficiency: Immunodeficiency disorders are a
group of disorders in which part of the immune system is
missing or defective. Therefore, the body's ability to fight
infections is impaired. As a result, the person with an
immunodeficiency disorder will have frequent infections
that are generally more severe and last longer than usual.
Auto Immune Diseases: The immune system attacks the
body’s own cells. When the immune system makes a
mistake and attacks part of the body, it is called
autoimmunity. One example of an autoimmune disease is
type 1 diabetes, in which the immune system destroys the
cells in the pancreas that produce insulin
Working together
Our body systems work together to defend us from pathogens. Each system
has specific jobs that help the immune system keep us healthy. From the list
below, choose 2 systems and explain how the system helps the immune
system keep us safe.
Circulatory
Lymphatic
Respiratory
Skeletal
Musculatory
Skin (Integumentary)
Review of the Lymphatic System
The lymphatic system includes a system
of lymphatic capillaries, vessels, nodes,
and ducts that collect and transport
lymph fluid. It works along with the rest
of the immune system (mainly, the white
blood cells) to fight infections.
There are many clusters of lymph nodes.
The most abundant places lymph nodes
are found are in the neck, the armpit,
and the groin. Swelling of these nodes
indicates infection.
Lymphatic tissue is also found in the
thymus, spleen, tonsils, and appendix,
along with some special tissue in the
gut.
Movie of Lymph Node Function
http://training.seer.cancer.gov/anatomy/cardiovasc
ular/blood/pathways.html. Public Domain.
How does lymph fluid move?
How does the Lymph nodes work?
The lymph fluid moves through the vessels as you move
the voluntary muscles in your body. Ever go on a plane
and have your feet swell up? Because you are sitting in
one place and not moving around, fluid collects in your
feet and they swell. The more you move, the more
effective your lymphatic system becomes.
Lymph nodes work like a filtering system. When the
body is invaded by foreign organisms, painful swelling
can sometimes be felt in the neck, armpits, groin, or
tonsils. The swelling comes from pathogens being
trapped inside the lymph nodes. Eventually these
organisms are destroyed by a type of white blood cell
that lines the walls of the lymph node causing the
swelling and pain to go away.
By Michaelbladon at en.wikipedia
(Transfered from en.wikipedia)
[Public domain], from Wikimedia
Commons
References and Information
"The Immune System - in More Detail". Nobelprize.org. Nobel Media AB 2013.
Web. 16 Feb 2014.
http://www.nobelprize.org/educational/medicine/immunity/immunedetail.html
“BAM Body and Mind”. CDC.gov. Page last updated: June 7, 2012.
http://www.cdc.gov/bam/diseases/immune/learnhow.html
“ Immune Cells”. KidsHealth.org.
http://kidshealth.org/kid/closet/movies/ISmovie.html?tracking=59983_F
Florida Science Fusion. Holt McDougal. Houghton Mifflin Harcourt. Unit 8:
Lesson 1 “The Immune System” Pages 544-553