Download The Inflammatory Response

• Unit 1 – Human Cells
• Unit 2 – Physiology and Health
• Unit 3 – Neurobiology and
Communication
• Unit 4 – Immunology and Public
Health
2nd prelim
after
Easter
holidays
KA 1: Non-Specific Defences
(a)
Physical &
Chemical
Defences
KA1: NonSpecific
Defences
(b) The
inflammatory
response
(c)
Phagocytes
and Natural
Killer cells
KA 1a: Non-Specific Defences
By the end of this section you will
be able to …..
• State 3 reasons why the body has to
protect itself
• State what is meant by a pathogen
• State the role of epithelial cells
• Give 3 examples of physical and
chemical barriers
What do you already know?
In pairs, write down and discuss possible answers:
1) What does the term
‘immunity’ mean?
2) What does the body defend
itself against on a daily
basis?
3) How does the body defend
itself? Clue – think physical
and chemical barriers
4) What would happen if we
didn’t have an immune
system?
3 minutes
The Immune System
• The human body has the capacity to
protect itself against pathogens
(disease causing organisms), some toxins
(poisons produced by living things) and
cancer cells through the immune system.
• Immunity can be described as the
ability to resist infection by a pathogen
or to destroy the pathogen if it
successfully invades and infects the
body
3 Lines of Defence
• The body employs 3 lines of defence:
Line of
defence
Type of
defence
Method
1st
Non-specific
2nd
Non-specific
Physical & chemical
barriers
The inflammatory
response and action
of phagocytes and
natural killer cells
KA 1
3rd
Specific
Action of T- and Blymphocytes
KA 2
Entry points for pathogens
eyes
ears
mouth
nose
skin
genitals
cuts
Physical barriers in the skin
• The surface of
the skin is
composed of
layers of
closely packed
epithelial cells
Physical Barriers
• Epithelial cells form a physical barrier.
Densely packed layers are found in 2 areas
of the body:
1. In the surface of the skin
2. In the mucous membranes that line the body’s
digestive and respiratory tracts
•
Epithelial cells provided an effective
physical barrier against pathogens, so long
as they remain intact.
Chemicals barriers in the skin
Chemical barriers
in the mucous
membranes of the
respiratory system
Chemical Barriers
1. Sweat glands and sebaceous (oil) glands
found in the skin produce secretions
– These secretions keep the pH of the skin
too low for most microbes to thrive
2. Epithelial cells in the mucous membrane
secrete sticky mucus which traps
microbes.
– The mucus is the swept up away from the
lungs by ciliated epithelial cells
Chemical barriers in the stomach
Epithelial
cells – line
the outer
and many
inner
surfaces
of the
body
Physical & Chemical Barriers
3. Hydrochloric acid is secreted by
epithelial cells which make the lining of
the stomach.
– The acid destroys many ingested microbes,
but some survive the acidic conditions and
may gain further access to the body.
4. Secretions such as tears and saliva
contains lysozyme.
– This enzyme digests bacterial cell walls.
Can you now ….
• State 3 reasons the
body has to protect
itself against
• State what is meant
by a pathogen
• State the role of
epithelial cells
• Give 3 examples of
physical and
chemical barriers
KA 1b: Non-Specific Defences
By the end of this section you will
be able to …..
• State when an inflammatory response might
occur
• Name the cells which produce histamine
• State 2 effects of histamine
• Name the cells which produce cytokines
• State the role of cytokines
• Name 2 other structures which accumulate at
the site of infection
• Overall: Describe the steps and cells involved in
the inflammatory response
WHAT HAPPENS IF A
PATHOGEN DOES GET PAST
THE PHYSICAL BARRIER?
The body’s inflammatory response kicks in!
The inflammatory response
What’s going on?
Chilblains – inflammation of the toes (or other extremities) caused by prolonged
exposure to moisture and cold.
The inflammatory response
What’s going on?
Acne – inflammation of the skin caused by bacteria in the pores
The inflammatory response
What’s going on?
Inflammation is a common response to bee/wasp stings
The inflammatory response
What’s going on?
Tonsilitis – inflammation of the tonsils
The Inflammatory Response
• The inflammatory response (inflammation)
occurs when tissues are injured in some way.
Inflammation is
characterised
by five signs:
Pain
Heat
Redness
Inflammation
Swelling
Immobility
Why does the body bother with
the inflammatory response?
• It’s a protective
process!
– Designed to remove the
harmful stimulus (once
stimulus has been
removed, inflammation
will end)
– Begins the healing
process
Cell/Substance Effect
The Inflammatory Response
1. Following injury,
mast cells
become activated
and produce
histamine and
cytokines
2. Release of these
chemicals trigger
the inflammatory
response
Granules containing chemicals
Cell/Substance Effect
The Inflammatory Response
3. Histamine causes:
a) Vasodilation &
•
This increases blood
flow allows for more
white blood cells to
reach the infected
area quicker (results
in swelling)
Cell/Substance Effect
The Inflammatory Response
3. Histamine causes:
b) Increased capillary
permeability
• This means that white blood
cells and other proteins can
now squeeze in-between the
cells to get to the wound site
Cell/Substance Effect
The Inflammatory Response
4. The release of
cytokines by mast cells
causes phagocytes to
be attracted to the
area.
• Antimicrobial
proteins called
“complement
proteins” and
proteins known as
“clotting elements”
also arrive at the
site of infection
Cell/Substance Effect
The Inflammatory Response
5. Clotting elements
help to seal the wound
•
Clotting elements:
LINK BACK to Unit 2
KA 7 (activates
conversion of
prothrombin to
thrombin)
While phagocytes clean
up the injured site of
debris as well as engulf
pathogens
Inflammation Animation Summary
• http://www.sumanasinc.com/webconten
t/animations/content/inflammatory.ht
ml
Task – 10 minutes
• Use the following
Information slide to
complete:
1. The flow chart on the
inflammatory response
2. Functions table
Info Slide on the Inflammatory Response…
•
•
•
•
•
•
The inflammatory response (inflammation) occurs when tissues are injured
by bacteria, trauma, toxins, heat or any other cause.
Following injury, mast cells in the tissues become activated to produce
histamine and various cytokines, which then trigger the start of the
inflammatory response.
Histamine causes vasodilation and increased permeability of blood
capillaries. This results in an increased blood flow to the infected area
and allows other cells of the immune system to reach the infected
tissues.
Cytokines are small signalling molecules that attract phagocytes to the
site of infection. Phagocytes are white blood cells that engulf and destroy
the bacteria that have caused the infection, they also engulf and destroy
damaged tissue cells.
The presence of bacteria at the site of infection stimulates antimicrobial
proteins known as ‘complement’ to arrive at the site of infection. The
complement system, which include antimicrobial proteins, help the body to
rid itself of infection by amplifying the immune response.
Clotting elements are also attracted to the site of infection, where they
act to promote clotting (coagulation) of the blood. This prevents the site
of infection from bleeding and allows the infected area to heal.
Inflammatory
Response Flow Chart
Stimulus,
E.g. when tissues are injured
by bacteria, trauma, toxins,
heat or any other cause
Mast Cells
activated.
Histamine
released.
Cytokines
released.
Histamine
Cytokines
causes vasodilation
Phagocytes
released.
released.
and increased
attracted to site of
infection.
permeability of blood
capillaries
Cells of the
immune system
reach site of
infection.
Cells of the
immune system
reach site of
infection.
Complement
(antimicrobial proteins)
amplifies the immune
response.
Clotting elements
promote
Clotting (Coagulation)
of the blood.
Healing
Factor involved
in inflammatory
response
Mast Cell
Description & Function
Specialised white blood cell that releases histamines and
cytokines when injury occurs.
Triggers the inflammatory response.
Histamine
Chemical released by mast cell.
Causes vasodilation and increased permeability of blood
capillaries
Cytokine
Chemical released by mast cell.
Small signalling protein molecules that attract phagocytes to the
site of infection
Phagocyte
Specialised white blood cell.
Surrounds and engulfs pathogens.
Part of the complement system.
Antimicrobial Helps the body to rid itself of infection by amplifying (or
proteins
complementing!) the immune response.
Clotting
proteins
Proteins that promote coagulation (clotting) of the blood
Can you now ….
• State when an inflammatory
response might occur
• Name the cells which produce
histamine
• State 2 effects of histamine
• Name the cells which produce
cytokines
• State the role of cytokines
• Name 2 other structures which
accumulate at the site of
infection
• Overall: Describe the steps and
cells involved in the inflammatory
response
KA 1c: Non-Specific Defences
By the end of this section you will
be able to …..
• Name the 2 types of specialised white blood cells
involved in non-specific defence
• State the process that is carried out by
phagocytes
• State the process that is carried out by Natural
Killer cells
• Describe the process of phagocytosis
• Describe the process of apoptosis
• Name the 2 white blood cells which produce
cytokines
• State the effect of these cells producing cytokines
The many types of White blood cells
AKA
phagocyte
Engulfing
• All your cells have protein
surface markers on them.
• These markers let your
immune cells know that
your cells are yours and
belong in the body.
• However, pathogens such
as bacteria or viruses also
have markers on their
surface. But because they
do not belong in the body
and are ‘foreign’, they are
known as surface antigen
molecules
• The phagocytes
RECOGNISE these
foreign markers and
engulf the cell!
Phagocytosis
http://www.youtube.com/wat
ch?v=Rh_vqYn2hhs&feature=
related
Phagocyte (a.k.a.
Mr / Mrs / Ms Pac
Man or Mrs / Ms
Pac Woman)
Bacterial
particles
Lysosome containing powerful
digestive enzymes
Phagocytosis
Lysosomes
Digestive enzymes
bacterium
Phagocytosis
White blood cell
moves towards the
bacterium
Oh no !!!!!!
Phagocytosis
White blood cell
changes shape
to surround the
bacterium
Oh no !!!!!!
Phagocytosis
Phagocytosis
PhagocytosisLysosomes
Discharge their
enzymes into the
vacuole
Help I’m melting!!!
Non-specific Cellular Action
• A variety of specialised white blood
cells provide protection against
pathogens.
• Phagocytes and Natural Killer (NK)
cells are part of the non-specific
defence.
• They provide protection against a wide
range of pathogens.
Non-specific Cellular Action
• Phagocytes and Natural Killer (NK) cells
can also release cytokines which
stimulate the specific immune
response (more detail in key area 2)
Phagocytes
• Phagocytes recognise surface antigen
molecules on pathogens and destroy
them by phagocytosis:
– The foreign particle is engulfed and then
digested by enzymes present in lysosomes.
Process of
phagocytosis
(Figure 21.5
– page
310/314)
Apoptosis – programmed cell
death
Apoptosis – programmed cell
death
Natural Killer Cells
• Natural killer (NK) cells have an important role
in destroying a viral infected cell or a cancer
cell.
• NK cells induce the viral infected cells to
produce self-destructive enzymes in a process
called apoptosis (programmed cell death):
– NK cells recognise an infected cell because it does
not have the normal ‘self’ surface antigens.
– It then releases toxins and a ‘signal’ molecule
which enters the infected cell.
– This signal induces the cell to produce selfdestructive enzymes. These enzymes destroy the
cell by breaking down DNA and vital proteins.
– The cell then shrinks and dies.
Natural Killer (NK) cells
• https://www.youtube.com/watch?v=qjjH
KDn12qI (apoptosis summary)
• http://www.youtube.com/watch?v=HNP1
EAYLhOs (NK cells in LOTS of detail)
Can you now ….
• Name the 2 types of specialised
white blood cells involved in nonspecific defence
• State the process that is carried
out by phagocytes
• State the process that is carried
out by Natural Killer cells
• Describe the process of
phagocytosis
• Describe the process of
apoptosis
• Name the 2 white blood cells
which produce cytokines
• State the effect of these cells
producing cytokines