Immune response to disease Flashcards
Name three substances the blood transports.
Oxygen, carbon dioxide, glucose, water, urea
What are the adaptations of red blood cells?
Red blood cells have adaptations that enable them to carry a maximum amount
of oxygen. They contain the protein haemoglobin, which gives them their red
colour. Haemoglobin can combine reversibly with oxygen. This is important - it
means that it can combine with oxygen as blood passes through the lungs, and
release the oxygen when it reaches the cells.
*They have no nucleus - - so they can pack in more haemoglobin.
*They are small and flexible so that they can fit through narrow blood capillaries.
*They have a biconcave shape - they are the shape of a disc that is curved
inwards on both sides - to maximise their surface area for oxygen absorption.
*They are thin, so there is only a short distance for the oxygen to diffuse to reach
the centre of the cell.
What is the role of White Blood Cells?
White blood cells form part of the immune
system which is composed of:
1. Lymphocytes – produce antibodies or
antitoxins
2. Phagocytes – engulf and digest invading
microorganisms.
What is phagocytosis ?
Phagocytes carry out phagocytosis by engulfing and digesting
pathogens
* Phagocytes have a sensitive cell surface membrane that can detect
chemicals produced by pathogenic cells
* Once they encounter the pathogenic cell, they will engulf it and release
digestive enzymes to digest it
* This is a non-specific immune response
What colour is plasma ?
The plasma is a yellow
colour, blood is only red
because of the
haemoglobin in red
blood cells!
What is blood made of?
Blood has four main components: red blood cells, white
blood cells, platelets all of which are carried in a fluid called plasma.
Within the plasma dissolved substances like oxygen and
glucose (plus other products of digestion), urea and carbon
dioxide will also be carried.
What is the role of the platelets ?
Platelets are small fragments of
cells without a nucleus.
◦ They are involved in clotting of
blood. The clotting process forms
a network of fibres that traps
more platelets and red blood
cells to form a scab which
protects the new skin as it grows
underneath. Scabs also prevent
microorganisms from getting into
the cut.
What would happen
if our platelets don’t
work or we don’t
produce sufficient
amount?
We would be at risk of bleeding -
this is called a Platelet Related
Disease (PRD).
* On the other hand, if our platelets
form clots excessively or at the
wrong time, the clot can block an
important blood vessel. This is called
thrombosis and can lead to a heart
attack or a stroke. Thrombosis can
happen in arteries or veins
What is the function of red blood cells?
Red blood cells carry the oxygen from the air in
our lungs to our respiring cells.
They are packed with haemoglobin which binds
to oxygen. It contains an atom of iron (Fe) which
gives the pigment it’s red colour it is brightest
when there is lots of oxygen bound to the
haemoglobin.
What happens to people who have sickle-cell anaemia ?
People who suffer with sickle cell anaemia have misshapen
red blood cells, they have a smaller volume so they cannot
hold as much haemoglobin which means they cannot carry
as much oxygen.
The shape also causes diffusion of oxygen to be slower as it
has a smaller surface area. The shape can also cause blood
vessels to block blood vessels which can slow blood flow.
Sufferers can get breathless quickly and are
often tired. They are also less able to do
exercise as their muscles get tired or fatigued
quickly.
What type of blood cells are involved in the immune response?
White blood cells.
Why is there a delay between being infected and feeling the symptoms ?
Time needed for bacteria/virus to reproduce.
How do viruses make you feel ill?
Viruses damage host cell as they reproduce.
What’s the difference between bacteria and
viruses in how they replicate [make copies]?
Bacteria can make identical copies, whereas a virus needs a host cell to reproduce .
How do bacteria make you feel ill?
Bacteria release toxins.
Explain how phagocytes work.
Phagocytes envelop the pathogen within their cell and use enzymes to kill and digest the pathogen.
Explain the difference between antibodies
and antitoxins.
Antibodies are chemicals that are specific to each pathogen, and are released from white blood cells. They can send signal for help from other white blood cells. They can destroy the pathogen directly. They can also clump together to make phagocytosis easier . Antitoxins are she,icals that simply neutralise the harmful effects of toxins .
Why do you think phagocytes are classed as a
non-specific response whereas antibodies are
a specific response?
Phagocytes will attack all pathogens (non-self structures)
the same way whereas the antibodies are made specifically according to the antigen structure on the surface of the invading pathogen .
What are lymphocytes ?
Lymphocytes can easily be recognised under the microscope by their large round nucleus which takes up nearly the whole cell and their clear, non-granular cytoplasm
Lymphocytes produce antibodies
Antibodies are Y-shaped proteins with a shape that is specific (complementary) to the antigens on the surface of the pathogen
This is a specific type of immune response as the antibodies produced will only fit one type of antigen on a pathogen
The lymphocytes produce antibodies that are specific to the antigen on the pathogen
Antibodies attach to the antigens and cause agglutination (clumping together)
This means the pathogenic cells cannot move very easily
At the same time, chemicals are released that signal to phagocytes that there are cells present that need to be destroyed
Agglutinated pathogens cannot move easily
Lymphocytes also produce antitoxins to neutralise toxins released by pathogens
Antitoxins,
Lymphocytes produce specific antitoxins to specific pathogens
What are phagocytes ?
Phagocytes carry out phagocytosis by engulfing and digesting pathogens
Phagocytes have a sensitive cell surface membrane that can detect chemicals produced by pathogenic cells
Once they encounter the pathogenic cell, they will engulf it and release digestive enzymes to digest it
This is a non-specific immune response
Phagocytes can be easily recognised under the microscope by their multi-lobed nucleus and their granular cytoplasm.
What is the bodies response to an infection ?
The stages of infection and the subsequent immune response are as follows:
The pathogen enters the blood stream and multiplies
A release of toxins (in the case of bacteria) and infection of body cells causes symptoms in the patient
Phagocytes that encounter the pathogen recognise that it is an invading pathogen and engulf and digest (non-specific response)
Eventually, the pathogen encounters a lymphocyte which recognises its antigens
The lymphocyte starts to produce specific antibodies to combat that particular pathogen
The lymphocyte also clones itself to produce lots of lymphocytes (all producing the specific antibody required)
Antibodies cause agglutination of pathogens
Phagocytes engulf and digest the agglutinated pathogens
After the patient has recovered, they retain antibodies specific to the disease as well as memory cells (lymphocytes that recognise the pathogen)
If the patient encounters the same pathogen again, it will trigger a secondary immune response
Memory cells can produce much larger quantities of the required antibody in a much shorter time to fight off the pathogen before the patient suffers any symptoms
What is the function of blood?
The red liquid that circulates in the blood vessels of the circulatory system.
What the the function of the Arteries ?
Blood vessels that carry blood away from the heart.
What is the function of Capillary?
Tiny blood vessels with walls one cell thick where exchange of materials occurs.
