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.
What is the circulatory system ?
The system that circulates blood through the body, consisting of the heart, blood vessels, and blood.
What is the function of the heart ?
Muscular organ that pumps blood around the body.
What is the function of a vein ?
A blood vessel with valves that transports blood to the heart.
State the three types of blood vessels in the body .
Most animals have a closed circulatory system. In a closed circulatory system, the blood stays inside blood vessels as it travels around the body. Humans have a double circulation system because blood moves through the heart twice. The right side of the heart and blood vessels carries blood from your heart to the lungs and back again (pulmonary) and the left side of the heart pumps blood from to all other organs of your body and back again (systemic). The double circulation system allows lots of oxygenated blood to be transported quickly.
Describe and explain the structure of each blood vessel type.
What is the structure of the heart ?
The heart organ is a double pump
Oxygenated blood from the lungs enters the left side of the heart and is pumped to the rest of the body (the systemic circuit)
The left ventricle has a thicker muscle wall than the right ventricle as it has to pump blood at high pressure around the entire body,
Deoxygenated blood from the body enters the right side of the heart and is pumped to the lungs (the pulmonary circuit)
The right ventricle is pumping blood at lower pressure to the lungs
A muscle wall called the septum separates the two sides of the heart
Blood is pumped towards the heart in veins and away from the heart in arteries
The coronary arteries supply the cardiac muscle tissue of the heart with oxygenated blood
As the heart is a muscle it needs a constant supply of oxygen (and glucose) for aerobic respiration to release energy to allow continued muscle contraction
Valves are present to prevent blood flowing backwards
cross-section-of-a-human-heart-from-the-side
Structure of the Heart
The pathway of blood through the heart
Deoxygenated blood coming from the body flows through the vena cava and into the right atrium
The atrium contracts and the blood is forced through the tricuspid (atrioventricular) valve into the right ventricle
The ventricle contracts and the blood is pushed through the semilunar valve into the pulmonary artery
The blood travels to the lungs and moves through the capillaries past the alveoli where gas exchange takes place
Low pressure blood flow on this side of the heart prevents damage to the capillaries in the lungs
Oxygenated blood returns via the pulmonary vein to the left atrium
The atrium contracts and forces the blood through the bicuspid (atrioventricular) valve into the left ventricle
The ventricle contracts and the blood is forced through the semilunar valve and out through the aorta
Thicker muscle walls of the left ventricle produce a high enough pressure for the blood to travel around the whole body.
What is the function of the right atrium ?
Deoxygenated (low in 02) blood from the body enters the right atrium. This blood is under low
pressure.
What is the function of the right ventricle ?
Blood passes into the right ventricle, which contracts to pump blood to the lungs, where
the blood is oxygenated.
What is the heart structure and function ?
What is Ultrafiltration ?
The Kidneys have around 1 million tiny tubules called nephrons, each
associated with a blood capillary. Waste products leave the blood
and enter the nephron to form urine.
1. Dirty blood enters the kidney via the renal artery.
2. The artery splits up into a ball of capillaries called the
glomerulus.
3. The Blood is under high pressure (coming from the pumping
heart and also because the blood vessel leading away from the
glomerulus has a smaller diameter)
- The high pressure forces all small molecules out of the holes in
the capillary walls leaving only large molecules like proteins in
the blood. - The small molecules enter the Bowman’s capsule (now called
glomerular filtrate) and travel into the proximal convoluted
tubule where glucose is reabsorbed back into the blood by
active transport. - The filtrate travels down through the loop of Henlé where
water is reabsorbed by osmosis. - The filtrate then enters the distal convoluted tubule where
minerals, amino acids and other useful substances are
reabsorbed back into the blood. - The remaining fluid containing urea, excess salts and excess
water passes into the collecting duct. - The distal convoluted tubules from several other nephrons join
up to form the collecting duct. - The collecting ducts from the other nephrons join to
form the ureter, which leads to the bladder. - The fluid (urine) is stored in the bladder ready for excretion.
- The urine travels down the urethra to the outside.
Label diagram of a kidney .
What is an example of homeostasis ?
What happens when there Is too high/low concentration of plasma ?
What is the function of receptors?
They can detect changes in the environment (stimuli)
Receptors are often found in sense organs. Can you remember the
sense organs? Hint: Most the sense organs are found in the head
When a receptor is stimulated it sends a signal along the nerve cells
(neurones), to the brain. Neurones are specialised for transmitting
messages in the form of an electrical impulse.
What are the three neurones ?
1)Sensory neuron
2)Motor neuron
3)Relay neurones
What is the function of a sensory neurone ?
carry signals from the receptors to the CNS (spinal
cord and brain).
They have an extended shape so that they can carry nerve impulses
from one part of the body to another.
Dendrites attach to receptor (sensory organs)
Cell body is in the middle
Transmit impulses from receptor to the CNS
What is the function of a motor neurone ?
Motor neurones carry signals from the CNS to effectors.
The motor neurone has a cell body that lies within the brain or
the spinal cord.
It has a nucleus within its cell body and the cell body has thin
extensions on its surface called dendrites.
It has a very long axon which conducts impulses over very long
distances.
The ends of the axon branches have large numbers of
mitochondria .
What is the eye?
The eye is a highly specialised sense organ containing receptor cells that allow us to detect the stimulus of light
The retina of the eye contains two types of receptor cells:
Receptor cells that are sensitive to light, known as rods, and receptor cells that can detect colour, known as cones
What are the eyes structure and functions ?
Other structures of the eye include the:
conjunctiva - a clear membrane that covers the white of the eye and the inside of the eyelids; it lubricates the eye and provides protection from external irritants
ciliary muscle - a ring of muscle that contracts and relaxes to change the shape of the lens
suspensory ligaments - ligaments that connect the ciliary muscle to the lens
sclera - the strong outer wall of the eyeball that helps to keep the eye in shape and provides a place of attachment for the muscles that move the eye
fovea - a region of the retina with the highest density of cones (colour detecting cells) where the eye sees particularly good detail
aqueous humour - the watery liquid between the cornea and the lens
vitreous humour - the jelly-like liquid filling the eyeball
choroid - a pigmented layer of tissue lining the inside of the sclera that prevents the reflection of light rays inside the eyeball
blind spot - the point at which the optic nerve leaves the eye, where there are no receptor cells
What happens to the eye when it focuses on distant and near objects ?
What happens to the function of the eye when responding to changes in light intensity ?
The pupil reflex is a reflex action carried out to protect the retina from damage
In dim light, the pupil dilates (widens) in order to allow as much light into the eye as possible to improve vision
In bright light, the pupil constricts (narrows) in order to prevent too much light from entering the eye and damaging the retina
What happens to the eye when it focuses on a dim light ?
What happens to the eye when it focuses on a bright light ?
