Cells of the haematopoietic system Flashcards
stinky
lots of RBC, WBC (big purple dot) little purple dot = platelets
NORMAL
fluffy (look at ppt) week 1 sem 2
lots of WBC - some kind of lymphocyte
WBC cancer or fighting illness
tufty sample?
lack of RBC
RBC destruction disorder?
anaemia
not making enough
patch?
parasitic infection - parasite in RBC
what does plasma contain?
water
proteins
nutrients & metabolic waste
electrolytes
Buffy coat?
<1% total volume
contains:
neutrophils
eosinophils
basophils
monocytes
lymphocytes
platelets
what two type of cells can a haematopoietic stem cell differentiate into?
myeloid progenitor cell
or
lymphoid progenitor cell
who has nucleated RBC?
Fish, reptiles, birds (so not too heavy w/ bone marrow)
most common blood cell type - 25% of cells in body?
erythocytes
structure of erythocytes?
rounded with small area of central pallor
lifespan of erythocytes?
life of 100-120 days
diameter of erythocytes?
6-8 microns
erythocytes organelles?
lack most organelles but metabolically active
erythocytes nucleated?
anucleate in mammals but some vertebrates have nuclei RBC
main function of erythocytes?
to carry oxygen to tissues and return carbon dioxide to the lungs
production of RBC called?
erythropoiesis
production of RBC regulated by?
growth factor hormone erythropoietin
where is EPO made?
in kidney and liver
where are erythocytes found?
blood vessels of circulatory system unless pathological
Reticulocytes
immature RBC
what are platelets?
they are tiny (2-4microns) anucleate cell fragments that circulate in the blood in an inactive state
what are platelets generated from?
megakarynocytes - this happens in response to the growth factor Thrombopoetin (TPO)
how long do circulating platelets live for?
7-10 days
populaion of platelets in blood?
massively high number (not as high as RBC tho)
1/3 platelets live where?
in spleen, dip in and out
they are sequestered to the spleen and this population alternates with circulation
species difference - platelets?
avian species have nucleated platelets called thrombocytes which do not form clots as well in arteries
which species are platelets found in ?
in mammals - most likely to offset danger from bleeding to death during birth
blood vessel damage - platelets?
rapidly activated when they sense blood vessel damage
Haemostasis?
localised stopping of bleeding at the injury site
diabetes? - thrombosis (innaporporiate activation of blood clotting with no vascular injury
first stage of wound healing - platelets?
platelet plug
what does tissue damage promote?
leukocyte attraction - helps remove bacteria and debris to promote repair and remodelling - platelets attract and interact with these cells
tissue damage promote attraction of what leukocytes?
WBC, intially neutrophils and then macrophages
how do platelets interact with cells of damaged tissue?
via receptors
how do platelets attract cells?
chemical mediators in granules - the chemicals come and get involed
rapid amplification
cell surface receptors? - platelets
promote adhesion to the damaged vessel and responsiveness to other substances in the blood and platelet activation
how do platelets manage to cover wound?
changes in membrane invagination and spreading of platelets in order to cover and to create a large procoagulant surface for activation of coagulant factors
storage granules? platelets
these are released and they contain prothrombotic factors including clotting factors, ADP and ATP, calcium and immune modulators e.g. CD40L
what allows a dynamic shape change of platelets?
rapid changes to cytoskeletal proteins which allow the shape change
what gives rise to granulocytes?
common myeloid progenitor
give e.g. of monocyte?
granulocytes
granulocytes AKA?
polymorphonuclear leukocytes
What cells are classed as granulocytes?
neutrophils, eosinophils and basophils - together they constitute 60-70% of WBC in circulation
monocytes are?
circulating cells in blood in tissue and they become macrophages
neutrophils size?
they are large cells (10-20 microns)
multilobes nuclei
lifespan of neutrophils?
2-3 days
what makes up 60% of WBC?
neutrophils
90% of granulocytes are?
neutrophils
size of macrophages?
large tissue
differentiated monocytes, greater than 20 microns in size
lifespan of macrophages?
long lived
nomenclature of macrophages?
depends on where they are found
e.g. Kupffer cell in liver, microglia in CNS, osteoclast in bone, alveolar macrophages in lungs
functions of macrophages?
phagocytosis
stimulation of adaptive immune response
tissue/wound repair/remodelling
iron homeostasis
size of eosinophils?
large granulocytes around 12-17 microns
lifespan of eosinophils?
in circulation of 8-12 hours
short lived
survive in tissues for up to 12 days
what percentage of WBC are eosinophils?
2-3%
what do eosinophils stain eosin?
red
what do eosinophils contain?
prominent granules pack with a crystalline core of major basic protein which is cytotoxic for parasites
eosinophils have an important role in immunity to what?
Helminth infections
what receptors do eosinophils have?
IgE receptors on surface for antibodies
what cells contribute to allergic reactions e.g. in asthma?
eosinophils
basophils?
least common granulocyte cell type
monocytes?
phagocytic cells
precursors to macrophages
percentage of WBC population of monocytes?
5-10%
how are monocytes identifiable?
by their kidney bean shaped nucleus or notched nucleus in smears
what stores the monocytes?
spleen
found primarily in blood or spleeen
spleen acts as? - monocytes
blood filter and stores monocytes for rapid deployment
circulation of monocytes?
precursor for macorphages
circulate in blood for 1-3 days before migrating to tissues to become macrophage cell types
response of monocytes?
rapidly respond inflammatory stimuli and migrate in large numbers of infection site or injury site
mast cells circulation?
they circulate as immature cells and migrate to tissues where they mature into mast cells
types of mast cells depend on?
on location and chemicals/substances contained in their granules
where are mast cells found?
in connective tissue and mucosal tissues e.g. GI tract
why are mast cells important?
for the response to a range of pathogens e.g. helminths, in wound healing and in allergy repsonse
what receptors do mast cells have?
they have receptors for IgE antibody, which cross linking causes degranulation releasing many activating/inflammatory factors e.g. histamine
cells from the lymphoid progenitor include what cells?
B,T,NK cells
cells from lymphoid progenitor represent?
most abundant population in the lymphatic system
what % of WBC do lymphoid progenitor cells represent?
30
how are cells from the lymphoid progenitor distinct?
large deeply staining nucleus that may be eccentric in location and a small amount of cytoplasm
what is impossible to determine from blood smear? - t/b lym
whether they are T or B lymphocytes
NK cells?
they are innate immune repsonse and have lower numbers
cells from lymphoid progenitor are mahor constituents of what?
of the adaptibe immune system
where does t lymphocyte name come from?
from maturation in the thymus
NK cells?
natural killer cells
B lymphocyte?
other major type of adaptive immune system
where does the B lymphocyte name come from?
from its maturation in birds in the bursa of fabricus
what are erythocytes mostly made of?
haemoglobin, 96% dry weight
what is haemoglobin?
it is a complex metalloprotein containing Haem groups which use iron atoms to bind oxygen in lungs or gills
how many molecules of oxygen can each haemoglobin carry?
4
how many oxygen molecules can a fully saturated erythrocyte carry?
up to a billion
how saturated are erythrocytes in vivo normally?
between 70-95%
as well as oxygen, what can haemoglobin also carry?
some waste CO2 back from tissues but this is mostly transported in the plasma as dissolved bicarbonate ions
what are neutrophils?
they are large cells (10-20 microns) with multilobed nuclei
how long do neutrophils live for?
2-3 days
what are neutrophils innate function?
innate immune function
meaning of innate?
when you are born with something already there
cytoplasmic granules stain what colour?
neutral
cytoplasmic granules contain what enzymes?
lysozyme
what function do neutrophils contribute to?
phagocytic function - kill bacteria and fungi
what is the species difference with neutrophils?
AVIAN orthologs are called heterophils
orthologs?
homologous genes that relate through speciation
which is the least common granulocyte? - and what is the % circulating WBC?
basophils
only 0.01-0.3% circulating WBC
do basophils have cytoplasmic granules?
yes
describe the cytoplasmic granules in basophils:
these are large and they obscure the cell nucleus when stained w/ basic dyes
what are basophils most closely related to?
to tissue resident mast cells
what reactions do basophils participate in?
in inflammatory reactions in response to parasites and allergens
what causes the release of inflammatory mediators? and give examples of these mediators - basophils
activation of their IgE receptors
e.g. histamine, leukotrienes and prostaglandins
what are dendritic cells related to?
monocytes/macrophages
describe the precursor of dendritic cells:
these are present in low numbers in blood and migrate to populate both lymphoid and non-lymphoid tissues
describe the dendrites of dendritic cells:
have long cytoplasmic dendrites
what can monocytes differentiate into?
into inflammatory dendritic cells
what type of dendritic cell does not belong to the haematopoietic system?
follicular dendritic cells
what do follicular dendritic cells play a key role in?
in orchestrating B cell responses in lymphoid tissue
what do dendritic cells act as sentinels of?
the immune system - sampling the environment for antigens
what do plasmacytoid dendritic cells do for the immune system?
they induce an anti-viral response
what do conventional dendritic cells do for the immune system?
professional antigen-presenting cells, presenting foreign antigens to T cells to induce adaptive immune response
Where does the name of a T lymphocyte come from?
from maturation in the thymus
What system do T lymphocytes belong to?
belong to the adaptive immune system
what receptor do most T lymphocytes express?
the αβ T cell receptor (TCR)
what does the αβ T cell receptor (TCR) recognise?
the foreign peptides that are presented on other cells major histocompatibility complex (MHC) molecules
T cells express a broad repertoire of TCRs that recognise what?
different antigenic peptides BUT each T cell has a unique specificity
What are the three categories of T cells?
Helper
Cytotoxic
Memory
What is a helper T cell?
CD4 expressing cells that help drive immune responses against different types of pathogens
What is a cytotoxic T cell?
CD8 expressing cells which recognise and kill infected or cancerous cells
What is a memory T cell?
effector cells that can be rapidly produced to counter a familiar pathogen
What system are B lymphocytes part of?
the adaptive immune system
Where do B lymphocytes get their name from?
from their maturation in birds in the bursa fabricus
what receptor do B lymphocytes express?
they express the B cell receptor
what is the B cell receptor?
it is an immunoglobulin that recognises foreign molecules (protein or carbohydrate)
What do B lymphocytes have a broad repertoire of and what does this allow them to do?
receptors - enables them to recognise an array of antigens
What happens once a B lymphocyte encounters an antigen?
it transforms to become a plasma cell which secretes antibodies (immunoglobulins) to counter pathogens
As well as turning into plasma cells, what can B lymphocytes also act as?
antigen presenting cells
B cells acquire memory, what does this allow them to do?
allows them to produce antibodies when they re-encounter an old pathogen. THIS IS THE BASIS FOR IMMUNITY TO REINFECTION AND THE PRINCIPLE BEHIND VACCINATION
What innate like lymphocytes do we have?
Natural killer cells (NK) cells
NK T cells
γδ-T cells
Innated lymphoid cells
What is the role of innate like lymphocytes?
they have a role in protective immunity and the regulation of homeostasis
What can dysfunction of innate like lymphocytes cause?
it can cause allergy or autoimmune disease
what do γδ-T cells do?
they recognise pathogen metabolites or stress molecules and perform a variety of functions - important for veterinary species e.g. pigs, ruminants & chickens
What are innate like lymphocytes?
they are families of lymphoid cells that are lacking in BCR or conventional TCR
BCR?
B cell receptors
TCR?
T cell receptors
