(04) Intro to Blood and Immune Flashcards
name the components of blood
Top to bottom:
Plasma = water and dissolved substances
White blood cells and platelets (buffy coat)
Red blood cells
in what component of blood are antibodies found?
in Plasma
name and describe the appearance of the types of white blood cells
lymphocytes (round, round nuclei)
neutrophils (uneven, multilobed nuclei)
monocytes (bean-shaped nuclei)
what do neutrophils do
phagocytic cells, capable of engulfing a microbe
the capability to move out of blood into infected tissue (extravasation)
what do monocytes do
precursors to macrophages
scavenging cells
secrete cytokines - immune signalling
name the two types of lymphocytes and their functions
B and T cells
B lymphocytes make antibodies
T lymphocytes help kill Tumour cells and control immune responses
what are the two major functions of the immune system?
differentiate self and non-self
seeks and destroys non-self
what is tolerance?
immune system learning to not react to self and react to something foreign
TOLERANCE IS LEARNED
what is pathology
the study of disease and how they progress
define pathogen
something that causes a disease
eg. bacteria / virus / fungi
define immunogenic
something that induces an immune response in the body
(eg. a part of a bacteria - the immune system can recognise it as non-self)
define antigen
the specific PART of the molecule / protein that the immune system responds to via a lymphocyte
pathogens have many antigens on their surface
define antibody
molecular component of the immune system, Y-shaped
recognises and binds (interacts with) antigens
produced by B cells
name the two phases of immune response
innate immunity - always deployed, immediate
adaptive immunity - takes time to develop
how do pathogens enter the body?
eat / breathe / touch them
name the first line of defence in external innate defences
PHYSICAL barriers:
skin
secretion - eg. tears, sweat, bile, stomach acid
mucous membranes - eg. lining digestive tract
describe the internal innate defences
bleeding, swelling, vasodilation –> allows immune cells in blood to reach injury site
phagocytic cells are first to arrive - recognise general features of bacteria, engulf and destroy
natural killer cells - generally deal with viruses
cascade - initial responders send signals to other immune cells (eg. defensive proteins)
describe inflammation
invasion causes chemical signals (eg. histamine) under skin
causes local blood vessels to dilate, increased leakiness (permeability),
migration of phagocytic cells to area
engulf
tissue heals
describe the phagocytosis process
phagocyte recognises bacteria, engulfs it –> phagosome (inside phagocyte)
merges with lysosome to form phagolysosome
bacteria killed, spat out the other end of the phagocyte
describe the internal adaptive defences
third line of defence
lymphocytes - B and T cells, and antibodies
they require signalling / activation so they take a longer time to respond
how are B / T cells activated?
we are born with a massive library of B / T cells for specific pathogens
activated by exposure to specific pathogens (specific reactors) - causes B / T cells to divide and deal with infection (undergo CLONAL EXPANSION)
what are epitopes
a smaller part of the antigen
lock and key - B / T receptor recognises it
two characteristics for antigens
immunogenicity - provokes immune response
reactive - the ability to react specifically with provoked antibodies / cells
how does the immune system “remember” past invaders
Memory B or T cells developed after primary immune response, living for decades in lymph nodes
activated if the body is exposed a second time to the same pathogen
faster / stronger / longer-lasting secondary response
