(04) Intro to Blood and Immune

Question 1

name the components of blood

Answer 1

Top to bottom:
Plasma = water and dissolved substances
White blood cells and platelets (buffy coat)
Red blood cells

Question 2

in what component of blood are antibodies found?

Answer 2

in Plasma

Question 3

name and describe the appearance of the types of white blood cells

Answer 3

lymphocytes (round, round nuclei)
neutrophils (uneven, multilobed nuclei)
monocytes (bean-shaped nuclei)

Question 4

what do neutrophils do

Answer 4

phagocytic cells, capable of engulfing a microbe
the capability to move out of blood into infected tissue (extravasation)

Question 5

what do monocytes do

Answer 5

precursors to macrophages
scavenging cells
secrete cytokines - immune signalling

Question 6

name the two types of lymphocytes and their functions

Answer 6

B and T cells
B lymphocytes make antibodies
T lymphocytes help kill Tumour cells and control immune responses

Question 7

what are the two major functions of the immune system?

Answer 7

differentiate self and non-self
seeks and destroys non-self

Question 8

what is tolerance?

Answer 8

immune system learning to not react to self and react to something foreign
TOLERANCE IS LEARNED

Question 9

what is pathology

Answer 9

the study of disease and how they progress

Question 10

define pathogen

Answer 10

something that causes a disease
eg. bacteria / virus / fungi

Question 11

define immunogenic

Answer 11

something that induces an immune response in the body
(eg. a part of a bacteria - the immune system can recognise it as non-self)

Question 12

define antigen

Answer 12

the specific PART of the molecule / protein that the immune system responds to via a lymphocyte

pathogens have many antigens on their surface

Question 13

define antibody

Answer 13

molecular component of the immune system, Y-shaped
recognises and binds (interacts with) antigens

produced by B cells

Question 14

name the two phases of immune response

Answer 14

innate immunity - always deployed, immediate
adaptive immunity - takes time to develop

Question 15

how do pathogens enter the body?

Answer 15

eat / breathe / touch them

Question 16

name the first line of defence in external innate defences

Answer 16

PHYSICAL barriers:
skin
secretion - eg. tears, sweat, bile, stomach acid
mucous membranes - eg. lining digestive tract

Question 17

describe the internal innate defences

Answer 17

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)

Question 18

describe inflammation

Answer 18

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

Question 19

describe the phagocytosis process

Answer 19

phagocyte recognises bacteria, engulfs it –> phagosome (inside phagocyte)
merges with lysosome to form phagolysosome
bacteria killed, spat out the other end of the phagocyte

Question 20

describe the internal adaptive defences

Answer 20

third line of defence
lymphocytes - B and T cells, and antibodies
they require signalling / activation so they take a longer time to respond

Question 21

how are B / T cells activated?

Answer 21

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)

Question 22

what are epitopes

Answer 22

a smaller part of the antigen
lock and key - B / T receptor recognises it

Question 23

two characteristics for antigens

Answer 23

immunogenicity - provokes immune response
reactive - the ability to react specifically with provoked antibodies / cells

Question 24

how does the immune system “remember” past invaders

Answer 24

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