wk 6- innate immunity

Question 1

difference between primary and secondary lymphoid organs/tissues

Answer 1

Primary lymphoid organs are the site of lymphocyte maturation and
secondary lymphoid organs and tissues are the sites of pathogen encounters.

Question 2

what are muscosa-associated lymphatic tissue

Answer 2

nodal patches of lympathic tissue in the mucosal linings

Question 3

where do B-lymphocytes and T-lymphocytes mature?

Answer 3

primary lymphoid organs that mature in
B- red bone marrow of long bones
T- thymus

Question 4

changes in thymus during adulthood, what happens

Answer 4

it is large in early life but atrophies in adulthood and is replaced by fatty connective tissue

Question 5

difference between afferent lymphatic vessels and efferent?

Answer 5

a- the point of unfiltered lymph into the lymph node
e- the point of exit of filtered lymph out of the lymph node

Question 6

what is mucosa-associated lymphatic tissue?

Answer 6

nodal patches of lymphatic tissue in the mucosal linings

Question 7

what 2 responses is the immune system made up of? and what do they do?

Answer 7

innate immune response and adaptive immune response. They work together to recognize, target and remove infectious agents from the body. The innate response is more rapid and less specific than the adaptive immune response

Question 8

characteristics of innate immune response 4

Answer 8

non specific response (one size fits all)
rapid response (minutes to hours)
no memory
present at birth

Question 9

characteristics of adaptive immune response 4

Answer 9

specific response (targeted)
slow response (lag time, delays)
immunological memory
antibodies
develops over time

Question 10

components of innate immune response 3

Answer 10

physical/mechanical factors:(skin/mucous membranes)
cellular factors: (phagocytic cells, antigen presenting cells)
soluble factors (enzymes, pyrogens (fever) , complement)

Question 11

list and describe phagocytic cells

Answer 11

cell eaters

monocytes
macrophages
neutrophils
dendritic cells

Question 12

myeloid progenitor cells include what cell types

Answer 12

red blood cells, granulocytes (dendritic),monocytes and platelets

Question 13

lymphoid progenitor cells include what cell types

Answer 13

lymphocytes and NK cells

Question 14

myeloid cells are apart of what immune respnse

Answer 14

innate

Question 15

lymphoi are apart of what immune response

Answer 15

adaptive

Question 16

components of adaptive immune responses 2

Answer 16

cellular factors (lymphocytes, NK cells)
soluble factors (antibodies, enzymes)

Question 17

where do immune cells come from?

Answer 17

immune cells are derived from red bone marrow in a process called haemoatpoiesis.
from here they transition from stem cells to progenitor cells and finally mature cells via two lineages.

the myeloid progenitor cells produce the innate immune response cells and the lymphoid progenitor cells produce the adaptive immune response cells.

Question 18

most common cell in the innate immunity to respond

Answer 18

neutrophils

Question 19

an effective Immune system must be able to: 6

Answer 19

1. remain inactivated/switched-off under normal physiological conditions
2. be activated by infectious agents (recognition of pathogens)
3. produce a tailored response to specific pathogen groups (extracellular versus intracellular)
4. respond at the site of infection (recruitment of immune cells)
5. be regulated (turned off when pathogen is cleared)
6. prevent/minimise damage to self-tissues

Question 20

chemotaxis is?

Answer 20

used to describe the recruitment/movement of immune cells towards a chemical stimulus (site of infection or trauma)

Question 21

soluble facts for innate immune responses

Answer 21

complement system - soluble complement proteins which initiate opsonisation: coat infectious agents for easy phagocytosis, membrane attack complex: causing cell lysis,
causes inflammation: reducing reproduction of agent
chemotaxis: recruitment of phagocytosis

also
sweat, oil, digestive enzymes, mucous, etc

Question 22

what does phagocytosis do? what do they target, what is the process?

Answer 22

target EXTRACELLULAR pathogens
Phagocytosis is triggered by pattern recognition. Phagocytic cells enclose infected cells in vesicles, to which enzymes from lysosomes are added, resulting in destruction of the pathogen. Phagocytosis is effective for targeting extracellular pathogens such as bacteria, protozoa and fungi.

Question 23

what do natural killer cells and interferon (NK and IFN) do?

Answer 23

target intracellular pathogens

Production of interferon interferes with viral replication via:
1. inhibition of viral protein synthesis
2. degradation of viral nucleic acids
3. inhibition of viral gene expression and virion assembly

(viruses are intracellular pathogens)

Question 24

what cells target intracellular and extracellular pathogens?

Answer 24

intra- NK and IFN
extra- phagocytic cells

Question 25

what is an early innate response to exposure of an infectious agent?

Answer 25

fever

Reproduction of microbial cells is optimal at core body temperature, if the temperature is increased by one to two degrees Celsius, then the replication rate of microbial cells is significantly impaired. A reduction in the replication rate of the pathogen allows time for the host immune cells to be recruited to the site of infection. Pyrogens are chemical mediators of hypothalamic temperature control and a reproduced by phagocytic cells.

Question 26

steps of acute inflammation 8

Answer 26

1. disruption to barrier integrity (trauma/infection)
2. epithelial cell activation pattern recognition receptor signaling: production of host antimicrobial peptides
3. activation of complement pathway: opsonisation, inflammation, killing
4. activation of resident phagocytes: phagocytosis and cytokine production
5. cytokines and complement activate local vascular endothelium: increased cell recruitment and vascular leakage
6. increased phagocytosis, complement and HDP activity
7. resolution of infection
8. activation of adaptive immunity

Question 27

what is complement and what does the activation result in / steps ?

Answer 27

Activation of complement results in a cascade of proteolytic cleavage of large proteins to facilitate the effects of antibody. Without the production of complement, antibody cannot destroy invading pathogens.

steps:
1. inflammation
2. opsonisation to coat the infectious agent for easy capture by phagocytic cells (C3b)
3. phagocytosis (C5a) via chemotaxis results in recruitment of phagocytic cells to the site of infection
4. cell lysis caused by pore formation caused by membrane attack complex (MAC)

Question 28

initiation of complement activation can happen how? 3

Answer 28

complement activation (C3) can be activated via three pathways:
(1) the lectin pathway,
(2) the classical pathway, and
(3) the alternative pathway.

Question 29

examples of mechanical factors 5

Answer 29

intact skin
mucous production
ciliated epithelium
low pH
acid production

Question 30

examples of soluble factors 4

Answer 30

pyrogens (fever)
lysozymes
interferon
complement

Question 31

examples of cellular factors

Answer 31

neutrophils
macrophages
dendritic cells
monocytes
phagocytic cells

Question 32

what turns on innate immunity?

Answer 32

pattern recognition through toll-like receptors, responsible for recognizing molecules that are highly conserved across classes of pathogens

can be intracellular to recognize viruses or extracellular.

Question 33

what are antigen presenting cells

Answer 33

present infection to the adaptive immune system