Intro to Immune & Lymphatic System

Question 1

List the 3 main things that make up the immune system.

Answer 1

Barriers, cells and proteins

Question 2

What is the lymphatic system made of?

Answer 2

vessels and nodes

Question 3

Summarise the drainage of the lymphatic system

Answer 3

Lymph capillaries collect leaked tissue fluid which is filtered through successive lymph nodes, returns to venous system via two large ducts with one way flow to heart, surveys for gunk and threats, high pressure in tissues opens gaps between cells = leaking

Question 4

What is the function of the lymph nodes?

Answer 4

to filter lymph and site of activation for lymphocytes

Question 5

Define:
erythrocytes
platelets
leukocytes

Answer 5

erythrocytes: RBCs
platelets: help clotting and play role in inflammation
leukocytes: WBCs, immune cells of blood eg neutrophils and monocytes

Question 6

Compare the innate and adaptive immune systems

Answer 6

innate: non-specific, fast response, same every time
adaptive: educated as we grow, slow response, specific protection, cellular immune-t cells, humoral immune- b cells

Question 7

How is the innate immune system activated?

Answer 7

1) damage (DAMPs): system recognises warning signs eg increase of K+ or DNA in tissue indicates damaged cell
2) pathogens (PAMPs): system recognises part of bacterial cell wall, viral proteins

Question 8

How is the adaptive immune system activated?

Answer 8

If the innate immune system can’t clean up the mess, it relays message to adaptive system by presenting fragments of foreign invader in lymph nodes, adaptive system agrees that it is threat and antigens activate response, cells communicate via chemical mediators cytokines and chemokines

Question 9

Describe phagocytosis

Answer 9

A process where a cell uses its plasma membrane to engulf a large particle giving rise to internal compartment called phagosome, digests and kills particle

Question 10

Describe Phagocyte: neutrophils

Answer 10

most abundant WBC, first responders to bacterial infections, levels increase upon infection (diagnostic)

Question 11

Describe phagocyte: macrophages

Answer 11

big eaters, circulating monocytes become macrophages when leave blood and enter tissue, can be fixed tissue residents or migratory, long lived, secrete cytokines -> amplify inflammation

Question 12

What happens once innate immune system is activated?

Answer 12

inflammation

Question 13

What is the purpose of inflammation?

Answer 13

to localise and eliminate injurious agent, remove damaged tissue and components, clean mess and begin to heal

Question 14

Describe the two different phases of acute inflammation.

Answer 14

1) vascular: injured cells and neurons release chemical mediators (chemokines), induces vasodilation and increases cap permeability causing influx of plasma proteins -> propagate inflammation, blood clotting, complement and kinin production. complement system + inflammatory mediators = WBCs to inflammatory site
2) cellular phase: neutrophils and macrophages enter inflamed tissue through leaky blood caps, phagocytic cells ingest invading paths, dead cells and debris, release cytokines and pyrogens -> fever

Question 15

Which cells present antigens to adaptive immune system?

Answer 15

macrophages and dendritic cells

Question 16

compare the 2 antigen presenting cells

Answer 16

macrophages: can take sample of virus cell when eating and show lymph node
dendritic cells digest and show t cell in lymph node via MHC-II

Question 17

Compare T and B cells

Answer 17

T cells: cellular immunity, mature in thymus, born in bone marrow, T helpers have direct adaptive response, t killer cells directly kill infected cells
B cells: born in bone marrow and stay there, go to lymph nodes in uni, produce antibodies that recognise antigen and bind to it

Question 18

Describe antigens

Answer 18

molecule provoking immune responses, large molecules, reactive by themselves, immunogenic (stimulate a response), trigger adaptive immunity

Question 19

Describe the role of the thymus in the lymphatic system

Answer 19

site of T-lymphocyte maturation, differentiate into t helper and cytotoxic t cells, learn self tolerance and recognise self from non-self

Question 20

describe red bone marrow role in lymphatic systyem

Answer 20

site of origin of all blood cells, maturation of b cells

Question 21

differentiate between signs of infected or cancerous lymph nodes

Answer 21

infected: swollen and painful
cancerous: swollen but not painful