Immune + Lymphatic

Question 1

How does the skin contribute to immunity?

Answer 1

Physical barrier
Produces anti microbial peptides and IgA to destroy/inhibit pathogens
Epidermal Langerhan’s Cells capture and activate immune response
Skin has own microbiota to compete

Question 2

How do mucous membranes contribute to immunity?

Answer 2

Physical barrier covered in mucous to trap microbes
Substances within mucous inhibits microbes
Immune cells in membrane capture and activate immune response if mucous breached
Some have cilia to expel trapped microbes - mucociliary clearance

Question 3

How do tonsils and adenoids contribute to immunity?

Answer 3

Lymphoid tissue has B + T cells to capture invaders
Helps produce IgA
Helps develop immune tolerance by exposing to harmless antigens regularly in early life

Question 4

How does the appendix contribute to immunity?

Answer 4

Lymphoid tissue with lymphocytes and IgA
May assist with gut microbiota
May help with immune tolerance

Question 5

How does the spleen contribute to immunity?

Answer 5

Filters blood using macrophages to engulf invaders
Surveils the blood with lymphocytes and antigen-presenting cells to identify and activate response
Produces antibodies from B cells
Houses memory B and T cells for immune memory
Hematopoiesis (makes blood cells) can occur here if failing in usual areas of body

Question 6

What is a lymphocyte?

Answer 6

Main WBC
Includes natural killer cells, T and B cells
Recognise and destroy antigens

Question 7

What is a macrophage?

Answer 7

WBC that surrounds and destroys pathogens or dead cells
Can stimulate other immune cells to respond

Question 8

What is a dendritic cell?

Answer 8

WBC that identifies and captures an invader and shows to other immune cells to activate them

Question 9

What is innate immunity?

Answer 9

Natural
Non-specific
Immediate defence

Question 10

What are the 3 components of innate immunity?

Answer 10

Physical (skin, mucous membranes)
Chemical (enzymes, pH, peptides etc)
Inflammatory response

Question 11

Describe the inflammatory response

Answer 11

Recognition of injury/infection
Vasodilation and permeability occurs (improve flow to area)
Cytokinins release which recruit immune cells
Immune cells are activated (including phagocytosis)
Inflammatory mediators are released (histamine, prostaglandin)
Tissue repair and resolution begins

Question 12

What are phagocytes?

Answer 12

WBC engulf and destroy via phagocytosis

E.g. neutrophils, macrophages

Question 13

What are natural killer cells?

Answer 13

Type of lymphocyte
Destroys infected cells without needing activation or prior exposure

Question 14

What is the complement system?

Answer 14

Group of proteins that enhance the immune response
Can kill pathogens, recruit immune cells and increase inflammation

Question 15

What is adaptive immunity?

Answer 15

Acquired
Specific to antigens
Mediated by lymphocytes (B & T cells)

Question 16

What is clonal selection?

Answer 16

When T and B cells recognise an antigen, duplicate themselves and an army of antibodies is formed

Question 17

What is humoral immunity?

Answer 17

Adaptive immunity with B cells producing antibodies
B cell identifies antigen, differentiates into plasma cell which produces antibodies. These bind to antigen to kill or mark for other immune cells

Question 18

What is cell mediated immunity?

Answer 18

Adaptive immunity with T cells
Helped T cells release cytokinins to activate other cells and help B cells produce antibodies
Cytotoxic T cells recognise and destroy infected or cancerous cells

Question 19

What does the lymphatic system do?

Answer 19

Balance fluid by regulating interstitial fluid
Absorb dietary fat
Transport immune cells

Question 20

Describe lymphatic vessels

Answer 20

Thin vessels run parallel to blood vessels
Collect leaked interstitial fluid to return to blood

Question 21

What is lymph?

Answer 21

Fluid of the lymphatic system comprising of interstitial fluid, immune cells, waste products and fat

Question 22

What do lymph nodes do?

Answer 22

Filter foreign particles and waste from lymph
Site of immune cell activation

Question 23

What are the lymphoid organs and why are they significant?

Answer 23

Spleen, thymus, tonsils and peyers patches
Produce and mature T cells

Question 24

What is lymphoedema?

Answer 24

Build up of interstitial fluid causing oedema due to damaged lymphatic system
Primary: genetic abnormality
Secondary: from injury

Question 25

What are symptoms of lymphoedema?

Answer 25

Swollen
Tight
Pain
Reduced ROM
Skin change - pitted, hardened

Question 26

How do paediatric immune and lymphatic systems differ?

Answer 26

Rely mainly on innate defence
Receive some maternal antibodies
Get sick a lot from exposure during childhood which services their adaptive immunity
Present with more allergies

Question 27

How do geriatric immune and lymphatic systems differ?

Answer 27

Immune system degenerated so more susceptible
Reduced immune cells
Reduced lymphatic system causes oedema

Question 28

What is an allergy?

Answer 28

Hypersensitivity to a normally harmless substance

Question 29

What is the disease process of an allergy?

Answer 29

B cell detects allergen and differentiates into plasma cell which produces antibodies
Antibodies attach to mast cell
When allergen detected again it activates the antibodies on mast cells causing them to release histamine

Question 30

What is anaphylaxis?

Answer 30

Severe life-threatening reaction
Systemic inflammatory response with multi-organ involvement

Question 31

What is sepsis?

Answer 31

Life threatening inflammatory state
Starts with an infection and is a dysregulated, over exaggerated response
4 stages

Question 32

What are the 4 stages of sepsis?

Answer 32

Systemic inflammatory response syndrome (2 SX with infection must be present to then confirm sepsis)
Sepsis
Severe sepsis - organ dysfunction
Septic shock - low BP not responding to fluid

Question 33

What are the 4 SX criteria for systemic inflammatory response syndrome?

Answer 33

Temp >38 or <36
HR >90
RR >20 or CO2 <32
Abnormal WBC

(Infection needs to be confirmed)

Question 34

What is disseminated intravascular coagulopathy?

Answer 34

Widespread activation of clotting system
Microthrombi form in small vessels causing ischemia and organ damage
Microthrombi consume platelets and clotting factors causing bleeding