Lymphatic system

Question 1

How is the lymphatic system closely associated with the cardiovascular system?

Answer 1

Lymphatic system includes a network of vessels that assist in circulating body fluids

Question 2

Why do lymph enter lymph nodes?

Answer 2

Purifies and remove toxins in lymph so these aren’t present in interstitial fluid when returned back to cardiovascular system

Question 3

What cations are found in the body fluid?

Answer 3

Na+, K+, Ca2+, Mg2+

Question 4

What anions are present in the body fluid?

Answer 4

Cl-, HCO3-, HPO4^2-, SO4^2-

Question 5

Main cation and anion found in ECF?

Answer 5

Na+

Cl-

Question 6

Main cation and anion in ICF?

Answer 6

K+

HPO4^2-

Question 7

What makes up ECF?

Answer 7

Plasma

Interstitial fluid

Question 8

What makes up ICF?

Answer 8

Intracellular fluid

Question 9

What do lymphatic vessels transport?

Answer 9

Excess interstitial fluid in most tissues and return it to blood system

Question 10

What are lymphatic capillaries called?

Answer 10

Lacteals

Question 11

Where are lacteals found?

Answer 11

Lining of small intestine at centre of each villus

Question 12

What do lacteals in the small intestine do?

Answer 12

Absorb fats

Transport fats to venous circulation

Question 13

What allows movement of fluid in/out of lacteal capillary

Answer 13

Fenestrations in endothelial cells of lacteal

Question 14

How is lymph moved?

Answer 14

Smooth muscle action
Valves
Compression due to skeletal muscle contraction
Arterial pulsation

Question 15

What are special about lymphatic capillaries?

Answer 15

They have valves

Question 16

Abundance of leukocytes (most abundant to least abundant)

Answer 16

Neutrophils 
Lymphocytes
Monocytes
Eosinophils
Basophils

Question 17

What releases pro-inflammatory cytokines?

Answer 17

Macrophages

T helper cells

Question 18

Components of the innate immune system

Answer 18

Inflammation
interferon
Complement system
Natural Killer cells

Question 19

What activates acute phase proteins in the innate response?

Answer 19

Cytokines released by macrophages- IL-6

Question 20

What stimulates natural killer cells?

Answer 20

Type 1 Interferons- IFN alpha and IFN beta

IL-12 released by macrophages

Question 21

Why is it good that MHC genes are polymorphic?

Answer 21

Able to identify a range of genes

Question 22

What do lymphocytes originate from?

Answer 22

Progenitor lymphoid stem cell in the bone marrow

Question 23

During B cell development what are the B cell surface markers called?

Answer 23

Clusters of differentiation (CD)

Question 24

What are clusters of differentiation (CD)?

Answer 24

Most= proteins
Include cell surface receptors, cell signalling and adhesion molecules
range from CD1-371
Useful in identifyting types of leukocytes
CD number tells us what stage of maturation B/T cell is at

Question 25

Where are CD3 found on?

Answer 25

T cells

Question 26

Where are CD19 found on?

Answer 26

B cells

Question 27

How do CDs show us stage of development of B/T cells

Answer 27

CD1 found on thymocytes(immune cell in thymus before It becomes a T cell) but not on mature T cells

Question 28

Where are CD22 found on?

Answer 28

Mature B cells

Question 29

What happens when B cell binds to antigen?

Answer 29

``` B cell engulfs and phagocytoses pathogen (process of phagocytosis) Pathogen is chooped up by phagolysosomes Antigens are loaded onto MHC II in the phagolysosome Activates CD4+ T helper cells ```

Question 30

WHere is CD10 found?

Answer 30

Germinal centre of lymph node

Question 31

CD38

Answer 31

plasma cells

Question 32

CD4

Answer 32

T helper cells

Question 33

CD8

Answer 33

Cytotoxic T cells

Question 34

CD16, CD56

Answer 34

Natural killer cells

Question 35

Antigen route in lymph node

Answer 35

APC and antigen enter lymph node through afferent vessel Dendritic cell in paracrotex processes antigen in paracortex Dendritic cell APC activate antigen specific T helper cells T helper cell activates B cells B cells proliferate T and B cells migrate to primary follicle in cortex and interact with follicular dendritic cells In secondary follicle- germinal centre= b cell proliferates and produces antibody making plasma cells

Question 36

What does the white pulp of the spleen consist of?

Answer 36

Primary follicle Marginal zone PALS

Question 37

What is the marginal zone?

Answer 37

Edge of PALS | has B cells and primary follicles

Question 38

Antigen route in spleen

Answer 38

Antigen enters spleen via splenic artery Antigen captured by dendritic cell in marginal zone Dendritic cell APC moves to PALS where T cells are Dendritic APC cell activates T cell (costimulation=B7,CD28, Cytokines) Activated T helper cell activates B cell Activated B and T cells move to primary follicle in marginal zone Secondary follicle made= germinal centre

Question 39

What happens in medulla of thymus?

Answer 39

``` VDJ recombo (somatic recombination) of TCR T cell develops CDs (cell surface markers (CD4+ and CD8+) ```

Question 40

What is central immune tolerance?

Answer 40

Key role of thymus (and bone marrow) In thymus if T cell recognises self antigen= apoptosis of these cells= clonal deletion to prevent automminuty In thymus cortex T cells with non functional TCR= removed and cells with functional TCR= selected and moved into thymic medulla (become mature naive T (CD4+/CD8+) cells

Question 41

Order of T cell

Answer 41

Progenitor lymphoid cell to progenitor T cell in bone marrow In thymus= mature naive CD4+/CD8+ T cell (gain TCR via VDJ and CD cell surface markers) In lymph node= activated CD4+ T hlper cell (when it meets non-infected phagocyte MHC II) Activated CD8+ T cytotoxic cell (When meets infected phagocyte MHC I)