anatomy and physiology Flashcards
1
Q
what are the functions of the lymphatic system
A
- monitor body surfaces and internal fluid compartments
- removal of excessive fluid
- provide defence mechanisms
- produce immune system cells
- fatty acid absorption and transport of fat
2
Q
what are the components of the primary lymphatic system
A
bone marrow and thymus
3
Q
what are the components of the secondary lymphatic system
A
- spleen
- tonsils
- lymph nodes
- diffuse lymphatic tissue
- lymphatic nodules
4
Q
what are the principle effector cells in the lymphatic system
A
- lymphocytes
- B cells
- T cells
- Natural killer
5
Q
what are the support cells in the immune system
A
- monocytes
- macrophages
- neutrophils
- basophils
- eosinophils
- dendritic cells
- follicular dendritic cells
6
Q
what are the specialised epithelial and stromal cells in the lymphatic system
A
- reticular cells
- langerhans
- epithelioreticular cells
7
Q
how do you identify immune cells
A
- leukocytes subsets are by combination of histological slides
- labels glycoprotein differentiation antigens expressed on their cell surface
- cluster differentiation numbers assigned
8
Q
what are the CD numbers for T cells
A
CD3+
9
Q
what are the CD numbers for T helper cells
A
CD3+ and CD4+
10
Q
what are the CD numbers for T c cells
A
CD3+ and CD8+
11
Q
what are the CD numbers for T reg cells
A
CD4+ and CD25+ and Foxp3+
12
Q
what are the CD numbers for B cells
A
CD19+ and CD20+
13
Q
what are the CD numbers for macrophages
A
CD68+
14
Q
what are the CD numbers for NK cells
A
CD3-, CD16+ and CD56+
15
Q
What are t receptor cells
A
they are antigen receptors that recognise antigen attached to identification molecules
16
Q
what do t helper cells do
A
recognise antigens presented by antigen presenting cells
- express CD4
17
Q
what do cytotoxic lymphocytes do
A
recognise antigens presented on cancer or viral infected cells
- cells infected with intracellular microorganisms killed
- express CD8
18
Q
how are T helper cells activated
A
- first signal when they interact with MHC-Ag complex
- constimulatory signal between T cell and APC
- synthesis of interleukins - CD4+
19
Q
describe the process of what TH1 cells do
A
- recognise AG presented by APCs
- synthesis - IL2, IFN, TNF alpha
- interact with cytotoxic lymphocytes, cells and macrophages to control intercellular pathogens
20
Q
describe the process of what TH2 cells do
A
- recognise Ag presented by APCs
- synthesis of IL4, IL5, IL10 and IL13
- interact with B lymphocytes to initiate antibody mediated immune response for extracellular pathogens
21
Q
describe the cell mediated response
A
- destruction of a transformed or virus infected cell by cytotoxic lymphocytes
- activation by TCR binds to MHC-1-Ag complex on target cell
- clonal expansion - cell division and differentiation into killer cells
22
Q
what do regulator T lymphocytes do
A
suppress the immune response to self and foreign in antigens by influencing other cells
23
Q
what do gamma/ delta T lymphocytes do
A
- develop in the thymus
- reside and form first line of defence in epithelia
24
Q
describe the characteristics of B lymphocytes
A
- differentiate into bursa equivalent organs
- humoral immunity
- express antigen binding site, b cell receptors and MHC II on surface
- CD9, CD19, CD20, CD40
25
what do plasma cells do
produce and secret antibodies, Ig
26
what do memory B cells do
respond to secondary encounter with same antigen
27
how are b cells activated
- first signal when they interact with BCR antigen forming Ag complex
- antigen engulfed by B cell and eliminated by NK cells or macrophages
- constimulatory signals between B cells and TCD on TH - secret cytokines to stimulate B cell differentiation and proliferation
28
what are myeloid cells
- first line of defence, innate immunity
- neutrophils, eosinophils, basophils, mast cells, monocytes, macrophages and dendritic cells
29
what are lymphoid cells
non- specific, adaptive immunity
- natural killer cells
humour and cell mediated specific immunity
- B lymphocytes, T lymphocytes
30
what do basophils do
- type 1 hypersensitivity reactions
- high affinity Fc receptors for IgE
- produce heparin - anticoagulant
- cytokines - modulated adaptive immune response
- histamine - vasodilation and inflammation
- lipid mediators - regulate inflammation
31
what do eosinophils do
- cytoplasmic granules contain toxins that are active against helminths and parasites
- major basic protein and peroxidase
- degranulation into extracellular space or phagocytosis
32
what are eosinophils regulated by
cytokines which regulate maturation, growth and differentiation
33
what are the functions of neutrophils
accumulation at sites of infection and injury
phagocytosis
secrete enzymes that contribute to tissue remodelling and repair
34
what do dead neutrophils make
pus
35
what is the function of dendritic cells
express major histocompatibility complex - 1 and 2
36
how do dendritic cells fight infection
- antigen uptake
- processing and migration to lymph nodes
- phenotypic changes to present antigen to T and B cells
37
describe myeloid dendritic cells
migrate from tissue to lymph node
- secret IL-12
- promote CD4+ and TH1 immune response
38
describe plasmacytoid dendritic cells
migrate from blood to lymph nodes
- secrete IFN-alpha
- anti viral immunity
39
describe mast cells
contain granules with preformed mediators that are released after stimulation - histamine, prostaglandins and leukotrienes
40
describe how degranulation of mast cells is stimulated
- PAMP recognition, direct injury, binding of anaphylatoxins or surface IgE cross linking
41
what is the mast cells role
innate response and allergic reaction
42
where are langerhans cells found
skin
43
where are dendritic cells found
spleen and lymph nodes
44
where are epithelioreticular cells found
thymus
45
where is secondary lymphoid found
- tonsils and adenoids
- bronchus
- spleen
- lymphoid nodules
- mesenteric lymph nodes
- Peyers patches
- urogenital lymphoid tissue
46
what causes enlargement of the spleen
when there is many abnormal cells (infected or abnormal in shape) eg. leukemia or malaria
47
why is a splenic injury significant
- internal bleeding - death within minutes
48
how can a splenomegaly be identified
CT, ultra sound or physical examination
49
where is cancer found in lymph nodes
early - sub capsular cortical sinus
late - medulla
50
what lymph node should be removed first with breast tissue
sentinel nodes
51
what are tonsils a part of
gut associated lymphoid tissue
51
what do crypts in the palatine tonsils contain
live and dead lymphocytes and bacteria
52
what does the germinal centre do
- lymphocyte activation, proliferation and differentiation
- develop from secondary lymphatic nodules after exposure to antigens
53
what cells are found in lymphatic nodules
- B lymphocytes
- reticular cells
- dendritic cells
- macrophages
- follicular dendritic cells
54
what is the function of diffuse lymphatic tissue
- protects body from antigens
- initial immune response
55
where is diffuse lymphatic tissue found
Lamina propria
56
where would you do a lymph node biopsy in the breast
sentinel nodes
57
describe the structure of a lymph node
1) capsule - DCT
2) outer cortex - abundance of B lymphocytes
3) inner cortex/ paracortex - abundance of T lymphocytes
4) medulla - cored and sinuses
5) hilum - blood vessels and nerves
58
describe the lymph node flow
afferent lymphatic vessel ---> subcapsular cortical sinus ---> trabecular sinus ---> medullary sinus ---> efferent lymphatic vessel
59
what is bone marrow for
mammalian haematopoietic site
- all blood cells except mature T cells
60
what is bone marrow regulated by
growth factors, cytokines and reticular stroma
61
what is reticular stroma
fibrous, collagenous mesh secreted by reticular cells
62
what is haematopoiesis
generation of leukocytes and erythrocytes
63
what maintains haematopoietic stem cells
contact dependent signals with stromal cells and soluble factors
64
what are haematopoietic stem cells
multipotent and self renewing
65
where is the thymus located
superior mediastinum
66
what is found in the cortex of the thymus
mainly immature T lymphocytes (thymocytes) and epithelial reticular cells
67
what is found in the medulla of the thymus
mature T lymphocytes and epithelial reticular cells
68
why is the thymus classed as a lymphoepithelial organ
multipotent lymphoid stem cells invade epithelial rudiment to differentiate as T lymphocytes
69
what is DiGeorge syndrome
- deletion of small piece of chromosome 22 at q11.2 resulting in no thymus and defects of 3rd and 4th branchial pouches and arches
70
what are the symptoms of DiGeorge syndrome
- cardiac anomalies
- abnormal facies
- thyme aplasia
- cleft palate
- hypocalcemia
71
where is the spleen located
left posterior abdominal wall
72
what is the function of the spleen
- filtration of blood to remove old erythrocytes and platelets
- site where immune response to antigens occurs
73
what is found in the red pulp of the spleen
- cords of cells
- sinusoids - capillaries
74
what is found in the white pulp of the spleen
- thick accumulations of lymphocytes
- lymphatic nodules
75
how does spleen white pulp fight infection
lymphocytes first come in contact with antigen and marginal zones of the nodule trap the antigen from circulation and present the antigen to lymphocytes of the spleen
76
what is the function of red pulp in the spleen
filtration of antigens, senile abnormal erythrocytes and platelets
