Foundations in Immunology 2 Flashcards
What are functions of the lymphatic system?
Drainage of tissues
Absorption and transport of fatty acids and fat
Immunity
What is the lymphatic system?
Network of tubes that carry clear fluid called lymph
How does lymph move through the lymphatic system?
By contraction of skeletel muscles
What eventually happens to the fluid in the lymphatic system?
Enters the blood after entering the right lymphatic duct or thoracic duct
What happens to molecules in the interstitual space that are too big to pass through cappilary walls?
They pass into the lymphatic system which has more permeable walls
What are some lymph nodes?
Cervical
Axillary
Bronchial
Abdominal
Inguinal
What are the two kinds of lymph vessels?
Afferent
Efferent
What prevents backflow in lymph vessels?
Valves
What are the two lymphatic ducts?
Right lymphatic duct
Thoracic duct
What is the path that lymph being drained from interstitual space takes?
- Lymph
- Afferent vessel
- Lymph node
- Efferent vessel (filtered lymph)
- Lymphatic duct
- Venous system
- Blood
What are the 3 phases of immune defence?
- Recognition of danger
- Production of specific weapon
- Transport of weapon to the site
Where are white blood cells produced and recieve their early training?
Primary lymphoid organs
What are some primary lymphoid organs?
Bone marrow
Thymus
What happens to bone marrow as you get older?
You have less because long bones get filled with fat
What is the site of maturation of T cells?
Thymus
What kinds of cells are found in the thymus?
Macrophages
Dendritic cells
Numerous thyrocytes (T cell precurders)
What is a secondary lymphoid organ?
Site of lymphocyte activation by antigen
What are examples of secondary lymphoid organs?
Lymph nodes and lymphatic system
Spleen
Tonsil
Cutaneous immune system
Mucosal immune system
What is the spleen composed of?
Red pulp
White pulp (lymphocytes)
What are functions of the spleen?
Filter blood
APLs, B cells and T cells promote interactions for development of humoral immune response
What are functions of lymph nodes?
Filter and purify lymph
99% of antigens are removed here
In response to antigen detection T and B cells are stimulated and adaptive immune response initiated
Maintain and produce B cells and house T cells
What does the structure of a lymph node look like?
Where are payer’s patches found and what do they do?
Small intestine, prevents the gorwth of pathogenic bacteria
What are payer’s patches covered by?
A layer of M cells
What are M cells?
Transport antigens from the lumen of the intestine to the payer’s patch, then carried to lymph then lymph node
What are tonsils involved in?
Defence from infection of the upper respitory tract
What is lymphoma?
Caner of the lymphatic system
What is one of the most common pathways for the spread of cancer?
Lymphatic system
What are T cells derived from?
Bone marrow
What are MHC1 and MHC2?
Proteins that express antigens on their surface (antigen presenting cells)
Where is MHC1 found?
On every cell
Where is MHC2 found?
On macrophages and dendritic cells
What are T cells responsible for?
Cell mediated immunity and assisting B cells
What do cell surface receptors in the T cell receptors (TCR) recognise?
Antibodies when bound to MHC
What are different T cells?
Helper of CD4+ T cells
Cytotoxic or CD8+ T cells
What do helper T cells do?
Stimulate B cells to produce antibodies
What do cytotoxic T cells do?
Work similar to natural killer cells, destroying the pathogen
What is the process of the origin of T cells?
- Immature in bone marrow and head to thymus
- Mature in thymus, where receptor markers are given to them
- Head to secondary lymphoid organ
What is T cell selection?
T cells must learn not to recognise out own self antigens, restricted to recognise antigen in association with out own MHC
What does T cell selection happen?
Thymus
What are the two types of T cell seleciton?
Positive selection
Negative selection
What happens during positive selection?
T cells are presented with self MHC on epithelial cells
If they do not recognise it they are destroyed by apoptosis
(tests immature)
What happens during negative selection?
T cells are presented with dendritic cells, if they recognise self antigens they are destroyed by apoptosis
(tests mature)
What does MHC1 do?
Presents virally induced peptides to killer T cells to triger cytotoxic response
What does MHC2 do?
Found on macrophages, B cells, T cells and presents exogenously produced antigen to helper T cells to activate macrophages and B cells
What do helper T cells do?
They cannot kill, they activate and direct other immune cells
What do cytotoxic T cells do?
Release perforin when exposed to infected cells
Creates a pore
Releases granzyme B that enters pores and enduces apoptosis
What do memory T cells arise from?
Memory T cells arise from both differentiated and partially differentiated T cells
What do memory T cells allow?
Potential for further differentiation on reexposure to antigen
What is the difference between Th1 and Th2 cells?
Th1 cells are a cellular response and produce memory cells
Th2 cells are a humoral response and result in antibodies
What can a Th1/Th2 imbalance be caused by?
Genetic factor
Environmental factor
What can an imbalance between Th1 and Th2 cells cause?
Asthma
