Exam 1: Immune System Flashcards
3 mechanisms of protection
Surface protection
Acute inflamm
Immune response
2 main types of adaptive immunity
Humoral and cell mediated
Humoral immunity is mediated by
B cells and plasma cells w/ T cell involvement
Humoral immunity involves
Ab production
Cell mediated immunity is mediated by
T lymphocytes
Cytotoxic response
General components of immune system
Diffuse lymphatics
Lymphatic organs
Primary lymphoid organs provide environment where
Lymphocytes become immunocompetent
Secondary lymphoid organs provide environment where
Lymphocytes contact foreign antigens
MALT
Mucosal-associated lymphatic tissue
GI, respiratory and urogenital tracts
2 categories of MALT
GALT (gut associated)
BALT (bronchial associated)
Tonsils w/ epithelial folds (pleated tonsils)
Pharyngeal tonsils
When inflamed pharyngeal tonsils are called
Adenoids
Block auditory tuber — ear infections
Tonsils w/ tonsillar crypts
Palatine tonsils (faucial tonsils) Lingual tonsils
Palatine tonsils covered by
Stratified squamous epi
Advantages to tonsillar crypts
More surface area for:
- detecting foreign antigens
- lymph nodule formation in CT
Disadvantage of tonsillar crypts
Bacteria thrive — inflamm — tonsillitis
Surface epi of lingual tonsils
Strat squamous
2 major functions of lymph nodes
Filter lymph (phagocytosis) Humoral and cell-mediated immunities
Capsule of lymph nodes made up of
Dense irregular CT
Septa also
Both afferent and efferent lymph vessels contain
Valves
Subcapsular sinus
AKA marginal sinus
1st to receive afferent lymph
Cortical sinus passes thru
Cortex
Sinus that passes thru paracortex
Deep cortical sinus
Sinus that passes through medulla
Medullary sinus
Cells w/in regions and sinuses of lymph node are supported by
Reticular fibers
Primary cell type in cortex of lymph node
B lymphocyte
Activity in cortex
Phagocytosis and humoral immunity
Primary lymphoid nodules
Areas where naive B cells congregate
Secondary lymphoid nodule
Forms in response to antigen
Active B cell division
FDCs here
Primary cell type in paracortex
T lymphocyte
Activity in paracortex
Phagocytosis
Storage for T cells
Cell mediated immunity
HEVs
High endothelial venules
Function of HEVs
Facilitate passage of B/T cells into lymph node from blood
Primary cell type in medulla of lymph node
Plasma cells
Activity in medulla
Phagocytosis
Some cell-mediated immunity
Lots of humoral immunity
Process of involution of thymus after puberty
1=septa
2= cortex
3= medulla
Function of thymus
Create Immunocompetent T cells
Thymocyte
T lymphoblast in thymus
Thin capsule of thymus made up of
Dense irrecular CT
Lobules in thymus have a peripheral ____ and a central ____
Cortex; medulla
Microstroma is made up of
Thymic epithelial cells (TECs)
Functions of TECs
- Support
- Secrete thymic hormones/cytokines
- Form thymic corpuscles
- Blood-thymic barrier
Functions of thymic hormones/cytokines
Influence T cell maturation
Thymic corpuscles are only in
Medulla
Function of thymic corpuscles
Secrete cytokines to influence dendritic and T cells
Blood-thymic barrier perivascular compartment
CT w/ many macrophages
To destroy foreign molecules
Function of blood-thymic barrier
Prevent T cells from contacting foreign antigens
What types of TECs present self antigens to maturing T cells
Type II and III
Thymus cortex contains what cell types
T lymphocytes
Macrophages
TECs I, II, III
Medulla of thymus cell types
Fewer but larger T cells
Macrophages
Dendritic cells
TEC IV, V, VI
T lymphoblasts are produced in
Bone marrow
T lymphoblasts enter thymus as
ImmuniINcompetent T cells
T lymphoblasts go to cortex where they:
Divide, tested through positive selection process
T cells that fail the selection process
Apoptosis (98%)
T cells that survive migrate to
Medulla
In the medulla the T cells go through
Negative selection process
Negative selection process turns T cells into
Cytotoxic T and Th cells
Mature immunocompetent T cells leave thymus in
Post-capillary venules or efferent lymph
Thymus is lacking
Afferent lymph vessels
Reticular fibers and cells
Hemopoietic organ in fetus
Spleen
Spleen stores
T cells
Some WBCs and platelets
(Large # of monocytes)
Capsule of spleen
Thick dense irregular CT
Has some smooth muscle (myofibroblasts)
Trabeculae of spleen
Dense irregular CT
Carry BVs, lymphatics and nerves
Cells in spleen are supported by
Reticular fibers
2 areas of splenic parenchyma
White and red pulp
White pulp are areas of concentrated
Lymphocytes
White pulp general function
Immunity
Areas of white pulp
Next to capsule/septa
Splenic nodules
Periarteriolar lymphoid sheaths
Splenic nodules
B cell structures
MC in children
Humoral immunity
Periarteriolar lymphoid sheaths (PALS)
Storage for T cells
Surround central arterioles
Cell-mediated immunity
Red pulp functions
Rapid blood filtration
Contact w/ blood-borne antigens
Closed circulation in red pulp
Capillaries connect to venous sinuses made of stave cells
Stave cells
Elongated endothelial cells
Open circulation in red pulp
Capillaries end abruptly
Splenic cords contain
MANY mactophages Recitular cells Monocytes APCs Plasma cells
Splenectomy causes blood changes
Inc in platelets and abnormal RBCs
Splenectomy causes increased risk of
Infection — bacterial septicemia
Splenectomy causes liver to
Take up blood filtration
Symptoms of mono
Sore throat
Fever
Swollen lymph nodes
Virus that causes mono
Epstein-Barr Virus
