Exam2Lec8LymphoidSystem Flashcards
List lymphoid tissues of the lymphatic system (6)
- Lymph node
- Spleen
- Thymus
- GALT
- BALT
- Bone marrow
List immune cells (6)
- macrophages
- granulocytes
- NK cells
- T cells
- B cells
- dendritic cells
Does the response time for innate immunity take days or hours?
hours
Does the response time for adaptive immunity take days or hours?
days
What is the specificity of innate immunity?
limited and fixed
What is the specificity of adaptive immunity?
- highly diverse
- improves during course of immune response
What is the response of innate immunity to repeat infection?
identical to the primary response
What is the response of the adaptive immunity to repeat infection?
much more rapid than primary response = immune memory
What are the two types of barriers of innate immunity?
- anatomical
- physiological
ex: skin, bronchi, gut
What does innate immunity use to recognize PAMPS on antigens?
pattern recognition receptors (PRRs)
Pattern recognition leads to ____ and ____.
- phagocytosis
- killing
Adaptive immunity is different from innate immunity because it requires which type of cells?
lymphocytes
takes longer bc need to present antigen
What cells are involved in humoral immunity (3)?
- B cells
- antibodies
- serum mediators such as cytokines
Which two cells does cellular immunity use?
- killer T lymphocytes (CD8+)
- phagocytes
What do both humoral and cellular immunity require?
- T helper cells (CD4+ = MHC II)
- APC
Is a Tc cell (cytotoxic T = CD8+ = MHC I) part of humoral immunity, cellular immunity, or both?
only cellular immunity
What is the function of cellular immunity?
kills microbes (cytotoxicity)
What is the function of humoral immunity?
generates plasma cells to produce antibodies
What is an important feature of adaptive immunity? Why?
- memory
- future exposure elicits a faster/better response = have antibodies specific to antigen
What are the results of inflammation and tissue damage during infection which leads to an influx of serum factors and cells?
- swelling, heat, pain, redness,
- allergy and asthma
- graft rejection and graft vs. host disease
- autoimmune disease
keep in mind we have vasodilation occur first then we have multiple issues
Where are T cells located?
thymus
Where are B cells located?
bone marrow & GALT
List the secondary organs/tissues (5)
- diffuse lymphatic tissue (e.g. peyer’s patch, appendix, GALT)
- lymphoid nodules
- tonsils
- lymph nodes
- spleen
Which organ is primary and secondary lymphoid organ?
GALT
What are the 2 types of lymphoid nodules? What do they consist of?
- primary lymphoid nodule = consist of small lymphocytes (inactive B cells) with no germinal center
- secondary lymphoid nodule = consist of large lymphocytes in the peripheral zone & large lymphocytes (active B cells) located in germinal center
secondary=activated b/c germinal center
activated B cells become plasma cells
What are the characteristics of germinal cells (4)?
- located in the center of the nodule (follicle)
- stains light due to large amount of cytoplasm and euchromatin
- develop in response to antigens
- site of active B cells (B cells proliferate = differentiate into plasma cells = produce antibodies)
What is lymphadenitis? What causes it?
- Enlargement/swelling of lymph nodes
- Caused by edema and hyperplasia of lymphatic nodules
What are the symptoms of lymphadenitis? (4)
- swollen, palpable, and tender lymph nodes
- fever
- chills
- general weakness
What are the most common causes of lymphadenitis in the neck region (2)?
tonsillitis and pharyngitis
Which organs/tissues (2) have a single nodule or aggregates with no capsule?
- Peyer’s patch (ileum)
- Appendix
nodules + no capsule
Which organ has nodules and a partial capsule?
tonsils
nodule + partial capsule
Which organs have nodules and a well-developed capsule (2)?
lymph node and spleen
nodules + complete capsule
Recent evidence suggests that lymphatic tissue in the appendix is a site for what?
B cells differentiation into immunocompetent cells
What does the pharyngeal lymphoid tissue of the Waldeyer’s ring comprise (4)?
- Nasopharyngeal tonsil or adenoid
- The paired tubal tonsils
- The paired palatine tonsils
- The lingual tonsil
What type of epithelium lines the adenoid (pharyngeal) tonsils?
ciliated pseudostratified columnar epithelium
Does the adenoid (pharyngeal) tonsil contain fewer or many primary and secondary lymphoid nodules (follicles)?
fewer
What type of epithelium lines the palatine tonsil?
stratified squamous epithelium
Does the palatine tonsil contain many or fewer primary and secondary nodules (follicles)?
many
What is the function of crypts in the palatine tonsil?
increase tonsil surface area = allows antigens to hide
Lymph nodes are found in ______ throughout the body as ______ lymphoid structures
- clusters
- encapsulated
What is the function of the lymph nodes?
filters and entraps antigens from the lymph and supports the immune system
What composes the lymph nodes (4)?
- capsule
- cortex
- medulla
- sinuses = interconnected channels (subcapsular, trabecular, medullary) where lymph travels and is filtered
Lymph enters via ___ lymphatic vessel to ____ sinuses, percolates (filters) through tissue of lymph node and exits the ____ lymphatic vessel
- afferent
- subcapsular
- efferent
What does the outer cortex of the lymph nodes contain?
lymphoid nodules = B cell zones
What does the inner cortex (deep cortex, paracortex) of the lymph nodes contain?
T cell zones
Which structure of the brainstem contains a high number of plasma cells?
medulla
List the order of lymphatic flow (5)
- Afferent vessel = lymphatic fluid (lymphocytes) arrive
- Subcapsular sinus
- Trabecular sinus
- Medullary sinus
- Efferent vessel = lymph fluid (lymphoytes) exit
Where are the majority of T cells located in the lymph node?
deep cortex
Where are B cells located in the lymph node?
germinal centers in superficial (outer) cortex
What are high endothelial venules (HEV) and where are they found?
- specialized postcapillary venules
- lymph nodes
- tonsils
- aggregated or solitary lymph nodules (peyer’s patches) (not in the spleen)
What is the function of HEV?
support high levels of B and T lymphocyte migration from the blood
What type of endothelium does HEV have and what is it able to do?
*cuboidal endothelium
*has the ability to recruit large amounts of lymphocytes (possess receptors for antigen-primed cells)
What type of fibers produce fibroblasts?
reticular
Which cells produce reticular fibers in lymphatic tissue?
reticular
How are reticular fibers arranged?
arranged in a mesh-like network
Which type of collagen are reticular fibers?
Type III
What type of endothelium lines lymphatic capillaries?
simple sqaumous
Do lymphatic capillaries have complete or incomplete basal lamina? Is this fenestrated or non-fenestrated?
*incomplete basal lamina
*fenestrated
fenestrated capillaries = digestive organs and pancreas
Where do lymphocytes enter major lymphatic vessels on the right side of the body?
right lymphatic trunk
Where do lymphocytes enter major lymphatic vessels on the left side of the body?
thoracic duct
What are the functions of the spleen (5)?
- filtration of blood
- removal of aged or damaged RBCs, old platelets, and blood-born foreign matter
- site of immune response
- platelet storage
- filters antigens out of the blood and promotes immune response = w/o spleen more susceptibility to blood-borne infections (e.g. post-splenectomy sepsis)
What are the 6 structures of the spleen?
- capsule
- trabeculae
- reticular meshwork
- red pulp
- white pulp
- lymphatic vessels
What does the reticular meshwork of the spleen contain?
reticular cells and reticular fibers
What does the red pulp of the spleen consist of?
splenic cords and splenic sinuses
What does the white pulp of the spleen contain?
- periarterial lymphatic sheath (PALS) (around central artery) = T cells
- lymphoid nodules = B cells
What does the lymphatic vessels of the spleen contain?
- efferent only
- present in white pulp, trabeculae, and capsule b/c lymphocytes enter through blood since spleen does not filter lymph
What do discontinuous capillaries contain and where are they found?
- gaps between endothelial cells
- discontinous basal lamina
- spleen and liver
Explain open and closed circulation in the spleen
closed circulation - blood empties from the vessels of the white pulp into sheathed capillaries of the red pulp and then directly into the sinuses.
open circulation - blood empties from the sheathed capillaries into the splenic cords and then enters the sinuses through slits in the wall.
Case: Hereditary Spherocytosis
A 25-year-old Japanese man was seen at the doctors office with mild anemia with reticulocytosis, increased serum unconjugated bilirubin and splenomegaly suggesting the presence of persistent hemolysis. The blood film showed a moderate anisocytosis (variability of size of erythrocytes), increased spherocytes (small, globular erythrocytes). Additional tests were done and the results were consistent with a diagnosis of hereditary spherocytosis (HS). **The splenomegaly in this disease was associated with spleen’s involvement in active removal of abnormal red blood cells, spherocytes.
**
Question: Which of the following cells in the spleen were primarily involved in this process?
A. Endothelial
B. Macrophages
C. Periarterial Lymphatic sheath
D. Reticular
E. Lymphoid nodule
B. Macrophages = phagocytosis of abnormal RBCs
Endothelial = gaps allow passage of RBCs
Periarterial Lymphatic sheath = T cells
Reticular = type III collagen = capsule
Lymphoid nodule = B cells
