IMMUNOLOGY- Lymphoid structures Flashcards
How are consider the lymph nodes?
Secondary lymphoid organ
How many afferents can lymph node have?
Many afferents
How many efferents can lymph node have?
1 or more efferents
What is an important outer structure of Lymph nodes?
Encapsulated with trabeculae
Which are the functions of lymph node?
Nonspecific filtration by macrophages, storage of B and T cells and immuneresponse activation
Which are the structures of a Lymph node?
Follicle
Medulla
Paracortex
Site of B cell localization and proliferation in lymph node
Follicle
Where is located follicle in lymph node?
Outer cortex
Which are the types of follicles of lymph node?
1º follicles
2º follicles
What is the main characteristics of 1º follicles in lymph nodes?
Are dense and dormant
What are the 2º follicles of lymph nodes?
Have pale central germinal centers and centers
Structuraly how is medulla composed of lymph nodes
Consists of medullary cords and medullary sinuses
What is contained in medullary cords?
Closely packed lymphocytes and plasma cells
What is the importance of medullary sinuses in lymph nodes?
Communicate with efferent lymphatics and contain reticular cells and macrophages
In Lymph node what is the purpose of Paracortex?
Houses T cells
Where is located the paracortex in lymph nodes?
Region of cortex between follicles and medulla
What does the paracortex contains?
High endothelial venules
This is the importance of high endothelial venules
Through which T cells enter from blood
What structure of Lymph node is affected in DiGeorge syndrome?
Paracortex
When is Paracortex enlarged?
In a exteme cellular immune response (Viral infection)
Which structure of lymph nodes is enlarged during viral infections?
Paracortex
These lymph node cluster drain head and neck
Cervical
Lymph nodes responsable of draining Lungs
Hilar
Which area of the body is drained by Mediastinal Lymph nodes?
Trachea and esophagus
Which lymph nodes drain Upper limb, brasr, skin above the umbilicus?
Axillary
Which areas of the body are drained by Celiac nodes?
Liver, stomach, spleen, pancreas upper duodenum
These structures are drained by Superior mesenteric lymph nodes
Lower duodenumm jejunumm ileum, colon to splenic flexure
Which lymph node cluster manage the drainage of Colon from splenic flexure to upper rectum?
Inferior mesenteric
What is drained by internal iliac lymph nodes?
Lower rectum to anal canal (above pectinate line), bladder, vagina (middle third), protate
These structures are drained by para-aortic lymph nodes
Testes, ovaries, kidneys, uterus
This lymph node cluster drains Anal canal (below pectinate line), skin below umbilicus (except popliteal territory)
Superficial inguinal
What does the Popliteal lymph nodes drain?
Dorsolateral foor, posterior claf
What is the function of Right lymphatic duct?
Drains right side of body above diaphragm
What does the thoracic duct drains?
Everything else into junction of left subclavian and internal jugular veins
What are the sinusoids of the spleen?
Long, vascular channels in red pulp with fenestrated “barrel hoop” basement membrane
Where are located the macrophages in the spleen?
Nearby sinusoids of spleen
Where are located the T cells in the spleen?
Periarterial lymphatic sheat wiyhin the white pulp of the spleen
This is the location of B cells in the spleen
Found in follicles within the white puplp of the spleen
Where is located the Marginal zone of the spleen?
Between the red pulp and white pulp
Which is the importance of the marginal zone of the spleen?
Contains APCs and specialized B cells, and is where APCs present blood borne antigen
What is the funcion of the macrophages in the spleen?
remove encapsulated bacteria
Which cases are consider Splenic dysfunction?
Postsplenectomy
Sickle cell disease
What is affected in splenic dysfunction?
↓ IgM→ ↓ complement activation → ↓C3b opsonization → ↑ susceptibility to encapsulated organisms
Which bacterias are encapsulated?
SHiNE SKiS Streptococcus pneumoniae Haemophilus influenzae type B Neisseria meningitidis Escherichia coli Salmonella spp Klebsiella pneumoniae Group B Strectococci
Which cells can be found in postsplenectomy patients?
Howell Jolly bodies
Target cells
Thrombocytosis
What are Howell Jolly bodies?
Nuclear remnants
What is the importance of Thymus?
Site of T cell differentiantion and maturation. Encapsulated
Which is the origin of Thymus?
From epithelium of 3rd pharyngeal pounches
This is the origin of Lymphocytes
Mesenchymal origin
Structurally how is Thymus composed?
Cortex and Medulla
What does Thymus cortex contains?
Dense immature T cells
How is Thymus medulla composed?
Pale with mature T cells and Hassall corpuscules containing epithelial reticular cells
Which is the site of T cell differentiation?
Thymus
This is the site for B cell maturation
Bone marrow