Organization of Cortex
- Lymphoid follicles
- B-cell
- Secondary follicles
- germinal centers
- Large lymphs
- follicular DC
- Macrophage surrounded by a rim of small lymphs (mantle zone)
- Paracortex
- Tcells
- in btwn lymphoid follicle and medulla
Organizations of medulla
- Medullary cords
- Sinuses drain lymph
- plasma cells –> Ab secretion
- lymphocyte
- Macrophages
Flow of Lymph thru LN
Afferent lymphatics (carrying Ags) –> subcaspular sinus –> cortex –> medulla –> efferent lymphatics at hillus
Flow of lymphocytes (in blood)
Enter via artery at hilus–> Leave vessels at HEV (paracortex) –> leave via lymph (if not stimulated)
stay in LN if stimulated
Birds Lymph nodes
THEY AIN’T GOT NONE!!!!!
Inverted Lymph Node structure
- Pigs
- Elephants, hippos, rhinos
- Dolphins
Lymphoid nodules in middle
Medulla at periphery
Pigments found in LNs
- RBC’s –draining hemorrhage
- Hemosiderin –RBC-lysis, hemorrhage
- Fe Dextran –Piglet
- Melanin
- Carbon -Anthracosis
- Cholorphyll
- Fluke excretory products –Fasciolodes magna
Material found in LNs
- Chyle (mesenteric LN)
- Grayish white - Gas
- Emphysema, Anaerobic infection - Fat
- especially mammary - Parasites
- Demodex sp
Inflammation of LN
Lymphadenitis
Causes for Granulomatous lymphadenitis
- Mycosis
- Mycobacterosis
- A. lignieresii, A. bovis
- Parasite
- FB –Plant, Hair
Atrophic Lymph nodes
- Age
- Protein-energy malnutrition
- Cachexia
- Chronic inflammation
- acute viral infection
-lymphoid atrophy
Lymphoid hyperplasia
- Chronics stimulation
- Strong Ag stimulation
- Initial phase of FIV
Bovine leukemia virus
Adult form - 2-18yrs
-multicentric
Adolescent form - 6-30months
- Thymus
- Bone marrow
Calf form - 1-6 month
-multicentric
Common sites for lymphoma in HORSE
- Multicentric
- intestinal tract
- leukemia
Common site for lymphoma in DOG
- Multicentric
- enteric
- thymus
- skin
Common site for Lymphoma in CAT (and cause)
- Multicentric
- Enteric
- Mediastinum/thymus
FeLV
Why are LNs a common site for Mets?
Bc of their draining properies
