HLI 2 Flashcards
List the steps in granulopoesis and what characteristic at each stage
1, myeloblast - large round cell, sphericle nucleus
- Promyelocyte
- Large cell, Azurophilic granules appear - Myelocyte
- Specific granules appear
- Mitotic ability lost - Metamyelocyte
- Nucleus becomes kidney shaped - Band - nucleu looks like a band
- segmented form
- Further maturation
List 3 characteristics of immature granulocytes
1) stronger basophilic staining
2) larger cells
3) spherical or long nucleus
what is lymph
- itself is a clear, slightly yellowish and opalescent fluid derived from blood.
- Lymph draining the small intestines is milky since it contains chylomicrons & lipids
- carrying WBC, high percentages of lymphocytes
what are the 4 functions of the lymphatic system
- Controls blood & interstitial fluid volume
- Return excess filtered fluid and protein to blood - Specific transport systems
- Absorption of fat from gut
- (also lipid soluble vitamins eg A, D, E & K) - Turnover of extracellular matrix constituents
- glycosaminoglycans - Defense systems
- Immune surveillance
- Lymphocyte recirculation
What are primary and secondary lymphoid organs and give some examples
Primary - where lymphocytes mature
EG - bone marrow, thymus, ileal peyers patches near ileocacecal junction (B cells), bursa of fabricius (B cells chicken)
Secondary - where mature lymphocytes reside
EG - lymph nodes, spleen, tonsils, caecal tonsils (birds), hemal nodes (ruminants)
Variations of L.N between species
- Dogs and cats don’t have middle and caudal mediastinal
○ Pigs, horses and ruminants have a caudal mediastinal
○ Located between caudal lobes of the lungs - prominent - Dogs and cats don’t have subiliac (prefemoral)
○ Pigs, horses and ruminants do
○ Located in the hindlimb
What are the two main lymphatic ducts in the body, what do they drain and where do they drain
1) The right lymph duct drains the right forelimb, shoulder area, and the right side of the head and neck.
2) The left lymph duct, or thoracic duct, drains everything else, including the hindlegs, GI tract and other abdominal organs, thoracic organs, and the left side of the head and neck and left forelimb and shoulder.
- These ducts then drain into the external jugular veins or subclavian veins on each side
where is the cisterna chyli located
in the abdominal cavity
caudal to the diaphragm, dorsal to the aorta and ventral to the vertebral column
Loose vs dense lymphatic tissue
Loose lymphatic tissue
Between lymphatic nodules; in medullary cords and deep cortex of lymph nodes
- Stroma contains a reticular network for support
○ Reticular fibres and cells (+ macrophages, lymphocytes)
Dense lymphatic tissue - aggregation of lymphocytes
lymph nodes what are the characteristics of the cortex and medulla
CORTEX - More dense lymphatic tissue - Contain lymphatic nodules ○ Primary or secondary ○ Secondary have lighter staining centre - More B cells and cells in general in lymphatic nodules MEDULLA - More loose lymphatic tissue - Macrophages, T cells
What are the general structure of lymphoid tissues - primary and secondary nodules
- predominantly B lymphocytes
○ primary nodules – resting
○ secondary nodules – activated - Secondary nodules form following
○ contain a germinal centre (become activated)
○ large, pale staining cells; mitotic figures
→ clonal expansion of B cells
Bone marrow what are the two types and where are they found in adults
- Red marrow found in flat bones: skull, ribs, sternum, pelvis, vertebrae, heads of long bones
- Yellow marrow found in shaft of long bones
What is the thymus divided into in pigs and sheep
- Cervical lobe
- Intermediate lobe
- Thoracic lobe
Full of adipose tissues
Reticular epithelial cells where are they found and their function
- Direct the differentiation of T cells
• Thymic hormones – thymopoietin, thymosin α, thymulin - Cell contact – stromal macrophages
Thymic (Hassall’s) corpuscles where are they found, characteristics
The medulla of the Thymus
– Large, eosinophilic
– Degenerate epithelial cells form clumps in the medulla.
– Keratinised centre surrounded by elongated epithelial cells
– Seen mainly in older animals post puberty
Bursa of Fabricius
Found in birds
“Cloacal Tonsil”
Primary lymphoid organ for maturation and differentiation of B cells (Bone Marrow in mammals, Bursa in birds)
Bursa of Fabricius
Found in birds
“Cloacal Tonsil”
Primary lymphoid organ for maturation and differentiation of B cells (Bone Marrow in mammals, Bursa in birds)
What are Harderian glands, where are they found and list the structures of the Harderian gland
- chicken
- a pair, locates between the eye and the nasal cavity
- involved in the local immune responses of the conjunctivae and upper respiratory tract
- A central duct drains the gland secretion to the eye.
- play a role in terminal B cell differentiation and Ig class switch - PRIMARY LYMPHOID ORGAN
1. . capsule – thin connective tissue
2. lobes divided by septa
3. main ducts - compound tubuloacinar gland, unequal-sized tubular secretory units
- massive accumulations of lymphoid cells, majorly of plasma cells in the interstitium, particularly in the centre area of a lobule
Differences between Hemal nodes and lymph nodes
Hemal nodes unique to ruminants
- no lymphatic vessels; no typical medulla
- sinuses filled with blood
- receive cells, antigens from blood, and after Ag stimulation, many nodules may form
- Functional significance of hemal node is not fully understood
What are the two main sections of the spleen and how do the arteries branch into the spleen
White pulp - more white blood cells
Red pulp - more blood cells
Branches of the arteries in the spleen
splenic artery → trabecular artery → central artery
→ pulp artery → arteriole → capillary (remember)→ venous sinus (closed) or red pulp (open)
(a penicillus or penicillar arterioles )
What are the two main sections of the spleen, other structures and how do the arteries branch into the spleen
1) White pulp - more white blood cells
2) Red pulp - more blood cells
Trabecular - smooth muscle and collagen fibres
Branches of the arteries in the spleen
splenic artery → trabecular artery → central artery
→ pulp artery → arteriole → capillary (remember)→ venous sinus (closed) or red pulp (open)
(a penicillus or penicillar arterioles )
What are the two main sections of the spleen, other structures and how do the arteries branch into the spleen
1) White pulp - more white blood cells
2) Red pulp - more blood cells and smooth muscle present, more in ovine
Trabecular - smooth muscle and collagen fibres
Branches of the arteries in the spleen
splenic artery → trabecular artery → central artery
→ pulp artery → arteriole → capillary (remember)→ venous sinus (closed) or red pulp (open)
(a penicillus or penicillar arterioles )
What are ellipsoids and structures
- (pericapillary macrophage sheaths) or sheathed capillary
- surrounded by concentric layers of macrophages contained in a reticular framework
- leaky capillaries found in the spleen
what is the function of red pulp and are sinusoids present in the spleen
- Removal of deteriorating red cells and platelets
- Immune function: identification of antigens by macrophages and dendritic cells
sinusoids - present in dog but not other species (just leaky veins and venules) - lined by endothelial cells, free movement of blood, bound by rings of basement membranes with macrophages
What are the 3 locations of the tonsils and what epithelium covers them
1) lingual – base of the tongue
2) palatine – caudolateral to the tongue
3) nasopharyngeal – roof of the nasopharynx
covered by stratified squamous epithelium
Peyers patches where found, what cell is important and how distinguish between that cell and a normal epithelial cell
- Found predominantly in the ileum and at the ileocecal junction
- M cells within the epithelium cells, uptake and present antigens to lymphocytes within the peyer patches
○ No microvilli or brush boarder unlike epithelial cells
caecal tonsils where found, what are they
- Near junction of ileum and caecum
Aggregates of lymphatic tissues
megakaryocyte where present, what cell might be confused for and function
present in the bone marrow and might be confused for an osteoblast
Function - responsible for the production of platelets and thrombocytes
Why is it important to know the type of poison used in rodenticide poisoning and what if don’t know
For management of treatment
○ If third generation rodenticide - going to need 4-6 weeks of daily K1
○ If first generation - don’t need to treat with daily K1 for as long
If don’t know give for a few weeks then stop and wait 24-48hours do assays
If testing for poisoning and acute bleeds which test use and why
PT - prothrombin testing
tests function of the clotting factors in the extrinsic pathway where clotting factor 7 is. Clotting factor 7 has the shortest half-life and therefore will need to be replenished quicker in its active form and consequently will be decreased first and detected in lower functional levels first during Vit K antagonism
what is TT and the normal range
TT = thrombin time
- Time from when add thrombin to when fibrin clot forms
Very short 5-10seconds
Lymphadenomegaly what does local and generalised enlargement characterise
Local enlargement - reflects a pathologic process limited to the drainage area such as inflammatory or neoplastic disease
Generalised enlargement - more of a serious finding because it indicates a systemic disease or systemic neoplastic disease
- Don’t grow themselves but get fluid with cells or tissues
Reactive hyperplasia of the lymph node, is it common, what does it look grossly and histologically
most common change observed in lymph nodes
- Reactive response to an immune stimulus generally from the area the lymph node drains
- Such as enzootic pneumonia leading to enlarged tracheo-bronchial lymph nodes
Grossly
- Lymph nodes are enlarges and mobile - if cut capsule cortex may expand and parenchyma bulges
Histology
•Increased germinal centres (=proliferation of B cells), plasma cells, macrophages
Describe a histological change in germinal centers of lymph nodes responding to injury
Starry Sky appearance of germinal center
macrophages engulfing B cells that don’t make it
List 5 causes of lymph node hypoplasia/atrophy
- Lack of antigenic stimulation - animals raised germ free (SPF)
- Cachexia - neoplasm or starvation - loss of T cells little effect on B cells
- Aging - increased fibrous tissue - decrease T and B cels
- Radiation - lymphocytolysis but restored if normal BM can supply
- Viral infections - some target lymphocytes
lymphoid necrosis list 2 possible causes and what occurs microscopically and grossly
- Equine Herpesvirus infection - target high turnover lymphoid tissue
- Parvovirus infection of dog - necrosis of peyers patches, lymph nodes and spleen
Microscopically - lymphocytolysis with abundant karyorrhexis (fragmentation of the nucleus)
Grossly - not visible but lymph nodes could seem smaller
Pigmentation of the lymph nodes what does this suggest and characteristics grossly
lymphoid never produce the pigmentation - about where it is draining from
- pigmented
- cortex and medulla still distinct - REACTIVE
What are the 3 main reasons for lymphadenitis
- “Reactive” lymph node (the LN is reacting to inflammation elsewhere, but free of local invasion; hyperplasia is the main change)
- Inflammation (lymphadenitis) as result of direct infection
- Lymphadenitis as result of drainage of infectious agents from infected site
