Blood + Hematopoiesis + Lymphatics Flashcards
What are the functions of blood?
- transport of water,solute, and cells
- temperature regulation
- water balance (blood volume)
What is the makeup of whole blood?
- 5-10% of total body weight
- comprised of:
- 60% plasma (water, solutes)
- ~40% cells (RBC, WBC, PLT)
What is plasma? Why is this important?
- 90% water, 8% protein, 2% other solutes
- proteins and solutes can be measured, variations reflect different disease processes
What are the different kinds of blood cells? How prevalent are they? What is their life span?
What is this an example of?
- blood smear
T/F: white blood cells are erythrocytes
- false; leukocytes. RBCs are erythrocytes
What are features of erythrocytes?
- most numerous cell in blood (millions)
- shape:
- bioconcave disc
- flexible membrane
- high surface-to-volume ratio
- allow RBCs to pass through small capillaries
- facilitates transport of O2 and CO2
- size: varies between species
What are functions of erythrocytes?
- carry O2 to tissue and CO2 to lungs
- involved in acid-base homeostasis
What species have nucleated RBCs?
What are the three kind of blood cells?
- RBCs: erythrocytes
- WBCs: leukocytes
- PLTs: platelets
What are features of leukocytes? Functions?
- least numerous blood cells (thousands)
- reported as WBC or TNCC
- function: inflammation and immune response
What are the different kinds of leukocytes?
- neutrophils
- lymphocytes
- monocytes
- eosinophils
- basophils
What is indicated in the image?
- neutrophils
- size: ~12um diameter
- nucleus: segmented w/ dense violet chromatin
- cytoplasm: pale-staining “neutral”
What is shown in the image?
- heterophils
- size: ~12 um diameter
- nucleus: segmented w/ dense violet chromatin
- cytoplasm: red,rice-shaped to round granules
What is shown in the image?
- lymphocytes
- size: smaller than neutrophil (except in ruminants)
- nucleus: round to indented, dense/clumped chromatin
- cytoplasm: scant, blue
- high nucleus:cytoplasm ratio
What are features of lymphocytes?
- found in blood, lymphatic circulation, lymphatic tissue
- major part of adaptive immune response
- humoral immunity: B-cells, plasma cells
- cell-mediated immunity: T-cells
- lifespan: days to years
What is shown in the image?
- A: neutrophil
- B: lymphocyte
- C: monocyte
- size: typically largest cell on blood films
- nucleus: shape ranges from round to kidney to band to pseudo-segmented; chromatin is lacy/loosely clumped/magenta
- cytoplasm: abundant and blue, frequently vacuolated
What are features of monocytes?
- differentiate into macrophages in tissue
- mononuclear phagocytic system
- comprised of monocytes and tissue macrophages
- macrophages widely distributed throughout the body
- spleen, liver (kupffer cells), lungs (alveolar macrophages), brain (microglial cells), bone (osteoclasts),etc.
What are functions of monocytes?
- phagocytosis
- antigen presentation to T-lymphocytes
- iron storage + recycling
What is shown in the image?
- eosinophils
- size: ~neutrophil
- nucleus: segmented w/ clumped chromatin
- cytoplasm: usually stains pale, contains eosinophilic granules; bright red-orange, sometimes refractive/shiny; contains many arginine-rich proteins (anti-bacterial + anti-parasitic)
What are features of eosinophils?
- present in low numbers in the blood
- function: modulate delayed and immediate type of hypersensitivity reactions
What is shown in the photos?
- A: eosinphil
- B: neutrophil
- C: basophil
- size: larger than neutrophils
- nucleus: elongated + ribbon-like; segmented
- cytoplasm: abundant amphophilic (lilac) w/ purple granules
What are features of basophils?
- RARE in healthy animals
- usually seen with eosinophils
- morphology
- generally slightly larger than neutrophil
- “basophilic” granules: contain histamine and many other proteins
What are features of platelets (PLTs)? Function?
- second most numerous blood cell (hundred-thousands)
- 200k-800k cells/uL (varies by species)
- function:
- primary hemostasis (clotting)
- role in primary inflammatory response
What is indicated in this image?
- platelets: small discoid cytoplasmic fragments
- size: 2-4 um diameter
- nucleus: anucleate (no nucleus)
- granules: red-purple in most species
Fill in this diagram
What is shown in these images?
- eosinophils
Label the image
- A: basophil
- B: neutrophil
- C: eosinophil
Label the image
- A: neutrophil
- B: eosinophil
- C: monocyte
Label the image
- L: lymphocyte
- R: monocyte
What are the components of bone marrow?
- sinusoids
- stromal cells
- hematopoietic cells
- macrophages
What are features of sinusoids in bone marrow?
- large lumen
- formed by discontinuous endothelial cells
What are features of stromal cells in bone marrow?
- support structure of bone marrow
- composed of: fatty cells, reticular cells, and fibers
- cells occupy the space between stem cells and precursor cells
What are features of hematopoietic cells in bone marrow?
- aka hemic tissue
- stem cells and precursor cells of each lineage
What are feature of macrophages in bone marrow?
- store iron
- involved in moderating hematopoiesis
- regulate bone formation
What are the two kinds of macroscopic bone marrow?
- red marrow
- richer in hematopoietic cells
- produces al blood cells
- stores iron
- yellow marrow
- richer in fatty tissue
- replaces red marrow
- aging change
- richer in fatty tissue
What is indicated in this one marrow biopsy?
- large arrow: boney trabeculae
- small arrow: hematopoietic cells + adipocytes
T/F: bone marrow cellularity remains consistent
- false;
- neonate 100%
- young animal ~80%
- older animals ~25-50%
What is indicated in the image?
- sinusoidal capillaries
T/F: hematopoiesis is a process in which specialized cellular precursors develop into highly differentiated cells of peripheral blood
- true
Where does hematopoiesis take place?
- postnatal:
- bone marrow
- proximal end of femur + humerus *
- pelvis *
- sternum *
- ribs
- vertebrae
- scapulae
- skull
- liver (v little)
- spleen (v little)
- bone marrow
- prenatal FYI
- yolk sac, liver, spleen, lymph nodes, thymus, bone marrow
What are the steps of erythropoiesis?
- rubribast
- prorubricyte
- rubricytes
- metarubricytes
- polychromatophilic RBC
- mature RBC
What are the steps of granulopoiesis?
- myeloblast
- promyelocyte
- myelocyte
- metamyelocyte
- band neutrophil
- segmented neutrophil
What is granulopoiesis regulated by?
- colony stimulating factors (CSF) and inflammatory cytokines
- occurs in bone marrow
What are the steps of monopoiesis?
What are the steps of thrombopoiesis?
- pluripotent stem cell
- myeloid stem cell
- megakaryoblast (big arrow)
- promegakaryocyte (regular arrow)
- magekaryocyte (thin arrow)
- platelets
T/F: B lymphocytes mature in thymus, T lymphocytes mature in the bone marrow (or bursa of fabricius in birds)
- false;
- T lymphocytes mature in thymus,
-B lymphocytes mature in the bone marrow (or bursa of fabricius in birds)
What is the main site of hematopoiesis in adult mammals? Thymus, spleen, bone marrow, or liver?
- bone marrow
Which cells are part of the granulocytic lineage?
- eosinophil
- neutrophil
- basophil
What is the function of the lymphatic system?
- protect body against pathogenic organisms and their products and to help in removal/disposal of cells undergoing natural or induced degeneration
- via phagocytosis (macrophages) and production of immunologically competent cells (antigen presenting cells, B+T lymphocytes)
What are the primary organs producing lymphocytes?
- bone marrow
- cloacal bursa/ bursa of fabricus (in birds)
- thymus
** produced in marrow, mature in all 3
What are the secondary organs responsible for activation and presentation of antigens?
- lymph nodes
- spleen
- mucosal associated lymhoid tissue
- tonsils
What are features of primary lymphatic organs?
- where T and B cells originate and their unique features established
- access by antigens strictly controlled (barriers)
- apoptotic elimitation of self-reactive cells
- released to circulation sites where antigens are encountered (secondary organs)
What are features of bone marrow?
- sure of pluripotent stem cells (B + T cells)
- background of stromal cells release factors aiding in cell differentiation ad macrophages
What is this structure? What are some features?
- cloacal bursa
- dorsal wall of cloaca
- functionally equivalent to mammalian bone marrow
- surface mucosa of bursal fold covered by pseudostratfied columnar epithelium, cortices+ medulla, lymphocytes emigrate through surface epithelium
- basophilic big nuclei, very little cytoplasm
What is this structure? What are some functional features?
- thymus
- located in mediastinum cranial to heat in immature animals
- composed of epithelial reticulum (network) and developing lymphocytes
- lymphocytic cells migrate from bone marrow
- fill spaces between reticular epithelial cells of developing organ
- develop into T cells which migrate to areas of secondary organs and MALT
What part of the thymus is shown? What are some features?
- darker due to greater number of lymphocytes
- area of POSITIVE selection
- developing lymphocytes/thymocytes
- “good” weak binding, recognize antigens
- tingible body macrophages are near medulla
- phagocytose and eliminate dead/bad T cells (without correct receptor)
What part of the thymus is shown? What are some features?
- contains epithelial reticular cells
- area of NEGATIVE selection
- “bad” (autoreactive) lymphocytes phagocytosed by “tingible body” macrophages
-Some medullary reticular epithelial cells form thymic corpuscles or Hassall’s corpuscles - large central calcified or degenerated cells surounded by concentric circles of keratinized cells
- “bad” (autoreactive) lymphocytes phagocytosed by “tingible body” macrophages
What is this structure? What features are indicated?
- thymus
- hassall’s corpuscles
What are feature of vascularization in the thymus?
- arteries enter via corticomedullary junction within connective tissue septa
- divide into arterioles within the septa
- branch into capillary network in the cortex (cortical capillaries)
- cortical capillaries > blood thymus barrier
- continuous epithelium
- perivascular connective tissue
- sheath of epithelial reticular cell processes
What is the purpose of the blood thymus barrier?
- decreases antigen acccess to thymus
- limits interference with positive T cell selection and recognition of antigen as self
What is thymic involution?
- gradual depletion of lymphocytes and replacement by adipocytes after sexual maturity
What are the functions of the lymph nodes, spleen, and mucosal associated lymphoid tissue (MALT)
- lymph nodes: filter antigens from lymph before returning it to bloodstream
- liver: filters antigens from blood ONLY
- MALT: local immune response
What structure is shown? What are some features?
- lymph nodes
- capsule
- dense irregular CT, trabeculae
- cortex
- subcapsular sinus, lymphoid follicles (B cell rich), paracortex (T cell rich), high endothelial blood vessels
- medulla
- medullary cords (lymphocytes, macrophages, plasma cells), medullary sinus (macrophages, reticular cells) - stroma
- reticular cells and fibers
What is the flow of the lymph node?
- afferent lymphatic vessel > subcapsular sinuses > cortical (trabecular) sinus > medullary sinus > efferent lymphatic vessel
What is the difference between primary and secondary lymphoid follicles?
- when stimulated by antigens, histolic morphology changes from primary to secondary
- macrophages present in secondary follicle, and B cells produce antibodies
What type of epithelium lines the high endothelial venules? What part of the lymph node are they present in?
- cuboidal endothelium
- cortex
What is shown? What structures are indicated?
- medullla of lymph node
- medullary cords
- medullary sinuses
What structure is shown? What is indicated?
- medullary sinus off lymph node w/ lattice of fixed macrophages spanning the lumen
- plasma cell
What is different about porcine lymph nodes?
- cortex is central, medulla is peripheral
What are hemal nodes?
- nodes alongside (not connected) the bloodstream
- seen predominantly in ruminants - dark colour
- rich content of erythrocytes within sinuses
- no lymphatic supply
- near the spleen, kidney, and large blood vessels along entralside of vertebrae
- functions similarly to spleen
What are hemolymph nodes?
- in pigs
- lymph node containing RBCs in sinuses as result of hemorrhage in tributary field
What are functions of the spleen?
- filters blood
- senescent RBCs and WBCs
- recovers and stores iron
- macrophages of red pulp commonly contain portions of RBCs and hemosiderin
- samples/removes antigens from blood (phagocytosis)
- mounts immune responses against blood-borne antigens _b cells + T cells
- hematopoiesis in fetus, sometimes adults
- storage of RBC in horse, dog, and cat (“storage spleens”)
- more smooth muscle ad elastic in capsule for contraction and release of RBCs into bloodstream
- “defense” spleens have less smooth muscle in capsule (humans and rabbits)
- ruminants and pigs are intermediate
What are features of the capsule of the spleen?
- outer capsule is dense CT with underlying smooth muscle and elastic fibers
- capsule gives rise to: trabeculae - collagen, elastic fibers, smooth muscle cells
- each trabeculae contains a central artery or vein
What differentiates red and white pulp in the spleen?
- white pulp (basophilic blue)
- modifies cortex
- central arterioles
- periarterial lymphoid sheaths (PALS) - T cells
- follicles - B cells
- red pulp
- modified medulla
- venous sinuses (RBCs) - big component
- macrophages, lymphocytes, plasma cells
Describe splenic blood flow
- central artery > branches with periarterial lymphatic sheath (white pulp) > penicillary arteries > blind ended capillaries with periarteriolar macrophage (PAMS syn. ellipsoids) (red pulp) > capillaries drain into red pulp parenchyma and hen venous sinuses in OPEN circulation/ capillaries drain into venous sinuses directly in CLOSED circulation
- sinuses only well developed in DOG
Where is mucosal associated lymphoid tissue (MALT) found?
- gut-associated lymphoid tissue (GALT) > Peyer’s patches
- bronchial-associated lymphoid tissue (BALT)
- tonsil
- ocular
- urogenital
- mammary
What is indicated in the image?
- peyer’s patches
What is shown in the image?
- peyer’s patch (red dome)
What are M-cells?
- specialized epithelial cells
- simple columnar later of microfold (M) cells
- pinocytose GI contents and secrete content on the lymphocytes and macrophages of peyer’s patch
- Mac-macrophage, L-lymphocyte
What are lacteals?
What are features of lymphatic vessels?
- blind-ended tubes lined by endothelial cells
- absorb fluid from the interstitium, pass it back into bloodstream
- inflammatory cell and antigen movement from peripheral tissue
- lymph flows in one direction from periphery heart
- surrounding tissues compress or expand the vessel
- one-way valve prevents backflow
Label the image
- 1: small lymphatic vessel with a valve; clear content , NO RBC
- 2: arteriole - 1-3 Ayer’s of circular smooth muscle cells
- 3: venule - no smooth muscle in the wall
Understand how lymphatics drain tissue fluid
- lymphatics delver lymph or lymph nodes - regional monitoring centers for immune response
What is this structure? Some features?
