histology-j

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1995, 1997, 1998, 1998(II), 1999. Department of Anatomy, Histology and Embryology, University Medical School ofDebrecen

Histology

1. What is the chemical and histological background of basophilia? Attraction and binding of alkaline stains by the polyanionic tissue macromolecules.

2. Name types of stratified epithelia! Give examples!a) stratified squamous keratinizing epithelium: skin

b) stratified squamous non keratinizing epithelium: oral cavity, esophagus,vagina.c) transitional epithelium (urothelium): ureter.d) stratified columnar epithelium: spongy part of male urethra.

3. Which epithelium covers the skin? Describe its layers in baso-apical direction! Stratified squamous, keratinizing. Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum

(exclusively in thick skin), str. corneum.4. What are the most characteristic intermediate filaments of a) epithelial cells, b)muscle, c) neurons d) neuroglial cells?

a) cytokeratin,b) desmin,

c) neurofilamentd) glial fibrillary acidic protein (GFAP).

5. List the major intercellular attachment structures. Gap (communicating) junction, tight junction (occluding junction), intermediate junction (zonula adherens), desmosome (macula adherens).

6. Make a simple drawing of a desmosome and indicate theconstituents!

1. Looped intermediate filaments,2. dense (attachment) plaques,3. cell membrane,4. 20-25 nm space between the membranes filled with fibrillar material that appears to

provide attachment of the two cells through interactions of extracellular linkerfilaments.7. Describe the structure and functions of the gap junctions. 2-4 nm extracellular gap between adjacent cells. The cell membranes of the adjacent

cells are interconnected by protein components containing hexagonally arrangedintramembrane subunits (connexions) with 1-2 nm pore. The pores providecommunicating channels for small molecules (less than 1000 D), and low resistanceelectric coupling between adjacent cells.

8. What is the structure and function of the brush border? Numerous microvilli (membrane-covered cytoplasmic extensions) of the free cell

surface. Increase of surface area for absorption.

9. Which cytoskeletal component contributes to the structure of cilia? How are theyarranged?

Microtubules, 9 (peripheral) doublets + 1 central pair.10. List the major chemical constituents of the basal lamina and their site of

production! Collagen type IV, laminin, proteoglycans. Produced by the epithelial cells. Fibronectin: produced by the connective tissue cells.

11. Define the sublayers of the basement membrane and name at least two differentstaining methods that stain the basement membrane specifically! Lamina basalis + lamina reticularis. PAS, Ag-impregnation, Azan.

12. Define the pseudostratified columnar epithelium and give an example! Nuclei of columnar cells lie at different levels. All the cells contact the basal lamina,

but not all of them extend to the free surface of the epithelium. Upper part of the respiratory tract (up to bronchiolus terminalis), ductus deferens,

ductus epididymis.13. Make a drawing, which illustrates mucous and serous acini of salivary glands, anddescribe their characteristic histological features!

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Mucous: the flattened nuclei are in the basal half of the cells. Axis of nuclei isparallel with base of cell. Cytoplasm is faintly stained after conventional histologicalfixation, lumen is larger, Golgi is well developed.

Serous : spherical nuclei are located in the middle of cell, cytoplasm is stronglybasophilic, rough endoplasmic reticulum is well developed.

Mucus Serous14. Describe the difference between exocrine and endocrine glands! Exocrine: substances are secreted on to the outer body surface or into the body

cavities. Presence of excretory ducts. Endocrine: substances are secreted on to the extracellular space from which the

secretum enters the blood stream15. What are the characteristic features of holocrine, merocrine, and apocrine secretion!Give one example for each type of secretion! The secretum of the merocrine and apocrine glands are produced by cytoplasmic

organelles. Merocrine cells secrete -, without loose of cytoplasm. The duration and the rate of

secration is determined by their regulation. Eg. sweat glands Apocrine cells secrete by exocytosis of the apical portion of the cell, with the loss of

cytoplasm. Eg. apocrine sweat gland. Holocrine cell undergo progressive degeneration, followed by necrosis. Ultimately,

the entire cell transforms into secrete. Eg. sebaceous gland.16. Name the components of the resident and transient cell population of theconnective tissue! Resident cells: fibroblasts, fibrocytes, histiocytes (macrophages), mast cells, fat

cells, reticular cells. Transient cells: plasma cells, lymphocytes, granulocytes, monocytes.

17. Define the abbreviation "MPS"! Give at least 3 examples! Give the common originof these! Mononuclear Phagocyte System: System of tissue macrophages of the body.

Originate from monocytes. Histiocytes, Kupffer cells of liver, Septal macrophages of lung, etc.

18. Characterize the structure and function of the fibroblast. Flattened cell with processes, oval nucleus with nucleoli, basophilic cytoplasm rich

in RER. Formation of matrix macromolecules.19. Characterize the structure of the mast cells! By which staining can they beselectively stained? Large, ovoid connective tissue cell with spherical nucleus and the cytoplasm

contains numerous basophilic granules. Toluidine blue that stains the heparin containing granules metachromatically.

20. What materials are stored in the mast cell granules and what is the functionalsignificance of them? Heparin - anticoagulant, histamine - vasodilatator, increases the permeability of capillaries.

21. List the principal types of fibers that are found in the connective tissue! How canwe selectively stain them for LM? (Name of the histological staining + color) Collagen: azan - blue, van Gieson - red, Ag- impregnation - brown. Elastic: orcein - brown, resorcin fuchsin - black - violet Reticular: Silver-impregnation - black, PAS - purple

22. Describe the typical location of collagen type I, II, III and IV! type I: skin, tendon, bone, type II: hyalin cartilage, type III: (reticular fibers) lamina reticularis, type IV: basal lamina.

23. What are the major nonfibrillar macromolecules of connective tissue groundsubstance?

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Proteoglycans and glycoproteins. Proteoglycan molecules consist ofglucosaminoglycans and core protein.24. Describe the major structural features and functions of the proteoglycan moleculesof the connective tissue ground substance! Structure: they contain a core protein and covalently bound, strongly anionic

glycosaminoglycan side chains.

Function: space filling, water binding, diffusion barrier, support.25. What structures can be detected with PAS reaction? What is the mechanism of thePAS reaction? The PAS reaction can be used to visualize carbohydrates-like substances. The periodic acid oxidises the vicinal (located on neighbouring carbon atoms)

hydroxyl and amino groups, breaks the chain, and forms aldehydes. Basic fuchsinbleached by sulphuric acid (Schiff-reagent) reacts with these aldehyde groups andgains a magenta-red colour.

26. What are the differences in the structure of brown and white fat cells. What is theprimary function of the brown fat tissue? Brown: numerous, small lipid droplets, round nucleus. Rich blood supply. Many

mitochondria. White: single, large fat droplet, flattened nucleus. The energy produced by the oxidation of the small lipid droplets warms the blood

flowing through the tissue.27. Classify cartilage upon tissue structure! Give examples! Hyaline cartilage - Thyroid cartilage, Elastic cartilage - Auricular cartilage, Fibrocartilage - Meniscus, annulus fibrosus of intervertebral disk.

28. Why does the cartilage matrix show basophilic staining? Because of the high concentration of sulphated glycosaminoglycans.

29. List the components of the cartilage matrix that can be distinguished on the basis oftheir macromolecular composition and staining pattern. Capsule (pericellular) matrix, territorial matrix, interterritorial matrix.

30. Name the parts of intervertebral disk!

Annulus fibrosus and nucleus pulposus.31. List those tissues or organs that are free of blood capillaries! Cartilage, cornea, lens of the eye, vitreous body, Wharton jelly Epithelium.

32. Make a diagram of the cross section of an osteon and label parts!1. Haversian canals with blood vessels,2. concentric matrix lamellae,3. osteocytes.

33. List the cell types involved in osteogenesis and in boneresorption! Osteogenesis: osteoprogenitor cells, osteoblasts,

osteocytes, Bone resorption: osteoclasts.

34. Describe the a) origin, b) morphology and c) function of osteoclasts!a) Monocytes.

b) Multinucleated cells, ruffled border numerous lysosomes.c) Bone (calcium) resorption.

35. What are the major light microscopic structures in adult compact bone? Lamellae: concentric lamellae (laminae speciales), internal and external

circumferential lamellae (laminae generales), interstitial lamellae (laminaeintercalares).

Cells: osteoblasts, osteoclast and osteocytes Canals: Haversian and Volkmann canals Osteons: structural subunit of compact bone (Haversian canals, concentric lamellae

and osteocytes) .

36. What is the periosteum and describe its functions? Fibrous connective tissue investment of the bones.

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Functions: Blood and nerve supply of the bone. Fracture and bone repair, boneapposition and resorption.

37. What are the subtypes of bone marrow? Indicate places of occurrence and functionof them! Red bone marrow: in flat and irregular bones, epiphysis of long bones. Function:

hemopoiesis.

Yellow bone marrow: in diaphysis of long bones. Function: fat store, if required, it isreplaced by red bone marrow.38. Describe the zones of epiphyseal cartilage!

a) Zone of reserve cartilage,b) zone of cell proliferation,c) zone of cell maturation,d) zone of cell hypertrophy,e) zone of calcium deposition,f) zone of cartilage resorption and ossification.

39. What are the most important events in the zone of ossification of the epiphysealcartilage? Death of cartilage cells, removal of cartilage debris by chondroclasts, osteoblasts

deposit bone matrix upon persisting calcified cartilage matrix trabecules.40. Give examples for a) intramembranous and b) endochondral bone formation!

a) flat bones of the skullb) long bones of the extremities, ribs, etc.

41. Which structure separates the epiphyseal and the diaphyseal ossification centers andhow long does this structure persist? Epiphyseal plate. Until the growth of bone ceases.

42. Which is the characteristic intercellular attachment structure of smooth muscle cellsand what is its role? Gap junction. Transmission of impulses from one cell to another.

43. Make diagrams of a a) resting and b) contracted sarcomere illustrating changes inorganization of the sarcomere during contraction! Label structures!

a) 2 x Z, 2 x I/2, A, H, (M)b) 2 x Z, A, sarcomere shortens.

44. What is the name of the following

structures in skeletal muscle fibers: a) cellmembrane, b) cytoplasm, c) endoplasmicreticulum?

a) Sarcolemma,b) sarcoplasm,c) sarcoplasmic reticulum.

45. Define the terms "sarcoplasmic reticulum" and"transverse tubular system", and give theirlocalization! Describe their functional importance! The sarcoplasmic reticulum is an elaborate

endoplasmic reticulum, a network of cisterns ormembranous tubules, which course between and around the myofibrils. In thevicinity of I band or Z disc it expands into terminal cisterns.

Transverse tubules are regular (periodic) and transverse invaginations of thesarcolemma at the Z lines (cardiac muscle) or at the two ends of A band (sceletalmuscle) making contacts with the terminal cisterns of the sarcoplasmic reticulum.

Functional significance: Signal transfer. Transverse tubular system plays importantrole in signal transfer from nerve endings to sarcoplasmic reticulum, whereas thesarcoplasmic reticulum serves as a reservoir and regulator of Ca ions. Thedepolarization of T tubule membrane results in a calcium release from sarcoplasmicreticulum to the sarcoplasm. Calcium is necessary for the actin-myosin interaction,resulting in muscular contraction.

46. What are the light microscopic characteristics of cardiac muscle? Intercalated disks, branching muscle cells, network formation, nucleus is in the center of cell, cross striations,

(rich capillary network).47. Define the structure, and list the fine structural components of intercalated discs inthe cardiac muscle!

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0.5-1 m thick cross bands of cardiac muscle fibers that represent the major sites ofattachment between cardiac muscle cells.

The junctions are composed of fasciae adherentes, desmosomes, and gap junctions.48. What are the major types of blood capillaries on the basis of the morphology ofendothelial cells? Continuous, discontinuous, fenestrated.

49. Define the most characteristic features of fenestrated capillaries! Fenestrated capillaries are characterized by 70-100 nm fenestrae in endothelial cells.

Fenestrae are frequently covered by non-membranous diaphragm that resemblesglycocalyx in its appearance and chemical composition.

50. List the layers of the wall of a continuous capillary! Endothelial cells, basement membrane, pericytes.

51. Describe the composition of the intima in large veins! Endothelium, intermediate layer (subendothelium: delicate connective tissue with smooth muscle

cells), internal elastic lamina.

52. What is the difference between the histological structure of a capillary andarteriole? The arteriole is larger in diameter and its media contains 1-2 layers smooth muscle

cells.53. In which layer do we find the most important differences of the wall of arteries andveins ? What are these differences? In Media. In veins: media is relatively thinner, smooth muscle cells are loosely arranged, We

find more collagen and less elastic fibers, The media-adventitia border in indefinite.54. What is the most prominent difference between vasa vasorum of large veins andlarge arteries? What is its significance? Vasa vasorum penetrates the entire media of veins, while only the periphery of the

media is penetrated by them in arteries. The internal part of the media in arteries is,therefore, predisposed to degeneration.

55. Characterize the structure and function of high endothelial venules of lymphaticorgans!

Cuboidal endothelial cells line them. Occluding junctions are poorly developed between the endothelial cells. The wall of such venules can be penetrated bylymphocytes (from the blood into the lymphatic tissue). They are involved in therecirculation of the lymphocytes (homing).

56. Define the terms a) the hematokrit value, b) the blood serum!a) value that shows how many percent of the blood is constituted by cells (for normal

blood: 45)b) Fibrinogen - free blood plasma.

57. Give the number of a) erythrocytes, b) leukocytes, c) platelets in peripheral bloodof normal adults?

a) 4-5x106/mm3 or 4-5 T/l,b) 6-10x103/mm3 or 6-10 G/l,c) 150-300x103/mm3 or 0.15-0.3 T/L

58. Describe the differential count of the blood! Neutrophils: 60-70 % Basophils: 0.5 % Eosinophils: 2-3 % Stab: 1-2 % Lymphocytes: 20-30 % Monocytes : 3-8 %

59. Describe the following characteristics of the erythrocytes: a) form, b) diameter, c)lifetime, d) function!

a) biconcave disc,b) 7.2 m,c) 100-120 days,d) oxygen and carbon dioxide transport.

60. Which juvenile form of erythropoiesis can be found in normal peripheral blood?

Describe its structure! Reticulocytes. Their cytoplasm contains scattered groups of ribosomes which

explain their reticulated appearance when stained for LM with vital dyes.

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61. What is meant by a) leukocytosis, b) leukopenia, c) thrombocytopenia?a) Number of leukocytes is greatly increased,

b) Reduction of leukocytes in number,c) Reduction of platelets in number.

62. Describe the a) structure, b) function, c) origin of plasma cells!a) Basophilic cytoplasm rich in RER, eccentric nucleus containing chromatin cords,

b) production of antibodies,c) B lymphocytes63. Classify the lymphocytes on the basis of their involvement in cell mediated andhumoral immune response! Cell mediated immune response, T cells: helper, cytotoxic, suppressor, memory Humoral immune response: B cells: memory, plasma cell precursors -

64. Describe the way how lymphocytes recirculate in the human body! Blood and tissues- secondary lymphatic organs - efferent

lymphatic vessels - thoracic duct- blood.65. Make diagrams showing a) a lymphocyte, b) a monocyte.Indicate the cell diameters!1. Lymphocyte: 7-8 m,2. Monocyte: 12-20 m

66. Make proportional drawings of the leukocytes found in peripherial blood! Indicatealso the names and size of the cells!

1. small lymphocyte : 5 (6-12) m2. large lymphocyte : 7 (6-18) m3. monocyte : 12-20m4. eosinophil : 12-15 m5. neutrophil : 10-12m6. juvenile : 12-15 m7. basophil : 10-12 m

67. What is meant by the "shift to theleft" of peripheral blood smears? An increase of relative numbers of

nonsegmented neutrophils(metamyelocytes or juveniles and

band forms).68. What is the function and

predominant ultrastructural constituentof the neutrophils? Phagocytosis (in the connective tissue), lysosomes.

69. What is the a) size, b) origin, c) life span and d) function of the platelets?a) 2-4 m

b) megakaryocytesc) 5-10 daysd) They are involved in blood clotting.

70. What does the abbreviation CFU-S, CFU-M and CFU-L stand for in hemopoiesis?Explain the expression! CFU: A colony forming unit is a stem cell that gives rise to blood cell lines found in

the bone marrow. CFU-S: pluripotent ("true", uncommitted) stem cell. Its derivatives are the CFU-M

and CFU-L, and it has a capacity for renewal. CFU-M: pluripotent myeloid cell (progenitor, committed). Derivatives: CFU cells

for the erythroid, megakaryocytic, leukocytic cell line except the lymphocytes. CFU-L: pluripotent lymphoid cell (progenitor, committed). Derivative: CFU cell for

the lymphoid cell line.71. What are the homeopoietic organs in the intrauterine development ? Name them insequence of development! Yolk sac, liver, spleen, red bone marrow.

72. Describe the stages of granulocyte development in the order of differentiation!

CFU-S, CFU-M, CFU-GM, CFU-G, myeloblasts, promyelocytes, myelocytes (neu.,eo., bas.), metamyelocytes (juvenile), band forms, granulocytes.

73. Describe stages of erythrocyte development in the order of differentiation!

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CFU-S, CFU-M, CFU-E, proerythroblasts, basophilic erythroblasts,polychromatophilic erythroblasts, normoblasts, reticulocyte, erythrocytes.

74. At which stage of erythrocyte development can hemoglobin be first detected byconventional staining methods? What does the appearance of polychromatophilic stainingindicates? Polychromatophil erythroblasts.

Appearance of hemoglobin.75. Describe stages of monocyte development in order of differentiation! CFU-S, CFU-M, monoblast, promonocyte,

monocyte.76. Name the structures that are indicated bynumbers in the drawing!

1. Afferent,2. efferent lymphatic vessels,3. capsule,4. cortex,5. medulla,6. cortical follicles,7. subcapsular sinus,8. cortical sinus,

9. medullary sinus,10. medullary cords,11. trabeculae,12. paracortex.

77. In which parts of the lymph node are the a) B lymphocytes, b) T lymphocytes and c)plasma

cells most densely located?a) In follicles,

b) in paracortex,c) in medullary cords.

78. Describe the pathway of lymph through lymph node from vas afferent to vas

efferent!1. afferent lymphatic vessels2. subcapsular sinus3. cortical sinus4. medullary sinus,5. efferent lymphatic vessels.

79. What histological structures the white and red pulps of the spleen consist of? White: periarteriolar lymphatic sheath (PALS), lymphatic nodule, periarteriolar macrophage

sheath (PAMS) Red: splenic sinuses and splenic cords.

80. List at least five primary functions of the spleen!Production of antibodies.Phagocytosis of damaged blood cells.Storage of blood cells.Proliferation of lymphocytes.Formation of blood cells during fetal life.Removal of macromolecular antigens from the blood.Retrieval of the iron from red blood cell hemoglobin.

81. Define the term lymphatic nodules! Describe the histological composition of primaryand

secondary lymphatic nodules! Lymphatic nodules are oval concentrations of lymphocytes located in meshwork of

reticular cells. Primary nodules: nodule consisting chiefly of small lymphocytes. Secondary nodule: it can be divided into a central region, called germinal center,

and an outer ring of small lymphocytes. The germinal center appears to stain lessintensely due to the fact that it contains follicular dendritic cells,centroblasts,

centrocytes and macrophages.82. List the most important cell types that are involved in the immune response! Lymphocytes, plasma cells, macrophages.

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83. What is the morphological basis of the blood-thymus barrier and what is itssignificance? Barrier: endothelial cells, basement membrane of endothelial cells, perivascular

connective tissue, basement membrane of epithelial cells, epithelial reticular cells. This barrier forms an impermeable layer for blood-born macromolecules, so the

lymphocytes can mature in an antigen free environment.

84. What is the characteristic histological structure of tonsils? Many primary and secundary lymphatic follicles, epithelium infiltrated by lymphocytes, lymphoreticular meshwork,

lacunae covered by epithelium, high endothelial venules (HEV).

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