histo

• Sebaceous gland.

  
• Section of sweat gland.

  
• Pararosaniline—toluidine blue (PT) stain.

  
• Section of a bronchus wall showing the respiratory epithelium with goblet cells and columnar ciliated cells. The connective tissue of the lamina propria contains serous glands and smooth muscle (SM). In the lower half of the photomicrograph is a large piece of hyaline cartilage. PT stain.

  
• Section of a bronchus wall with bronchus-associated lymphoid tissue (BALT), a component of the diffuse mucosa-associated lymphoid tissue (MALT)

  
• Clara cells in the epithelium of a terminal bronchiole. These cells show secretory granules and a bulging apical cytoplasm. PT stain. High magnification.

  
• Bird’s-eye view of a lung section showing branching of bronchioles with different sizes of bronchioles (1, 2, 3), large blood vessels, and alveoli. PT stain. Low magnification.

  
• Section of bone tissue showing an osteocyte with its cytoplasmic processes surrounded by matrix. The ultrastructure of the cell nucleus and cytoplasm is compatible with a low level of protein synthesis.

  
• Photomicrograph of dried bone ground very thin. The lacunae and canaliculi filled with air deflect the light and appear dark, showing the communication between these structures through which nutrients derived from blood vessels flow. Medium magnification

  
• A: Thick section of bone illustrating the cortical compact bone and the lattice of trabeculae of cancellous bone.

  
• Section of cancellous (spongy) bone with its characteristic random disposition of collagen fibers. Picrosirius—polarized light (PSP) stain. Low magnification

  
• . Section of a haversian system, or osteon. Note the alternation of clear and dark circles resulting from the alternation in the direction of the collagen fibers. The collagen fibers appear bright when cut longitudinally and dark when cross-sectioned. In the center of the osteon is a channel.

  
• Photomicrograph of the epiphyseal plate, showing its 5 zones, the changes that take place in the cartilage, and the formation of bone. PT stain.

  
• The beginning of intramembranous ossification. Mesenchymal cells round up and form a blastema, from which osteoblasts differentiate, producing primary bone tissue.

  
• Section of endochondral ossification. The osseous matrix, rich in collagen type I, is specifically stained with picrosirius-hematoxylin. The cartilaginous matrix, containing collagen type II, stains blue with hematoxylin because of its high content of chondroitin sulfate. Medium magnification.

  
• Section of the extremity of a long bone showing the epiphysis, epiphyseal plate and newly formed bone tissue. PSP stain. Low magnification

  
• Diarthrosis

  
• . Photomicrograph of a motor neuron, a very large cell, from the spinal cord. The cytoplasm contains a great number of Nissl bodies. The large cell process is a dendrite. Note the large, round, stained nucleus, with a central dark-stained nucleolus. Pararosaniline—toluidine blue (PT) stain. Medium magnification.

  
• . Section of spinal cord gray matter. The meshwork of cell neuron and glial processes appears distinctly. The small nuclei are from glia cells. Note that these cells are more numerous than neurons. H&E stain. Medium magnification.

  
• Cross section of a thick nerve showing the epineurium, perineurium, and endoneurium. The myelin sheath that envelops each axon was partially removed by the histologic technique. PT stain. Medium magnification.

  
• Striated skeletal muscle in longitudinal section (lower) and in cross section (upper). The nuclei can be seen in the periphery of the cell, just under the cell membrane, particularly in the cross sections of these striated fibers. H&E stain. Medium magnification

  
• Photomicrograph of cardiac muscle. Note the cross-striation and the intercalated disks (arrowheads). Pararosaniline—toluidine blue (PT) stain. High magnification.

  
• Photomicrographs of smooth muscle cells in cross section (upper) and in longitudinal section (lower). Note the centrally located nuclei. In many cells the nuclei were not included in the section. PT stain. Medium magnification

  
• Muscular artery


  • Tunica intima and tunica media are highly developed
• Capillary


  • Has fenestrae in its wall
  • Wall is formed by 2 endothelial cells
  • Has basal lamina surrounding endothelial cells
• Microcirculation formed by small blood vessels

  1. Arteriole -> metarteriole -> capillary -> venule and vein

  2. Arteriovenous anastomosis

  3. Arterial portal system (kidney glomerulus)

  4. Venous portal system (liver)
• Arteriole and venule


  • Venule has elongated, large nucleus of a pericyte surrounding the wall
• Blood smear


  • Neutrophils
  • Erythrocytes

  
• Eosinophil


  • Bilobed nucleus
  • Coarse cytoplasmic granules
• Basophil


  • Many granules covering the cell nucleus
• Leukocytes


  • Neutrophil
  • Basophil
• Lymphocytes


  • Small lymphocytes with round, dark-stained nuclei
• Monocyte


  • Kidney-shaped nucleus with delicately stained chromatin
  • Slightly basophilic cytoplasm
• Erythrocytes


  • Biconcave shape
• Red blood cells and platelets

  • In Wright's stained blood smear

  
• Hematopoiesis


  Differentiation of pluripotential stem cells
• Development of erythrocytes and granulocytes

  Stages
• Cells participating in innate immunity

  • Mast cells
  • Neutrophils
  • Eosinophils

  
• Lymph node cortex


  • Lymphoid nodule activated by antigen injection
  • Macrophages surrounded by B lymphocytes
• Thymus


  • Cortical zone
  • Medulla with Hassall corpuscles