Department of Zoology
Southern Illinois University at Carbondale

ZOOL 409, Lab Week 5

Lab notes offer a preview of upcoming labs and links to more information about tissues examined during lab.

• Week 5 lecture notes
• SYLLABUS (including links to all note pages)
• 409 Homepage (index of course resources)
• Dr. King's School of Medicine histology page
• Slide summary

TUESDAY
Primary objectives: 

1. Recognize three types of muscle tissue. 
    
   Notice the distinguishing characteristics of each muscle fiber type.
    
   Also notice the tissue context (i.e., where muscle occurs in relation to other tissues), including the cells (such as muscle satellite cells, fibroblasts, and endothelial cells) which may occur in close association with striated muscle fibers.
    
• Compare muscle types on slide 24.  (You might also look at the motor innervation of striated muscle on slide 79.)
   
• Look for striated, skeletal muscle in the following slides.:
  • tongue -- slides 46.  (Skeletal muscle comprises the bulk of the organ.)
  • soft palate:  12
  • esophagus -- slides 06, 07, 85.  (Skeletal muscle is only present in some specimens of upper esophagus.)
  • bone:  14, 18, 19.  (Muscle may not be included in all specimens.)
     
• Look for smooth muscle in the following slides.  Note that in the gut, most clearly in the small intestine, smooth muscle occurs in two layers with distinctly different orientation of the fibers (i.e., "circular", wrapping around the organ, and "longitudinal", approximately paralleling the long axis of the organ).
  • esophagus -- slides 06, 07, 85.  (Some specimens may show skeletal muscle.)
  • intestine -- slides 03, 05, 37, 47, 61, 70. 
  • colon -- slides 09, 38, 48. 
  • stomach -- slides 40, 41, 50, 68. 
  • vagina -- slide 56. 
  • bladder -- slide 08. 
  • ureter -- slide 94.
       
    
• Look for cardiac muscle in the heart, slides 93, 34.
   
2. Recognize blood vessels.
    
• Examine the examples of artery and vein on slide 30, 74 (note that slide 74 is a trichrome stain; collagen is blue). 
  • Note the three layers.
    • intima (innermost lining, with endothelium);
    • media (usually the thickest layer, with smooth muscle);
    • adventitia (surrounding connective tissue.
  • Note elastin (especially the internal elastic lamina in the artery).
     
• Find examples of arteries and veins on additional slides.  
  

THURSDAY
Primary objectives:   

1. Recognize blood cells on normal blood smears (slide 20.)
      
• To sample a smear adequately, systematically scan an area until you have counted at least 100 white blood cells.
• Keep a running count of each type.
  • Neutrophils should be the majority, 60-65 % of the total count.
    • You might try to distinguish "band neutrophils" (or "bands") from "segmented neutrophils" ("segs").  The bands are immature; a high proportion of bands is indicative of rapid production of neutrophils.
  • Lymphocytes should also be fairly common, 20-30 %.
  • Monocytes are much less common, roughly 5%.
  • Eosinophils are rarer still, 1-4 %.
  • Basophils are quite rare, less than 1 %.  You may not find any.
     
• How does slide 21 differ from slides 20?
• How does slide 23 differ from slides 20?  (Try to find megakaryocytes, very large cells with very large nuclei.)
   
2. Recognize the special tissues/organs which comprise the immune system.
    
   • Mucosal lymphoid tissue (e.g., tonsil, Peyer's patches of ileum) -- 82, 47.
     • Try to distinguish lymph nodules with their pale germinal centers and darker "caps" with more densely packed lymphocyte nuclei.
        
   • Lymph nodes -- slides 16, 36.
     • Look for capsule, cortex with lymph nodules, medulla.
        
   • Spleen -- slides 81.
     • Look for capsule, trabeculae (narrow bands or small patches of dense fibrous connective tissue).
     • Distinguish white pulp (patches densely packed with lymphocytes, typically with small arteries in the center) from red pulp (background texture, with more red blood cells than in the white pulp).
     • Notice lymph nodules, most often associated with white pulp.
        
   • Thymus-- slides 58, 59.
     • Notice lobular organization; in each lobule distinguish cortex and medulla (with cortex having cells more densely packed).
     • Notice Hassall's corpuscles.
     • Notice absence of lymph nodules.
        

Complete slide list:
01, 02, 03, 04, 05, 06, 07, 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100

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