Lab 8: The Immune System | Lymphoid Tissues &Organs Flashcards Preview

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Flashcards in Lab 8: The Immune System | Lymphoid Tissues &Organs Deck (28):

Identify the cells indicated by the arrows and give one function that these 
cells perform.


Identify the circled area and describe:

This is the ileum, part of the small intestine. Although we have not
examined the GI tract in detail yet, identify the gut lumen, epithelium
CT and muscle. Embedded in the submucosa (CT) are confluent 
groups of lymphoid nodules (within the oval). Solitary nodules are also present.


Peyer's patches: Identify numbered areas and describe 

 Peyer’s patches are accumulations of lymphatic nodules that can involve both layers of CT in the wall, being in the submucosa and the lamina propria, often confluent (contiguous) on one side of ileum, as opposed to single nodules. Nodules often have a cap of small lymphocytes

(1) outside of a core of activated lymphocytes and antigen-presenting cells called the germinal center
(2) Note diffuse infiltration of white blood cells in the loose CT especially 
in the lamina propria.


What is within the circle?

Within the circle are the finger like-extensions of villi on the right and a 
shorter villus filled with lymphocytes. The lumen in this region is covered 
by M-cells. Lymphocytes lie beneath the thin portions of the cells and 
receive antigenic peptides


Examine the outer cortex and find if possible:

  • containing nodules 
  • (follicles) inner paracortex
  • without nodules
  •  medulla 


Examine the outer cortex and find if possible:

  • containing nodules 
  • (follicles) inner paracortex
  • without nodules
  •  medulla 


Examine the outer cortex and find if possible:

  • containing nodules 
  • (follicles) inner paracortex
  • without nodules
  •  medulla 


Identify structures 1-6:

Where would you expect to fine the high 
endothelial venules?


This lymph node shows many of the key features. Note the capsule (1), where afferent lymphatic vessels enter, the subcapsular sinus (2), the trabeculi(3) and trabecular sinuses (4) (or cortical and paracortical sinuses,) and the medullary cords and sinuses (5). Note the cortex, the 
paracortex and the medulla, as well as the hilus (6). 


Find elongated nuclei:

What is the collagen type?

Note the fibers in the capsule, along and projecting into the cortical sinuses and supporting the lymph node. Reticular cells lay down the reticular fibers. Look for cells with elongated nuclei, particularly in the sinus spaces.
Collagen type: 


Identify 1-4:

  1. Capsule
  2. Trabeculum
  3. White pulp
  4. Red pulp



Identify 1 and 2:


Identify: 4-8, 10, 13

Red pulp:
4 arteriole
5 endothelial cell
6 reticular cells
7 interstitial space
8 venous sinusoid
10 macrophages
13 hematopoiesis




A thin capsule surrounds the thymus. Note the incomplete septa that divide the 
thymus into lobules. The lobules have a dark staining cortex without nodules and a paler staining central medulla that is irregular in shape and intercommunicates with other medulla throughout the organ.



Note the incomplete septa that divide the thymus into lobules. The lobules have a dark staining cortex without nodules and a paler staining central medulla that is irregular in shape and intercommunicates throughout the organ. The medulla has concentrically arranged epithelioreticular cells (type VI) that form the thymic or Hassall’s corpuscles. Both the cortex and medulla have epithelioreticular cells forming their framework.


What is displayed in this image?

This light micrograph shows a thymus with a thymic or Hassall’s corpuscle



Note the high endothelial venules in the paracortical zone. The lymphocytes 
return to the lymph nodes, leaving the blood through these high endothelial 
venules by migrating between the endothelial cells. They can re-circulate many 
times this way. High endothelial venules can also be found in spleen, tonsils and Peyer’s patches as well.


Identify E and L.

An example of a postcapillary venule with an abnormally thick endothelium (E = endothelial cell). A lymphocyte (L) is squeezing through the endothelial cell.


Identify E, L, R, N: 

  • E: cubodial epithelium
  • L: lympocyte
  • R: red blood cells
  • N: neutrophil


Identify: LB




Identify: arrows, G

see attached text


Identify: S, Sh, N, C.

see attached text


Identify N, M

see attached text


Identify: N, O, S, E, P, PC

see attached text


Identify: ly

see attached text


Describe this image:

The black material in this unstained section is an extracellular tracer that was injected into the bloodstream.  The insert shows that passage from the lumen to the cortex is blocked by endothelial tight junctions.  What gets across is taken up by macrophages, processes of which are above and below the capillary.  Sheets of cytoplasm of epithelial reticular cells are visible around the capillary.


What is the arrow pointing to:

See attached text:


Identify L:

See attached text:


Identify T, E and circles

See attached text:

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