Connective Tissues Lab

Connective Tissues Lab

Connective tissue consist of cells embedded in an extracellular matrix. The matrix consists of fibers and ground substance. The characteristic traits of different classes of connective tissue are due to differences in the composition, relative density and arrangement of its components. Note how each of these connective tissues is unique in composition, and the manner in which that is related to its function.
We will first examine organs in the dissected cat which exemplify the types of connective tissue whose histology you will be studying:

Loose connective tissue

Loose Areolar C.T.– superficial fascia showing collagen fibers (ties skin to body)
Adipose C.T. — perirenal fat, fat tissue near the inguinal regions

Dense regular connective tissue

Reticular C.T.– lymph nodes (especially imbedded in the mesenteries
White Fibrous C.T.– Achilles tendon, attaches gastrocnemius to calcaneus
Yellow Elastic C.T.– nuchal ligament (dorsal neck), wall of the aorta

Dense irregular connective tissue

Dense Irregular C.T.– Dermis (inner portion of skin), renal capsule

Black board summary of traits of various types of connective tissue.

Examine the following slides, identify the listed features, and illustrate a typical 400x field displaying these features (100x for Areolar). (Follow instructions given in Notebook Illustrations and general directions given in Epithelial Tissues Lab Protocols.)

Loose connective tissue (Areolar)

Areolar Connective Tissue
Areolar Connective Tissue

Slide 7 Areolar Connective Tissue
(VE: fig 2-1, p 31)  (subcutaneous tissue smeared) 100x

Here is superficial fascia showing collagen fibers.
Here is a labeled view of loose areolar connective tissue.


Fibroblast pale, most common cell
collagenous fibers pink, in masses
elastic fibers stained purple

difficult to distinguish:
macrophage, larger and darker than a fibroblast
mast cell, possesses granular cytoplasm

Adipose Tissue
Adipose Tissue

Slide 8 Adipose Tissue
(VE: fig. 2-11, p 39)
also see Fig. 16-6 for ureter.)
(many slides have a cross section of a ureter )


adipose cells (or “adipocytes”) cytoplasm looks empty because fat is dissolved away
adipose nuclei compressed along edge of cell (“signet ring” appearance)
fibroblast cells between adjacent adipose cells
mesothelium at the edge, if present

Reticular Tissue
Reticular Tissue

Reticular Tissue from  a lymph node, slide 14 from lymphatic system

(VE: fig . 8-3. p. 127)

reticular fibers (stained with Ag/Au stain)

Note the trabeculae (partitions) also composed of reticular fibers.

Dense regular connective tissue

White Fibrous Tissue (tendon)
White Fibrous Tissue (tendon)

Slide 9 White Fibrous Tissue (tendon)
(VE: fig.2-5, p 35)
Draw a longitudinal section.

fibroblasts flattened in rows
collagenous fibers in parallel bundles [bundle of tendon fibers seen in c.s.]
Here is a labeled version of the Dense Regular Connective Tissue.

Yellow Elastic
Yellow Elastic

Slide 10 Yellow Elastic (slide is from bovine nuchal ligament)
(VE: fig. 8-4, p 115 in the aorta)

Draw the longitudinal section
(contrast appearance with white fibrous tissue)

fibroblast nuclei distributed through tissue
collagenous fibers woven in appearance (due to the contraction by elastin)
elastic fibers occupy “open spaces” (visible only if specially stained as with Verhoeff’s stain)

Here is a labeled version of the Yellow Elastic Connective Tissue

Dense irregular connective tissue

Dense Irregular Connective Tissue
Dense Irregular Connective Tissue

(slide 15) Dense Irregular Connective Tissue
(VE: fig. 2-7, p 37) (skin, mammal):

Here is a 100x view of a cross section of skin. Note that the epidermis is on top, and the dermis underlies it.
fibroblasts scattered throughout dermis
collagen bundles in masses, irregularly arranged in various directions
venule  Here is the dermis labeled.

Follow these links to pictures of bone histology and cartilage which are classes of connective tissue

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