Histology


This page last updated November 09, 2007


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This lab focused on the examination and identification of tissues that make up the organs of the body.  The tissues are divided into four main categories: epithelial, connective, muscle, and neuronal.  Click on the thumbnail images to see a larger version.  All of the photomicrographs were taken using the 40X objective (400X magnification), which is the highest magnification we use in this lab.

Other resources include linked web pages on the "Resources" page and the histology tutorial on the PhysioEx 7.01 CD.

Remember, for the practical, you are expected to:

1) Identify the tissues
2) Know where the tissues are found
3) Know one function for the tissues

Epithelial tissue

Simple squamous epithelium

Epithelial tissue that lines the air pockets (alveoli) of the lungs. 

Stratified squamous epithelium

The identification is from the shape of the top layer of cells.

Simple cuboidal epithelium

This tissue lines the tubules of the kidney.  You can see the lumen (open area) and the single layer of cuboidal cells that enclose a tubule.  The cells are cuboidal in shape with the nucleus in the center.

Simple columnar epithelium

This tissue lines the digestive tract.  The light fuzz on the apical surface of the cells are microvilli that increase the absorptive area of the cell.  The light purple structures are goblet cells, which are unicellular glands that secrete mucous.

 

 

Pseudostratified epithelium


This tissue lines the trachea. On the apical surface are cilia that are used to move mucous along the surface of the trachea. The cells vary in shape but there is only one layer of cells attached to the basement membrane. The shorter cells mixed with columnar cells give this epithelium the appearance of being made up of layers of cells.
 

Transitional Epithelium

This tissue lines the bladder.  The cells are stratified and are capable of changing their shape to accommodate the stretching of the bladder.

Connective tissue

Bone

There are two osteons in this micrograph.  The dark and light ovals are the central canals or Haversian canals through which blood vessels and nerves project.  Surrounding  central canals are the lamellae with the osteocytes embedded in the solid calcium and phosphate matrix.  The fine lines radiating out from the center are canaliculi.

 

Blood

This micrograph shows red blood cells (erythrocytes), white blood cells (leukocytes), and platelets

Adipose tissue

Most of the cell volume is taken up by a triglyceride droplet.  On some of the cells you can see the nucleus pushed up against the plasma membrane.

Areolar connective tissue

This tissue is characterized by oval plasma cells and 3 different kinds of fibers: collagen (thick and light pink), elastic (thinner and dark), and reticular (thinnest and dark).

Reticular connective tissue

Small pink reticular cells are surrounded by dark brown reticular fibers.

Elastic tissue

The branching pink structures are the elastic fibers.  Embedded you can see the nuclei of some fibroblasts.

Dense regular connective tissue (white tissue)

This tissue makes up the tendons and ligaments.  The cell bodies are darkly stained and elongated.

Hyaline cartilage

Lacunae (small openings) contain the chondrocytes, which are embedded in a smooth matrix.  Chondroblasts, which secrete the matrix, can be seen at the top of the micrograph.

Elastic cartilage

Lacunae containing the chondrocytes, which are characteristic of cartilage, are embedded in a matrix with elastic fibers.  The fibers are dark and canbe seen most clearly on the right side of the micrograph.

Fibrous cartilage

The lacunae are not as numerous in this cartilage and they are smaller.  the nuclei of the chondrocytes is a red-purple color. 

Muscle tissue

Skeletal muscle

Skeletal muscle cells are cylindrical in shape.  They are multinucleate and striated.  The nuclei are found against the plasma membrane.

You should be able to see the striations on the larger image or on this micrograph.

Cardiac muscle

Cardiac muscle cells are also striated but unlike skeletal muscle, they have a single nucleus and are branched.  The cardiac muscle cells are attached to each other through desmisomes.  The desmisomes and gap junctions together make up the intercalated discs, which are the dark blue lines that run perpendicular to the muscle fiber.

Smooth muscle

Smooth muscle has a spindle shape and a single nucleus.  It is NOT striated.

Nerve tissue

Nerve tissue

The large central structure is a motor neuron surrounded by the small dark nuclei of the glial cells that are important in maintaining the tissue environment.  The motor neuron is multipolar and exhibits an axon and dendrites extending from the body of the cell.