Bio111Guides

University of Alaska Southeast

Histology Lab 1: Identification of Tissues

Background:

This lab introduces you to the study of tissue histology which is an important subtopic of Anatomy and Physiology. Your textbook defines histology as: “the branch of anatomy dealing with microscopic structures of tissues.” In order to understand how organs and organ systems function, it really helps if you understand the cells and cellular arrangements that they are constructed from. Histology will be an important component of every chapter we study for the rest of this course and throughout Biology 112.

This lab will introduce a great site from the University of Iowa called the Virtual Slide Box of Histology. This, great tool, allows you to explore histology slides on your computer by giving you the ability to control both magnification and field of view the way you wound with a real microscope.  We will use the Virtual Microscope in each Unit this semester. You may find some start up instructions for using the virtual microscope helpful.  The Southern Illinois School of Medicine also has a great histology site with lots of pictures and explanations and pictures that you may want to bookmark and reference.

We will also be using an excellent set of videos that tour you through the University of Iowa Virtual Slidebox series.  Watch this introductory video to get you started.

The voice you hear on the Shotgun video series is Dr. John Minarcik.

Dr. John Minarcik received his medical degree from the University of Illinois College of Medicine, and completed residencies in Pathology and Nuclear Medicine at Northwestern University and Michael Reese Hospital in Chicago, achieving board certification in both. He engaged in the private practice of medicine until 2003 but maintained workshops in computer applications to pathology at national ASCP meetings.

What do you need do for this assignment?

This lab has two parts: Part 1: Identification of Epithelial Tissues and Part 2: Examination of Connective Tissues. For each part there is a worksheet below which you should print out. Watch the Shotgun Histology videos and then spend ~ 5 minutes examining the Virtual SlideBox slides to fill out the worksheets. Once you have viewed all of the slides and completed the worksheets, take the Histology Quiz in the Week 3 folder of the Blackboard Course site. You do not need to turn in your worksheets.

 

Part 1: Identification of Epithelial Tissues

Watch the introductory videos on epithelial cells and begin to familiarize yourself with the different shapes and cellular arrangements of epithelial cells.  Try and distinguish between squamous, cuboidal and columnar and see if you can tell whether there is a single row (simple) or multiple rows (stratified) of the epithelial cells.  Once you have these down, look for pseudostratified (really a simple 1 cell layer, but because the cells differ in height, it has the appearance of being stratified) and transitional (surface cells on this stratified epithelium look rounded and flatten when the epithelium is stretched).

 

There is no specific section of the Virtual Slidebox of epithelia, rather slides showing epithelia are found within the other organ systems. Print a copy of the Epithelial Tissues Worksheet and start exploring the Virtual Slidebox slides for examples of each of the epithelial types.  You might find the following table useful in finding examples of the different types of epithelia to complete the Epithelial tissue worksheet.

When searching slides for epithelial cells look for the following:

  • Can you tell if it is stratified or simple or pseudostratified?

  • Can you tell if it is squamous, cuboidal, columnar, or transitional?

  • Can you identify the apical and basal sides of the epithelial cells?

    Simple squamous

    Kidney glomeruli, air sacs of lungs, lining of heart, lining of ventral body cavities

    Simple cuboidal

    Kidney tubules, portions of small glands, ovary surface

    Simple columnar

    Digestive tract, gall bladder, small bronchi, uterine tubes, some regions of uterus

    Psuedostratified

    Male ejaculatory ducts, upper respiratory tract

    Stratified squamous

    Moists lines of esophagus and mouth, vagina, outer layer of skin

    Transitional

    Lining ureters, bladder and part of urethra

    Stratified cuboidal

    Sweat glands, mammary glands

    Stratified columnar

    Pharynx, male urethra

Self Study Questions for Review

  1. Can you identify epithelia (because they are boundary cells there is usually one side that is pointed toward an opening or outside) when the slide may have more than one tissue type?

  2. Can you find the basement membrane of an epithelia (the basal side: opposite of the side pointed toward an opening or outside: apical side)?

  3. Can you tell if the apical side is ciliated or has microvilli on it?

  4. Can you tell if it is simple or stratified when you look at the slide?

  5. Can you tell if the cells are squamous, cuboidal or columnar?

Part 2: Identification of Connective tissue:

 

Watch the introductory video to the components and types of connective tissue.

 

Print the Connective Tissue Worksheet, which is focuses on adipose tissue, loose areolar connective tissue, dense regular connective tissue, hyaline cartilage, elastic cartilage and fibrocartilage.  For each connective tissue type, watch the Shotgun video and spend ~ 5 minutes exploring the Virtual Slidebox Slide in order to complete the worksheet. Look at the connective tissue slides at different magnifications to observe the appearance of the fibers, ground substance and to find the fundamental cell types.  Look at lower magnifications to get a feel for the overall appearance of the tissues and look at higher magnifications to get familiar with the details of the fibers, cells and ground substance.

When observing the connective tissue slides look for the following:

    • Can you see the ground substance?

    • Can you see fibers (what magnification is needed)

    • What magnification is needed to observe the cells?

    • How much of the tissues appears to be cells versus extracellular material (ground substance and fibers).

 

Examination of Loose Connective Tissue:

Start by watching the Shotgun Video of areolar (loose connective) tissue.  Notice that the areas that are pinker have denser collagen fibers and the areas that are less pink have less collagen. The lower density of collagen in areolar connective tissue makes it a form of loose connective tissue.

 

Examine the Areolar Connective Tissue Slide found in the  Supporting Tissue and Muscle section of the Virtual Slidebox for collagen, ground substance and fibroblasts. Add the Areolar Connective Tissue information to the Connective Tissue Worksheet

Next watch the Shotgun Video of adipose (loose connective) tissue. 

Examine the Fat (Adipose) Tissue Slide found in the  Supporting Tissue and Muscle section of the Virtual Slidebox for collagen, ground substance and fibroblasts. Add the Adipose Tissue information to the Connective Tissue Worksheet

 

Examination of Dense Connective Tissue:

Watch the Shotgun Video of Dense Regular Connective tissue. 

 

Examine Tendon Slide found in the  Supporting Tissue and Muscle section of the Virtual Slidebox to examine a dense regular connective tissue for collagen, ground substance and fibroblasts. Notice the density of collagen fibers and the linear arrangements of both the fibers and the fibroblasts.  What do you think the purpose of this linear arrangement of fibers and cells? Notice the absence of large round cells. Add the Dense Regular Connective Tissue information to the Connective Tissue Worksheet

 

Examination of Cartilage

Cartilage is a subtype of connective tissue that is strong and flexible.  There are three types of cartilage found in the body that differ in their fiber composition and density. Watch the video introducing the 3 kinds of cartilage.

 

Start by watching the Shotgun Video of Hyaline Cartilage. 

Examine the Hyaline Cartilage Slide found in the  Supporting Tissue and Muscle section of the Virtual Slidebox for collagen (you cannot see these at any magnification, but they are there), ground substance and chondrocytes.  Make sure you can identify the lacunae that the chondrocytes are found in. Add the Hyaline Cartilage information to the Connective Tissue Worksheet

Next watch the Shotgun Video of Elastic Cartilage. 

 

Examine the Elastic Cartilage Slide found in the  Supporting Tissue and Muscle section of the Virtual Slidebox for collagen (you cannot see these at any magnification, but they are there), ground substance and chondrocytes.  Make sure you can identify the lacunae that the chondrocytes are found in. Add the Elastic Cartilage information to the Connective Tissue Worksheet

Finally watch the Shotgun Video of Elastic Cartilage. 

Examine the Fibrocartilage Slide found in the  Supporting Tissue and Muscle section of the Virtual Slidebox for collagen (you cannot see these at any magnification, but they are there), ground substance and chondrocytes.  Make sure you can identify the lacunae that the chondrocytes are found in. Add the Fibrocartilage information to the Connective Tissue Worksheet.

 

Questions for Self Study:

  1. Can you find the cells in each of the connective tissues you observed?

  2. Are fibers visible (try the highest magnification) because not all connective tissues have visible fibers (cartilage is a good examples in contrast to the dense regular connective tissue for example)?

  3. Can look at a connective tissue and tell whether it is cartilage, connective tissue proper (both loose and dense), blood and bone?

  4. Which tissue type has more extracellular material (epithilia or connective tissue)?

Each semester, Biology 111 students ask what connective tissue types they should be able to recognize or identify from a histology slide. The following table highlights (in red) the connective tissue we will be talking about a lot this semester. You should be able to recognize from a slide each of the connective tissue types highlighted in red and know where in the body those tissues are found. The other tissue types you should be familiar with how they fit into the connective tissue family tree (i.e., what type of connective tissue they are). These you will learn in more detail when you student the particular organ systems that they contribute to.

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