General Information

Lab 4 has students observe different and/or defining histological aspects of several tissue types.

This lab is typically run as a “tissue buffet,” where the instructor sets up all slides in advance for students.  Students rotate from station to station to view each tissue slide.

Although it would be better if students could use this lab to practice their microscope skills, there are a few reasons not to:

• Lots of instructor support required — There is often more than one tissue type on a single slide, and students can get confused easily.  Compound this with a class with little microscope experience and they need significant instructor support.
• Time-consuming — Students may be capable of setting up their own slides, but this is quite time-consuming, and even the classes with the strongest microscope skills may not get through all of the slides in a 2-hour lab.
• Expensive — If you set this up as a demo slide, you need only 1 of each tissue slide. If the students set up their own, you need a class set of each slide, which is expensive.

Purchasing Information

Required materials for Lab 4 include:

(If you are setting up demo slides, 1 of each. If the students set up, a class set of each)

• Tissue slides of the following:
  • Stratified squamous — Human skin
  • Simple cuboidal — Kidney tubule
  • Simple columnar — Intestine with goblet cells
  • Pseudostratified ciliated columnar — Trachea lining
  • Loose fibrous connective tissue (areolar tissue)
  • Dense fibrous connective tissue (white fibrous)
  • Compact bone
  • Spongy bone (cancellous bone)
  • Hyaline cartilage — Trachea rings
  • Fluid connective — Blood
  • Skeletal muscle
  • Smooth muscle
  • Cardiac muscle
  • Nervous tissue — Spinal cord smear or neural smear
• Tissue posters — 1 poster for each tissue category
  • Tissue categories — Epithelial, connective, muscular, and nervous
  • Flinn Scientific (n.d.) has some nice ones.

Lab Setup

Lab Activity Setup

Time:

• Demo slides – Approx. 1.5 to 2 hours
• No demo slides – Approx. 15 minutes

Tissue Buffet Setup

Microscopes with slides are set up along the outside of the room for students to walk around like it is an all-you-can-eat buffet.

Notes for those who are new to histology:

Epithelial Tissues

If there are multiple tissue types on the slide, remember to look for the free surface. These are typically best viewed at medium light intensity and medium setting on the iris diaphragm.

Stratified Squamous — Best viewed at high power (400x magnification)

Simple Cuboidal — Best viewed at high power

Simple Columnar — Best viewed at high power

Pseudostratified Ciliated Columnar — Best viewed at high power

Connective Tissues

A couple of these slides have multiple tissue types, so make sure you know what the matrix is supposed to look like.

Loose Fibrous — Best viewed at high power.

Try to get some fibroblasts in the field of view.

Dense Fibrous — Best viewed at low (100x magnification) or high power

This one is tricky because students often mix it up with smooth muscle.  The main difference is where the nuclei show up.  In smooth muscle, the entire tissue is made up of cells, and you will see the nuclei INSIDE the cells.  In dense fibrous connective tissue, the cells live in between the fibres, so the nuclei show up OUTSIDE the fibres.  Low power shows the long fibres and high power can show the fibroblasts.

Compact Bone — Best viewed at low or high power

Low power is best if you want students to see several osteons but not the osteocytes and/or canaliculi.  High power is best if you want students to see these details but not how the osteons are packed together.

Spongy Bone — Best viewed at low or high power

Low power is best for identifying trabeculae.  High power is best for identifying osteocytes in lacunae.

Hyaline Cartilage — Best viewed at high power

This slide is typically a cross-section of a piece of trachea and will have many different tissue types on it.  Look for the “googly eyes,” which will be the pairs of chondrocytes in lacunae within the hyaline cartilage.

Blood — Best viewed under an oil immersion lens (1000x magnification)

Try to find a spot on the slide with all three types of blood cells and, if you can, a couple of different types of leukocytes.

Muscular Tissues

These are pretty easy since there are only three.

Skeletal Muscle — Best viewed under high power

Smooth Muscle — Best viewed under high power

Cardiac Muscle — Best viewed under high power

Hopefully, you can track down an intercalated disc.  Sometimes you cannot, as different slide makers may use different staining, and only some really make the discs show up. You will have to look around to find them; they are at all cell junctions.  Play with the iris diaphragm to see if you can get them to show up a bit better.

Nervous Tissue

This lab manual has only one slide, but you can also set up a cross-section of a spinal cord so students can see the distinctive butterfly pattern in the white and gray matter.

Spinal Cord Smear — Best viewed under low or high power

Low power will show a couple of neurons and numerous neuroglia.  High power will zoom in on an individual neuron but may not capture the entire length of the axon.  Talk to students about how this is an actual smear; unlike some other slides, this slide does not represent what cells would actually look like in a person.

Spinal Cord Cross Section (if you decide to set it up as a bonus) — Depending on the size of the spinal cord cross-section (mouse = tiny, human = huge), you want a scope that can show the entire cross section.

You will use the scanning power (40X magnification) on a compound lens microscope or, for larger slides, a dissecting scope.  Play with the lighting/iris diaphragm to highlight the difference between the regions of gray matter and white matter.

References

Flinn Scientific. (n.d.). Tissue charts for anatomy studies. https://www.flinnsci.com/products/biology/anatomy–physiology/tissue-charts-for-anatomy-studies/.