A&P 1 Histology Lab Week 2

In-lab Guide – Dense Connective Tissue ID Lab Exercises

Many connective tissues have more than one name. This guide will include alternative names in parentheses. For example, when you look at the next page, you will see:

Step 1. Dense Regular Tissues (White, Fibrous, Collagenous)

This is because this tissue has a lot of common names!

PLEASE NOTE: Make sure you have 2 scopes at your station.

We are going to be comparing tissues

next to each other! All of the steps in this guide are designed to be done at the workstation. DO NOT use a microscope that is already set up in the room, being used as a demo. Instead, get a new one from the microscope storage, get out a power

cord, plug the cord into the microscope, and use the microscope at your station! YOU WILL NEED THE IMAGES IN YOUR TEXTBOOK OR LAB MANUAL!

Our lecture book has an excellent section on the tissues, including summary tables. Of course, there are usually extra textbooks in lab.

Read me!

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Step 1. Comparing two tissues:

Dense Regular (White, Fibrous, Collagenous) and Dense Irregular Connective Tissue

Have someone in your group read the following out loud, while the others read along:

Opening Paragraph

Dense regular is found in tendons and ligaments. Dense irregular is a widespread tissue. Here, we are going to look at in the dermis of the skin. Some books (and instructors) include a THIRD tissue called "Elastic" in this group. Watch out for that in your book’s tissue table! This guide will not discuss "Elastic Tissue". Instead, we will include it as a type of Dense Irregular, with a high concentration of elastic fibers. Visual ID: Compare the two tissues

Follow the numbered steps: First, let's get TWO slides: "Fibrous Tissue (tendon)" and "Skin". Check that you have a “darkly stained” slide.

Make sure you have 2 scopes at your station.

Also note the image on the next page, as we will be referring to it! Find the table in either your lecture or lab book that shows “dense regular” (or “fibrous” or “collagenous”) and “dense irregular” tissues. Look at the image in your book. Find where they indicate the cell that is responsible for producing and maintaining both these tissues. It is called a fibroblast. Notice that all you can really see is a little dark nucleus. See Image A. Notice how much collagen there is in the matrix of these two tissues. Go ahead and hold the dense regular slide up to the light, letting everyone see it before putting it in the scope. Most of these slides have a large pink rectangle next to small pink rectangle. We are going to put the large piece under the objective lens. Make sure the scanning objective (4x = 40x total) is pointing down. Clip in the slide, getting the larger pink square under the lens. Look into the lens and move around the stage until it is in view. Still at scanning power, and using FIRST the course focus knob and THEN the fine focus knob, get the slide focused, using the eyepiece with the pointer in it. Put the pointer in the middle of the pink square. See Image B (next page). Call the instructor over if this is difficult. We are going to have to quickly go to medium or high power on this one. Go up to 100x power. Adjust the light & FINE focus the slide (don’t you dare touch the big focus knob at this power! You will break the slide!). It should look something like Image B (see next page).

Read me!

Please refer to your “Pre-lab Guide” for notes on these tissues!

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Please refer to your “Pre-lab

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Depending on your slide, you may want to go up to 400x. Make it look as much like Image B as you can. Using the fine focus, you should be able to get a nice, crisp focus on the nuclei and collagen – the thick pink wavy lines running through the slide. Go ahead and hold the skin slide up to the light, letting everyone see it before putting it in the scope. On the slide, we see a dark staining epithelial layer next to a lumen (which, in this case, is the “outside of the body”). This is the epidermis, and it is going to be a protective layer of stratified squamous. Under that is a lighter staining layer called the dermis. Here we will see a lot of dense irregular tissue. We are going to zoom into this area, just below the epidermis like Image C. On your second scope, make sure the scanning objective (4x = 40x total) is pointing down. Clip in the slide, getting the large stained area under the lens. Look into the lens and move around the stage until it is in view, and the pointer is about where it is in Image C. Still at scanning power, and using FIRST the course focus knob and THEN the fine focus knob, get the slide focused, using the eyepiece with the pointer in it. Make sure the pointer is about where it is in Image C. Call the instructor over if this is difficult. We are going to have to quickly go to medium or high power on this one. Go up to 100x power. Adjust the light & FINE focus the slide (don’t you dare touch the big focus knob at this power! You will break the slide!). It should look something like Image C (see next page). Using the fine focus, you should be able to get a nice, crisp focus on the collagen – the thick pink wavy lines running through the slide.

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B C Put pointer in an area with a lot of tissue Put pointer just below the epithelial layer

(dark next to lumen)

Zoom

Zoom Epidermis: Note the stratified squamous, just like the

esophagus!

Dense irregular

in dermis

Lumen next to epidermis. Of course, your slide might be

“upside down”!

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Here’s how people often describe these two tissues:

"Tranquil sea waves" "Lasagna"

“Stormy Sky”

Van Gogh's “Wheatfield with Cypresses”

Put the slides back in their tray!

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Step 2. Comparing three types of cartilage:

Hyaline Cartilage, Fibrocartilage, and Elastic Cartilage I will no longer be repeating the instructions for using the microscope. It will be assumed that you have the procedure down. You may use this as a reference in the future. Have someone in your group read the following out loud, while the others read along:

1. We will always make sure the scanning objective (4x = 40x total) is pointing down to begin. 2. We will always hold the slide up to the light in order to orient ourselves. We will also check that we have a “darkly stained” slide. 3. We will always clip in the slide, getting the stained tissue under the objective lens. We will then look into the lens and move around the stage until it is in view. 4. We will call the instructor over if this is difficult. 5. Still at scanning power, we will FIRST use the course focus knob and THEN the fine focus knob, get the slide focused, using the eyepiece with the pointer in it. We will not worry about having both eyes open. 6. We will put the pointer in the middle of where we want to zoom into. 7. We will quickly go to medium or high power. We will adjust the light & FINE focus. We will not dare touch the big focus knob at higher powers!

Please refer to your “Pre-lab Guide” for notes on these tissues!

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Follow the numbered steps: Make sure you have 2 scopes at your station.

First, let's get TWO slides: "Trachea” and "Cartilage Elastic Human". Check that you have a “darkly stained” slide. During the epithelial lab, we looked at a trachea slide. You may recall that there are 2 versions: small mammal and human. It doesn’t matter which one you use. Find the table in either your lecture or lab book that shows “cartilage types” (it should have all 3 types: hyaline, elastic cartilage, and fibrocartilage). Look at the image in your book. Find where they indicate the cell that is responsible for producing and maintaining both these tissues. It is called a chondroblast. Notice that all you can really see is a little dark nucleus inside a lacunae. Go ahead and hold the trachea slide up to the light, letting everyone see it before putting it in the scope. Decide if your slide looks like version “A” or version “B” below. See Images A & B. Put the slide in the first scope, follow the numbers on the image:

Discuss where you think the lumen is on your slide. See Image B above. Notice that there is always more

than one tissue on the slide, so you are going to have to move the stage & slide around to see what you want to see! Here, we want to zoom into the cartilaginous ring. Move the stage so that the pointer is on the hyaline cartilage.

View the tissue at 100x. There will probably be some glands in the view, as shown below:

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Version A Small mammal

Start HERE

Version B Human

Start HERE

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Now do Image B

Note the cells in lacunae

If you can, get some glands in view

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#3 Compare Elastic Cartilage Hold the Elastic cartilage slide up to the light. The image below is indicating where we will be locating under the scope: the elastic cartilage pad in the middle:

Now put the Elastic cartilage slide in the other scope. We will be studying this slide at low power. Clip the slide on the stage, and take a look at scanning power: Now we’ll go to medium power, and compare it to the hyaline slide:

Our slides are usually a dark blue stain

"Ice with water drops" "Vampire eyes"

#5 Compare Fibrocartilage

In the slide tray labeled “Fibrocartilage”, there are a couple of types of slides. Try to get one that looks like this when you hold it up:

Other slides will work, but these instructions are for a slide like this one. This is the hip and pubic symphysis of a small mammal….maybe a rabbit. The pubic symphysis is a pad of fibrocartilage that attaches the 2 hip bones together (see image “B” below). By using cartilage instead of bone, our hip has some flexibility, especially important during childbirth. Follow the red arrows on the image below while reading this. We have cut out the public symphysis along with the hip bones. Image “C” is a slide of a section through a hip, looking down. Notice that “down” is “anterior”!!! Read the captions on Image “C” below - in their numbered order - comparing the slide to Image “B”:

See the “dark area” between the 2 bones? We are going to stay away from that. It is mostly fibrocartilage, but it has a lot of collagen and other “stuff”. Instead, we are going to aim for the anterior “lump of fibrocartilage”.

Clip the slide onto the microscope’s stage, making sure you are at scanning power!

Put the elastic cartilage slide away, but keep the hyaline slide in its scope. Now we are going to compare Hyaline &

Fibrocartilage.

Read me!

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B C

Anterior

Follow the numbered steps:

At low power, move the stage around until you get the pointer just below the dark area between the bones. Go to medium power. Now, get your pointer pretty far anterior, away from the dark stain. We will examine this at high power. Note the chondrocytes in lacunae. Note that fibrocartilage looks very similar to Dense Regular tissue, except that it has lacunae like the hyaline cartilage. Look at the hyaline slide if you need reassurance that you can see lacunae. It looks like Dense Regular because they both have a lot of collagen in their matrix. But you can clearly see that it has chondrocytes in lacunae, so it is cartilage.

In the document entitled “Connective Tissues – Other Activities”, I show you the cartilage types

on a gross level, connecting the tissue slides to their function & location.

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Put the slides back in their tray!

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Step 3. Bone (Osseous) Tissue: Have someone in your group read the following out loud, while the others read along:

Opening Paragraph There are 2 osseous (bone) tissues in the body: spongy & compact. We will be identifying both tissues on a gross level. We will only be looking at compact bone on a microscopic level. Here is a quick reference guide to the microscopic structure of compact bone tissue. The detailed notes, which we covered in the videos, is in the “Pre-lab Guide”. We will be studying this in more detail in the “Bone Lab”. Here, we just want to be able to ID Compact Bone tissue: Visual ID:

Follow the numbered steps: Get a slide labeled “Compact Bone – Ground”. Follow the images below.

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You will be tested at 100x

Please refer to your “Pre-lab Guide” for notes on these tissues!

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Notice that compact bone looks like a bunch of tree rings.

Inspect the 2 bone tissue types on a gross level. There may be examples of both spongy bone and compact bone in the room. If not, we will be doing this during the “Skeleton labs”. ID compact bone, spongy bone, and trabeculae on the image of a frontal section of a femur below.

Put the slides back in their tray!

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Pile of cut logs

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Now, go to the next document covering muscle and nervous

tissues