A&P 1 Histology Lab Week 2

In-lab Guide –

Loose Connective Tissue ID In-Lab Exercises

In this "In-Lab Guide", we will be looking at the 4 common Loose Connective Tissues.

We will include "Blood".

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. Areolar Tissues (Loose Proper)

This is because "Loose Proper" is an alternative name for "Areolar". 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. PLEASE NOTE: Your group will be needing a microscope at the workstation. 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!

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Step 1. ID Areolar Tissues (Loose Regular Proper) Have someone in your group read the following out loud, while the others read along:

Opening Paragraph (we'll be referring to this later) Areolar tissue is the most widespread tissue in the body. However, areolar tissue can be difficult to ID, simply because it doesn't look like very much under a regular light microscope! So, when you first see it, it doesn't look like any of the images in the book or on a wall chart. Of course, this scares you, the student! But ... this is easy to solve. The reason for this difference is simple: areolar tissue is mostly water, with some dispersed cells, fibrous proteins and fat cells. So, even under high power, areolar doesn't look like much. In fact, its name, areola, is Latin for "a little open space".

You know the “slimy” stuff that is under the skin of an uncooked chicken? That’s areolar tissue. Look at the image below, following the numbered steps: However, here is the good news: we usually show you Areolar tissue using a special slide called a "SPREAD". This allows you to see the individual components! Here is what the image in your text probably looks like (you need to ID fibroblasts, collagen threads, elastin threads!). Fibroblasts look “spikey”, while mast cells look “bumpy”.

Areolar

This preparation makes it easy to ID the cells and protein fibers!

Areolar tissue spread, 400X

Please refer to your “Pre-lab

Guide” for notes on this

tissue!

Read me!

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Visual ID: Follow the numbered steps: First, let's find the "Areolar" or "Loose Regular" table in either our lecture or lab book. Look at the image in your book. Find where they indicate the cell that is responsible for producing and maintaining this tissue. It is called a fibroblast. The image probably points out a couple of other cells, such as a mast cell and an adipocyte. There are several slide trays in the room. Each tray has a different set of slides. Go and get a slide from the Areolar trays. The slide will be marked "Areolar Tissue". This slide is a SPREAD! Go ahead and hold the areolar slide up to the light, letting everyone see it before putting it in the scope. It doesn’t look like much, does it? Just a little pink square in the middle of the slide, like Image A below. We are going to have to quickly go to high power on this one. Make sure the scanning objective (4x = 40x total) is pointing down. Clip in the slide, getting the little pink square under the lens. Look into the lens and move around the stage until it is in view. Call the instructor over if this is difficult. 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. I know…you still don’t see much. Put the pointer in the middle of the pink square. Call the instructor over if this is difficult. 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. Go up to 400x. Adjust the light & FINE focus (don’t you dare touch the big focus knob at this power! You will break the slide!). You should be able to get a nice, crisp focus on the elastin threads – the thin dark hair-like lines running through the slide. It should look similar to the accompanying image. In Image C, my pointer is on an elastin thread. Call the instructor over if this is difficult. Fibroblasts look “spikey”, while mast cells look “bumpy”.

2.

1.

3.

4.

5.

6.

You will be tested at 400x

A B

C

Please refer to your “Pre-lab

Guide” for notes on this

tissue!

In the videos, I told you to come up with a “descriptor term” for each slide. Take out a clean piece of paper and label it “Stratified squamous epithelium”. Make a drawing of the tissue, if you’d like. Under it, write down your Descriptor Term and the magnification you need to study.

A lot of people think the tissue looks like a bunch of dead flies caught in a spider’s web:

Under that, write down a representative location for this tissue. I talked about how it surrounds all other tissue, found in the submucosa of the visceral organs. Write down any extra information your instructor wants you to know (special cell names, etc.). If the answer is "none", just write that!

Put the slide back in its tray!

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Step 2. ID Adipose Tissue Visual ID: Adipose ID is easy. Let's get right to it! First, let's find the "Adipose" table in either our lecture or lab book. Look at the image in your book. Find where they indicate the cell that is responsible for storing lipids. Go and get a slide from the Adipose tray. The slide will be marked "Adipose Tissue". It is important you get the darkest stained slide available. Get one where you can see a little hint of “pink” on the slide. Most stains do not color the fat droplet in the cell, so adipose doesn’t stain darkly. Don’t bother looking at it by holding it up; you won’t see much.

We are going to have to quickly go to high power on this one. Make sure the scanning objective (4x = 40x total) is pointing down. Clip in the slide, getting the little pink square under the lens. Look into the lens and move around the stage until it is in view. It can be hard to focus on. You may have to move the course focus knob all the way up and down. Eventually, it should look something like you see in Image A. Call the instructor over if this is difficult. Below I am showing you how it will look at various magnifications. 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. I know…you still don’t see much. Put the pointer in the middle of the pink square. Call the instructor over if this is difficult. 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!). Go up to 400x. Adjust the light & FINE focus the slide (don’t you dare touch the big focus knob at this power! You will break the slide!). Determine the outline of a cell. Try to ID the nuclei, although might be difficult on your slide. Call the instructor over if this is difficult.

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1.

3.

4.

5.

6.

A

Look at this on

the slide!

Something else ... Ignore It! 2.

1.

B C

D

Please refer to your “Pre-lab

Guide” for notes on this

tissue!

You may see nothing, and really have to

move the course focus!

#2

In the videos, I told you to come up with a “descriptor term” for each slide.

Make a drawing of the tissue, if you’d like. Under it, write down your Descriptor Term and the magnification you need to study.

A lot of people think the tissue looks like honey combs or marshmallows

Under that, write down a representative location for this tissue. I talked about the subcutaneous fat in the hypodermis. Write down any extra information your instructor wants you to know (special cell names, etc.). If the answer is "none", just write that!

Last Step: Compare & Contrast! This photo is from an intestines slide at 100X. I on purpose got a slide that is not in perfect focus, and a little bit of a challenge. Find the lumen, mucosa, submucosa, and muscularis externa.

Can you find some adipose tissue on the photo below? Which layer is it in? What do you suppose the other tissue is, surrounding it? Ask your instructor if

you got it right!!

Put the slide back in its tray!

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More

Below is a photo with 3 tissue slides that are sometimes confused on an exam: Please ID them. Compare them. Do you see why they are sometimes confused?

Below is a photo of a trachea slide. Note that the lumen is “up”. Look at the submucosa. Can you see examples of “A” and “B” from the last challenge?

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3.

A B

C

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Step 3. ID Reticular Tissue Visual ID: Reticular ID is easy. Let's get right to it! First, let's find the "Reticular" table in either our lecture or lab book. Look at the image in your book. Find where they indicate the cell that you are responsible for. Go and get a slide from the tray marked “Reticular” or “lymph node”. It is important you get the darkest stained slide available.

We are going to have to quickly go to high power on this one. We are going to use the reticular fibers as the identifying feature, not the cells. Make sure the scanning objective (4x = 40x total) is pointing down. Clip in the slide, getting the little pink square under the lens. Look into the lens and move around the stage until it is in view. Eventually, it should look something like you see in Image A. 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. I know…you still don’t see much. Now, go to 100x, remember that you will be moving towards the pointer! In image B, I am showing what we are shooting for at 100X. I have highlighted the fibers in green on the image. Adjust the light & FINE focus the slide (don’t you dare touch the big focus knob at this power! You will break the slide!). Don’t worry … we are going to a higher magnification! Go up to 400x. Adjust the light & FINE focus the slide (don’t you dare touch the big focus knob at this power! You will break the slide!).

Call the instructor over if this is difficult.

Notice in Image C, I am pointing out that this slide can look different depending on the stain used. Determine what a lymphocyte is. Try to ID the nuclei, although might be difficult on your slide.

Please refer to your “Pre-lab

Guide” for notes on this

tissue!

2.

1.

3.

4.

5.

6.

A

B

Depends on the stain

C

You will be tested at 400x

In the videos, I told you to come up with a “descriptor term” for each slide. Make a drawing of the tissue, if you’d like. Under it, write down your Descriptor Term and the magnification you need to study.

A lot of people think the tissue looks like “trees in autumn” or “coral”

Under that, write down a representative location for this tissue. I talked about the lymph nodes and spleen. Write down any extra information your instructor wants you to know (special cell names, etc.). If the answer is "none", just write that!

Put the slide back in its tray!

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Step 4. ID Blood Tissue Visual ID: Blood ID is easy. Let's get right to it! First, let's find the "Blood" table in either our lecture or lab book. Look at the image in your book. Find where they indicate the cells you need to ID, referring to your wordlist and Pre-lab guide. Go and get a slide from the Blood tray. The slide will be marked "Blood Smear, Wright's Stain" (Image A). It is important you get the darkest stained slide available. The matrix of blood, called “plasma”, does not pick up much stain. Hold it up to the light and get the darkest one available.

We are going to have to quickly go to high power on this one. Make sure the scanning objective (4x = 40x total) is pointing down. Clip in the slide, getting some of the stained area under the lens. It can be hard to focus on. I am showing you how it will look at various magnifications. 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. I know…you still don’t see much. Eventually, it should look something like you see in Image B. Call the instructor over if this is difficult. 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!). Eventually, it should look something like you see in Image C.

You can stop here if you’d like. But continue reading. If you are curious, go up to 400x. Adjust the light & FINE focus the slide (don’t you dare touch the big focus knob at this power! You will break the slide!). Eventually, it should look something like you see in Image D.

Notice the white blood cells have nuclei (although they look oddly shaped), while the red blood cells do not!

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1.

3.

4.

5.

6.

B

Please refer to your “Pre-lab

Guide” for notes on this

tissue!

A

C

D

You will be tested at 400x

You may see nothing, and really have to

move the course focus!

In the videos, I told you to come up with a “descriptor term” for each slide. People often do not feel the need to do this with blood, saying it looks like “blood”. Make a drawing of the tissue, if you’d like. Under it, write down your Descriptor Term if you feel you need one for blood. Under that, write down a representative location for this tissue. I talked about it occurring within arteries and veins within the cardiovascular system. Write down any extra information your instructor wants you to know (special cell names, etc.). If the answer is "none", just write that!

Put the slide back in its tray!

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