Lab 2-3 Pre Lab Activity Sheet – Bring this with you to Lab 2
 Getting Started - Before You Come to Lab.
First read the Introduction to the Lab carefully.
Here is a list of tissue types you are responsible for in this exercise. Pictures and
descriptions of these tissues can be found in the lab manual. Most are in exercise 6A.
Note: Use only these tissue types in the assignment.
simple squamous epithelium
simple cuboidal epithelium
simple columnar epithelium
pseudostratified columnar epithelium
stratified cuboidal epithelium
stratified squamous epithelium
areolar connective tissue
adipose tissue
dense regular connective tissue
dense irregular connective tissue
hyaline cartilage
bone
skeletal muscle
cardiac muscle
smooth muscle
1. Read through the sections on epithelial, connective and muscle tissue in Exercise 6A
and note the general characteristics of epithelial tissue, connective tissue, and muscle
tissue.
2. Cut out the attached color pictures of tissues, attach each to an index card, and label
them on the back, using the figures in the lab manual for reference. I have index
cards if you need them. Just ask.
Note: The picture of simple squamous epithelium I have attached is different from
the picture in your lab manual, but I think it shows the simple squamous cells more
clearly. Refer to Lab Manual Figure 40.6. It is the layer called the parietal layer of
the glomerular capsule.
A. Epithelial Tissue
1. Make a list of the assigned tissues that have an apical surface (have a free edge).
These are all epithelial tissues. There should be 6 when you have finished. List the
6 types of epithelial tissue here. Separate these cards from the group and mark them as
epithelial tissue. Note; the photo marked 2 is simple squamous epithelium (at the
arrow). It is from the kidney slide. The photo in your lab manual is lung tissue.
Types of Epithelial Tissue
_____________________________
_____________________________
_____________________________
_____________________________
_____________________________
_____________________________
2. Epithelial tissue cells have three different shapes - squamous, or flat, cuboidal and
columnar. Most epithelia have either one layer and are called simple, or more than
one layer and are called stratified. (Figure 6A.1) Thus, most epithelia have a twopart name. For example, simple squamous means one layer of flat cells, stratified
cuboidal means several layers of cube-shaped cells. There are exceptions. Sometimes
an epithelium looks stratified, but is actually one layer of cells. The term for this is
pseudostratified. Pseudostratified epithelial cells are columnar.
List the 4 epithelia from your list above that have one layer of cells, and indicate the
cell shape. Put their picture cards together in one pile. Be careful, one is tricky!
_____________________________________
______________________________________
______________________________________
____________________________________
____________________
cell shape
___________________
cell shape
___________________
cell shape
_____________________
cell shape
√ Check your work. There should be one each of squamous and cuboidal, and two
columnar epithelia.
3. List the 2 epithelia with more than one layer of cells, and indicate the cell shape at
the apical surface. These cards will be in a separate pile.
____________________________________
_____________________
cell shape at apical surface
____________________________________
_____________________
cell shape at apical surface
B. Connective and Muscle Tissues
Read this carefully before you begin.
Now look at the nine remaining cards with pictures of the tissues. Make a list of the
assigned tissues that have a large amount of extracellular matrix. These are all
examples of connective tissue. If the description mentions fibroblasts, gel-like
matrix, firm matrix, hard calcified matrix, collagen, elastin, or fibers other than
muscle fibers, the tissue has a matrix, but in one example the matrix is sparse. Read
the descriptions carefully. There should be 5 when you have finished (all examples of
connective tissue). Sort these out into a group called Connective Tissue with large
amount of matrix. If you have 6 you have one too many! Be careful, there is a
connective tissue example that does not fit here. Large amount of matrix is the key.
1. a. Connective Tissues with a large amount of matrix
______________________________________
______________________________________
______________________________________
______________________________________
______________________________________
b. List the tissues named above that have visible fibers in the matrix (outside the cell).
The word visible is important here. In some cases the fibers are stained pink, in others
they are dark purple. In all cases they are outside the cells. Separate these 3 cards
from the group of connective tissue figures, and write the tissue types here. Label the
pile Connective Tissue - visible fibers.
_____________________________________
_____________________________________
_____________________________________
c. Look carefully at the 3 tissues with visible fibers in the matrix. Distinguish among
the three tissue types by describing how the fiber arrangement looks different to you.
Tissue____________________________ Fiber_______________________________
Arrangement
Tissue____________________________ Fiber_______________________________
Arrangement
Tissue____________________________ Fiber_______________________________
Arrangement
d. Which tissue with a large amount of matrix has a matrix described as amorphous?
Separate it out and write its name here. __________________________________
e. Which tissue with a large amount of matrix has a matrix with a pattern organized
around central canals (routes for blood vessels)? Separate it out and put its name
here.
__________________________________
2. Tissues that are not epithelial tissue and do not have a large amount of
extracellular matrix (includes both a type of connective tissue and muscle tissue.)
Now look at the four remaining pictures that have not yet been sorted out.
Which tissue has a sparse matrix and many large cells? This is a type of connective
tissue that does not have a large amount of matrix between the cells. Write its name
here. _________________________ Describe the appearance of this tissue. What does
it look like to you?
The remaining three tissue types are all muscle tissue and all have myofilaments (strands
of muscle protein) inside the cell. Look carefully at these three tissues. Distinguish
among the three muscle types based on things you can observe. This should include
things like number of nuclei per cell, striations, branching cells, intercalated discs. Label
these three pictures Muscle.
Cardiac Muscle
Observations_____________________________________________________
Skeletal Muscle
Observations_____________________________________________________
Smooth Muscle
Observations_____________________________________________________
You have now begun to sort out the tissues based on things that can be seen under the
microscope. These are features that will be useful to you as you use the microscope to
identify tissues on prepared slides.
√ Check your work!
You should have a pile of 6 pictures labeled Epithelial Tissue. Four of the pictures are
simple and two are stratified epithelia.
You should have a pile of 5 pictures labeled Connective Tissue – large amount of matrix.
3 of these are in a pile marked visible fibers. One is amorphous, one has central canals.
You should have a picture of a type of Connective Tissue with sparse matrix.
You should have a pile of 3 pictures labeled muscle.
DO NOT COME TO LAB UNPREPARED. IT WILL SET YOU BACK AND
MAKE THE ASSIGNMENT MUCH MORE DIFFICULT.
Lab 2 and Lab 3
Classification and Identification of Tissues
Exercise 6
Introduction to Histology - Read this before you begin.
This exercise uses information in Exercise 6A in your lab manual. The study of tissues is
called histology. Tissues are defined as groups of cells that are similar in structure and
perform a common or related function. There are four basic adult tissue types: epithelial,
connective, muscle and nervous tissue. Tissue structure is closely related to tissue
function, and because of that, we will continue to look at histology throughout both
semesters of the course. In this exercise we will identify several types of epithelial,
connective and muscle tissues. Nervous tissue will be studied along with other aspects of
the nervous system, and more detail on other tissues will be studied later on as well.
This exercise is designed to help you practice looking at tissue slides and recognizing
important visible characteristics of different tissue types. Identification here is based on
things that can be seen with the microscope. It is important to remember that while
there are other important tissue characteristics that cannot be seen easily with the
microscope, they will not be useful in this exercise.
One important characteristic of epithelial tissue is polarity. This means that there is an
apical or free surface exposed to a cavity or the exterior, and a basal surface attached to
underlying glycoproteins called the basal lamina. The basal lamina and an underlying
layer of the protein collagen form the basement membrane which reinforces the
epithelium and marks its boundary. (See page 68 for more on special characteristics of
epithelium.) Epithelia tissue covers surfaces and lines cavities. It is often supported by
underlying connective tissue.
Here is an example of epithelium lining a cavity or tubule (Atlas Plate 3).
Apical Surface
Lumen of Tubule
Here is an example of epithelium covering a surface with underlying connective tissue.
(Atlas Plate 6)
Lumen
Apical Surface
Underlying Connective Tissue
Connective tissue characteristics are described on page 74. For identification purposes,
most connective tissues have a large amount of extracellular matrix, non-living material
that separates the cells of the tissue. Adipose is an exception as it has a sparse matrix,
but it shares other connective tissue characteristics.
Here is an example of cells and extracellular matrix. (Atlas Plate11)
Cell Nuclei
Extracellular Matrix
Many connective tissue cells are hard to see. The nucleus picks up dark stain but the
plasma membrane cannot be distinguished with the light microscope. See Figure 4.8 in
the text for a drawing of some cell shapes. Bone slides do not contain actual cells. You
will see empty lacunae, where bone cells (osteocytes) are usually found, surrounding a
large central canal.
Muscle cells contain myofilaments made of the proteins actin and myosin. In some
muscle tissue types the myofilaments are organized and give the cells a striped or
striated appearance. Smooth muscle is not organized in the same way and often looks
similar to a type of connective tissue called dense regular connective tissue. It is
important to remember that the myofilaments are inside the muscle cells, while the matrix
fibers are outside the connective tissue cells.
In this lab you will be provided with prepared slides that contain each of the tissue types
listed below. It is your responsibility to be able to locate and identify the tissues correctly
on the slides. It can be a bit tricky at first as some slides have more than one tissue type
on them. As you practice and become better at tissue recognition, you will find yourself
identifying several different tissue types on some of the slides.
One way to help you begin to recognize different tissues on prepared slides and in figures
is to prepare a dichotomous key. This key will lead you through a series of questions,
and at the end will identify the tissue for you. In order to make the key, you need to do
some background work at home. Once you have prepared the key you can use it to work
on identifying tissue unknowns. You may also bring it to the lab practical to help with
tissue identification.
Activity Sheet - in Lab
Using the information you have added to the activity sheet, develop a dichotomous
key in flowchart format to use in lab.
1. Short exercise on how to make a dichotomous key. We will do this as a group.
2. Prepare a draft of a dichotomous key. The rules are simple.
a. The question asked can have only yes or no as an answer.
b. The question should separate out one or several of the tissues from the whole
group.
c. Continue asking questions until each tissue type is standing alone at the end of the
flow chart.
d. Using the sheet provided, start with the question "Is there an apical
surface?" The answer is either yes (Epithelial Tissue) or no (Connective or
Muscle Tissue in this exercise).
Ask the question and draw a line for Yes and a line for No
e. Use the cards in your pile labeled Epithelial Tissue. Now separate the cards into
simple and stratified epithelium by asking the question “Is it simple”? The
answer is either yes (4 cards) or no (2 cards)
f. Look at the pile of 4 cards. These are all simple epithelia. Ask a question about
cell shape to do the next sort. (You have already done this work on your
worksheet). Continue asking questions until each of the 4 tissues is alone at the
end of a sort. Name each tissue at the end of the sort.
g. Go back to the remaining 2 cards. These are not simple so are in the “no”
column. Ask a question about cell shape to separate the 2 tissue types. Name
each tissue at the end of the sort.
h. Now put away the Epithelial Tissue cards and look at the cards from B. on your
worksheet ( Connective and Muscle Tissues). These 9 cards are in the “no” pile
from the first question you asked. Follow the questions you asked on your
worksheet to write sorting questions for these 9 tissue types. Name each tissue at
the end of the sort. Hint: the first thing you did was separate tissues with a large
amount of matrix (5) from the other tissues (4). Use the piles you have already
created to help you do your sort.
Note: The questions do not have to be technical in every case. You are basing your
decisions on what the tissue looks like under the microscope. Students in the past have
referred to "owl eyes", "tree rings", "bubbles" etc. in their questions.
You are finished when all 15 tissue types have been sorted out and are alone at the end of
a branch of the flow chart or key.
3. Once you have finished the key, look at the prepared slides and make sure that the key
is useful to you. I will collect the first draft of the key at the end of the lab. It must
eventually fit neatly onto 8 1/2" x 11" paper. I will return the key with comments
before the next lab.
When studying anatomy and histology, it is important to develop good observational
skills. This takes practice, and may be easier for some of you than others at first. It is
also important to develop the habit of logical and sequential thinking. Developing and
using a dichotomous key for tissue identification will help you enhance these skills.
Your skills will be tested by identifying several unknown tissues. I will give you the
number of your tissue unknown slide for the next part of the project when I have
looked at the draft of your key.
Using A Key to Identify Unknown Tissues
1. If your key was not correct when you turned it in earlier, reconstruct it so that it is
useful. Please note that the final key is a part of the tissue identification grade. The key
should allow you to identify15 tissue types.
2. I will assign a slide to you when I return your key to you with comments.
Record the number of your assigned slide here. _________ These slides are in a
labelled box in the lab. Each slide contains four or more tissue types.
Your assigned a slide contains a section of an organ. The identification of the
organ is not important at this time. Each slide has four or more different tissue
types on it. Please do not remove the slide or the box from these rooms, as
other students may be using the same slide.
Using your key, identify on the assigned slide three different tissue types
from the 15 you have sorted on the key. In your report clearly describe how
you used your key to come to your conclusions about the tissue types. Use the
provided sheets for your report.
For each tissue type, the report should include:
a. The name of the tissue and its description (from the lab manual).
b. A colored pathway through the attached key from the first question to the
tissue type. If you do not have colored pencils, see me as I have many!
c. A pencil drawing of what you observed. Color is preferred, but not
required. The figure should be labeled, indicating characteristics of the
tissue you described. Use a ruler to construct leader lines, and print the
labels.
For epithelial tissue, label nuclei, epithelial cells (including cell
shape), underlying connective tissue, apical surface and basal
surface.
For connective tissue, label cells or cell nuclei, matrix, fibers (if
applicable), lacunae (if applicable).
For muscle tissue, label nuclei, striations (if applicable), intercalated
discs (if applicable), branched cells (if applicable).
Turn in the dichotomous key on 8 1/2" x 11" paper, along with the three tissue
identification sheets and the grading sheet. Be sure to include your name on
each sheet. The key and tissue identification are worth 5% of your grade in
this class. The grading sheet is attached at the end so that you can make sure
that you are doing the project correctly and have included everything that is
required.
Tissue Identification Sheet 1
Name __________________________
Unknown Tissue Slide # __________
Tissue Type 1 _____________________________
Pathway to this decision marked clearly in color on the attached key.
Tissue Description (from the lab manual):
Labeled drawing of what you observed (in pencil or colored pencil). I must be able to
recognize the tissue from your drawing. Do not copy figures in the text. Use the 10X or
40X lens.
For epithelial tissue, label nuclei, epithelial cells (including cell shape),
underlying connective tissue, apical surface and basal surface.
For connective tissue, label cells or cell nuclei, matrix, fibers (if applicable),
lacunae (if applicable).
For muscle tissue, label nuclei, striations (if applicable), intercalated discs (if
applicable), branched cells (if applicable).
Tissue Identification Sheet 2
Name __________________________
Unknown Tissue Slide # __________
Tissue Type 2 _____________________________
Pathway to this decision drawn in a different color on the attached key.
Tissue Description (from the lab manual):
Labeled drawing of what you observed (in pencil or colored pencil). I must be able to
recognize the tissue from your drawing. Do not copy figures in the text. Use the 10X or
40X lens.
For epithelial tissue, label nuclei, epithelial cells (including cell shape),
underlying connective tissue, apical surface and basal surface.
For connective tissue, label cells or cell nuclei, matrix, fibers (if applicable),
lacunae (if applicable).
For muscle tissue, label nuclei, striations (if applicable), intercalated discs (if
applicable), branched cells (if applicable).
Tissue Identification Sheet 3
Name __________________________
Unknown Tissue Slide # __________
Tissue Type 3 _____________________________
Pathway to this decision drawn in a third color on the attached key.
Tissue Description (from the lab manual):
Labeled drawing of what you observed (in pencil or colored pencil). I must be able to
recognize the tissue from your drawing. Do not copy figures in the text. Use the 10X or
40X lens.
For epithelial tissue, label epithelial cells (including cell shape), underlying
connective tissue, apical surface.
For connective tissue, label cells or cell nuclei, matrix, fibers (if applicable),
lacunae (if applicable).
For muscle tissue, label nuclei, striations (if applicable), intercalated discs (if
applicable), branched cells (if applicable).
Grading Sheet
Dichotomous Key and Unknown Tissue Identification
_____Key (55 points)
Each tissue is separated into its own category. (15)
Questions on the key correctly sort the tissues. (30)
The map arrangement is orderly and neat (10)
_____Tissue Unknown (45 points)
Tissue Unknown 1
Tissue identification is correct (6)
Tissue is described (2)
Tissue is neatly drawn and correctly labeled (5)
Logical path through attached key is used (2)
Tissue Unknown 2
Tissue identification is correct (6)
Tissue is described (2)
Tissue is neatly drawn and correctly labeled (5)
Logical path through attached key is used (2)
Tissue Unknown 3
Tissue identification is correct (6)
Tissue is described (2)
Tissue is neatly drawn and correctly labeled (5)
Logical path through attached key is used (2)
_____Total Grade