TISSUE IDENTIFICATION ACTIVITY
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 powerpoints posted to the SWIFT site.
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
**When you identify each tissue type, label flash cards on the back. You may use the
figures in the available powerpoint for reference.
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 on the back of the card. Hint: the photo marked 2 is simple squamous
epithelium (at the arrow). It is from the kidney slide.
Types of Epithelial Tissue
_____________________________
_____________________________
_____________________________
_____________________________
_____________________________
_____________________________
2. Remember: 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. Thus, most epithelia have a two-part
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. Try to do this without peeking at your labels. 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 on the powerpoint tissue image
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. 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.
If you have not already done so, at this point your should completely identify the
tissue on your reference card (ie: simple squamous epithelial tissue, hyaline
cartilage, etc)
Directions for Creating a Dichotomous Key
Using the information you have added to the activity sheet, develop a dichotomous
key in flowchart format to use in lab.
Short exercise on how to make a dichotomous key. You can do this in pairs or
tables.
1. 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. Use the sheet provided on the next page as a starting point--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 (keep track of these questions on your dichotomous
key)--you have already done some of this work as your sorted the tissues earlier.
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.
Day 2
Using A Key to Identify Unknown Tissues
1. You can use your key to identify the tissues on the following slides. If it is unhelpful,
you may want to consider revisions--you will be able to use your dichotomous key on
the lab practicum section of the tissues exam (!!!), so you really want to make sure that
you create a solid tool.
2. Each slide contains more than one tissue type. See how many you can identify on
each slide.
In your journal. clearly describe how you used your key to come to your
conclusions about the tissue types. Make sure you record the number of each
slide you assess. Use the observation sheet (attached to the end of the packet)
as a template for your notes.
For each tissue type, the observation should include:
a. The name of the tissue and its description (you can reference the ppt if
needed).
b. 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.
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)
For muscle tissue, label nuclei, striations (if applicable), intercalated
discs (if applicable), branched cells (if applicable).
Tissue Identification Sheet
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).