Lab work
aleenab
Momlab2.pptxLab Report 5: Tissues
Name:
Date:
Adapted from jtcc.edu
Lab Materials
Online access
Computer (with PowerPoint software)
Dr. Hogan’s Tissues for Lab Report 5 Album on Google Photos: find the link in the Canvas Instructions for this lab
Safety Instructions:
Students must abide by the safety instructions in the Biology Lab Safety Contract
Safety Equipment & Instructions
Adapted from jtcc.edu
Lab Introduction
The organization of living tissue starts with chemicals, then progresses through cells, tissues, organs, organ systems and lastly organisms. In this lab you will examine the middle of the hierarchy, how tissues are put together to make organs.
This is a really important concept; if you can figure out which tissues make up an organ and you understand the features and functions of the individual tissues, then you can start to understand how the organ works.
You will first look at slices of organs and figure out which tissues you are looking at. Next, you will look at some individual tissue types and their function.
Adapted from jtcc.edu
General Lab Instructions
Readable Labels
Typed (not handwritten)
Use appropriate font size (24 or 26)
Reading frame is left-to-right, with horizontal, right-side-up textboxes
Use appropriate line weight for arrows, brackets, etc (4.5 or 6); do not use block arrows (please & thank you)
Contrasting Colors
Arrows and brackets should be of a high contrast color that is easily seen against the background.
Labels on the Slide, not off to the side; use the neutral spaces for textboxes.
Arrow in the Middle of the structure, not between structures
Photos should be sized proportionally
Use Lock Aspect Ratio
Resize using the corners, not the sides
No Criss-Cross
Arrows should not overlap
Photos from the Google Album (where applicable) should be oriented as they are in the album.
The completed lab needs to be submitted in Canvas upon completion in PowerPoint format (pptx) or as a pdf. If you are using a different program, you can Save As or Export As pptx or pdf file from the File Menu.
Adapted from jtcc.edu
4
Sample
Sample
Adapted from jtcc.edu
Tissue Classification
Review the tissue classification scheme covered in lecture and the textbook. Make sure you can list the four basic tissue types (epithelial, connective, muscle and nervous) and the major sub-types. You should be able to attach special functions to specific tissue types and suggest examples/locations for each type.
This lab focuses on epithelial tissues and most of the connective tissues. You will look at cartilage, bone, muscle and nervous tissue in other labs.
For each tissue, note how the structural features contribute to the function of the tissue and the overall organ.
Adapted from jtcc.edu
Histology and Tissue Organization
Almost all of the slides you will look at will be labeled as one tissue subtype, but that doesn’t mean that’s the only tissue on the slide. Most slides are sections of organs that are made up of several tissues, which can make finding a particular tissue confusing (especially when looking for epithelial tissues).
Makes sure you have access to a reference (APR or a textbook) so you know what you are trying to find!
When you are looking at epithelium slides, only a small portion of the slide will be epithelium and the majority typically connective tissue and smooth muscle. Much of the time the organ on the slide will have a “lumen”, the hollow portion of a tube. The blood in an artery travels through the lumen, as does food in your digestive tract.
Adapted from jtcc.edu
Organ Organization
Another problem is that most slides are not easy to orient, they are not perfect slices of the target organ. Most will be at weird angles that can add to the confusion.
Just remember that most of the epithelium slides will have a lumen and use that to orient yourself (the epithelium will be lining the lumen).
The connective tissue slides will mostly just have that one tissue type on the slide.
Adapted from jtcc.edu
Organ Organization
How can you tell which cells are which?
Epithelial layers tend to stain darkly (because the cells are more densely packed than connective tissue) and lining a lumen.
Epithelial cells will (almost) always be supported by some loose areolar connective tissue deep to the basement membrane.
Adapted from jtcc.edu
Organ Organization
Deep to the areolar connective tissue there will often be two or three layers of smooth muscle (not shown in the figure)
Some of the organs you see will have all four types of tissue (but it is very difficult to find nervous tissue in most organs; this figure shows a nerve, but you would be unlikely to see this in a real histological section).
Adapted from jtcc.edu
Artifacts
Always remember these are real pieces of tissue. The thin slices can get damaged during the preserving process.
You will often find areas that get torn as the slice is “fixed” onto the glass slide. This almost always is found in the areolar connective tissue because that tissue is mostly ground substance.
Remember that areolar connective tissue is mostly fluid (which all gets washed off during the slide prep). There are few cells (fibroblasts) and fibers (collagen) to hold the tissue together.
The images to the right show a typical artifact (something that doesn’t represent the original structure). All the gaps you see (red star) are torn areolar connective tissue, not lumens.
With practice you will easily be able to distinguish artifacts from actual lumens.
Lumen
Adapted from jtcc.edu
Photo 1. Epithelium, Stratified Squamous
Open the Google photo album from the Lab Materials slide and find the image Stratified squamous, ET, esophagus. The function of the esophagus is just to quickly move chewed-up food from the mouth to the stomach.
It makes sense that this epithelium is stratified squamous. Absorption is not needed, secretion is minimal (saliva is already present), and there’s no diffusion taking place.
Stratified squamous epithelium is the best option when just protection from abrasion is required.
Capture the image and add it to the region to the right. Label: apical surface (the squamous-shaped cells), basal surface (rounder, younger cells), connective tissue, lumen. Use textboxes and arrows.
Adapted from jtcc.edu
Photo 2. Epithelium, Simple Cuboidal
Find the image Simple cuboidal, ET, kidney. Simple cuboidal epithelium is good for balancing secretion, absorption and diffusion (not too thick, not too thin).
These cube-shaped cells are kidneys and some glands, but they can be difficult to image as they line very small tubes (not large lumens like other epithelia).
Look for tiny, circular lumens lined by the epithelium. There will only be a small amount of connective tissue between the densely packed tubes. Add the image to the box on the right and label: simple cuboidal epithelial cell nucleus, lumen, basal surface, apical surface. Use textboxes and arrows.
Adapted from jtcc.edu
Photo 3. Epithelium, Simple Columnar & Exocrine Gland
Find the image Simple columnar, ET, small intestine. Simple columnar epithelium is also good for secretion and absorption, but it is more selective than simple cuboidal epithelium.
These cells have microvilli, tiny brushy extensions that are immobile (not cilia). They increase surface area for more absorption. There are also large, lightly stained goblet cells, single-celled exocrine glands that secrete mucus to protect the lining of the small intestine.
Add the image to the box on the right and label: simple columnar epithelial cell, connective tissue, lumen, goblet cell. Use textboxes and arrows.
Adapted from jtcc.edu
Photo 4. Epithelium, Pseudostratified Columnar (ciliated)
Find the image Pseudostratified columnar, ET, trachea.
This tissue appears stratified because the nuclei are at different levels, but every epithelial cell touches the basal side.
Add the image to the box on the right and label: pseudostratified epithelial cell, connective tissue, cilia. Use textboxes and arrows.
Adapted from jtcc.edu
Photo 5. Epithelium, Simple Squamous
Find the image Simple squamous, ET, kidney.
It’s difficult to find a cross-section of simple squamous epithelium as all you see is a slice of a very thin cell.
Add the image to the box on the right and label: simple squamous cell. Use a textbox and arrow.
Adapted from jtcc.edu
Photo 6. Epithelium, transitional
Transitional epithelium is a stratified epithelium. The multilayers of rounded cells are good at both protecting and stretching, which makes it perfect for the urinary system (i.e. urinary bladder).
Find the image Transitional, ET, urinary bladder, distended.
Add the image to the box on the right and label: lumen, transitional epithelial cell, connective tissue. Use textboxes and arrows.
Adapted from jtcc.edu
Photo 7. Connective Tissue, Areolar
You have already seen plenty of (loose) areolar connective tissue. Almost every epithelium is supported by this tissue (deep to the basement membrane).
The image for Areolar, CT, unknown is a “spread”, the tissue has been squished and stained so you can see what’s there.
Remember most of the tissue is fluid (ground substance). Add the image to the box at the right and label: a fiber (collagen), and a fibroblast. Use textboxes and arrows.
Adapted from jtcc.edu
Photo 8. Connective Tissue, Reticular
Reticular connective tissue is rare, it’s only found in a few organs and glands. It’s simply a few fibers (reticular) that provide anchoring spots for cells (often leukocytes, immune system cells). There’s plenty of space for fluid to move through so the immune cells can check for antigens.
Find the image Reticular, CT, lymph node, and add it to the box at right. Label the following: a reticular fiber and a fibroblast. Use textboxes and arrows.
Adapted from jtcc.edu
Photo 9. Connective Tissue, Adipose
Adipose connective tissue is very easy to identify. Almost all the cell contents have been washed away (most fats are removed during the slide preparation process) so all you can find is the cell membrane and maybe a few nuclei.
Find the image, Adipose Tissue, CT, unknown, and add it to the box at right. Label: adipocyte plasma membrane and adipocyte nucleus. Use textboxes and arrows.
Adapted from jtcc.edu
Photo 10. Connective Tissue, Dense
Dense regular connective tissue makes up tendons and ligaments. It is ”dense” with collagen; there are very few fibroblasts.
Notice the linear pattern of the extracellular matrix.
Insert the image, Dense Regular, CT, tendon, in the box at right.
Label: fibroblast. Use a textbox and arrow.
Adapted from jtcc.edu
Photo 11. Connective Tissue, Elastic
Dense elastic connective tissue is ”dense” with elastic fibers. It is only found in a few large arteries like the aorta and a few other places. It doesn’t look much different from dense regular connective tissue.
Find the image, Elastic, CT, ligamentum nuchae, and insert it on the box at right.
This has wavy lines of elastic fibers, not as straight as the collagen in dense regular connective tissue.
Label: fibroblast. Use a textbox and arrow.
Fun fact – the ligamentum nuchae is the band of elastic tissue that keeps your head from bobbing around like a pig’s head will while running. You have it, as do horses, so we run majestically with a stable head.
Adapted from jtcc.edu
Photo 12. Connective Tissue, Dense Irregular
Dense irregular connective tissue is common and widespread. It is “dense” with collagen, but the collagen is arranged in a random pattern.
It forms most of the thick dermis layer of skin (next lab) and the periosteum (bone covering, in two labs).
Insert the image, Dense Irregular, CT, mitral valve, in the box at right.
Label: fibroblast. Use a textbox and arrow.
Adapted from jtcc.edu
Photo 13. Connective Tissue, Hyaline Cartilage
Hyaline cartilage has a dense, glassy-textured extra-cellular matrix. It has tiny openings called lacunae where you can find the chondrocytes (cartilage cells).
Hyaline cartilage is found on the ends of bones and in the rings that reinforce the trachea to prevent its collapse.
Find the image, Cartilage, hyaline, CT, trachea, and add it to the box at right. Label: chondrocyte and extracellular matrix (ground substance). Use textboxes and arrows.
Adapted from jtcc.edu
