Physiology Laboratory V

Macroscopic and Microscopic Study of Tissues

Cells are highly organized units, but they do not function by themselves. They work together in groups of similar units called tissues. Knowledge of tissue structure and function is important in understanding how individual cells are organized to form tissues, organs, organ systems and the complete organism. The microscopic study of tissues is called histology. The four basic tissue types are: epithelial, connective, muscular and nervous tissue. In this two part lab you will be examining representatives of the four tissue groups both macroscopically, through a dissection of a chicken wing and microscopically, using the oil immersion lens with prepared tissue slides.

Part I: A Study of Tissues Through the Dissection of a Chicken Wing

Introduction:

A bird’s wing is made up of groups of tissues working together to perform the job of flight. In this investigation you will dissect a chicken wing and look for the following tissues: epithelial (skin); muscle (skeletal); connective (adipose, bone, cartilage, blood vessels, ligaments, tendons, fascia) and finally nerve tissue.

Procedure:

  1. You will be working in pairs and each pair needs a dissecting tray, chicken wing, scissors, probe, and forceps. Everyone needs to ‘3G’ - glove, gown & goggle.
  1. Before you begin the actual dissection, study the external appearance of the wing. Examine the web-like skin between the bones. Look for evidence that the skin was covered with feathers. What evidence did you find?
  1. Remove the skin from the largest bone and joint. The most efficient way to do this is to start at the proximal end of the chicken wing with your thumb and lift the skin (epithelial tissue), place your thumb under the skin and pull back on the skin. When you do this you will be ripping below the dermis and above the muscle. Remove as much skin as possible.
  1. Locate the tissues below. The following descriptions may help you identify each tissue.
  1. Connective tissue proper – this tissue resembles a flat, thin, clear film or membrane (like saran-wrap). It is found in many places in a chicken’s and human’s body.
  2. Muscle tissue – The pink orange bundles of fiber found in the wing are skeletal muscle. Skeletal muscles are attached to bones via tendons. When the fibers expand or contract they produce motion in the wing. You should be able to identify several muscle bundles and determine whether they are extensor muscles(straightens wing out) or flexor muscles(bends wing) by pulling on them. I will demonstrate this in class.
  3. Adipose Tissue– Fat is stored in many places in the chicken’s body. Fat can be recognized by its yellow color and greasy feel.
  4. Tendon– Especially strong connective tissues attach skeletal muscle to bones and are shiny white in appearance. Pull on a tendon gently, and see what effects your action has.
  5. Bone– these hard tissues are made primarily of calcium. Inside many bones are hollow spaces where red blood cells are manufactured. The mass of red tissue that manufacture the red cells is called “red marrow”
  6. Cartilage– This white glassy, firm but flexible tissue is found at the end of bones. Move the joint back and forth and you can surmise what the function of the cartilage is.
  7. Ligament– Not as easily seen as tendons, these strong white bands of connective tissue are similar to tendons. Ligaments connect two bones together and can best be located at the joints.
  8. Blood Vessels– Arteries, veins and capillaries are the vessels that transport blood throughout the body. Arteries have a thicker wall than veins and capillaries are too small to be seen without the microscope. Blood vessels are the thin red tubes that are frequently seen at the surface of the skeletal muscle.
  9. Nerves– Nerves are usually buried deep within an organism, often lying close to the bones. Sometimes an artery, vein and a nerve are held together in one bundle of connective tissue running along a muscle. Nerves can be recognized by their thin, white threadlike appearance.
  1. Clean-Up: Take the chicken pieces parts and wrap them in paper towel and throw them in the large gray garbage pail by the back sink/door! That is the ONLY garbage we use for dissected animals!!! All the dissecting equipment must be washed using warm soapy water. This can be done at the sinks at your desks OR at the large sink at the side of the room. Dry everything and return it to the supply tables in front of the hood. Make sure you then wash down your lab table. I will tell you what solution to use for this in class. Finally, remove your lab gown, fold it nicely and put it away, put away your goggles and wash your own hands with SOAP and WATER before you leave class!

Part II: Microscopic Study of Tissues

Introduction: The aim of this part of the lab is to fine-tune your microscopic techniques by studying several representative samples of the different tissue groups found in the human body.

The following is a list of tissue samples that will be available for study. You are to choose ONE from each category to view. Since our VHP objectives are not working, ALL SLIDES are to be DRAWN under high power (400x - TM). Make sure you label as many of the following structures as you can, BUT, ONLY IF YOU SEE THEM!!

Before you view your slide under the microscope, log onto the desktop computer you have been assigned and open the program Real Anatomy. Under the histology section you will be able to view examples of all the tissue slides you can choose from today. You CANNOT draw from Real Anatomy, but this program will be extremely helpful to you for identifying structures and labeling, as well as making sure you are looking at the right cells. SO…make sure you look at your cell types on Real Anatomy BEFORE you try to find them on your microscope.

Cell structures to identify in your drawings:

cell membranenucleuscytoplasm

ciliagoblet cellsvacuoles

  1. Epithelial – this tissue group either covers or lines both internal and external organs. The cells are differentiated based on their shape, number of layers and special features. In all members of this category, the cells rest on a basement membrane.
  2. Simple squamous
  3. Simple cuboidal
  4. Pseudostratified ciliated columnar epithelial
  1. Muscle - special proteins that cause contractions, which allow for all types of movement, characterize this tissue group.
  1. SkeletalORb. Smooth
  1. Nerve – is made up of neurons, which conduct bioelectrical messages and other cells, which serve to support the neurons in a number of ways.
  1. Connective – is a varied group of tissues, though all connective tissues types are characterized by cells embedded in an intracellular matrix, which may be solid, semisolid, liquid or fibrous.
  1. Cartilage
  2. ????? Let’s see what I can find in the cabinet.

5. CLEAN – UP: When you are done with a slide, return it to the tray from which you took it. At the end of the period, make sure you put your microscope away properly

  • lowest magnification (4x)objective over the stage
  • wrap the electric cord around the arm under the stage
  • put cover over microscope
  • place the microscope in the correct #’d space in the cabinet in my office

What goes in your lab notebook?

  1. Team Introduction – on Google Docs: Write two paragraphs about a disease that affects one of the tissue types. Be detailed and descriptive in your discussion as to how the disease affects the tissue. Remember toproperly cite your 2 sources of information!
  1. Observations: Write a paragraph about the tissues you saw during the dissection (macroscopic observation) and then write a few sentences about the microscopic view of the same tissues. Hint: once again think structure to function.
  1. Drawings: 4 drawings…one tissue from each category. Large and labeled.All four must be under high power (40x). 3 bullet points per tissue slide from Real Anatomy
  1. Analysis Question: Most chickens have short, rounded wings, not suitable for flying long distances. Think of birds that spend much of their life in flight. In what ways would you expect the wings of a flying bird to be different from that of the wings of a chicken, a non-flying bird.(Remember to cite your source of information.)
  1. Conclusion: reflection paragraph - this is your first dissection – what did you think?

Name: ______

Chicken Wing Diagram