Graduate Microanatomy, 1998
Graduate Microanatomy, 1998
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Date page was last edited 05/14/99 |
Laboratory Exercises: Skin Exercise 1. Epidermis View Slide 25. This is a slide of thick skin in which you have already identified the tissues in the epidermis, dermis, and hypodermis. 1) Just for review, what tissue type is in each layer? epidermis____________________ dermis_______________________ hypodermis_____________________ The following photo shows a slide of thick skin. 2) Identify the layers of the epidermis on the photo.
Exercise 2. Look at slide 25 at high magnification.3) Identify the basal layers and the stratum spinosum. Answer the questions (4-6) about these layers on the following photographs:
The following photographs show higher magnifications of the lucidum and keratinizing layers.7) Identify each.
Exercise 3. Thin skin is found in slide 24. You may compare pigmented and non pigmented skin by looking at the epidermis of scalp (slide 24 ) and the penis (slide 67). As you study thin skin, first be sure you know each layer. Also identify the different layers of the epidermis in slide 24. Then, answer the questions 8-10 under the photographs.
Exercise 4. Dermis In both slides 24 and 25, you have already identified the dermis. There are really two layers with rather indistinct boundaries. They can be distinguished by the type of connective tissue in each layer, the number of cells, etc. 11) Name these layers________________________________________ Answer question 13 in the photograph
12) How does the dermis serve the following functions? . Thermal Regulation Touch (review the unit on Nerve) Vibration (review the unit on Nerve) Pain (review the unit on Nerve) In your slide, find the reticular layer of the dermis. The following photograph shows reticular dermis with elastic fibers (specially stained).
Exercise 5. Structures in the hypodermis: 14) How would you know you were in the hypodermis?_____________________________ 15) How does the hypodermis perform the following functions:
Sweat glands In your slide of thick skin (slide 25) identify secretory and duct portions of eccrine sweat glands. The following photographs show both portions. 16, 17) You will be asked to find a myoepithelial cell and classify the type of epithelium in the duct.
Hairs Look at hair follicles in your slide of thin skin (Slide 24). Hairs are also found in the hypodermis growing up into the dermis. Each hair arises from an epidermal invagination, the hair follicle, that teminates in a dilation called the hair bulb. 18) Find these structures in the following photographs.
At the base of a hair follicle sebaceous glands are found. These glands secrete oil, or sebum, into the follicle. They secrete via a process called "holocrine secretion" in which the cell fills with secretory material and then essentially distintegrates. 19) In the following photographs and in your slide of thin skin find sebaceous glands.
Just for fun, here are three views of hair, including straight hair, curly hair and gray hair. Note the differences in the density of the hair. It would be fun to see if "extrastrength protein conditioned hair", or "permed hair" have different densities.
Exercise 6. Mammary Glands: Mammary glands are essentially modified sweat glands. So many of the same structures that you studied in the above exercise will be found. However, in this exercise, we will be studying lactating and non-lactating mammary glands. You will learn to distinguish the two. The following photograph shows views of non-lactating mammary gland cells. Find slides 80 and 81 in your slide set. In the non-lactating mammary gland, there is a lot of connective tissue around the glandular cells (intralobular connective tissues) and also a lot of connective tissue inbetween the lobules (interlobular connective tissue). In these photographs, use your sweat gland photos as a guide. Identify the mammary gland cells and the myoepithelial cells.
Lactating mammary glands show little intralobular connective tissue and spaces are filled up with the glands themselves. Myoepithelial cells are still present and very important to aid expulsion of milk into the ducts. What hormone stimulates myoepithelial cells in the mammary gland?________________________________
Slide 79 shows a section of the nipple. This region demonstrates stratified squamous epithelium, and a dermis that contains large bundles of smooth muscle. These stand out from the connective tissue. Also you can identify large lactiferous sinuses lined with stratified cuboidal epithelium. Be able to find these on your slide.
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