Laszlo Vass, Ed.D. Version 42-0280-00-01
Lab Report Assistant
This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor.
What is the purpose of this exercise? The purpose of this exercise in to learn about structures and functions of the skin.
Is there any safety concerns associated with this exercise? If so, list what they are and what precautions should be taken. As always take precautions when handling the microscope and slides and always have a clean safe work area.
Exercise 1: Structures of the Skin
Before beginning, set up a data table similar to this Data Table 1. Fill in the names of the numbered structures.
(National Library of Medicine at http://nih.nlm.gov)
Data Table 1: Structures of Skin|
1.| Hair shaft |
2.| Arrector pili muscle |
3.| Sebaceous gland |
4.| Hair follicle |
5.| Sweat gland |
6.| Pacinian corpuscle |
7.| Subcutis (hypodermis) |
8.| Dermis |
9.| Epidermis |
10.| Sensory nerve ending |
11.| Dermal papilla |
12.| Sweat pore |
A. How does the skin tan when exposed to ultraviolet light? When ultraviolet light penetrates skin it begins to break down DNA causing the body to produce melanin. The melanin makes the body become darker or tanner and when the body is darker the more protected it is from the sun and sunburn.
B. Describe the functions of the epidermis. The epidermis is the outermost layer that has keratinized squamous epithelium and the dermis. The epidermis has a bunch of different cells which allow it to perform many different functions. The keratinocytes produce keratin that produce fibrous protein that gives skin protective properties while the melanocytes produce melanin to protect deeper cells from ultraviolet radiation and allows the skin to tan. Merkel cells from sensitive touch receptors on nerve endings and langerhans’ cells are involved in the immune response of the skin. . Stratum basale constantly go through cell division to produce million of new skin daily. Stratum spinosum has think bundles of protein and stratum granulosum contain lipids that provide waterproofing for the skin. The stratum lucidum is a layer of flattened keratinocytes are only found in thick skin. Stratum corneum is the outer layer of the epidermis made of squished and flattened layers of dead keratinocytes.
C. Describe the functions of the sweat glands. Sweat glands are controlled by sympathetic nervous system and regulate body temperature. When the body becomes to hot they secrete water to the skin surface and the heat is removed by evaporation.
D. Compare the structure of the epidermis to that of the dermis.
The epidermis consists of several different types of cells while the dermis canonists of dense, irregular connective tissue.
E. Fill in the following table by either inserting the name of the structure/cell or by giving its function(s):
melanocytes| Makes a pigment for tanning|
Langerhans cells| Small and involved in the immune response| Merkel cells | Found on nerve endings|
Stratum lucidum| Provides protection, thick found of palms a soles makes skin waterproof | Reticular layer | The blood supply here provides radiational cooling for the body|
Exercise 2: Microscopic Structure of the Skin