Sectioned Sebaceous

1. Review the textbook sections on skin and accessory organs of the skin.

2. As a review activity, label figures 10.1 and 10.2. Locate as many of these structures as possible on a skin model.

3. Complete Part A of Laboratory Report 10.

4. Use the hand magnifier or dissecting microscope and proceed as follows:

a. Observe the skin, hair, and nails on your hand.

b. Compare the type and distribution of hairs on the front and back of your forearm.

5. Use low-power magnification of the compound microscope and proceed as follows:

a. Pull out a single hair with forceps and mount it on a microscope slide under a coverslip.

b. Observe the root and shaft of the hair and note the scalelike parts that make up the shaft.

6. Complete Part B of the laboratory report.

7. As vertical sections of human skin are observed, remember that the lenses of the microscope invert and reverse images. It is important to orient the position of the epidermis, dermis, and subcutaneous (hypodermis) layers using scan magnification before continuing with additional observations. Compare all of your skin observations to figure 10.3. Use low-power magnification of the compound microscope and proceed as follows:

a. Observe the prepared slide of human scalp or axilla.

b. Locate the epidermis, dermis, and subcutaneous layer, a hair follicle, an arrector pili muscle, a sebaceous gland, and a sweat gland.

c. Focus on the epidermis with high power and locate the stratum corneum and stratum basale (stratum germinativum). Note how the shapes of the cells in these two layers differ.

d. Observe the dense connective tissue (irregular type) that makes up the bulk of the dermis.

e. Observe the adipose tissue that composes most of the subcutaneous layer.

8. Observe the prepared slide of heavily pigmented human skin with low-power magnification. Note that the pigment is most abundant in the epidermis. Focus on this region with the high-power objective. The pigment-producing cells, or melanocytes, are located among the deeper layers of epidermal cells. Differences in skin color are primarily due to the amount of pigment (melanin) produced by these cells. The number of melanocytes in the skin is about the same for members of all racial groups.

Martin: Human Anatomy I 10. Integumentary System I Text I © The McGraw-Hill and Physiology Companies, 2002

Figure 10.1 Label this vertical section of skin.

Figure 10.1 Label this vertical section of skin.

Skin Slide Labeled Adipose Gland

Dermal papilla

Dense connective tissue

Nerve fiber

Hair follicle

Apocrine sweat gland

Eccrine sweat gland Hair papilla Adipose tissue

Blood vessels

Dermal papilla

Dense connective tissue

Nerve fiber

Hair follicle

Apocrine sweat gland

Eccrine sweat gland Hair papilla Adipose tissue

Blood vessels

Critical Thinking Application

Explain the advantage for melanin granules being located in the deep layer of the epidermis.

9. Observe the prepared slide of thick skin from the palm of a hand or the sole of a foot. Locate the stratum lucidum. Note how the stratum corneum compares to your observation of human scalp.

10. Complete Part C of the laboratory report.

11. Using low-power magnification, locate a hair follicle that has been sectioned longitudinally through its bulblike base. Also locate a sebaceous gland close to the follicle and find a sweat gland. Observe the detailed structure of these parts with high-power magnification.

12. Complete Parts D and E of the laboratory report.

Figure 10.2 Label the epidermal layers in this section of thick skin from the palm of the hand.

Figure 10.2 Label the epidermal layers in this section of thick skin from the palm of the hand.

Label Epidermal Layers

OPTIONAL ACTIVITY

O bserve a vertical section of human skin through a tattoo using low-power magnification. Note the location of the dispersed ink granules within the upper portion of the dermis. From a thin vertical section of a tattoo, it is not possible to determine the figure or word of the entire tattoo as seen on the surface of the skin. Compare this to the location of melanin granules found in heavily pigmented skin. Describe reasons a tattoo is permanent and a suntan is not._

Web Quest

Identify skin layers from micrographs and review the functions of the skin structures. Search these at http://www.mhhe.com/ biosci/abio/martinlmwq.mhtml

Figure 10.3 Features of human skin are indicated in these micrographs. Magnifications: (a) 290x; (b) 30x micrograph enlarged to 280x; (c) 45x; (d) 110x.

Stratum corneum Stratum granulosum

Stratum spinosum

Stratum basale Melanin

Dermal papilla

Figure 10.3 Features of human skin are indicated in these micrographs. Magnifications: (a) 290x; (b) 30x micrograph enlarged to 280x; (c) 45x; (d) 110x.

Human Skin Showing Sweat Gland 45x

Epidermis

Dermis

Epidermis

Dermis

Thick Skin Blood Vessel Dermal PapillaeHuman Skin Histology Sweat Gland
Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

Get My Free Ebook


Responses

  • Julia Zimmermann
    Is the apocrine sweat gland in the hypodermis?
    5 years ago
  • lina
    What does thick skin look like and the epidermal layer and label the strata?
    5 years ago
  • MARIE
    How thick is the human layers skin?
    4 years ago
  • Annunziata
    How to orient scalp specimen?
    4 years ago

Post a comment