Structure and Functions of Skin
Session 11: Structure and Functions of Skin
Total Session Time: 60 minutes
Students Learning Tasks
By the end of this session students are expected to be able to:
Resources Needed:
SESSION OVERVIEW
|Step |Time |Activity/ |Content |
| | |Method | |
|1 |05 minutes |Presentation |Introduction, Learning Tasks |
|2 |05 minutes |Presentation |Definition of the skin |
| | |buzzing | |
|3 |15 minutes |Presentation |Structure of the Skin |
|4 |25 minutes |Presentation | Functions of the Skin |
| | |Brainstorming | |
|5 |05 minutes |Presentation |Key Points |
|6 |05 minutes |Presentation |Evaluation |
SESSION CONTENTS
STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)
READ or ASK students to read the learning tasks and clarify
ASK students if they have any questions before continuing
STEP2: Definition of the Skin (05minutes)
|Activity: Buzzing (5 minutes) |
| |
|ASK students to pair up and buzz on the following question for 2 |
|minutes |
| |
|What is the skin? |
| |
|ALLOW few pairs to respond and let other pairs to add on points not |
|mentioned |
| |
|WRITE their response on the flip chart/board |
| |
|CLARIFY and SUMMARIZE by using the content below |
Skin:
body of a person or animal
o The body's outer covering, which protects against heat and light,
injury, and infection.
o Skin regulates body temperature and stores water, fat, and vitamin D.
o The skin, which weighs about 6 pounds, is the body's largest organ.
STEP 3: Structure of the Skin (15minutes)
structures such as hair nails and glands.
imbalances in the body.
Structure of the skin
o Dermis
o Epidermis
Dermis
o The deeper reticular layer, is dense irregular connective tissue, is
the main layer of the dermis consisting of layers of interlacing
collagen fibers
o This layer is of elastic and collagens are oriented more in some
areas than others creating tension lines (cleavage lines) and
wrinkle lines in the skin
o The more superficial papillary is called from projections called
papillae that extend toward the epidermis
o It is less dense than reticular and sometimes called loose
connective tissue, it also contain large number of blood vessels
o These fibers provide skin tone and account for the strength and
toughness of the skin
o The pattern of collagen fibers in a particular region determines the
characteristic
o The deep layer of the dermis contains hair follicles, with their
associated smooth arrector muscles and sebaceous glands
o Contraction of the arrector muscles erects the hairs (causing goose
bumps), thereby compressing the sebaceous glands and helping them
secrete their oily product onto the skin
o The dermis composed of , nerve endings, hair follicles, smooth
muscles, glands, and lymphatic vessels
o Skin ligaments, consisting of numerous small fibrous bands, extend
through the subcutaneous tissue and attach the deep surface of the
dermis to the underlying deep fascia
o The length and density of these ligaments determine the mobility of
the skin over deep structures
[pic]Handout 11.1: Layers of the Skin
Epidermis:
composed of keratin (a fibrous protein).
extends from the deepest germinative layer to the surface stratum corneum
namely:
o Basal layer (stratum basale)
o Spinous or prickle cell layer (stratum spinosum)
o Granular layer (stratum granulosum)
o Clear layer (stratum lucidum)
o And cornified layer (stratum corneum)
replacement of new cells from the basal layer.
o Most of the cells are called keratinocytes because they produce
protein called keratin
o Melanocytes which contribute to skin colour
o Langerhans’ cells which are part of immune system
o Merkel’s which are specialized epidermal cells associated with nerve
endings responsible for detecting light touch and superficial
pressure
o This process renews the epidermis of the entire body every 25 to 45
days
o The epidermis is avascular (no blood vessels or lymphatics) and is
nourished by the vessels in the underlying dermis
o The skin is supplied by afferent nerve endings that are sensitive to
touch, irritation (pain), and temperature
o Most nerve terminals are in the dermis, but a few penetrate the
epidermis
[pic]
Source: Standring, 2005
Figure 11.1: The
Epidermis
STEP 4: Functions of the Skin (25minutes)
|Activity: Brainstorming (5 minutes) |
| |
|Ask students to brainstorm on the following question: |
| |
|What are the functions of the skin? |
| |
|ALLOW few students to respond |
| |
|WRITE their responses on the flip chart/ board |
| |
|CLARIFY and SUMMARISE by using the content below |
o Abrasions
o Melanin absorb ultraviolet light and protect underlying tissue
o Skin prevent the entry of microorganisms and other harmful substances
o Prevent dehydration by reducing water loss from the body because its
lipids act as barrier to the diffusion of water
o Nail protect the ends of the digits from damage and can be used in
defence
o Hair follicles act as insulator and protect from ultraviolet light
deposits
detect heat, cold, pain, touch, temperature and pressure)
skin produces a molecule that can be transformed into vitamin D
in gland secretions
STEP 5: Key Points (05minutes)
structures such as hair nails and glands
when exposed to ultraviolet light and excretion of small amount of waste
products are lost through the skin and in gland secretions
the body of a person or animal
protein called keratin, Melanocytes which contribute to skin colour,
Langerhans’ cells which are part of immune system and Merkel’s which are
specialized epidermal cells associated with nerve endings responsible for
detecting light touch and superficial pressure
STEP 6: Evaluation (05 minutes)
References
Seeley, R. R., Stephens, T. D., &Tate, P. (2003). Anatomy and Physiology.
New York:
McGraw-Hill.
Shier, A., Butler, J., & Lewis, R. (2004). Hole’s Human Anatomy &
Physiology. New York:
McGraw-Hill.
Standring, S. (2008). Grays’s Anatomy The anatomical basis of clinical
practice. United
Kingdom: Churchill Livingstone Elservier.
Thibodeau, G. A., & Patton, K. T. (1999). Anatomy & Physiology. Saint
Louis: Mosby, Von
Hoffman Press, Inc.
Waugh, A., & Grant, A. (2006). Ross and Willson Anatomy and physiology in
Health and
illness. United Kingdom: Churchill Livingstone Elservier.
|[pic] |Handout 11.1: Layers of the skin |
[pic]
Source: Standring, 2005
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