skin and body membranes - mrs. pike -...

PowerPoint® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings

4

Skin and Body Membranes


Integumentary System §  Skin (cutaneous membrane or integument)

§  Skin derivatives

§  Sweat glands

§  Oil glands

§  Hair

§  Nails


I. Skin Functions A. Protects deeper tissue from:

1. mechanical damage (bumps)

- physical barrier (epidermis) contains keratin (protective protein) to toughen & waterproof cells, fat cells to cushion blows, & pressure receptors which alert the nervous system to possible damage

2. chemical damage (acids & bases)

- relatively impermeable keratinized cells, pain receptors which alert the nervous system to possible damage


I. Skin Functions cont.

3. bacterial damage

- has unbroken surface, has acid mantle – where skin secretions are acidic, and thus inhibit bacteria

4. ultraviolet radiation (damaging effects of sunlight)

- melanin (pigment) produced by melanocytes offers protection/suntan

5. thermal damage (hot or cold)

- contains hot/cold/pain receptors

6. desiccation (drying out)

- contains a waterproof glycolipid & protein


I. Skin Functions cont. B. Aids in body heat loss or heat retention

- heat loss: activating sweat glands & allowing blood to flush into skin capillary beds so heat can radiate from skin surface

- heat retention: NOT allowing blood to flush into skin capillary beds


I. Skin Functions cont.

C. Aids in excretion of urea & uric acid

- contained in perspiration produced by sweat glands

D. Synthesizes Vitamin D

- modified cholesterol molecules in the skin are converted to vitamin D when exposed to UV radiation/ sunlight


Skin Functions

Table 4.1 (1 of 2)


Skin Functions

Table 4.1 (2 of 2)


‘I CAN’ OBJECTIVES

____ 1. I can describe the functions of the integument.


Skin Structure §  Epidermis—outer layer

§  Stratified squamous epithelium

§  Often keratinized (hardened by the protein keratin) by keratinocytes/waterproof

§  Dermis

§  Dense connective tissue


Skin Structure

Figure 4.3


‘I CAN’ OBJECTIVE

____ 2. I can compare and contrast the tissue of the epidermis with that of the dermis.


Skin Structure §  Subcutaneous tissue (hypodermis) is deep to

dermis

§  Not part of the skin

§  Anchors skin to underlying organs

§  Composed mostly of adipose tissue



____ 3. I can describe the subcutaneous membrane.


White Board Review 1. Give one example of a function our skin protects us from.

2. Which feedback mechanism for homeostasis is in action in the Integumentary system?

3. Which integument layer is made up of stratified squamous epithelium? dense fibrous connective tissue? adipose connective tissue?

4. What other body system works with the Integumentary system to maintain our body temperature for homeostasis?

5. What vitamin is produced in our skin and in the presence of what?


At The Clinic Homeostasis & Integument Functions

1. Explain a scenario in which someone would have a Vitamin D deficiency.

2. The AHS track coach is explaining to his athletes the importance of staying fully hydrated when training outside in the heat. Why should these student athletes pay close attention and adhere to this?

3. The water of a swimming pool is hypotonic to our cells. Why do we not swell and pop when we go swimming?

4. After an athlete finishes an after school practice, they are red-faced and sweating. Which type of homeostatic feedback mechanism is in action? What variable are these symptoms trying to keep at an equilibrium? Which body systems are working together to achieve homeostasis?


At The Clinic Tissues

1. Which type of injection would allow a drug to be absorbed more rapidly – intradermal (into the dermis) or subcutaneous (a shallow injection just deep to the epidermis)? Why?

2. Ally got sunburned on her recent trip to the beach. Her skin is peeling off in sheets. Why?

3. Both newborn infants and aged individuals have very little subcutaneous tissue. How does this affect their sensitivity to cold environmental temperatures?


EXIT TICKET 1. Which type of feedback mechanism is functioning in the Integumentary System to maintain health.

2. Give one example of homeostasis within the Integumentary system functions.

3. Name two ways in which our skin protects our deeper tissues.

4. Give one possibility of an outcome if the Integumentary System was run by positive feedback.

5. What type of tissue is found in the epidermis? dermis? subcutaneous layer/hypodermis?


Layers of the Epidermis §  Stratum basale (stratum germinativum)

§  Deepest layer of epidermis

§  Lies next to dermis

§  Cells undergoing mitosis

§  Daughter cells are pushed upward to become the more superficial layers

§  Stratum spinosum

§  Stratum granulosum


Layers of the Epidermis §  Stratum lucidum

§  Formed from dead cells of the deeper strata

§  Occurs only in thick, hairless skin of the palms of hands and soles of feet

§  Stratum corneum

§  Outermost layer of epidermis

§  Shingle-like dead cells are filled with keratin (protective protein prevents water loss from skin)


Layers of the Epidermis §  Summary of layers from deepest to most

superficial

§  Stratum basale

§  Stratum spinosum

§  Stratum granulosum

§  Stratum lucidum (thick, hairless skin only)

§  Stratum corneum



____ 4. I can list the layers of the epidermis and explain why there is an extra layer in certain body regions.


Melanin §  Pigment (melanin) produced by melanocytes

§  Melanocytes are mostly in the stratum basale

§  Color is yellow to brown to black

§  Amount of melanin produced depends upon genetics and exposure to sunlight



____ 5. I can explain skin pigment colors concentrating on melanocytes and melanin and the cultural differences.


Dermis §  Two layers

§  Papillary layer (upper dermal region) §  Projections called dermal papillae

§  Some papillae contain capillary loops §  Other house pain receptors and touch receptors §  On palms & soles, papillae are arranged in

patterns that increase friction & gripping ability - fingerprints

§  Reticular layer (deepest skin layer) §  Blood vessels §  Sweat and oil glands §  Deep pressure receptors



____ 6. I can distinguish between the papillary layer and the reticular layer of the dermis.


Dermis §  Overall dermis structure

§  Collagen and elastic fibers located throughout the dermis

§  Collagen fibers give skin its toughness

- attract & bind water to keep the skin hydrated

§  Elastic fibers give skin elasticity

- as we age, the number of both fibers decreases, as a result, skin begins to sag & wrinkle


Blood Vessels §  Blood vessels play a role in body temperature

regulation for homeostasis

- when body temp is high, dermal capillaries become engorged, or swollen & skin becomes reddened & warm, allowing heat to radiate from the skin surface

- when body temp is low, blood bypasses the dermal capillaries temporarily, allowing internal body temp to stay high


Nerve Endings §  Dermis also has a rich nerve supply

- many nerve endings have specialized receptors that send messages (from environmental factors – pressure & temp) to the central nervous system


Skin Structure

Figure 4.4



7. I can describe the overall structure of the dermis including collagen and reticular fibers, blood vessels and nerve supply.


*HOMEOSTATIC IMBALANCE*

- Decubitus Ulcers- bed sores – a restriction of blood supply to the skin resulting in cell death and skin ulcers

- the weight of the body puts pressure on the skin, especially over bony projections


Normal Skin Color Determinants §  Melanin

§  Yellow, brown, or black pigments

§  Carotene

§  Orange-yellow pigment from some vegetables

§  Hemoglobin

§  Red coloring from blood cells in dermal capillaries

§  Oxygen content determines the extent of red coloring


Appendages of the Skin §  Cutaneous glands are all exocrine glands §  Sebaceous glands

§  found all over skin, except for palms of hands & soles of feet

§  Produce oil, called sebum §  Lubricant for skin §  Prevents brittle hair §  Kills bacteria

§  Most have ducts that empty into hair follicles; others open directly onto skin surface

§  Glands are activated at puberty



8. I can explain the structure and function of sebaceous glands.


*HOMEOSTATIC IMBALANCE*

- Acne Vulgaris is an infection of the sebaceous glands accompanied by pimples on the skin

§  - if a sebaceous gland is blocked by sebum, a whitehead appears on the skin surface

§  - if the accumulated material oxidizes and dries, it darkens, forming a blackhead

§  - Seborrhea is known as “cradle cap” in infants, is caused by overactivity of sebaceous glands


Appendages of the Skin

Figure 4.6a


Appendages of the Skin §  Sweat glands also called sudoriferous glands

§  2.5 million per person

§  Widely distributed in skin

§  Two types

§  Eccrine

§  More numerous & found all over body

§  Open via duct to pore on skin surface


§  Apocrine

- Ducts empty into hair follicles

- Largely confined to axillary & genital areas

- Secretes sweat that also contains fatty acids &

proteins which may cause a milky or yellowish

color

- When bacteria are present, they use the proteins

& fats as a nutrient source & causes an

unpleasant odor



Figure 4.6b


‘ICAN’ OBJECTIVES

9. I can explain the structure and function of sudoriferous glands.

10. I distinguish between eccrine and apocrine sudoriferous glands.


Sweat and Its Function §  Composition

§  Mostly water §  Salts and vitamin C §  Some metabolic waste §  Fatty acids and proteins (apocrine only)

§  Function §  Helps dissipate excess heat §  Excretes waste products §  Acidic nature inhibits bacteria growth

§  Odor is from associated bacteria



11. I can explain the composition and function of sweat.


Appendages of the Skin §  Hair

§  Found all over the body except palms of hand,

soles of feet, nipples & lips

§  Produced by hair follicles

§  Part of hair enclosed in the follicle is the root

§  Part of hair projecting from surface is shaft


Hair §  Mitosis, or formation of epithelial cells, occurs in the

matrix (growth zone) at the inferior end of the hair bulb in the follicle

§  As daughter cells are pushed away from the growing region, they become keratinized & die (bulk of hair shaft is dead & almost entirely protein)

§  Melanin provides the pigment for hair color

§  Shape of hair shaft determines hair type (straight, wavy or curly)



Figure 4.7c


Appendages of the Skin §  Hair anatomy

§  Central medulla

§  Cortex surrounds medulla

§  Cuticle on outside of cortex

§  Most heavily keratinized & most subject to abrasion which causes split ends at tip of shaft

Figure 4.7b


Appendages of the Skin §  Associated hair structures

§  Hair follicle

§  Dermal (connective) and epidermal (epithelial) sheath surround hair root

§  Arrector pili muscle

§  Smooth muscle

§  Pulls hairs upright when cold or frightened –

“goose bumps”



Figure 4.7a



Figure 4.8


‘I CAN’ OBJECTiVE

12. I can explain hair as an appendage of the skin, including the terms follicle, shaft and arrector pili muscle.


Appendages of the Skin §  Nails

§  Scale-like modifications of the epidermis

§  Heavily keratinized

§  Free edge, body (visible attached portion), root (embedded in skin), cuticle (proximal nail fold), lunula (white crescent) & nail bed (beneath the nail body)

§  Stratum basale extends beneath the nail bed – proximal end (matrix) is responsible for growth

§  Like hairs, mostly nonliving material



Figure 4.9



13. I can explain nails as an appendage of the skin, including the terms free edge, root, body, lunula, and cuticle.


Skin Homeostatic Imbalances §  Infections & Allergies

§  Athlete’s foot

§  Itchy, red, peeling condition of skin between the toes

§  Caused by fungal infection

§  Boils and carbuncles

§  Inflammation of hair follicles & sebaceous glands

§  Common on dorsal neck

§  Caused by bacterial infection


Skin Homeostatic Imbalances §  Cold Sores

§  Fluid-filled blisters that itch & sting

§  Caused by herpes virus

§  Virus localizes in cutaneous nerves, where it remains dormant until activated by emotional upset, fever, or UV radiation


Skin Homeostatic Imbalances §  Contact dermatitis

§  Itching, redness & swelling progressing to blistering

§  Exposure to chemicals cause allergic reaction

§  Impetigo

§  Pink, water-filled, raised lesions (common around nose & mouth) which develop yellow crust & rupture

§  Caused by highly contagious bacterial infection


Skin Homeostatic Imbalances §  Psoriasis

§  Overproduction of skin cells resulting in reddened lesions covered with silvery scales

§  Believed to be an autoimmune disorder (where your body attacks your body) triggered by trauma, infection or stress


Skin Homeostatic Imbalances

Figure 4.10



14. I describe the following disorders of the skin, athlete’s foot, boils, cold sores, psoriasis, contact dermatitis, and impetigo.


Skin Homeostatic Imbalances §  Burns

§  Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals

§  Associated dangers

§  Dehydration

§  Electrolyte imbalance

§  Circulatory shock due to loss of fluids

§  Bacterial infection


Rule of Nines §  Way to determine the extent of burns

§  Body is divided into 11 areas for quick estimation

§  Each area represents about 9% of total body surface area


Rule of Nines

Figure 4.11a


Severity of Burns §  First-degree burns

§  Only epidermis is damaged

§  Skin is red and swollen

§  Second-degree burns

§  Epidermis and upper dermis are damaged

§  Skin is red with blisters

**1st & 2nd degree burns are partial thickness burns


Severity of Burns §  Third-degree burns (called full thickness burns)

§  Destroys entire skin layer

§  Burn is gray-white or black

§  Regeneration is not possible & skin grafting must be done to cover the underlying exposed tissues


Severity of Burns

Figure 4.11b



15. I can explain the severity between the three different degrees of burns.


Critical Burns §  Burns are considered critical if

§  Over 25% of body has second-degree burns

§  Over 10% of the body has third-degree burns

§  There are third-degree burns of the face, hands, or feet


Skin Cancer §  Cancer—abnormal cell mass

§  Classified two ways

§  Benign

§  Does not spread (encapsulated)

§  Malignant

§  Metastasized (moves/spreads) to other parts of the body

§  Skin cancer is the most common type of cancer


Skin Cancer Types §  Basal cell carcinoma

§  Least malignant

§  Most common type

§  Arises from stratum basale

§  Occurs most on sun-exposed areas of the face

§  Shiny, dome-shaped nodules


Skin Cancer Types

Figure 4.12a


Skin Cancer Types §  Squamous cell carcinoma

§  Metastasizes to lymph nodes if not removed

§  Early removal allows a good chance of cure

§  Believed to be sun-induced

§  Arises from stratum spinosum

§  Appears most often on scalp, ears, dorsal hands & lower lip


Skin Cancer Types

Figure 4.12b


Skin Cancer Types §  Malignant melanoma

§  Pigmented spot or mole

§  Most deadly of skin cancers

§  Cancer of melanocytes

§  Metastasizes rapidly to lymph and blood vessels


Skin Cancer Types

Figure 4.12c



16. I can describe the three different cancers of the skin, squamous cell carcinoma, basal cell carcinoma and malignant melanoma.


ABCD Rule

§  A = Asymmetry §  Two sides of pigmented mole do not match

§  B = Border irregularity §  Borders of mole are not smooth

§  C = Color §  Different colors in pigmented area

§  D = Diameter §  Spot is larger then 6 mm in diameter **E = Elevation above the skin surface



17. I can explain the ABCD rule in determining melanoma.

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