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Chapter 4. Guiding Question: What are the components of the integumentary system?

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Presentation on theme: "Chapter 4. Guiding Question: What are the components of the integumentary system?"— Presentation transcript:

1 Chapter 4

2 Guiding Question: What are the components of the integumentary system?

3  Not just a covering for the body Largest organ  Blood vessels, connective tissue structures, glands, hair, nails, nerves, skin Plays a large role in homeostasis  Has inherent and adaptive characteristics Calluses Darken in sun Elasticity Sensitive to moisture

4 Guiding Questions: 1.) What embryonic layers form the integumentary system? 2.) Describe the development of the integumentary system. 3.) What are some various causes of hair loss?

5  Ectoderm & mesoderm in origin  Skin is a complex structure  Many things can go wrong in its development  Let’s make a timeline!

6  Simple ectoderm epithelium over mesenchyme outermost layer of skin form a simple squamous tissue that becomes stratified as the embryo develops from the ectoderm

7  Deeper parts of skin begin to form from mesoderm (dermis, hypodermis)

8  8-9 wks: mesenchyme begins to mature and fibroblasts form, and dents occur in the upper squamous layer  form lanugo.

9 10 weeks: ridges form between the outer and inner layers of skin—so don’t separate when rubbed 11 weeks: small nails at the tips of fingers & toes, followed by development of special blood vessels in the layers of skin  Angiogenic factors stimulate the production of these vessels

10 20 weeks: Glandular structures form  Inward growths of the outermost squamous cell layer  Will eventually produce oils and sweat 25 weeks: Pigmentation

11 About 26 weeks: melanoblasts mature into melanocytes (build pigments) nervous tissue structures develop


13  What are the three major layers of the skin?  Describe the basic characteristics of the three major layers of the skin (recommend a chart)

14 1. Epidermis: Epithelial  Superficial & thinnest  cells are very tightly packed  New cells produced here 2. Dermis: Connective  Deep to epidermis & thick  Primarily connective tissue  loosely packed cells 3. Subcutaneous/Hypodermis (adipose tissue) Deep to the skin/dermis Layer of insulation


16  Outermost: Stratum corneum Dry, dead, keratin filled (waterproof, tough)  Stratum Granulosum Waterproof Contains granules of keratin  Stratum Spinosum “Prickly” layer Contains Langerhans cells (fight infections)

17  Stratum germinativum / basale Cells undergoing mitosis, move up and horizontally Contains malpighian layer or “Pigment layer” with melanosomes Forms epidermal ridges


19 Stratum corneum: Dead squamous cells Stratum corneum: Dead squamous cells Stratum Germinativum/ Basale: dividing columnar cells Stratum Spinosum: cuboidal cells, desmosomes hold together >> spiny Stratum Spinosum: cuboidal cells, desmosomes hold together >> spiny Stratum granulosum: Granules with lipids and keratin – forms waterproof layer Stratum granulosum: Granules with lipids and keratin – forms waterproof layer Stratum lucidum: (only in thick skin); oils from lysosome disintegration

20  Specialized cells within epidermis: Melanocytes  Melanin: pigment, inc. w/sun (protection) Keratinocytes  Keratin: tough, waterproof material  Abrasion resistance for cells Langerhans cells  Immune response against microbes invading the skin

21 Second layer of the skin

22  Collagen, elastin fibers– scattered

23  Dense, irregular connective tissue  Loose, connective tissue = areolar connective tissue Binds blood vessels, membranes, muscles, nerves, and skin to other structures Contains extensive meshwork of protein fibers (fibroblasts)  Involved primarily in body growth  Connective tissue maintenance  Wound healing

24 Dermal papillae: parallel rows of peg-like projections Unique to each individual; akin to fingerprints

25 Third layer of the skin

26  Third, innermost layer of the skin  Thickness, composition vary throughout body  Composed of loosely-arranged elastic fibers that anchor the skin to the fascia Sheet of fibrous connective tissue Covers muscles, skull bones, some organs  Large amount of adipose (fat) cells  Large network of blood vessels, capillaries, lymphatic vessels

27  Glands  Nerves  Nails  Hair

28  3 Types: Ceruminous Sebaceous Sweat/sudoriferous

29  Produce cerumen (waxy secretion), an apocrine secretion (ear wax)  Found lining ear canal

30  Holocrine glands (secrete whole dead cells)  Produce, store abundance of fat, which burst and die, releasing sebum

31  Sebaceous Glands Secrete oil (sebum) for hair/skin Ducts open into hair follicles Accumulated sebum enlarges ducts>>white heads Darkened sebum>>black head

32  Sudoriferous/Sweat Glands Eccrine Glands  Widespread  Watery Fluid  Separate pore Apocrine Glands  Armpits/Genitals  Thick/milky fluid  Secrete into hair follicle

33  Aprocrine Odorous, sweat-like material in armpits, navel, groin region, areolae Inactive until puberty Contain pheromones Broken down by bacteria, creating odor  Eccrine Skin of armpits, foreheads, palms, soles Mostly secrete water, w/ salts, organic compounds, and wastes (like urea) Microbes feed on these as well, producing odors


35  Specialized structures: Hair follicle: cells of the epidermis extend into the dermis forming a small tube Hair bulb: base of the follicle Hair papilla: cluster of cells (live); nourished by BV’s Root: part of hair hidden in follicle Shaft: visible part of hair

36  Sensory receptors Communicate information from environment to the body Found in all skin layers  Mostly in innermost regions, fascia  Free nerve endings/Nociceptor Pain-sensing structures Found throughout inner part of epidermis Detect chemicals associated with tissue damage and bleeding


38  Merkel cells Sensitive to gentle physical sensation Found in stratum germinativum Abundant in fingertips

39  Elongated, club-shaped pile of connective tissue  Upper region of dermis (in dermal papilla)  Respond to touch

40  Look like onions  Deeper parts of hypodermis  Hard pressure, vibrations

41  Pressure, constant touch

42  Sensitive touch receptors  Found mostly in mucous membrane of mouth


44  Merely a keratin secretion  Nail root Lies beneath skin-nail fold Grow back as long as nail root and skin-nail fold are not severely damaged Grow 1/8 in per month

45  Modified stratum corneum  Grows from an individual follicle buried in subcutaneous layer



48  Specialized Structures (continued) Arrector pili: tiny, smooth muscle attached to base of dermal papillae & side of hair follicle  Contracts: pulls on both simultaneously>>goose bumps



51  What are the major roles of the integumentary system?  What are “commensals”?  How does heat regulation in the skin work?  How does sensation in the skin work?  Briefly describe the three classifications of burns

52  Protection  Heat regulation  Sensation  Waste excretion

53  The skin protects from: Chemical Damage  Can break down connections between cells  Can disintegrate cells  Sweat dilutes & neutralizes  Cerumen and sebum are oily barriers  Repels water  Repels dangerous chemicals that are dissolved in water  Prevents water from escaping the body through the skin.

54  The skin protects from: Mechanical Damage  Any type of force that can compress, erode, stretch or tear the skin.  Loose connective tissue = flexibility  Shedding stratum corneum = reduce erosion  Calluses, adipose tissue and reticular fibers = shock absorption to minimize compression damage

55  The skin protects from Microorganism damage  Produce destructive secretions in sebum / sweat  Kept in check by chemicals that benefit commensals— ”good” bacteria and yeast that reduce the chance that harmful bacteria will survive on the skin.  Shedding of stratum corneum removes microorganisms

56  The body’s ability to maintain a constant internal temperature (98.6F) Blood vessels contract / expand Evaporation of the sweat from the surface Adipose tissue is a natural “blanket”

57  Sensation: received stimuli from the environment which is interpreted in a way that the brain can comprehend Done by sensory nerves in the skin Cold, heat, injury, pressure, stretching, touch Transducers: nerve cells that convert various environmental messages into body signals.

58  Eccrine sweat glands Removes urea, organic chemicals, and excess salts Not as efficient as the Excretory System  Other functions Vitamin D production when exposed to sunlight Predictor of a person’s health

59  Skin loses ability to maintain homeostasis locally and for the whole body  Sun, cooking, acids, bases, corrosive chemicals, electricity, fires, and steam rooms  Damage the skin differently  Severity of burn is based on the extent of the skin damage.

60  Reddening, swelling  Superficial damage  Steam, sun


62  Damage to Strata spinosum & basale  Blisters, reddening, swelling and fluid build up under the epidermis


64  Entire epidermis affected, could be missing so stratum basale not available  Damage to dermis: nerve cell loss  Pain registers b/c histamine from immune system is released in response to the damage.  Susceptible to dehydration, loss of body heat, and infection


66  Skin entirely damaged; bone, muscle underlying skin damaged as well.  (Too graphic to show)

67  Guiding Questions: What are the three major categories of disease in the integumentary system? What are the various types of degenerative skin disorders? Genetic skin disorders? Infectious skin disorders?

68  Degenerative Progressive deterioration of tissue, environmental or physical stress  Genetic Mutations  Infectious Microorganisms that damage tissues and organs

69  Solar lentigene People in their 30s w/ overexposure  Dermatitis Cosmetics Facial cleansers Toners Can accelerate skin aging

70  Skin Cancer Underlying genetic component—precancerous genes If damaged, genes cause abnormal divisions of cells Sun exposure  Irregularly shaped black or brown spots that can develop into open sores Injury deep in the skin  Discolored blisters or sores


72  Moles: flat squamous cell tumors  Skin tags: soft knobby tumors that grow out of skin  Seborrheic keratosis: Black to brown growth on face or body that creates a greasy, rough appearance to the skin  Sebaceous hyperplasia: caused by oil glands, small yellow bumps with an opening in the middle  Syringomas: sweat-gland duct tumor, small lumps on the cheeks and eyelids  Lipomas: fat cell tumor, don’t cause problems normally


74  Acne: stimulated by hormonal changes that cause and increase in sebum around the hair follicles. Furuncle or boil: a buildup of dead cells and blood components caused by the inflammation of hair follicles. Cysts or nodules: a sack-like structure filled with a fluid or semi-solid Bacteria that feed on the acne pimple produce chemicals that aggravate acne

75  Psoriasis Increased amt of skin cell production Causes a build up of thick scales on skin. Unsightly, inflamed, painful, swollen  Birthmarks Port wine: begins at birth and grows, can bleed Spider veins: central blood vessel with smaller vessels branching from it Strawberry hemangiomas: enlarged blood vessels

76  Vitiligo Michael Jackson White spots—hypopigmentation Reduced melanocytes  Albinism No melanin production in the eyes, hair or skin  Melasma Brown patches on both sides of the face Symmetrical Does not completely disappear

77  Staphylococcus aureus (bacteria) destructive secretions that erodes and inflame the skin Impetigo, SSSS, folliculitis  Candida albicans (fungus) Yeast in digestive system and female reproductive tract infect skin when immune system is compromised Degrade tissue and cause inflammation

78  More fungal infections = dermatophytes Eat keratin-rich materials: hair, nails, and outer layers of epidermis Itching, hair loss, deformation of nails Ringworm (aka tinea)  Contracted from furry pets  Spread from one person to another through contact via clothes and skin  Related to athlete’s foot or jock itch

79  Warts (virus) 60 types HPV (human papilloma virus)  Incurable  Removal procedure  Protists Exotic tropical diseases that are spread by insect bites. Can cause severe bodily damage if spread to internal organs

80  Arthropods Insects with exoskeletons, segmented bodies, jointed limbs Follicle mite—undetected until inflammation of eyelash follicle occurs Lice—blood sucking insects that irritate skin and spread infection as they feed

81  Guiding Questions What are “intrinsic” factors? How can they affect the skin’s aging? What kinds of extrinsic factors can affect skin aging? How does lifestyle accelerate skin aging?

82  Extrinsic Also external aging Environmental factors: disease, pollution, sun  Intrinsic Natural maturation Also internal aging Accelerated by stress—pathology of other organ systems or environmental interactions

83  Characteristics of skin aging Loss of head hair Graying and whitening of hair Excessive growth of body and facial hair Wrinkling Drying of the skin due to diminished oil secretion Skin sagging due to muscle atrophy Regular irritation due to microbial population changes on the skin

84  Impossible to stop Natural decline of cells Can be slowed by living in a mild environment Elastin is naturally degraded by the dermis and subcutaneous layers  Makes the skin less flexible, thinner, more brittle  Decrease in blood flow slows cell division in basale & causes thinning of the epidermis  More difficult to repair skin damage  People with vascular diseases exhibit premature aging

85  Decrease in melanocytes, nerves More susceptible to environmental damage Older skin can’t protect from UV and has difficulty registering injury.  Susceptible to DNA damage Oxidizing chemicals and sunlight Cause cancers and tumors

86  How to slow… Diet, reducing exposure to UV, avoiding skin irritation, not smoking, protecting from air pollutants  Smoking reduces blood flow to skin  Can’t heal  Decreases ability to maintain body’s temp  Skin needling  Promotes growth and swelling in wrinkled depression areas  Makes skin smooth for a while Take care of skin at a young age…difficult to reverse skin aging once the damage is done

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