Integumentary System PDF Oct 7, 2024

Describe the Structures and Functions of the Integumentary System Dr. Randy Brilz...

Describe the Structures and Functions of the Integumentary System Dr. Randy Brilz DEHY 105 Botox As a Dental Treatment Oct 7, 2024  Aka – skin Aka – cutaneous membrane Largest organ of the body Composed of epithelial tissue, connective tissue, Source: http://www.listoid.com/list/101 and accessory organs Helps maintain homeostasis Integument Layers of the Integument 2 distinct layers: Epidermis – outer Dermis - inner  Subcutaneous layer (Hypodermis): Layer beneath the skin Not part of the skin Loose connective tissue & adipose tissue Layers of the Integument  Keratinized stratified squamous epithelium Avascular Composed of 5 layers Stratum basale Deepest layer Contains cuboidal to columnar cells Mitosis occurs here Cells: Stem cells, keratinocytes (keratin), melanocytes (melanin), tactile cells - sensory Epidermis  Stratum spinosum Newest formed layer of cells Predominantly keratinocytes & dendritic cells Stratum granulosum Keratinization occurs here Keratin = tough waterproof protein Cells die Epidermis  Stratum lucidum Layer only in thick skin Palms & soles Protects from UV damage Stratum corneum Exposed surface Varies in size It takes 7-10 days for a cell to move from the stratum basale to the stratum corneum Epidermis Thin vs Thick Skin Epidermal Layers  Cells die and Older cells pushed become hardened toward the surface & flattened Keratinization Cells fill with On all exposed protein keratin skin surfaces Water resistant EXCEPT the eye  Influenced by carotene, melanin and hemoglobin Melanocytes produce pigment melanin Melanin production varies genetically Skin Color All have SAME amount of melanocytes, but genetically produce DIFFERENT amounts and color of melanin UV light stimulates melanin production Melanin protects skin from UV damage Freckles, moles High concentration of melanin Melanocytes  Vitamin D Epidermis produces vitamin D3 (cholecalciferol) in response to sun Absorbed by blood vessels in dermis Goes to liver then kidney Converted to calcitriol – active form Increases absorption of calcium & phosphate Healthy bones and teeth 10-15 min. sun / day  Binds epidermis to underlying tissues Vascular Nourishes itself & epidermis above 2 layers Papillary layer Areolar connective tissue Dermal papillae Reticular layer Dense irregular connective tissue Collagen & elastic fibers Dermis Epidermal Ridges/Dermal Papillae Anchor epidermis to dermis Epidermal ridges toward the dermis Dermal papillae toward the epidermis  Dermis Highly vascular Nourishes epidermis Helps control body temperature via blood vessels Innervation Sensory receptors - Pressure, touch, temperature, pain Control gland secretions Control blood flow Anatomical Cleavage Lines also known as Langer’s Lines Langer’s lines are patterns in the skin that correspond to natural orientation of collagen fibers in the dermis. They are important because they reflect the direction in which the skin is most elastic and resistant to being stretched  AKA hypodermis Composed of Areolar connective tissue aAdipose connective tissue NOT part of the integument Storage site for adipose cells Good injection site Subcutaneous Layer  Functions: Stabilizes & joins skin to tissues below Allows separate movement Insulation to conserve heat Shock absorber Nourishment via blood vessels Subcutaneous Layer  Functions of the Integumentary System Protective covering From injury, toxins, temp extremes, UV rays Retards H2O loss/gain Metabolic regulation Vitamin D3 synthesis Secretion & absorption Immune function Aids in regulation of body temperature Sensory reception Source: http://www.listoid.com/list/101 Integument Functions  How Skin form Influences its Function The Skin is composed of both an epidermis which is multiple layers of keratinized well-vascularized areolar and dense irregular connective tissue Together the epidermis and the dermis serve several functions: a)protection from the external environment b) Prevention of water loss and water gain c) Vitamin D synthesis d) Secretion e) absorption f) Temperature regulation g) immune function h) Sensory reception  a. Typically the skin thins and Q: Which of increases the risk of infection. these statements b. There can be as much as a would be 75% decrease in vitamin D production. consistent with facts about the c. Immune system function usually declines. skin of an elderly person? d. All of the above usually are characteristics of the elderly. The Answer is “D” Q: Some criminals sand the tips of their fingers as not to leave recognizable fingerprints. Would this practice permanently remove fingerprints? Why or why not? a. Yes, because the b. No, because the dermal papillae die if original ridge pattern exposed. regenerates. c. Yes, because the d. No, but completely stratum basale different ridge thickens, hiding the patterns will appear ridge patterns. with regrowth. The Answer is “B” To permanently damage fingerprints one would have to damage the dermal papillae, which are located about 1-2 mm below the skin’s surface. Even with significant damage, new growth may still show remnants of the original pattern. Q: Why does swimming in fresh water for an extended period cause epidermal swelling? a. Fresh water is hypotonic to skin cells and moves in by osmosis. b. Fresh water is hypertonic to skin cells and moves in by osmosis. c. Stratum basale divides rapidly in fresh water. d. Stratum corneum builds up in fresh water.  The Answer is “A” Fresh water is hypotonic to skin cells. This means it has a lower concentration of solutes compared to the fluids inside our skin cells. As a result water moves into the cells causing them to swell.  a. Sunlight stimulates erythrocyte production in skin. Q: Why does the skin of a b. Sunlight bleaches fair skin, fair-skinned allowing blood to be seen. person appear red c. It’s due to the vasodilation during of superficial blood vessels in exercise in the skin. hot weather? d. Heat stimulates cutaneous blood vessels causing leaks.  The Answer is “c” The body tries to cool down during exercise in hot weather by vasodilating (widening them) the blood vessels to cool down the body, this releases heat and gives the skin a reddish appearance. Q: Where would a subcutaneous injection be made in the skin? a. Reticular layer of dermis b. Epidermis c. Papillary layer of dermis d. Hypodermis layer  The Answer is “D” The subcutaneous layer of skin is also called the Hypodermis…. Hypo meaning below and dermis meaning the dermis layer of the skin “below the dermis” This layer of tissue contains the fat and connective tissue which is ideal for slow sustained absorption of medication. Subcutaneous is the same as the Hypodermis layer of skin. It is the deepest layer of skin.  a. subcutaneous layer b. hypodermis and and hypodermic layer; subcutaneous layer; elastic tissue and areolar and adipose collagen; stretching and tissue; stabilizing recoil position of the skin c. hypodermis and deep fascia; adipose d. both B and C and dense irregular tissue; heat production Q: Two terms for the connective tissue below the dermis are ___. It is made of ___ and its functions include ___.  The Answer is “B” Adipose tissue is made up of fat cells and areolar tissue is a loose contective tissue. It is soft and flexible, containing a gel-like matrix with collagen, elastic and reticular fibers to provide support and flexibility.  Nails Hair Accessory Hair follicles Structures of the Skin Exocrine glands Sweat glands Sebaceous glands Other glands  Epidermal modifications of stratum corneum Provide protection for Nails fingers & toes Contain keratin Harder than the epidermis and hair follicles Cuticle (‘little skin’) Small extension at the tip of proximal nail fold Lunula Whitish area of the proximal end of the nail Hair & Hair Follicles Present on all skin Palms, soles, lips, nipple & surfaces parts of external genitalia except: Protect Facial expression Insulate Function Guard openings to: Be sensitive to touch Visual identification Chemical signalling Hair & Hair Follicles Hair develops from epidermal cells at the base of a depression in the dermis called the hair follicle Hair & Hair Follicles Hair follicle Wrapped in a dense connective tissue sheath with the base surrounded by sensory nerves Hair root Lower part of hair attached to integument Hair shaft Projects above skin surface Composed of keratinized epidermal cells Keratin Added as hair is produced Hair & Hair Follicles Arrector pili muscle Attached to hair follicle Contracts & causes hair to stand up (“goose bumps”) Reacts to cold & fear  2 most common types of exocrine glands in the integument are: Exocrine Sweat glands Glands Sebaceous glands  2 types of sweat Both have ducts glands: Merocrine Transport (eccrine) secretions to the Apocrine surface of the epidermis from the dermis via a sweat pore Sweat Glands Merocrine Sweat Glands Also called eccrine sweat glands Most numerous Most common on palms and soles Function throughout life Secrete clear sweat Made of water, salts and wastes Involved in thermoregulation (sensible perspiration) Help to control body temperature Apocrine Sweat Glands Secrete viscous secretions with an odor (pheromones) Secrete through a duct into hair follicles Begin to function at puberty Secrete into hair follicles in axilla, nipple, pubic region, anal region Sebaceous Glands Exocrine glands secrete sebum into hair follicles and onto hair Activated at puberty Sebum Oily substance Lubricates and protects hair & skin Inhibits bacteria Contains lipids and other substances Other Integumentary Glands Ceruminous glands Mammary glands Modified sweat Structurally similar to glands in the ear canal apocrine sweat glands Produce cerumen Produce milk (wax) Lubricates ear canal, eardrum and traps foreign particles Q. What are the functions of sebaceous secretions? a. They inhibit the growth of bacteria. b. The sebum lubricates and conditions the surrounding skin. c. They lubricate and protect the keratin of the hair shaft. d. All of the above The Answer is “D” Q. Deodorants are used to mask the effects of secretions from which type of skin gland? a. Ceruminous glands b. Apocrine sweat glands c. Merocrine sweat glands d. Mammary glands  The Answer is “B” Deodorants are used to mask the odor caused by secretions from Apocrine Sweat Glands which are found in areas like the armpits and groin. The secretions are initially odorless but can develop an odor when broken down by bacteria on the skin. Q. Which type of skin glands are most affected by hormonal changes that occur during puberty? a. Ceruminous glands and sebaceous glands b. Sebaceous glands and apocrine sweat glands c. Merocrine sweat glands and mammary glands d. Merocrine sweat glands and sebaceous glands  The Answer is “B” These glands are significantly affected by hormonal changes during puberty  Repetitive mechanical stress to the integument stimulates thickening of the epidermis (mitosis) Damaged tissues have 2 repair pathways Complete regeneration of damaged and dead cells with the identical cell Repair and type Regeneration Restorative to organ function Scar tissue formation (fibrosis) – repair of damaged cells with fibroblasts and collagen Structural restoration is possible with loss of functionality Both pathways may occur to repair an injury  Repair and Regeneration Stages in wound healing *results are variable Bleeding into the wound (clotting proteins, WBC’s) Blood clot formation Soft tissue mass formation (granulation) Epithelial regeneration of the epidermis and connective tissue is replaced by fibrosis Abnormal Healing Normal Healing The End