Chpt 5 integumentary system Flashcards
Explain the functions of the skin. (6)
Protection: Acts as a barrier against pathogens, harmful chemicals, and mechanical injury.
Excretion: Removes waste products through sweat.
Temperature Regulation: Controls heat loss via sweat production and blood vessel dilation or constriction.
Sensory Perception: Contains nerve receptors that detect touch, temperature, and pain.
Synthesis of Vitamin D: Produces vitamin D when exposed to sunlight, aiding in calcium absorption.
Absorption: Allows for the absorption of certain substances, including medications.
Describe the structures and functions of the two tissue layers forming the skin.
Epidermis: The outer layer made of keratinized stratified squamous epithelium, lacking blood vessels. It is composed of four layers in thin skin and five layers in thick skin. The basal layer (stratum basale) continuously produces new cells that migrate to the surface, undergo keratinization, and are eventually shed. The epidermis contains:
Keratinocytes (produce keratin for protection)
Melanocytes (produce melanin for pigmentation and UV protection)
Dendritic cells (immune response)
Tactile epithelial cells (touch receptors)
Dermis: The inner layer consisting of:
Papillary layer (loose connective tissue, blood vessels, nerves, sensory receptors, and dermal papillae that form fingerprints)
Reticular layer (dense irregular connective tissue with collagen and elastic fibers for strength and elasticity)
Subcutaneous Tissue: Located beneath the dermis, it attaches skin to underlying structures, stores fat, and absorbs impact.
Describe how skin color is determined.
Skin color is inherited and results from the presence of three pigments:
Hemoglobin: Found in dermal blood vessels, giving skin a reddish tint.
Carotene: Deposited in the epidermis and subcutaneous tissue, contributing a yellowish hue.
Melanin: A brown-black pigment produced by melanocytes in the stratum basale, incorporated into keratinocytes.
Explain how the skin provides protection from ultraviolet radiation.
Melanocytes in the epidermis produce melanin, which absorbs UV radiation and reduces DNA damage, protecting against sunburn and skin cancer.
Describe the anatomy and function of each accessory structure formed by the epidermis.
Hair: Made of keratinized epidermal cells; provides insulation and protection.
Arrector Pili Muscle: Causes hair to stand up when contracted, trapping heat.
Sebaceous Glands: Produce sebum to lubricate hair and skin.
Sweat Glands:
Eccrine glands: Found all over the body, secrete watery sweat to cool the skin and remove waste.
Apocrine glands: Located in axillary and genital regions, produce thick sweat containing pheromones.
Ceruminous Glands: Found in the external ear, secrete cerumen (earwax) for protection.
Nails: Formed of keratinized cells, protect the tips of fingers and toes.
Describe how the skin aids in the regulation of body temperature.
When body temperature rises: Blood vessels in the dermis dilate to increase heat loss, and sweat is produced. Sweat evaporation enhances cooling.
When body temperature drops: Blood vessels constrict to reduce heat loss, arrector pili muscles contract (goosebumps), and shivering generates heat.
Contrast hypothermia and hyperthermia, including the causes and bodily effects of each.
Hypothermia: Occurs when body temperature drops below normal. Causes shivering, slowed metabolism, confusion, and potential organ failure.
Hyperthermia: Results from excessive heat. Causes dizziness, nausea, rapid heartbeat, and, in extreme cases, heat stroke.
Describe the common infectious and noninfectious disorders of the skin.
Infectious Disorders:
Acne: Inflammation of sebaceous glands.
Athlete’s Foot: Fungal infection causing itching and peeling.
Boils: Bacterial infection of hair follicles.
Fever Blisters: Caused by herpes simplex virus.
Impetigo: Bacterial infection causing blisters and sores.
Noninfectious Disorders:
Alopecia: Hair loss.
Bed Bugs: Parasitic skin irritation.
Bedsores: Skin ulcers from prolonged pressure.
Blisters: Fluid-filled skin pockets from friction or burns.
Burns: Skin damage from heat or chemicals.
Calluses and Corns: Thickened skin from repeated friction.
Common Moles: Clusters of pigmented cells.
Dandruff: Shedding of dead skin cells from the scalp.
Eczema: Inflammatory skin condition causing itching and redness.
Hives: Allergic reaction causing red, raised welts.
Psoriasis: Autoimmune condition causing rapid skin cell turnover, leading to scaly patches.
