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Integumentary System
body exam 1
Question | Answer |
---|---|
Epidermis | protective covering it gets hard & tough (from a protein – keratin) |
Dermis | dense tissue – anchors skin and contains essential structures |
Epidermis & Dermis | are firmly connected - but a burn or friction can cause them to separate (blister) |
Hypodermis | not technically part of skin, but anchors it to underlying organs Acts as a shock absorber and insulates deeper tissue from extreme temperature changes Responsible for curved surfaces |
Subcutaneous Layer | It is a layer of tissue that attaches the skin to underlying tissues and organs |
Hypodermis | houses larger nerves and blood vessels, as well as the fibroblasts, which are responsible for producing collagen. The collagen fibre's are then transported to the dermis to support the skin. |
Hair | is a flexible structure Part enclosed by follicle is the Root Part projecting from surface is the Shaft |
Nails | Produced from Dermal layer Body of a nail is composed of dead, tightly compressed cells packed with keratin For protection and to limit distortion of fingertips |
Arrector Pili Muscle | A small muscle Contracts to make the hair “stand on end” in response to cold or fear Cold - the muscles contract to prevent heat loss by tightening the skin layers Fear - muscles contract to provide a stronger skin surface for protection |
Sebaceous Glands | Ducts usually empty into a hair follicle (some go direct to skin surface) Provide sebum - an oily substance (with fragmented cells) This keeps the hair (mostly hard keratin) lubricated Also lubricates the skin and retards water loss from skin Sebum also c |
Sweat Glands/ Sweat (produced by Eccrine Glands | 2 Types: Eccrine (most numerous) Apocrine (sticky secretions) Clear secretion Primarily water Some salts (NaCl) Vitamin C Traces of metabolic wastes (ammonia, urea, uric acid) Lactic Acid (which attracts mosquitoes) |
Sweat (produced by Apocrine Glands) Sweat (from apocrine glands) | Located in the axilla, groin and around the nipples Coiled glands which communicate with hair follicles Produce sticky, cloudy secretions are controlled by hormones and part of the nervous system Contains all substances of eccrine sweat plus: Fatty acid |
Melanocytes | As the pigment accumulates within Stratum Basale cells - melanin forms protective pigment “umbrella” over nuclei Shields skin DNA from UV damage Freckles and moles seen where melanin is concentrated in one spot |
Keratinocytes (keratin cells) | Tough, fibrous water-repellent protein Abundant in most superficial layerHelps body resist biological, chemical and physical assaults All the cells of the epidermis are replaced every 35 to 45 days |