Integumentary system lecture

Integumentary system lecture

1. distinct regions

   • epidermis
   • dermis
     • tissue that connects your hide
     • cells present in it are fibroblasts, microphages, mast cells and also WBC's
     • the fibres present in it are collagen which is elastic and reticular
     • there are 2 layers
       • papillary - areolar conncective tissue
       • reticular - network of collagen and reticular fibres

2. functions

   • protection
   • synthesizes with vitamin D with UV
   • homeostasis
   • sensory reception

3. skin colour

   • three pigments
     • melanin - the most important
       • these pass from melanocytes in the form of granules
         • digested by lysosomes cause variation in colour protection from UV light
     • carotene - colour pigment of carrots and yellow vegetables
     • haemoglobin - the pink of light skin

4. disorders

   • burns
     • threat to life
       • 1.loss of body fluids 2.dehydration and fatal circulatory shock  
   • infections
   • skin cancer

5. finger, palm and footprints

   • dermal papillae lie atop dermal ridges
   • they elevate the overlying epidermis into epidermal ridges
   • They are also sweat films because of present sweat pores
   • are genetically determined

6. flexion creases

   • collagen adds strength and resilience
   • elastic fibres stretch recoil

7. fibres

   • collagen - strength and resilience
   • elastic fibres : stretch-recoil; striae: stretch-marks
   • tension lines - directs the bundles of fibres

8. hypodermis

   • below the skin
   • subcutaneous = below skin
   • also called superficial fascia
     • fascia = band, and in anatomy, refers to a sheet of connective tissue
   • fatty tissue which stores fat and anchors skin through areolar tissue and adipose cells

9. skin appendages

   • hair and hair follicles
     • everywhere except palms, soles, nipples and part of genitalia
     • functions of hair
       • warmth
       • sense light touches of skin
       • protection of the scalp
     • parts
       • root embedded in skin
       • shaft projecting above skin
     • three concentric layers
       • medulla which is the core
       • cortex which surrounds the medulla
       • cuticle which are overlapping single layers
     • types of hair follicles
       • vellus: fine short hairs
       • intermediate hairs
       • terminal: longer, courser hair
   • sebaceous (oil) glands
     • entire body except palms and soles
     • produce sebum by holocrine secretion
       • in holocrine secretion, the cell is destroyed through the process of secretion
     • oils and lubricates
   • Sudoiferous (sweat) glands
     • on entire body surface minus the nipple and parts of genitalia
     • prevents overheating and is produced in response to stress and heat
     • types of sweat glands
       • eccrine or merocrine
         • most numerous
         • true sweat: 99% water with some salts and traces of waste
         • open through pores
       • apocrine
         • axillary, anal and genital areas only
         • ducts open into hair follicles
         • the organic molecule in it decomposes with time in the form of odour
         • modified apocrine glands
           • ceruminous - secretes earwax
           • mammary - secretes milk
   • nails
     • hard keratin
     • correspond to hooves and claws
     • grow from the nail matrix

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