Chapter 5 Openstax Anatomy and Physiology

Chapter 5 Openstax Anatomy and Physiology 3 layers of the skin - ANS epidermis, dermis, and hypodermis Epidermis consists of.. - ANS Keratinized, stratified squamous epithelium Stratum Basale - ANS inner most layer of epidermis, mitosing basal cells (keratinocytes) Stratum Spinosum - ANS layer above stratum basale; keratinocytes produce keratin and glycolipids Stratum Granulosum - ANS layer above stratum spinosum; keratinocytes dying as they rise too far away from difused nutrients Stratum Corneum - ANS outer most layer of the epidermis; dead keratinocytes as layers of keratin and glycolipds Stratum Lucidum - ANS ONLY IN THICK SKIN; sits between granulosum and corneum Keratinocytes - ANS Synthesize keratin for toughness and glycolipids for water proofing Melanocytes - ANS ONLY in stratum basale; synthesize pigment melanin that absorbs ultraviolet radiation to protect DNA of mitosing cells Merkel Cells - ANS ONLY in stratum basale Langerhans cells - ANS macrophages originating in bone marrow, engulf and kill bacteria with lysosomal enzymes Two connective tissue layers - ANS Papillary & reticular Aerolar loos connective tissue - ANS basement membrane for the epidermis blood capillaries - ANS diffuse O2 and nutrients into the epidermisBare nerve endings Meissners corpuscle - ANS sesnses light touch Merkel disc - ANS sit under merkel cell to sense light touch Reticular Layer - ANS site of accessory structures i.e heair follicle, sebaceous gland and sweat glands Hypodermis - ANS connects skin to underlying bones and muscles Subcutaneous Fat - ANS Adipose- for shock absorption, thermal insulation, energy storage.