Amerman Anatomy & Physiology Chapter 5 Integumentary System

Amerman Anatomy & Physiology Chapter 5 Integumentary System two components of cutaneous membrane - ANS 1) epidermis: superficial 2) dermis: deep epidermis - ANS superficial layer made of keratinized, stratified, squamous epithelium, avascular dermis - ANS - deep to epidermis and basement membrane - made of loose connective tissue and dense irregular CT - vascular four accessory structures of skin embedded in cutaneous membrane - ANS 1) sweat glands 2) sebaceous glands 3) hair 4) nails hypodermis - ANS - deep to dermis, also known as superficial fascia or subcutaneous fat - anchors skin to deeper structures - has blood vessels five main functions of integumentary system - ANS 1) protection 2) sensation 3) thermoregulation 4) excretion 5) vitamin d synthesis four ways in which integumentary system provides protection - ANS 1) durable but flexible, protects from mechanical trauma 2) continuous barrier to invasion by microorganisms and pathogens, contains immune system cells that destroy pathogens 3) provides protection against UV 4) secretes hydrophobic, lipid based chemicals that protect against salt and water to maintain homeostasis acid mantle - ANS acidic pH of skin surface created by sebaceous glands, inhibits pathogen growth how integument functions in sensation - ANS contains sensor receptors that detect stimuli like heat, cold, pain how integument functions in thermoregulation - ANS negative feedback loops maintain stable internal temperature sequence of events when body temperature rises above normal range - ANS sequence of events when body temperature drops below normal - ANS vasoconstriction - ANS narrowing of blood vessels to reduce the amount of blood flow and limit the heat lost to the environment vasodilation - ANS response triggered by hypothalamus causing blood vessels to widen and increase the flood flow and increase the heat radiated away location and function of control center - ANS hypothalamus sensory receptors (thermoreceptors) - ANS detect changes in body temperature role of integument in excretion - ANS waste products and toxins mostly through kidneys, but skin plays a role too process for vitamin D synthesis - ANS - precursor cholesterol molecule converted to cholecaliferol when epidermis is exposed to UV - inactive cholecalciferol released to blood then modified by liver and then kidneys to make active calcitriol - calcitriol (active form of vitamin D) required for absorption of calcium ion in small intestine most numerous type of cell in epidermis - ANS keratinocytes function of keratinocytes - ANS manufacture keratin two ways keratinocytes make epidermis less susceptible to mechanical trauma - ANS 1) they make keratin, a strong protein 2) they're linked by desmosomes