B2: Integumentary system

• The components of the integumentary system include the skin, hair, nails, and exocrine glands.
• The functions of the relevant components of the integumentary system include vitamin D synthesis, protection, cutaneous sensation, and excretion.
• Sweating and shivering have an effect on body temperature.
• Vasoconstriction and vasodilation also have an effect on body temperature.
• Atopic eczema is a condition that causes inflammation of the skin.
• Common treatments for atopic eczema include emollients, topical corticosteroids, dietary changes, and environmental changes such as avoiding pollen, allergens, dust, and behavioural changes like avoiding scratching and certain fabrics, soaps, and detergents.
• Homeostasis is a principle that maintains the functions within the physiological systems which contributes to maintaining a healthy body.
• The principles of homeostasis include receptors, effectors, feedback systems, the role of the nervous system, and the role of the endocrine system.
• There are three main different layers of skin
• The top layer is the epidermis which contains keratin and squamous epithelial cells
• the middle layer is the dermis, it gives the skin its elasticity and ability to stretch
• the bottom layer is the basal layer, it is also referred to as the hypodermis, it stores fat in cells called adipose
• the epidermis is avascular = without blood cells
• keratin in the epidermis protects the body and prevents the skin from becoming waterlogged
• cutaneous senses = five sensations that relay different effects
• tactile = touch and pressure
• thermal = sense of warm and cold
• pruritic = tickle/itch
• modality = positive effect eg. pleasurable stroke
• 5 cutaneous sense = pain, thermal, tactile, pruritic, modality
• the dermis contains the vessels for vasodilation and vasoconstriction
• sudoriferous glands = secrete sweat
• ceruminous glands = secrete wax
• sebaceous glands = secrete oil
• hair follicles are situated in the dermis layer
• the basal layer contains melanocytes which produce the skin colouring/pigment known as melanin and this helps protect the deeper layers of skin from the sun
• the fingernail is made of keratin and it acts as a protective plate and enhances sensation of the fingertip
• UV A = causes ageing and wrinkling and is absorbed by the dermis layer
• UV B = causes burning and is absorbed by the epidermis
• vitamin D synthesis = in sunlight vitamin D3 cholecalciferol is produced
• The liver converts Cholecalciferol to -> Calciol then the kidneys convert it to -> Calcitriol
• The role of calcitriol is it is the catalyst to absorbing calcium
• Hypothermia = drop in body temp, less than 35°C
• Hyperthermia - high body temp 37.5-38°C
• These red blood cells are swollen - hypotonic

  
• These red blood cells are biconcave - isotonic

  
• These red blood cells are crenated - hypertonic

  
• skin diagram

  A) sweat gland

  B) sweat gland

  C) dermis

  D) epidermis

  E) basal layer

  F) hair shaft

  G) sweat pore

  H) hair root

  I) hair follicle

  J) sebaceous gland