physiology&histology of skin Flashcards
chapter 3
5 fun facts about skin
skin accounts for about 15% of body weight
every minute your body sheds 30 000 dead skin cells
everyone has the same amount of melanocytes
thickest of soles of feet
thinnest on eyelid
bonus: scar tissue lacks hair and sweat glands
why should aestheticians have a thorough understanding of the physiology and histology of the skin?
to understand how all body systems work together,
learn and understand the aging process, hormonal influences, and nutrition on skin health.
so much to study as our largest organ
what are the building blocks of body tissue?
proteins (which are made of amino acids, which form peptides)
appendages of the skin (most accessory organs)
hair, nails, sweat glands, oil glands
4 things to describe healthy skin
slightly moist, soft, smooth, and slightly acidic (5.5 pH)
what are the 5 functions of skin?
sensation, protection, heat regulation, excretion, absorption
describe sensation:
nerve fibers sense when we are touched: heat, cold, touch, pain, pressure
describe protection
the skin is a thin, strong, protective barrier to outside elements and organisms. includes the acid mantle made of sebum, lipids, sweat, and water.
describe heat regulation
internal thermostat usually 98.6 deg. feh. when the outside temperature changes, the skin automatically adjusts to warm or cool as necessary
describe excretion
sudoriferous glands excrete perspiration
describe secretion
sebum is an oily substance that protects and lubricates the skin and hair. slows down the evaporation of water which would cause dehydration/tewl
describe absorption
the skin selectively absorbs topical products, serums, and creams through the cells, hair follicles, and sebaceous glands
define barrier function
is the skin’s mechanism that protects us from irritation and intercellular transepidermal water loss, includes the acid mantle
what are the three layers of the skin?
subcutaneous, dermis, epidermis
what is subcutaneous tissue?
aka adipose tissue, 80% fat, creates protective cushion that gives contour and smoothness to the body, and is a source of energy for the body.
what is the dermis and what are the layers?
derma/corium/cutis/true skin is the support layer of connective tissues above the subcutaneous tissue. reticular and papillary layer.
the denser, deeper layer of the dermis, is comprised mainly of collagen and elastin
reticular layer of the dermis:
upper part of the dermis; connects the dermis to the epidermis
papillary layer of the dermis; dermal/epidermal junction
what are glycosaminoglycans?
large protein molecules and water binding substances found between fibres if the dermis, work to maintain and support collagen and elastin retain moisture.
what are the 5 layers of the epidermis?
stratum germinativum
stratum spinous
stratum granulosum
stratum lucidum
stratum corneum
what is composed of keratin and make up 95% of the epidermis?
keratinocytes
what is the fibrous protein that provides resiliency and protection
keratin
what is known as the basement, basal layer. in this active layer mitosis is happening consistently making new stem cells
germinativum layer
in which layer do cells continue to divide and change shape, enzymes create lipids and proteins. cell appendages that resemble spines help hold cells together. largest layer of the epidermis.
stratum spinosum, spiny layer
keratin filaments; the protein bonds that create the junction between the cells. they strengthen the epidermis and assist w intercellular communication
desmosomes
what is the second kind of cells found in the spiny/spinosum layer which help the body from infections by identifying foreign material?
langerhans immune cells