the skin Flashcards
what is the biggest consequence of losing your skin?
- loose barrier of protection from infection
- loose thermoregulation
- fluid loss
what type of epithelium makes up the epidermis?
stratified squamous keratinised
- designed to reduced impact
what type of cells make up the majority of the epidermis
keratinocytes
what are the layers of the skin
- epidermis
- dermis
- hypodermis
what is the structure of the epidermis
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum Basale
structure of the stratum corneum
- few layers (is thin)
- no limit in amount of dead cells
structure of the stratum lucidum
- only in thick skin
- holed down stratum corneum layers as this is where impact on the skin comes from
structure of the stratum granulosum
- cells is dying, nucleus is broken
- makes granules
structure of the stratum spinosum
- join together and become squamous
structure of the stratum basale
- stem cells of skim
- where the layers of skin originate from
structure of the dermis
- it’s the connective tissue
- has capillaries and the lymph
structure of the hypodermis
- large vessels
- adipose tissue
- fibrous regions forming compartments
what defenses are in the epidermis
- Langerhans dendritic cells in the stratum granulosm
- the first line of defence
- prevents things entering too far into the skin
what holds the epidermis together?
- desmolegens
- they are different between each layer of skin
- takes 60 days to get from the bottom to the top - stratum basale to stratum corneum
what is found in the epidermal transition region (epidermis to dermis)
- keratinocytes of stratum basale (dermal peg and rete ridge)
- tactile epithelial cells
- melanocytes in the stratum basale
what are tactile epithelial cells
- also called Merkel cells
- pale staining
- around cell that binds to free nerve ending to detect pain and itching
what do the melanocytes do
- cell processes fill adjacent cells with melanin
- insert melanin into the epithelial cells (melanin absorbs UV light and protects DNA
- activity of the melanocytes increases means more cells get melanin - changing skin colour
what is impetigo
infection of epidermis only spreading over the skin
what is psoriasis
hyper-proliferation of keratinocytes - can take 7 days for cells to move up to the surface, living cells on top can’t resist impact
what is vitiligo
autoimmune destruction of melanocytes
what are the parts of the dermis
- papillary dermis
- tactile corpuscle
- reticular dermis
- skin dendritic cells
papillary dermis
- small capillaries
- fibroblasts
- some immune cells
- composed of connective tissue
- dermal dendritic cells
- dermal macrophages
- basement membrane - hemi-desmosomes > collagen > elastin
tactile corpuscle
- detects fine touch (vibrations)
- located in dermal pegs
- coated in Schwann cells
reticular dermis
- collagen and elastin
- some immune cells
- larger vessels
- glandular tissue
- merges into the hypodermis
skin DCs
- Dc in epidermis and dermis
- not stationary
- LDC and DDC separated by surface molecules
parts of the hypodermis
- hypodermis (subcutis)
- lamellar (Pacinian) corpuscles
lamellar (Pacinian) corpuscles
- deep in the hypodermis
- very large
- detect deep touch
hair follicles
- start in the hypodermis
- epidermis stretches down coating the entire hair follicle
- sebaceous gland
- arrector pill muscle
what is lost in a first degree burn
layer of the corneum
what is lost in a 2nd degree burn
- loss of epithelium
- burnt off stem cells
- stem cells grow out of the hair follicles to repopulate the skin
what is lost in a 3rd degree burn
- no hair follicles left
- fibroblasts are left to cover over but aren’t able to full cover
- scaring and loss of function of the skin
- can’t bend skin
- loss of sensation
- need a skin graft for new stem cells to stop fluid loss
