Lecture 1 Flashcards
What percent of body weight does skin make up?
16%
How does human skin differ from other mammals?
We traded most of our hair for sweat glands to osmoregulate
What tissue types is skin made up of?
All four
List some functions of the skin (8):
- protect underlying tissues and organs
- excretes waste
- maintain body temp
- produce melanin to protect tissue from UV radiation
- produce keratin ( water repellant + protection)
- synthesise vitamin D3 ( calcium metabolism)
- store lipids in adipocytes in dermis and adipose tissue in subcutaneous tissue
- ## detect touch, pressure, pain, and temp stimuli
What are the 3 main layers of the skin?
- epidermis
- dermis
- hypodermis
What two skin layers make up the cutaneous?
- epidermis
- dermis
What is the epidermis?
Stratified barrier mostly made up of keratinocytes that is avascular.
Are cells in the epidermis dead or alive?
Dead
What is the role of the dermis in respect to the epidermis
Dermis in vascular so provides nutrients to the epidermis
What is contains in the hypodermis that is not found in the epidermis or dermis
Adipose tissue
Name the 6 types of epithelia?
- simple squamous
- simple cuboidal
- simple columnar
- stratified squamous
- stratified cuboidal
- stratified columnar
What type of epithelium is the epidermis made of?
Stratified squamous
Name the 4 layers of the epidermis?
- stratum corneum (horny layer)
- Stratum granulosum ( granular layer)
- stratum spinosum ( spiny layer)
- Stratum basale ( basal layer)
Describe the cells in the stratum corneum layer:
- dried out hard cells without nuclei
Describe the stratum granulosum layer:
- contains granules that promote dehydration of the cell and cross linking of keratin fibre ( killing cell)
- waxy material is secreted into the intercellular spaces
Describe the stratum spinosum layer:
- intercellular bridges called desmosomes link cells together
- cells become increasingly flattened as they move upwards
Describe the Stratum basale layer:
- columnar regenaterive cells
- as the basal cell divides the daughter cells migrates upwards to replenish above layer
What links the epidermis to the dermis?
Hemidesmosome
What is the difference between thick and thin skin?
thick skin has an extra layer the stratum lucidum superficial to stratum granulosum and is responsible for the capability of the skin the stretch and lowers effect of friction on skin
How many layers make up the dermis?
2
What are the names of the layers making up the dermis?
- papillary layer
- reticular layer
What is the main identifying feature of the papillary layer?
- consists of highly vascularised tissues ( for nourishment)
What is the main identifying feature of the reticular layer?
“Mesh-like” structure of collagen and elastin fibres for strength
What is contained in the dermis (generally):
- blood vessels
- lymphatics
- sensory nerve fibres
- accessory fibres
What is the cutaneous plexus:
- network of blood vessels present at the junction of the dermis/ hypodermis
- supplies the hyperdermis and deeper dermis, including the capillaries for hair follicles and sweat glands
What is the Subpapillaries plexus?
- branches from the cutaneous plexus
- lies deep to the papillary layer of the dermis
- network of blood vessels providing oxygen and nutrients to the dermis and epidermis
What is the hypodermis?
the hypodermis is the subcutaneous layer that is not actually considered to be part of the skin. It is dominated by adipocytes that produce subcutaneous fat which stores energy and provides insulation.
What layer of the skin is a common site of injection?
Hypodermis
Describe the main details of a first degree burn: ( layers involved, presentation, blisters?, example, barrier?, time to heal)
- superficial and only involve outer layers of epidermis
- present as red/pink dry and painful
- usually no blisters formed
- example is mild sunburn
- skin remains a functional barrier
- Heal in 3-10 days
Describe the main details of a second degree burn: ( layers involved, presentation, blisters?, example, barrier?, time to heal)
- involve epidermis and varying amounts of dermis
- painful, moist, red, blistered, deeper burns may include whitish waxy areas
- heal in 1-2 weeks or 1 month for deeper burns but require good dressings
- hair follicles and sweat glands may remain intact
- may be loss of sensation and scarring as a result
Describe the main details of a third degree burn: ( layers involved, presentation, blisters?, example, barrier?, time to heal)
- full thickness and extend into subcutaneous tissue and may involve muscle and bone
- various colours from waxy white through to deep red or black
- burns look hard dry and leathery
- no pain as sensory nerve endings are destroyed
- may require skin grafting
- weeks- years to heal
- ## very noticeable scarring
