skin and mucous Flashcards
what are the functions of skin?
- protection
- thermoregulation
- water regulation
- sensation
- absorption
- storage and synthesis
what does the skin protect from?
the external environment- pathogens, uv, injury etc.
how does the skin thermoregulate?
via blood vessels, sweating etc.
how does the skin regulate water?
it prevents loss of moisture
how is the skin involved with sensation?
touch, temperature, pain etc.
how is the skin involved with absorption?
drug delivery
how is the skin involved in storage and synthesis?
vit D, fats, salt, water and glucose
what are the layers of the skin?
- epidermis
- subcutaneous layer
- dermis
what structures are associated with the skin?
- nails
- sweat glands
- sebaceous glands
- hair follicles
- blood vessels
- nerves
what is the structure of the epidermis?
- stratified squamous epithelium
- keratinised
- layers
- flat cells
- basic tissue type
- no blood vessels
- 4-5 layers
what are the layers of the epidermis?
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
- dermis
what layer of the epidermis is the granular layer?
the stratum granulosum
what layer of the epidermis is the prickle cell layer?
the stratum spinosum
what are the cells found in the epidermis?
- desmosomes
- keratinocytes
- langerhan’s cells
- merkel cells
- melanocytes
what makes up 95% of the epidermis?
keratinocytes
what is the function of langerhan’s cells?
antigen-presenting
what is the function of merkel cells?
sensory receptors
what is the function of melanocytes?
produce melanin
describe thick skin structure
(not based on thickness, based on presence of stratum lucidum)
- stratum lucidum present
- thicker stratum corneum (prevents unwanted materials from entering, and excessive loss of water from exiting the body)
- found on palms of hands and soles of feet (areas of high friction and abrasion)
describe thin skin structure
- no stratum lucidum
- all of the epidermis layers are thinner
- covers all other areas of the body
what is the dermis?
strong flexible connective tissue layer which is rich in collagen/elastin fibres
what does the dermis contain?
- fibroblasts (produce collagen)
- macrophages
- adipocytes
- nerve endings
- blood vessels
- glands
- smooth muscle
- lymphatics
- hair follicles
what are the two layers of the dermis?
- papillary layer
- recticular layer
describe the papillary layer of the dermis
- top layer of the dermis
- thinner layer of the two
- has papillae (ridges) projecting into epidermis
- richly supplied with capillaries
describe the recticular layer of the dermis
- bottom layer of the dermis
- thicker layer of the two
- fewer capillaries than the dermis
how does acne arise?
over production of sebum from a change of hormones/diet/presence of bacteria/smoking
what is psoriasis?
- skin condition
- causes flakey patches
- autoimmune
- rapid turnover of epithelial cells
- causes skin thickening
- more blood underlying
- affects scalp, knees and elbows
what is pemphigus?
- rare skin disorder
- causes blistering of the skin and mucous membrane
- autoimmune
- desmoglien attaches and attacks antibodies
what is vitiligo?
- skin disorder
- loss of skin pigment
- antibodies form against melanocytes in the basal layer or melanocyte stimulating hormone
what are the two types of skin cancer?
- squamous cell carcinoma
- basal cell carcinoma
how can skin cancer arise?
- keratinocytes (specialised epithelial cells) in the epidermis grow out of control which forms a tumour
- can occur on any part of skin on the body
- commonly found in areas of sun damage
- appears as scaly/crusty areas of skin with red inflammation
what are malignant melanomas?
- skin cancer
- prevented by avoiding over exposure to sun/ sun-beds, checking moles growing/changing
- 5th most common UK cancer
- risk factors include: UV, moles (collection of melanocytes), fair skin, sunburn and family history
what is a mucous membrane?
- a specialised epithelial lining
- it produces a lubricating fluid containing mucin (sticky protein) which traps dirt and microbes
- it is the body”s first stage of protection
what are the functions of the mucous membrane?
- protection (from trauma/pathogens)
- in oral cavity, the mucous membrane protects the underlying tissue
- secretion- mucous secretions
- the stomach has specific acid secretions and digestive enzyme secretions
- absorption- drug delivery
- mucous membrane in the GIT absorb water and nutrients
- sensation- receptors in oral mucosa
where is the mucous membrane found?
The moist, inner lining of some organs and body cavities (such as the nose, mouth, lungs, and stomach).
what is the mucous membrane’s basic structure?
- epithelium stratified squamous and basement membrane
- lamina propria mucosa- supportive areolar layer between the mucous membrane epithelium and its basement membrane
what is another word for mucous membrane?
mucosa
what is the structure of the lamina propria?
- cells
*fibroblasts (collagen producing)
*immune cells
*lymph modules
*virtually lacking adipocytes - ECM- collagen and elastin fibres
what is the trachea made up of?
ciliated psueudostratified epithelium and an elastic, fibre-rich lamina propira
what is the small intestine made up of?
absorptive epithelium and goblet cells
describe the mucous membrane in the oral cavity
(oral mucosa)
- stratified squamous epithelium
- lamina propria
- types:
*lining mucosa- soft palate (non-keratinised)
*masticatory mucosa- hard palate (keratinised)
*gustatory mucosa- dorsal surface of tongue, tastebuds
what does orthokeratosis mean?
remains of nuclei
what does papakeratosis mean
no nuclei
what is the function of the oral mucosa?
- protection (from pathogens and trauma- acids, chemicals, smoking, food etc.)
- sensation (receptors for taste)
- secretion (minor salivary glands which maintain moisture)
- absorption (drug delivery)
why are elderly more susceptible to oral cancer?
because the oral mucosa thins overtime
