Skin Flashcards
what is emphysema
where elastin and collagen are destroyed. the air goes into the lung, however it gets stuck and can not come out on its own.
bronchioles collapse due to this, and alveolar walls and capillaries are destroyed. less surface area for O2 diffusion.
results in increased respiratory rate, and hypoxemia can develop in the latter stages of the disease
define metaplasia
transformation of epithelium into a diff type of epithelium
define dysplasia
enlargement of tissue caused by unusual cell proliferations.
define adenocarcinoma
malignant tumour formed from glandular structures in epithelium
what are the functions of skin
protection, thermoregulation, sensation, secretion, vit D synthesis
what are the three layers of skin and their primary structures
epidermis -> keratinocytes
dermis -> dense irregular connective tissue + dermal capillaries
hypodermis -> loose CT and adipose tissue
what type of parenteral route is used for administering vaccines
intramuscular
what are the major functions of the epidermis
maintain fluid and electrolyte balance
protect from UV light
sensory and immune function
what are the 4 layers of the epidermis
stratum corneum, stratum granulosum, stratum spinosum, stratum basale
what type of epithelium makes up the epiderms
stratified squamous epithelium
write about the stratum corneum
thickest layer - 20/30 cells thick. made of dead cells called corneocytes (final stage of keratinocyte differentiation) which contain keratin.
write a bit about stratum granulosum
thin layer, 3-5 keratinocytes thick. granules have glycolipids for waterproofing. cells appear darker in a sample due to the presence of these lipids
write about stratum spinosum
these are keratinocytes linked by desmosomes, and have bundles of prekeratin.
write about stratum basale
layer closest to dermis- has stem cells and younger keratinocytes
what cells may be seen scattered through the epidermis
melanocytes, merkel cell, langerhans cells
write about melanocytes
can be found in the stratum basale. they synthesise melanins which are taken up by nearby keratinocytes. they scavenge free radicals which protect against UV.
write about merkel cells
found in stratum basale, these are sensory receptors for touch.
write about Langerhans’ cells
these are aka epiderma dendritic cells. mainly found in the stratum spinosum. are a type of macrophage. they engulf invading pathogens, and become antigen presenting cells. they can release signalling molecules that attract cells of the immune sys.
write about basal cell carcinoma
most common, least dangerous, slow growing. arises from basal keratinocytes.
write about squamous cell carcinoma
can metastasize to lymph nodes. derived from mature and differentiated keratinocytes.
write about malignant melanoma
most dangerous type, and is developed from melanocytes
what are the two layers of the dermis
papillary dermis and reticular dermis
write about papillary dermis
includes dermal papilla which project into the epidermis. this increased contact area with epidermis preventing detachment
also responsible for dermatoglyphics (fingerprints).
this layer also has capillaries, free nerve endings and capsulated sensory receptors called meissners corpuscles
write about the reticular dermis
area between papillary dermis and the subcutaneous tissue. can find structures such as sweat glands, sebaceous glands, hair follicles and nails.w
which part of the dermis has collagen and elastin
reticular dermis
write a note on sweat glands
secrete NaCl and water. two types:
- eccrine glands: found everywhere. have a cooling purpose. secretion is slighly acidic - lubrication and antifungal. secretes directly onto the skin
- apocrine gland: found in axilla and anogenital area. secretes onto hair. secretions have fat and protein. involved in bacterial breakdown which causes body odour.
write a note on sebaceous glands
secretes oily sebum mainly on hair. is highly bactericidal, and is activated by androgens.
write a note on hypodermis
innermost layer, connects skin to underlying fascia of bones and muscle. well vascularised, loose, areolar connective + adipose tissue. is an insulator and shock absorber.
