Integumentary System Flashcards
What is the general function of this system?
appearance, protection, temperature regulation, water conservation, synthesis (vitamin D), sensory reception
how thick, weight and large is this system?
2 sq meters, 1-2mm thick, 10lbs
what are the major layers?
epidermis (epithelial tissue) and dermis (connective tissue, nerve and muscle)
what is the hypodermis called?
subcutaneous tissue
what is the subcutaneous tissue composed of?
adipose, and areolar tissue
what are the different cell types that make up the epidermis?
keratinocyte, melanocyte, merkel cell, langerhans cell
what does keratinocyte do?
produce keratin and lamellar granules
what is keratin?
tough protein (build more and more protein through lifecycle)
what is lamellar granules?
secrete lipid rich material, which waterproofs
what does melanocytes do?
produce melanin (brown pigment)
what does langerhans cell do?
involved in immune response, comes from red bone marrow
what does Merkel cells do?
sensation on touch, in deepest later of epidermis
what are the epidermis cell layers?
stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale
what is the stratum basale also called?
stratum germinativum
what is the most important layer and why?
stratum basale because it is closest to the blood supply, gets nutrients and oxygen from connective tissue
what does germinativum mean?
cell division
what happens in the stratum basale?
mix of merkel cells, melanocytes, keratinocytes, stem cells that divid rapidly
characteristics of stratum spinosum?
polyhedral cells with spiny projections that bind cells together
how thick is the stratum spinosum layer?
8-10 cells thick
what does stratum spinosum do?
gives strength and flexibility to skin, take in melanin from melanocytes
how does stratum spinosum get melanin from melanocytes?
by phagocytosis
how thick is the stratum granulosum layer?
3-5 cells thick
what is stratum granulosum composed of?
dying, flattened keratinocytes undergoing poptosis
what does stratum granulosum composed of?
dark staining keratinohyalin granules and lamellar granules
why is stratum granulosum important?
because it protects other layers
what is unique about stratum lucidum?
seen only in thick skin of palms of hands of soles of feet
how thick is the stratum lucidum?
3-5 layers of clear, dead, flat keratinocytes
what is stratum lucidum composed of?
large amount of keratin, and thickend plasma membranes
how thick is the stratum corneum?
25-30 layers thick
what is stratum corneum composed of?
flat, dead cells filled with keratin surrounded by lipids
what are the characteristics of stratum corneum?
continuously sheds, protects underlying tissues from light, heat, water, chemicals, bacteria
describe the keratinization and growth of epidermis
stems cells divide - keratinocytes fill with keratin - contents within cells starts to break down
how long does thekeratinization and growth of epidermis take?
4 weeks
what is the keratinization and growth of epidermis accelerated by?
EGF - epidermal growth factor
what protects keratinocytes?
melanocyte ( protects against mutation= cancer)
what is melanocytes stimulated by?
uv light, hormones(ACTH)
what does melanocytes do?
inject the protein melanin into surrounding epidermal calls
what is skin colour determined by?
genetics - abundance of melanocytes, colour of melanin, ability to break down melanin
what is skin colour affected by?
exposure to uv light, blood flow to skin, blood oxygen saturation, presence of abnormal pigment
what is the dermis composed of?
collagen, elastic fibers, fibroblasts, connective tissue, macrophages, fat cells, hair follicles, glands, nerves, blood vessle
what are the regions of the dermis?
papillary, reticular
what is the papillary composed of?
loose connective tissue, elastic fibers
what is the top layer of the dermis composed of?
dermal papillae (finger-like)
what does the papillae do?
feeds with capillaries and anchors to epidermis
what is the reticular layer of the dermis composed of?
dense irregular connective tissue, collagen and elastic fibers
what accessories are found in the dermis?
epidermal derivatives, hair, sweat glands, oil glands, nails
tell me about the hair shaft?
distributed over most of skin to provide limited protection
what are the parts of the hair?
hair shaft, hair bulb, hair follicle
what is connected to the hair shaft?
arrector pili (piloerector) muscle
what does the arrector pili muscle do?
pulls hair upright
what does the hair bulb do?
secretes protein and sheds cells
what does the hair follicle do?
protects from dermis
what is the hair follicle?
tubular epithelial sheath
what is the sensory receptors responsible for feeling?
touch, pain, temperature and pressure
what are the glands found in the dermis?
sebaceous (oil), sudiferous (sweat), ceruminous (wax), mammary (milk)
what does sebaceous glands do?
secrete sebum into hair shaft
what is sebum a combination of?
cholestreol, protein, fats and salts
what is sudiferous glands composed of?
eccrine glands and apocrine glands
what does eccrine glands do?
regulate body temperature
where is eccrine glands located?
most areas of skin
where is apocrine glands located?
armpit and pubic region
what does ceruminous glands do?
secrete cerumin
what does cerumin do?
helps forms barrier against foreign material
what are nails?
tightly packed dead keratinized cells
why is nail body pink?
due to capillaries
what is a cuticle?
stratum corneum
what is eponychium
cuticle
what is the lunula?
white area of nail body
why does the lunula look white?
thickened stratum basale
