Exam 2 Flashcards
functions of skin
- resistance to trauma: keratin give durability
- barrier functions: barrier from gaining/losing H2O; barrier to UV rays
- vitamin D synthesis; skin is 1st step of process
- sensation nerve endings: react heat, pressure, injury
- thermoregulation: retains blood vessels for heat, sweats for overheat
- nonverbal communication: skeletal muscles pull skin in face
keratinocytes
synthesis of keratin; cell of epidermis
stem cells
divide and rise keratin, found in stratum basal; cell of epidermis
melanocytes
synthesis melanin found in stratum basal
tactile cells
receptors for touch, dermal nerve fiber
dendritic cells
immune cells; in stratum spinosum plus granulosum
layers of epidermis (superficial to deep)
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basal
stratum corneum
30 layers of dead keratinzed cell; resists-abrasin, water loss
stratum lucidum
densely packed keratincytes in eledin protein-ONLY IN THICK SKIN
stratum granulosum
flat keratinocytes; dark-staining keratohyalin granules
stratum spinosum
thickest; deep cell, they push up and are flat, they cease
stratum basal
cuboidal or columnar cells; keratinocyts on basement mem.
stem cells divide and push keratinocytes to surface to replace epidermal cells
dermis layers (superficial to deep)
1.papillary layer
2. reticular layer
papillary layer
areolar tissue, rich in small blood vessels
reticular layer
thicker, dense irregular tissue; more fibers than cells
hypodermis (subcutaneous fat)
adipose tissue; energy reservor, thermal insulation, and protects by absorbing pressure to body (where shots are given)
melanin
factor of skin color; accumulates in keratinocytes (stratum basale and spinosum)
eumelanin
brownish/black skin color
pheomelanin
reddish/yellow skin color
skin color
same number of melanocytes, dark skin has more melanin
hair types
- downy hair- unpigmented hair on fetus; last 3 months of development
- vellus hair- fine pale; 2/3 hair for women, 1/3 men; all children (not hair on head)
- terminal hair- long, coarser, dark; eyebrow/lashes, scalp, auxillary, pubic, facial hair
histology of hair follicle
- shaft
- root
- bulb
- dermal papilla
- hair matrix
- bulge
- hair receptors
- arrector muscle
nail structure
nail includes: free edge, nail body, nail root (under the overlying skin)
- nail fold: (surrounding skin on edges)
- nail grove: (seperates nail and skin edges)
- lumule: (white crescent)
- eponychium: (cuticle)
apocrine sweat glands
- groin, axilla, areola, beard in men
- these ducts go to hair follicles; not onto skin
- use exocytosis
- have large lumen in middle of secretory cells
- active after puberty; stress and sexual stimulation (sex phermones)
eccrine (merocrine) sweat glands-
- entire body; especially palms, soles, forehead
- coil in dermis/hyperdermis leading to pose on skin; function to cool body
sebaceous glands
- make sebum (oil); flasked-shaped ducts
- some open on skin, some open into hair follicle
- holocrine glands
ceruminous glands
- only in external ear; sedum and dead cells makes earwax (cerumen)
- leads to skin surface of ear canal
- protects eardrum, kills bacteria, coats hair
mammary glands
- milk producing gland ONLY in women during pregnancy and lactation
- modified apocrine glands go through ducts to nipples
basil cell carcinoma
- most common, least deadly
- small bump -> depression
- arises from stratum basal to dermis
squamous cell carcinoma
- on scalp, ears, lips, back of hand; raised, reddened apperance
- arises from keratinocyates of stratum spinosum
melanoma
- 5% of skin cancer, aggressive, average 6 months to live
- arises from melanocytes
- large, flat mole looking spot with scalloped border
1st degree burns
- only epidermis; redness, pain; sunburns
2nd degree burns
- epidermis and some dermis; red, tan or blistered
3rd degree burns
- epidermis and all dermis; muscle or bone destroyed; require skin grafts
functions of skeletal system
- support- limbs and vertebral column support body
- protection- protect brain, spinal cord, heart, lungs, bone marrow
- movement- limbs move, breathing and other movements caused by muscles
- electrolyte- balance-stores calcium and phosphate; release according to blood
- acid-base balance- bone tissue absorb/release alkaline phosphate in blood
- blood formation- red bone marrow produces blood cells
functions of skeletal system
- support- limbs and vertebral column support body
- protection- protect brain, spinal cord, heart, lungs, bone marrow
- movement- limbs move, breathing and other movements caused by muscles
- electrolyte- balance-stores calcium and phosphate; release according to blood
- acid-base balance- bone tissue absorb/release alkaline phosphate in blood
- blood formation- red bone marrow produces blood cells
bone tissue (osseous tissue)
connective tissue with hard matrix and calcium phosphate and osseous and bone marrow, cartilage, adipose tissue, fibrous conn. tissue, make bone
- bone can mean organ with everything said above, or just osseous tissue
long bone (compact bone (cortical bone))
outer shell of white osseous tissue
components of long bone
- marrow cavity: contains bone marrow
- spongy (cancellous) bone: at ends of bones, loosely organized osseous tissue
- diaphysis: shaft
- epiphysis: head at each bone
- epiphysial line: between head and shaft; was epiphysial plate in children
- articular cartilage: hyaline cartilage; top of head where bones meet
- periosteum: tough outer fibrous layer sheath
- endosteum: thin layer of reticular connective tissue in internal marrow cavity
flat bones
curved bones, mostly carnial, sternum, scapula, ribs, and hip bones
osteogenic cells
stems cells; occur in endosteum and inner layer of periosteum; multiply continually
osteoblasts
bone forming cells synthesize organic matter of bone
osteogenesis
mineralization; bone forming action (osteoblasts)
osteocalcin
hormone that osteoblasts secrete; it stimulates insulin secretion in pancreas
osteocytes
osteoblasts trapped in bone matrix that they make
- located in lacunae
- connected by canaliculi
- some resorb/ some deposit bone matrix; it maintains bone density
osteoclasts
bone-dissolving cells on bone surface
- many stem cells fuse to make 1; so multiple nucleus (3-4 - 50)
- has RUFFLED BORDER: side facing bone surface; increases the surface area of osteoclasts
- they make RESORPTION BAY pit
osteolysis
breaks down bone; opposite of osteogenesis (osteoclasts)
organic bone matrix matter
cells, collagen, carbohydrates, glycosaminoglycans, proteoglycans, glycoprotein
- resists pulling
inorganic bone matrix matter
hydroxyapatite (calcium phosphate salt), Mg, Na, K, Fl, S, carbonate
- makes 85% of matrix
- resists pushing
osteon
basic unit of compact bone, circular
concentric lamellae
layers of matrix around CENTRAL (haversian) CANAL
- make up the osteon
- has multiple layers with different ‘corkscrew’ coil of collagen fibers
central canal
(haversian canal) where nerve and blood vessels are
perforating canals
smaller canals that transversely joined to central canal
histology of spongy bones
- spicules: rods or spines
- trabeculae: thin plates or beams
- spaces are filled with bone marrow
- osteoclast resorption largely from spongy bone
red bone marrow
(myeloid tissue) makes blood cells
- in nearly very bone in children
- in adults: skull, vertebrae, ribs, sternum, hips, humerus, femur
yellow bone marrow
fatty marrow
- can turn back into red marrow if needed to
intramembranous ossification
adds onto preexisting bone; grows in width (osteoblasts)
intersitial growth
endochondral ossification
develops from preexisting hyaline cartilage; bone elongation; takes place in epiphysial plate of children
appositional growth
epiphysial plate
bone elongation
interstitial growth
cartilage growth within; multiply chondrocytes
- bone elongation result of cartilage growth
zones of metaphysis
mineral deposition
(mineralization) calcium, phosphate, other ions taken from blood plasma and into bone tissue
mineral resorption
(osteoclasts) process of dissolving bone
- release mineral to blood for other uses
hypocalcemia
calcium deficiency
hypercalcemia
calcium excess
calcitriol
form of vitamin D; raises blood calcium
- like a hormone, called vitamin causes its found in our diet
- increase absorption by small intestine, increases resorption from skeleton, promotes reabsorption in kidney (less calcium lost in urine)
calcitonin
when calcium too high; thyroid gland lowers by:
- osteoclast inhibition: reduces osteoclast activity
- osteoblast stimulation: increases number and activity of osteoblasts
important role in children
parathroid hormone
by parathyroid glands, release PTH when calcium too low
- stimulate osteoclast population and increase bone resorption
- promotes calcium reabsorption by kidneys; less loss in urine
- inhibits collagen synthesis of osteoblasts
other factors of calcium homeostasis
estrogen (stronger)
testosterone
sex steroids
anabolic steroids
