int2 Flashcards
Lines of Cleavage - clinical significance?
Parallel cuts will close (since parallel to line of tissue) while perpendicular cuts will remain open (lines of tension are working against it, more pronounced scar)
Lines of Cleavage?
muscles under skin = tension = tendency for fibres to align this way - Collagen fiber bundles in dermis align differently in different regions of skin - they align along lines of tension and form lines of cleavage
Subcutaneous Layer - AKA? purpose?
- also called hypodermis or superficial fascia
- stabilizes position of skin relative to underlying tissues (attaches dermis to fascia, but gives a little bit of wiggle room)
Subcutaneous layer - CT?
Loose connetive tissue that stores fat - distribution of subcutaneous fat differs between sexes, influences body shape
Accessory Structures - 3?
Hair, nails and exocrine glands
Hair - #? location?
- ~5 million hairs on body (only 2% on head)
- covers all body surfaces except: palmar surfaces of hands/fingers, plantar surfaces of feet/toes
Hair - 3 functions/
- Head: UV protection, thermal insulation
- eyes and nose: filter air
- General body: touch sensation
Hair Growth - Scalp hair?
- grows: ~2 to 6 years
- rests: ~3 months
- ~85% in growth phase at any given time
Hair Types (3)
Vellus, intermediate, terminal
Vellus hairs?
fine “peach fuzz” hair found over most of the body
Intermediate hairs?
hairs of the upper and lower limbs, change in response to sex hormones
Terminal hairs?
heavy and more pigmented - scalp, eyebrow and eyelash hair
Nails?
protect exposed tips of the digits, limit distortion when digits subjected to mechanical stress
glands of the skin - two types of?
Two types of exocrine glands: sebaceous glands and sweat glands
Sebaceous glands - secrete? where? secretion type?
- secretes oily lipid (sebum)
- coats hair shafts and skin surface
- holocrine secretion
Sweat glands? - secrete and type?
- secrete water, electroyltes
- merocrin secretion - cells fill up with sebum, then die and sebum is released
Acne
inflammation of sebaceous glands and follicles, occurs at onset of puberty: glands in crease in size, and sebum secretion increases in response to sex hormones. Inflammation results from: blockage of ducts, bacterial infection of glands
Sweat glands - shape? release where? two types?
- simple, coiled tubular glands
- release secretions onto the skin
- two types: merocrine (eccrine) and apocrine
Merocrine (eccrine) vs. Apocrine Sweat glands?
- merocrine/eccrine: most numerous, secrete normal sweat
- apocrine: less numerous, secrete odiferous sweat
Merocrine Sweat Glands - distributions, secretions, purpose?
- most common, distributed over majority of body
- secrete water and electrolytes
- regulate body temp
All sweat glands secrete by…?
Merocrine - apocrine sweat glands is a misnomer
Apocrine Sweat Glands - secrete by? distribution/number?
- by merocrine - name is a misnomer
- less numerous than eccrine
- axilla, groin, areolae of breast, bearded region of face in males
Apocrine Sweat Glands - secretion and stimulation?
- secrete: water, electrolytes, lipids, proteins (acted on by bacteria to produce odors)
- stimulated during emotional stress and sexual excitement
Modified Sweat Glands - two types?
ceruminous and mammary
Ceruminous glands - located? secrete? modified?
- in external auditory canal of ear
- secrete waxy crumen aka ear wax
- are modified merocrine sweat glands
Mammary glands - modified? regulated by? purpose?
- modified apocrine sweat glands
- regulated by interaction of sexual and pituitary hormones
- supply nutrition for newborn
Hair Growth Cycle?
Active phase (2 - 5 years) > continued growth ~0.33 mm /day > regression > loosening of attachment in follicle > resting phase > loss of club hair > reactivation
Parts of the nail - nail root? nail bed?
- nail root: where nails are born, an extended linear structure
- nail bed: continuation of skin
Parts of the nail - eponychium and hyponychium?
- eponychium: aka cuticle, where skin merges from above
- hyponychium: where skin and nail merges from below
