Chapter 5 - The Integumentary System Flashcards
Functions of skin
- protection
- thermoregulation
- cutaneous sensation
- vitamin D synthesis
- blood reservoir
- excretion and absorption
Epidermis
- superficial layer
- keratinized stratified squamous epithelium
- avascular/own nerve supply
4 cell types of epidermis
- keratinocytes (90%)
- melanocytes (8%)
- Langerhans cells
- Merkel cells
Langerhans cells
immune function
Merkel cells
touch
Epidermal layers (deep to superficial)
- stratum basale
- stratum spinosum
- stratum granulosm
- stratum lucidum
- stratum corneum
Stratum basale
- contains all 4 cell types
- deepest layer
- mitosis occurs here
Stratum spinosum
- keratinocytes and Langerhans cells present
- projection of melanocytes (cells alive)
Stratum granulosm
- lamellar granules
- transitional layers (apoptosis)
- water repellent layer
Apoptosis
programmed cell death
Stratum lucidum
- present only in thick skin
- 10-15 layers fo dead skin cells
Stratum corneum
- keratin
- continuously shed (20-30 layers)
- most superficial
Psoriasis
shed cells rapidly
Skin graft
possible with stratum basale injury (mitosis disrupted)
Dermis
- deep layer
- vascular/nerves
- papillary layer
- reticular region
Papillary layer
- 1/5 of dermis
- areolar connective tissue
- dermal papillae
Dermal papillae
- finger-like projections
- superficial part of dermis
- contact point between dermis and epidermis
Reticular region
- attached to subcutaneous layer
- thickest
- dense irregular connective tissue (can’t be replaced, CT)
- oil, sweat glands, hair follicles
Hypodermis
- not layer of skin
- subcutaneous layer
- areolar connective adipose tissue
- stores fat; abundance of blood vessels
- Pacinian corpuscles (pressure)
Hemoglobin
- pigment in red blood cells that carrie oxygen
- degree of oxygenation of blood; amounts of blood in area
Carotene
- ingested (precursor of vitamin A)
- accumulates in stratum corneum with excessive dietary intake
Melanin
- only pigment synthesized in skin
- differences in color reflect amount of pigment and kind made
Albinism
inability to produce melanin (still have melanocytes)
Vitiligo
- loss of melanocytes from patches of skin
- symmetrical
- usually occurs later in life
- auto immune disease(?)
Functions of hair
protection and light touch (receptors- Merkel and Langerhans cells)
Anatomy of hair
- shaft
- root (penetrates dermis and subcutaneous layer)
Root
- medulla
- cortex
- cuticle
Hair follicle
- surrounds root
- epithelial root sheath
- dermal root sheath
Hair bulb
deepest part (onion shaped)
Hair papilla
- opening on bottom of hair
- contains blood vessels/nerves
Matrix
- layer of cells around papilla
- mitosis similar to stratum basale
Arrector pili muscles
smooth muscles that can contract when excited (i.e. goosebumps)
Alopecia
- condition characterized by the rapid onset of hair loss in a sharply defined area
- caused by genetics, endocrine disorders, chemotherapy, stress, etc.
Sebaceous (oil) glands
- simple acinar
- holocrine
- duct usually opens into hair follicle
- secretes sebum
- acne occurs when these glands get infected
Sebum
- prevents hair from drying out
- keeps skin soft and pliable
- prevents excessive evaporation of water
Merocrine sudoriferous (sweat) glands
- simple tubular
- duct terminates on epidermis
- water secretions (regulate body temperature, waste removal)
Apocrine sudoriferous (sweat) glands
- simple tubular
- duct open to hair follicles
- secretes sweat via merocrine method
- viscous secretions
- axillary and genital regions
Cerumonious (wax) glands
-simple tubular
-merocrine
-found in external auditory meatus
-duct terminates on epidermis or into ducts of sebaceous glands
secretes cerumen
Cerumen
provides sticky barrier that impedes entrance of foreign bodies inot the ear
Anatomy of a nail
- nail body
- nail root (buried under root)
- eponchium (cuticle) joins body and root
1st degree burn
- affects epidermis
- sunburn (no blisters)
2nd degree burn
- affects epidermis and dermis
- blistering occurs
- lasts 3-4 weeks
3rd degree burn
- affects epidermis, dermis, and subcutaneous layers
- nerve endings killed
- skin graft common- stratum basale/nerve endings damaged
Rule-of-Nines method
determine extent of burn rapidly
Hypertrophic scar
elevated within the boundaries of original wound
Keloid scar
extends into previously normal tissue, mind of its own
