1
Q
Integumentary System
A
- skin and its accessory structures
- provide protection
- thermoregulation
- sensory organ, role in immune system
- site of lipid storage
2
Q
Skins layers in order (superficial to deep, outer to inner)
A
- epidermis
- dermis (papillary dermis, reticular dermis)
- hypodermis (subcutaneous tissue)
3
Q
Epidermis
A
- consists of keratinized, stratified squamous epithelium
- 4 or 5 layers (depending on location)
- no blood vessels, avascular
4
Q
Order of Epidermis layers (inner to outer, deep to superficial)
A
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- stratum lucidum (only in thick skin)
- stratum corneum
5
Q
Thick skin
A
- contains stratum lucidum layer
- only in palms and soles
6
Q
Cells of epidermis
A
- Keratinocytes
- melanocytes
- dendritic cells
- tactile epithelial cells
7
Q
Keratinocytes
A
- dominant cell
- is not in stratum basale layer
- manufacture, store, and modify keratin (hardness and water resistant features)
8
Q
Keratin
A
- intracellular fibrous protein
- provides hardness and water resistant properties
- includes hair, nails, and skin
9
Q
Melocytes
A
- cells that produce pigment melanin (protect cells from UV)
10
Q
Melanin
A
- gives hair and skin color
- protects cells of epidermis from UV radiation damage
11
Q
Dendritic cells
A
- aka Langerhans cells
- found in stratum spinosum
- function as macrophages
- engulf foreign material, bacteria, and damaged cells in layer
12
Q
Tactile Epithelial Cells
A
- aka Merkel cells
- found in basal cells in stratum basale
- function like receptors
- responsible for stimulating sensory nerves (touch)
- most found on surfaces of hands and feet
13
Q
Stratum Basale
A
- single layer of cuboidal stem cells
- give rise to keratinocytes
- contain tactile cells for touch
- contain melanocytes for pigment production
14
Q
Stratum Spinosum
A
- lots of layers of keratinocytes
- thick bundles of intermediate filaments
- contain dendritic cells
15
Q
stratum granulosum
A
- 1-5 layers of keratinocytes
- where process of keratinization begins
- Proteins and lipids deposited outside make cells touch and water resistant
16
Q
Keratinization
A
- cells flatten
- nuclei and organelles disintegrate
17
Q
Stratum lucidum
A
- only found in thick skin
- thin layer of dead keratinocytes
18
Q
Stratum corneum
A
- 20-30 layers of dead keratinized keratinocytes
- layer is shed regularly
19
Q
Dermis
A
- contains blood, lymph vessels, nerves and other accessory structures (hair follicles, sweat glands)
- two layers of connective tissue
- contain collagen and elastin fibers (produced by fibroblasts)
20
Q
Papillary dermis
A
- loose areolar connective tissue
- superficial layer of dermis (by stratum basale)
- contain fibroblasts, adipocytes (fat cells), blood vessels, phagocytes.
- also contain: lymphatic capillaries, nerve fibers, touch receptors (tactiles corpuscle, Meissner’s corpuscle)
21
Q
dermal papillae
A
- when papillary dermis projects into stratum basale
- looks fingerlike
22
Q
fibroblasts
A
- produce collagen and elastin fibers
23
Q
reticular dermis
A
- thicker, mesh like
- dense irregular connective tissue
- very vascularized, rich nerve supply
- under papillary dermis
- Contain elastin fibers that provide elasticity
- contain collagen that provides structure and tensile strength
24
Q
Subcutaneous tissue
A
- below dermis
- connects skin to muscles and bones
- well vascularized
- loose aerolar connective tissue and adipose tissue
- stores fat
- provides insulation
- cushions
25
Hair
- keratinous filament growing out of epidermis
| - made of dead, keratinized cells
26
Hair follicle
- where hair penetrates the dermis
27
Hair shaft
- part of hair not anchored to follicle
| - mostly exposed at skins surface
28
Hair root
- rest of hair that is anchored in follicle
- under skin surface
- ends deep in dermis at hair bulb
- layer of basal cells (hair matrix)
29
Hair bulb
- surrounds hair papilla
30
hair papilla
- made of connective tissue
| - contains blood capillaries and nerve endings from dermis
31
Functions of hair
- protection
- sensory input
- thermoregulation
- communication
32
arrector pili muscle
- type of smooth muscle
- connects to hair root
- contracts in response to nerve signals
- makes hair shaft "stand up" (goosebumps)
- trap layer of air to insulate
33
Cutaneous Glands
- Sebaceous Gland (oil gland)
| - Sudoriferous Gland (sweat gland)
34
Sebaceous gland
- type of oil gland
- helps lubricate
- waterproof skin and hair
- generate and excrete sebum (to lubricate)
- inactive until puberty
35
sebum
- mixture of lipids and cellular debris
- fatty acids have antibacterial properties and prevent water loss
- secretion is stimulated by hormones
36
acne
- occurs in areas that are rich in sebaceous glands
- face and back
- overproduction and accumulation of sebum = block hair follicles
- initally white, when oxidized, turns black
37
Sudoriferous Glands
- aka sweat glands
- exocrine glands
- produce sweat to cool body
- two types: merocrine and apocrine
38
Merocrine sweat glands
- aka eccrine sweat glands
- produce hypotonic sweat
- thermoregulation: maintain homeostasis
- all over surface, mostly seen on palms, soles, forehead
- coiled glands deep in dermis
- releases onto skin surface
39
What is merocrine sweat composed of?
- water
- salt
- metabolic waste
- antimicrobial peptides
40
Apocrine Sweat gland
- associated w/ hair follicles
- found in armpits and genital regions
- larger and deeper than eccrine glands
- duct empties into hair follicle
- thicker and more smelly (bcos of organic compounds)
41
Aprocrine sweat composed of:
- water
- salt
- organic compounds (make sweat thicker and smell)
bio
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