Chapter 5: Integumentary System Flashcards
1
Q
functional characteristics of integumentary system
A
- protection
- regulation of body temperature
- excretion
- vitamin D synthesis
- sensory reception
2
Q
protection
A
cushions organs and protects from bumps, chemicals, water loss-UV radiation
3
Q
regulation of body temperature
A
- vasodilation/vasoconstriction of capillary network
- sweat glands
- adipose tissue of hypodermis
4
Q
excretion
A
urea, salts, and water loss through sweat
5
Q
Vitamin D Synthesis
A
(cholecalciferol) is produced photochemically in the skin from 7 dehydrocholestrol
6
Q
sensory reception
A
sensory receptors (nerve endings) keeps us aware of conditions at the body’s surface.
7
Q
the integumentary system is composed of:
A
- integument (skin): largest organ
- appendages: sweat and sebaceous (oil) glands, hair and nails
- Accounts for 7-15% of body weight
- varies in thickness from 1.5-4.4mm
- Divided into 2 distinct layers:
1. Epidermis
2. Dermis
3. Hypodermis/Superficial Fascia
8
Q
Epidermis
A
thick superficial epithelial layer
9
Q
Dermis
A
deep fibrous connective tissue later
10
Q
Hypodermis/Superficial Fascia
A
fatty later that lies deep to the dermis
-not part of the integumentary system
11
Q
Epidermis
A
- keratinized stratified squamous epithelium
- contains 4 main cell types
1. Keratinocytes
2. Melanocytes
3. Tactile epithelial cells (Merkel cells)
4. Dendritic Cells (Langerhans cells)
12
Q
Keratinocytes
A
most abundant cell type in epidermis
LOCATION: stratum spinosum.
- produce keratin, a touch fibrous protein that protects epidermis
- produce antibodies and enzymes; detoxify harmful chemical exposure
-keratinocytes arise from deep epidermis and are pushed to skin’s surface, keratin replaces cytoplasm and cells at surface are dead
13
Q
Melanocytes
A
LOCATION: stratum basale later; manufacture and secrete pigment-melanin-to be transferred to keratinocytes
14
Q
Tactile epithelial cells (Merkel Cells)
A
LOCATION: stratum basale layer; attached to disc-like sensory nerve endings
15
Q
Dendritic Cells (Langerhans Cells)
A
LOCATION: stratum spinosum; part of immune system macrophage; the cells endocytosis or foreign antibodies
16
Q
Layers of the Epidermis
A
- stratum basale (stratum germinativum)
- stratum spinosum (spiny layer)
- stratum granulosum (granular layer)
- stratum lucidum (clear layer)
- stratum corneum (cornified or horny layer)
17
Q
Stratum Basale (Stratum Germinativum)
A
- deepest epidermis layer
- attached to the dermis layer
- germinating layer where rapid mitosis of keratinocytes is occuring
18
Q
Stratum Spinosum (Spiny Layer)
A
- spine-like extensions of keratinocytes
- not seen in living cells only histology slides
19
Q
Stratum Granulosum (Granular Layer)
A
- thin layer (3-5 flattened keratinocytes)
- contains keratohyaline granules-helps form keratin
- containes lamellated granules-water proofing glycolipid that slows water loss
- dermal capillaries fo not extend beyond layer, cell begins to die
20
Q
Stratum Lucidum
A
- only occurs in thick skin
- few rows of dead keratinocytes; appears as a thin clear band
21
Q
Stratum Corneum
A
- external epidermis layer
- very thick layer of dead, keratin filled keratinocytes
- named derived from shed skin or dandruff
22
Q
Dermis
A
- second major layer of the skin
- strong, flexible connective tissue
- richly supplied with blood vessels and nerves
- two vascular plexus (network of diverging and converging vessels)
1. Cutaneous Plexus- located between hypodermic and dermis. Feeds hypodermic and deep layers of dermis
2. Subpapillary Plexus-located superficially, feed superficial dermal and epidermis
Dermis has two layers:
- Papillary Layer
- Reticular Layer
23
Q
Papillary Layer
A
- includes DERMAL PAPILLAE- fingerlike projections into epidermis
- 20% of superficial dermal layer
- composed of areolar connective tissue, thin collagen, and elastic fibers
- feet and hands: dermal papillae on dermal ridges (mounds) that project them into epidermis-epidermal ridges
- producing friciton ridges form fingerprints, footprints-genetically predetermined
- sweat pores that open along epidermal ridges cause FINGERPRINTS
24
Q
Reticular Layer
A
- 80% thickness of dermal layer
- composed of dense irregular connective tissue thick collagen and elastin fibers
25
what forms cleavage lines?
-separations or less dense regions between networks
- all over body; serve as demarcation lines for surgeons-less likely to gape open
- causes flexure lines-deep skin creases on palms
- extreme stretching could cause tearing of later-stretch (striae) marks
- receptive site for tattoo ink
26
Hypodermis
- also called superficial fascia
- deep to the skin
- contains areolar and adipose connective tissue
FUNCTIONS:
1. anchors skin to underlying structures
2. store fat (energy resource)
3. helps insulate the body
4. thickens with weight gain; differs between sexes
27
Three pigments contribute to skin color
1. Melanin
2. Carotene
3. Hemoglobin
28
Melanin
- Most important pigment
- Yellow-Red-Brown-Black
- Made from tyrosine (amino acid) using tyrosinase
- Freckles/ moles are accumulations
29
Carotene
- Yellowish pigment obtained from carrots and tomatoes
| - Accumulates in stratum corneum
30
Hemoglobin
- Caucasin skin contains little melanin
| - Allows crimson color go blood to show through
31
Appendages of the Skin
HAIR
- flexible strand of dead, keratinized cells
- hard keratin-tough durable and does not flake off unlike soft keratin on skin
CHIEF PARTS OF A HAIR
1. Shaft: projects above skin's surface; gives hair texture (flat=kinky, oval=wavy, round=straight)
2. Root: embedded in the skin; pigment (melanin) is transferred cell of root [white/gray is result of decreased melanin]
HAIT HAS THREE CONCENTRIC LAYERS OF KERATINIZED SKIN:
1. Medulla
2. Cortex
3. Cuticle
32
Medulla
- central core
- composed of large cells and air spaces
- absent in fine hairs.
33
Cortex
- surrounds medulla
| - composed of flattened cells
34
Cuticle
- outermost layer
| - composed of several overlapping cell layers (where conditioners work)
35
Hair follicles
extends from epidermis into dermis
36
Hair bulb
deep extended end of the hair follicle
37
Root Plexus
Knot of sensory nerves around wrapped around hair bulb (touch receptor)
38
Hair Papilla
Knot of capillaries that feed hair bulb to stimulate growth; if destroyed follicle stops producing hair
39
_______ destroys stem cells in hair follicle
Chemotherapy
40
Arrector Pili Muscle
- "Raiser of the Hair"
- bundle of smooth muscle
- relaxed: hair will lie flat
- Contracts: hair will stand up
- Stimulated: by cold or fight. Hair stands erect
- Horripilation
- "Goosebumps"
41
Sebaceous Glands
- skin's oil glands
- occur over entire body- except palms and soles (No hair)
Secrete SEBUM ("animal fat")- an oily substance
- simple alveolar glands-sacs collect sebum until filled
- holocrine secretion-entire cell breaks up to form secretion
- most are associated with a hair follicle
FUNCTIONS OF SEBUM
- collect dirt
- softens and lubricates hair and skin
ACNE: sebaceous gland becomes blocked by sebum (whitehead); if sebum oxidizes and dries (blackhead)
42
Sweat Glands
- SWEAT GLANDS widely distributed on body
- human produce - 500 mL of sweat per day
- exercising on hot day - 12 L
SWEAT- is a blood filtrate that passes through secretory cells and released by exocytosis
- 99% water w/ some salts (sodium chloride)
- contains traces of metabolic wastes (urea, ammonia, uric acid)
2 TYPES OF SWEAT GLAND
1. Eccrine Sweat Glands
2. Apocrine Sweat Glands
43
Eccrine Sweat Glands
- Most numerous - these produce "true" sweat
- Most abundant on palms, soles and forehead
- Coiled secretory base lies in deep dermis and hypodermic; duct runs superficially through funnel shaped pore
44
Apocrine Sweat Glands
- confined to axillary, anal, and genital areas
- larger than eccrine sweat glands
- duct open into hair follicles
- sweat is viscous and consists of fats and proteins-odorous
- start to function and puberty
45
Nails
- scale-like modification of epidermis
- corresponds to hoof or claw of other mammals
- made of hard keratin
PARTS OF THE NAIL
1. Free edge: distal portion
2. Body: visible attached portion
3. Root: proximal portion embedded in epidermis
4. Nail Matrix: pink actively growing portion
5. Lunula ("little moon"): white crescent under proximal portion
6. Nail Folds: skin folds at lateral and proximal borders
7. Eponychium: cuticle
