INTEGUMENTARY SYSTEM Flashcards

1
Q

Integumentary system

A

Consists of the skin and its associated structures. It is the largest organ in the body and makes up about 16% of body weight in adult human

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2
Q

3 main functions of integumentary system:

A
  • Protection: Skin protects from basic elements of nature (wind, water, UV sunlight)
  • Sensory function: Hair root plexus senses physical disturbance, epidermis/dermis/hypodermis contain sensory neurons that detect touch, temperature and pain
  • Thermoregulation: Sweat glands and accessory structures help cool body when it becomes warm
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3
Q

Skin

A

Organ composed of tissues that work together as a single structure to perform unique and critical functions

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4
Q

Skin function

A

Functions in protection of body

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5
Q

Skin structure

A

Made up of multiple layers of cells and tissues held to underlying structures by connective tissue and has sensory and nerve fibers ensuring communication from brain

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6
Q

Epidermis

A

Avascular (no blood vessels), composed of layers of keratinized stratified squamous epithelium

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7
Q

Thick skin

A

Refers to the 5 layers (everything including stratum lucidum) of cells in skin and is found only on palms of hands and soles on feet

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8
Q

5 layers of skin:

A
  • Stratum basale
  • Stratum spinosum
  • Stratum corneum
  • Stratum lucidum (only present in thick skin)
  • Stratum granulosum
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9
Q

Keratinocytes

A

Cell that manufactures and stores keratin protein

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10
Q

Keratin

A

Intracellular fibrous protein that gives hair, nails, and skin their hardness and water-resistant properties

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11
Q

Stratum basale structure (3):

A
  • Deepest layer attaching epidermis to basal lamina
  • Cells bond to dermis through collagen fibers of basement membrane
  • Single layer of cells primarily composed of basal cells which are cuboidal shaped stem cells and precursors of keratinocytes
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12
Q

Dermal papillae

A

Finger like projections or folds, strengthens connection between epidermis and dermis

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13
Q

2 types of cells that can be found in stratum basale:

A
  • Merkel cells: Receptors for touch
  • Melanocytes: Produce pigment melanin
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14
Q

Stratum Spinosum structure (2)

A
  • SPINY in appearance due to protruding cell processes that connect via desmosomes
  • 8-10 layers of keratinocytes formed from cell division in stratum basale
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15
Q

Langerhan cells

A

Immune cells scattered on stratum spinosum functioning in macrophages by engulfing bacteria, foregin particles and damaged cells

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16
Q

Keratinocytes function in stratum spinosum

A

Produce keratain and release water-repelling glycolipid that helps prevent water loss from body making skin waterproof

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17
Q

Stratum granulosum structure (3)

A
  • GRAINY appearance due to changes by keratinocytes moving from stratum spinosum
  • Cells become flatter and cell membrane thickens
  • Production of fibrous keratin and accumulation of keratohyalin granules
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18
Q

What happens to nuclei and other organelles as cells die in stratum granulosum

A

Nuclei and other organelles disintegrate as cells die, leaving behind keratin, keratohyalin, and cell membrane

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19
Q

Reasoning for grainy appearance in stratum granulosum

A

Keratin and keratohyalin forms majority of keratinocyte mass, giving the layer its grainy appearance

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20
Q

Stratum lucidum structure (3):

A
  • SMOOTH seemingly translucent layer above stratum granulosum and below stratum corneum
  • Keratinocytes that compose stratum lucidum are dead and flattened
  • Cells densely packed with eleiden, a clear protein derived from keratohyalin which gives cells transparent appearance and provides barrier to water
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21
Q

Where is stratum lucidum found

A

Found ONLY in thick skin of palms, soles, and digits

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22
Q

Eleiden

A

A clear protein derived from keratohyalin which gives cells transparent appearance and provides barrier to water; found densely packed in stratum lucidum

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23
Q

Stratum corneum structure

A

Most superficial layer of epidermis with 15-30 layers of cells exposed to outside environment

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24
Q

Stratum corneum function

A

It is a dead, dry later so it helps prevent penetration of microbes and dehydration of underlying tissues and provides mechanical protection against abrasion and sheds periodically and replaced by cells pushed from layer below

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25
How does stratum corneum get its name
From the increased keratinization of cells in this layer of skin
26
Dermis
Considered the core of the integumentary system containing blood, lymph vessels, nerves, hair follicles, and sweat glands
27
Two layers of connective tissue that composes dermis:
- Papillary layer (superficial) - Reticular later (deep) - Compose an interconnected mesh of elastin and collagenous fibers produced by fibroblasts
28
Papillary layer (3):
- Made up of loose areolar connective tissue - Contains fibroblasts, small amounts adipocytes, abundance of small blood vessels, lymphatic capillaries, nerve fibers, and touch receptors called tactile (meissner) corpuscles - Contains phagocytes to fight bacteria and other infections
29
Reticular layer (2):
- Made up of dense, irregular connective tissue - Well vascularized, has rich sensory and nerve supply
30
Elastin fibers in skin
Provides elasticity to skin, enable movement
31
Collagen fibers in skin
Provide structure and tensile strength
32
Hypodermis
Layer directly below dermis and functions to connect skin to underlying fibrous tissue of bones and muscle. It is well vascularized, loose, areolar connective tissue and adipose tissue that functions for fat storage and provides insulation and cushioning
33
Proteins involved in skin pigmentation
Melanin, carotene, hemoglobin
34
Melanin
Gives hair and skin its color, and helps protect living cells of epidermis from UV damage; dark skinned individuals have more melanin than those who are pale
35
Exposure to UV rays of sun or tanning salons effects on melanin
Cause melanin to be manufactured and build up keratinocytes which darken skin
36
Increased melanin concentrations significance
Protects DNA of epidermal cells from UV damage but can interfere with vitamin D production
37
What happens after 10 days of initial sun exposure
Melanin synthesis tend to peak around 10 days which explains why pale skinned individuals tend to suffer sunburns of epidermis initially
38
Can darker skinned people get sunburnt
Yes, but their sunburns are more protected
39
Too much sun exposure impacts
Lead to wrinkling due to destruction of cellular structure of skin, or cause sufficient DNA damage resulting in skin cancer
40
Moles
Larger masses of melanocytes and although most are benign, they should be monitored for changes that could indicate presence of cancer
41
Hair
Keratinous filament growing out of epidermis and composed of dead, keratinized cells. Strands of hair originate in epidermal penetration of dermis called hair follicle
42
Hair shaft
Exposed part of hair above skin surface and not anchored to follicle
43
Hair root
Lies below surface of skin and anchored in follicle
44
Hair bulb
Deep end of hair follicle containing hair papilla
45
Hair matrix
Layer of actively growing basal cells
46
Hair papilla
Surrounded by hair bulb made of connective tissue containing blood capillaries and nerve endings from dermis
47
Basal cells of hair bulb
Divide and push cells outward in hair root and shaft
48
External hair
Completely dead and composed entirely of keratin
49
Hair general functions
Protection, sensory input, thermoregulation, communication
50
Hair functions (2):
- Protect skin from sun rays, trap/exclude dust particles containing allergens or microbes, and prevent sweat and particles from dripping in eyes - Hair is sensitive to air movement and disturbances in environment or on surface of skin due to hair plexus surrounding the base of each follicle
51
Arrector pili
Smooth muscle that each hair root is connected to making hair shaft become erect and adding an insulating layer of air for animals with heavy coat
52
Nail bed
Specialized structure of epidermis that is found at the tip of fingers and toes
53
Nail body
Forms at nail root and protects tips of fingers and toes because they are the farthest extremities that experience the maximum mechanical stress. They also form a back-support for picking up small items
54
Sudoriferous glands
Glands that produce sweat to cool the body when warm
55
Merocrine glands
Produce sweat that will assist in thermoregulation by evaporating and removing excess heat from the skin
56
2 main types of sweat glands:
- Eccrine sweat glands - Apocrine sweat glands
57
Eccrine sweat gland (3)
- Primary component of thermoregulation in humans and thus help maintain homeostasis - Produces hypotonic (relative to blood plasma) sweat for thermoregulation - This type of sweat released by exocytosis composed mostly of water with some salt, antibodies, traces of metabolic waste, and dermicidin (antimicrobial peptide)
58
Eccrine gland location
Found all over skin surface and most abundant on palms of hand, soles of feet, and forehead
59
Eccrine gland structure
Coiled glands deep in dermis with the duct rising to a pore on skin surface where sweat is released
60
Apocrine sweat gland (2):
- Usually associated with hair follicles in densely hairy areas such as armpits, and anogenital regions - This type of sweat includes water, salt, organic compounds that make sweat thicker and subject to bacterial decomposition and subsequent smell
61
Apocrine gland location and structure
Larger than eccrine and deeper in dermis, with duct normally emptying into hair follicle
62
Mammary gland
Found in breasts and produce/secrete milk, nourish growing offspring
63
Ceruminous gland
Found in external ear canal and produce/secrete mixture of lipids and proteins, combines with sebum and dead keratinocytes to form cerumen (earwax)
64
Sebaceous gland (2):
- Oil gland found all over the body and helps lubricate and waterproof skin and hair - Associated with hair follicles and make sebum (mixture of lipids on skin surface)
65
Sebum
Mixture of lipids on skin surface that lubricates dry and dead layer of keratinized cells of stratum corneum, keeping it pliable
66
Fatty acids of sebum function
Has antimicrobial properties and prevent water loss from skin