Integumentary System (EXAM #2) Flashcards

1
Q

What do the Integumentary System consists of?

A
  • Skin
  • Hair, Nails, Glands
  • Muscles
  • Sense Receptors (nervous)
  • Hypodermis
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2
Q

What are the 2 Layers of Skin?

A
  1. Epidermis - superficial layer (outermost layer)
  2. Dermis - deep layer
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3
Q

What are the characteristics of Epidermis?

A
  • Stratified squamous epithelium
  • Avascular
  • Separated into 4-5 strata (sub-layers) based on cell types:
    1. Stratum Basale
    2. Stratum Spinosum
    3. Stratum Granulosum
    4. Stratum Lucidum
    5. Stratum Corneum
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4
Q

Stratum Basale

A
  • Single row of cells
  • 2 cell types:
    • Keratinocytes (90%)
    • Melanocytes (10%)
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5
Q

Keratinocytes (90%)

A
  • Actively undergo mitosis
  • Make keratin (tough protein)
  • Pushed towards surface as new cells are produced in basale
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6
Q

Melanocytes (10%)

A
  • Produce pigment (melanin) for UV light protection
    • e.g. sunburns, wrinkles (collagen damage), cancer (DNA damage)
  • Skin colour:
    • We all have the same relative number of melanocytes, but cells produce different amounts/shades of melanin
    • blood (hemoglobin) - in dermis can give a pinkish tinge to fair skinned people
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7
Q

Stratum Spinosum

A

Low levels of mitosis

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8
Q

Stratum Granulosum

A
  • No mitosis
  • Contains granules that help produce keratin (strength) and start to produce waterproofing glycolipids (prevents water loss)
  • Last layer of living cells
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9
Q

Stratum Lucidum

A
  • No mitosis
  • Flat, dead cells (too far from blood supply)
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10
Q

Stratum Corneum

A
  • Many layers of flat dead cells filled with keratin (tough protein)
  • Glycolipids between cells create a waterproof layer (prevents water loss)
  • Shed and replaced from below
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11
Q

What are the characteristics of Dermis?

A
  • Contains blood vessels, nerves, glands, hair follicles, arrector pili muscles
  • 2 sub layers (connective tissue):
    1. Papillary Layer (connected to epidermis)
    2. Reticular Layer (between papillary layer and hypodermis)
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12
Q

Papillary Layer (connected to epidermis)

A
  • Areolar connective tissue
  • Vascular
  • Has projection into epidermis = dermal papillae
    • In thick skin these form epidermal ridges = fingerprints (improve grip)
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13
Q

Reticular Layer (between papillary layer and hypodermis)

A
  • Forms most of dermis
  • Dense irregular connective tissue
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14
Q

Thin vs Thick Skin

A

Thickness refers to epidermis (not dermis)

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15
Q

What are the characteristics of Thin Skin?

A
  • Covers most of body
  • Lucidum absent
  • Has hair follicles, sebaceous glands, arrector pili muscles
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16
Q

What are the characteristics of Thick Skin?

A
  • Found on the palm of the hand and the sole of the foot
  • Lucidum present
  • No hair follicles, sebaceous glands, or arrector pili muscles
17
Q

What are all Epidermal Derivatives and Where are they form from?

A
  • ALL derived (formed) from the epidermis
    1. Hair
    2. Nails
    3, Skin Exocrine Glands
18
Q

Hair

A
  • All dead cells
  • Parts:
    1. Root = Part of hair embedded within skin
    2. Shaft = Visible part of hair above the skin surface
    3. Hair Follicle - surrounds root
19
Q

What are the parts of Hair Follicle?

A
  1. Epithelial root sheath = several epidermal layers extend into the dermis
  2. Bulb - expanded region at base of root
  3. Matrix = single layer of cells (derived from basale cells) - site of hair growth and melanin for hair colour
20
Q

What is associated with each hair follicle?

A
  1. Outer CT sheath → holds follicle in place (formed from the dermis)
  2. Hair papilla - extends upward beneath matrix
    • Contains blood supply for growing hair
    • Formed from dermis
  3. Root hair plexus - free nerve ending (touch)
  4. Sebaceous (oil) gland - opens into follicle
  5. Arrector pili muscle (Smooth Muscle) - causes “goosebumps”
21
Q

Nails

A
  • Very heavily keratinized epidermal cells
  • consists of:
    • Nail root (buried in skin)
    • Body (visible portion)
    • Free edge
22
Q

What are the Skin Exocrine Glands?

A
  1. Sebaceous Glands
  2. Sudoriferous Glands
  3. Ceruminous Glands
  4. Mammary Glands
23
Q

Sebaceous Glands

A
  • Connected mainly to hair follicles
  • Secretes sebum (oily - mix of fats, salts, proteins)
    • Softens, lubricates hair and skin, prevents drying out, antibiotic
24
Q

Sudoriferous Glands

A
  • Sweat glands
  • Secretory portions in dermis of thick and thin skin
  • Ducts open onto skin surface
25
Q

What are the Functions of Sudoriferous Glands?

A
  • Temperature regulation - cool the body
  • Antibiotic action (due to sweat being acidic)
  • Waste removal (e.g. urea)
26
Q

Ceruminous Glands

A
  • Modified sweat glands
  • in ear canal
  • Produce ear wax - prevents insects etc from entering
27
Q

Mammary Glands

A
  • modified sweat glands
  • Produce milk
28
Q

What are Cutaneous Sense Receptors?

A
  • Sensory receptors area sensory neuron (part of Nervous System)
  • Specialized cell that responds to stimuli (touch, temperature, pain)
29
Q

What are the 4 major types of Cutaneous Sense Receptors?

A
  1. Touch Receptors
  2. Pressure Receptors
  3. Thermoreceptors
  4. Nociceptors
30
Q

Touch Receptors

A
  • Free nerve endings
    • In Epidermis
  • Root Hair Plexuses
  • Tactile (Meissner’s) Corpuscles
    • In dermis papillae
    • Corpuscle is a connective tissue capsule surrounding a nerve ending
31
Q

Pressure Receptors

A
  • Free nerve endings
    • In dermis
  • Lamellar (Paciniaan) corpuscles
    • Deep in dermis or hypodermis
32
Q

Thermoreceptors

A

Free nerve ending for temperature

33
Q

Nociceptors

A
  • Free nerve endings for pain
  • 3rd degree burns destroy nociceptors, causing lack of pain sensation in affected areas
34
Q

What is Hypodermis?

A
  • NOT part of skin
  • Is also called the subcutaneous layer
  • Is also called superficial fascia
    • Fascia: connective tissue layers that surround and support organs
  • Adipose connective tissue below skin that stores 1/2 of body’s adipose tissue (insulation)
35
Q

What are some related Medical Conditions?

A
  1. Albinism
  2. Psoriasis
36
Q

What is Albinism?

A

Lack of melanin production by melanocytes

37
Q

What is Psoriasis?

A
  • Autoimmune disorder that causes accelerated mitosis of keratinocytes in the stratum basale
    • Accelerated cell cycle delays maturation and differentiation of keratinocytes
    • Immature keratinocytes accumulate in the epidermis and the stratum corneum fails to shed, resulting in a thick scaly area on the surface of the skin (plaque)