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BIOL235 Anatomy & Physiology > Chapter 5: The Integumentary System > Flashcards

Chapter 5: The Integumentary System Flashcards

1
Q

Two main parts of the skin

A

Superficial thin epidermis (epithelial tissue) and deep thick dermis (connective tissue)

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2
Q

What are the 6 functions of the integumentary system?

A

1) Regulates body temp, 2) Stores blood, 3)Protects body from external env 4) Detects cutaneous sensations, 5) Excretes and absorbs substances, 6) Synthesizes vitamin D

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3
Q

What is the function of the subcutaenous layer (hypodermis)?

A

Has areolar and adipose tissue. Storage depot for fat and contains large blood vessels that supply the skin.Also contains nerve endings called LAMELLATED CORPUSCLES (which are sensitive to pressure).

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4
Q

What are the 4 main types of cells of the epidermis?

A

Keratinocytes, melanocytes, intraepidermal macrophages, and tactile epithelial

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5
Q

What do keratinocytes do?

A

Arranged in 4-5 layers. Account for 90% of epi cells. produce the protein KERATIN (protects the skin and tissues from abrasions, heat, water loss, microbes and chemicals) and produces LAMELLAR GRANULES (releases a water repellant sealant which decreases water entry and loss and inhibits the entry of foreign materials).

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6
Q

What are melanocytes and what do they do?

A

Produces the pigment MELANIN. Long slender projections between keratinocytes and transfer melanin granules to them. Contibutes to skin colour and absorbs UV light. When inside keratinocytes, melanin granules cluster to form a protective veil over the nucleus (to shield the nuclear DNA from UV damage)

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7
Q

What do intraepidermal macrophages do?

A

AKA Langerhans cells. Arise from red bone marrow and migrate to epidermis. Participates in the immune responses mounted against microbes that invade the skin. Easily damaged by UV. Helps other cells of immune system recognize an invading microbe and destroy it.

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8
Q

What are tactile epithelial cells?

A

Least numerous epidermal cells. Deepest layer of epidermis. Contact the flattened process of a sensory neuron, a structure called a TACTILE DISC… detects touch sensations

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9
Q

What are the 4 strata/layers in most epidermis?

A

Stratum basale, stratum spinosum, stratum granulosum, and thin stratum corneum (thin skin)

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10
Q

Wat are the 5 layers/strata of the epidermis where exposure to friction is greatest (ie fingertips, palms, soles)?

A

Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum and a thick stratum corneum (thick skin)

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11
Q

What is the stratum basale composed of?

A

A single row of cuboidal columnar keratinocytes. Some cells are stem cells and produce new keratinocytes

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12
Q

What are keratin intermediate filaments?

A

In the stratum basale. They are in the cytoskeleton within keratinocytes and form the tough protein keratin in its more superficial layer. They attach to desmosomes which bind cells of the stratum basale to eachother and to the cells of the adjacent stratum spinosum and to hemidesmosomes, which bind the keratinocytes to the basement membrane between the epidermis and dermis

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13
Q

What is the stratum spinosum composed of?

A

Mostly consists of many keratinocytes arranged in 8-10 layers… cells in more superficial layers are somewhat flattened. Keratinocytes provide the stratum spinosum which are produced by the stem cells in the basal layer. The keratinocytes of this later produce coarser bundles of keratin in intermediate filaments. Under the miscroscope looks like cells of the stratum spinosum are covered with thorn-like spines. At each spinelike projection, bundles of keratin intermediate filaments insert into desmosomes which tightly join the cells together… provides strength and flexibility to skin. Intraepidermal macrophages and projections of melanocytes also present

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14
Q

What makes up the stratum granulosum?

A

3.5 layers of flattened keratinocytes that undergo apoptosis. The nuclei and other organelles of these cells begin to degenerate as they move further from their source of nutrition (dermal has blood vessels). A feature of cells in this layer are darly staining granules of a protein called KERATOHYALIN which assembles keratin intermediate filaments into keratin. Also present in the keratinocytes are membrane-enclosed lamellar granules which fuse with the plasma membrane and release lipid-rich secretion which is deposited in the spaces between cells of the stratum granulosum, stratum lucidum and stratum corneum ….. acts as water-repellent seal. Therefore the stratum granulosum marks the transition between deeper metabollically active strata and the dead cells of the superficial strata

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15
Q

What is the stratum lucidum made up of?

A

Only present in areas like fingertips, palms and soles (thick skin). 4-6 layers of flattened dead keratinocytes that contain lots of keratin and thickened plasma membranes.

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16
Q

What is the stratum corneum made of?

A

25-30 layers of flattened dead keratinocytes. Cells are thin flat plasma membrane-enclosed packages of keratin that no longer contain a nucleus or other organelles. Final profuct of the differentiation processes of keratinocytes. Cells continuously shed and replaced by cells in deeper strata

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17
Q

Describe the keratinization and growth of epidermis

A

Newly formed cells in the stratum basale are slowly pushed to the surface. As Cells move from one epidermal layer to the next, they accumulate more and more keratin (a process called KERITANIZATION) then they undergo apoptosis. Cells form in the stratum basale, become keratinzed and slough off which takes 4-6 weeks. The cells in the dermis produce the most keratinocytes via cell division because they have the most access to blood supply

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18
Q

What is dermis composed of?

A

Dense irregular connective tissue containing collagen and elastic fibres. Great tensile strength (resists pulling and stretching). Stretches and recoils more easily. Has mainly fibroblasts and some adipocytes near its boundary with the subcutaneous layer. Blood vessels, nerves, glands, and hair follicles are embedded in the dermal layer. Dermis is essential to survival of epidermis.

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19
Q

What are the 2 regions of the dermis?

A

The thin superficial PAPILLARY REGION and thick deeper RETICULAR REGION

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20
Q

What’s in the papillary region of the dermis?

A

Thin collagen and fine elastic fibres. SA increased by dermal papillae which are small nipple shaped structures that project into the undersurface of the epidermis. All dermal papillae contain capillary loops and some contain tactile receptor called corpuscles of touch (nerve endings sensitive to touch) or free nerve endings (dentrites that lack any apparent structural specialization)… initiates signals that give rise to sensations of warmth, coolness, pain, tickling and itching.

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21
Q

What is the reticular region of the dermis?

A

Attached to the subcutaneous layer, hasb undles of thick collagen fibres, scattered fibroblasts and wandering cells (ie macrophages). Also has some adipose cells and coarse elastic cells in the deepest layer. Collagen fibres in a more regular arrangement that those in papillary region… which helps resist stretching. Blood vessels, nerves, hair follicles, oil glands, sweat glands occupy the spaces between fibres. The collagen and elastic fibres in this region give the skin extensibility (ability to stretch) and elasticity.

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22
Q

What are the 3 pigments that impart a variety of colours to the skin?

A

1) Melanin, 2) hemoglobin 3) carotene

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23
Q

What are the two forms of melanin?

A

Pheomelanin (yellow/red) and eumelanin (brown and black)

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24
Q

Where are melanocytes most plentiful?

A

Epidermis of penis, nipples of breasts, area around nipples (areola), face, and limbs

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25
Q

WHat are age spots?

A

An accumulation of melanin in patches… builds up overtime due to exposure of sunlight

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26
Q

What is a mole/nevus?

A

A round, flat or raised area that is a localized growth of melanocytes

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27
Q

How do melanocytes synthesuze melanin?

A

Melanocytes synthesize melanin from the amino acid tryonise in the presence of the enzyme tyrosinase. Synthesis occurs in an organelle called MELANOSOME

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28
Q

What does exposure toUV light do to enzymes?

A

Exposure to UV light increases enzymatic activity within melanosomes so increases melanin production (tanned)

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29
Q

What are the functions of melanin?

A

Absorbs UV radiation, prevents damage to DNA and neutralizes free radicals. Small amounts of UV radiation necessary to start process of DNA synthesis

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30
Q

What is carotene?

A

Yellow-orange pigment that gives egg yolks and carrots their colour. Precursor of vitamin A, stored in stratum corneum and fatty areas of dermis and subcutaneous layer. Eat enough and skin may turn orange.

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31
Q

What is tattooing?

A

Foreign pigment is deposited with a needle into the dermis. Since dermis is stable (unlike epi which sheds 4-6 weeks) tattoos are permanent

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32
Q

How are tattoos removed via lasers?

A

Tattoo dissolves into small ink particles that are eventually removed by immune system

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33
Q

What are some complications of body piercing?

A

Infection, allergic reactions, anatomical damage, may interfere with some medical procedures (like resuscitation masks, airway maagement procedures, urinary catheterization. Radiographs, having a baby)

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34
Q

What are the accessory structures of the skin?

A

Hair, skin, glands, nails…. develop from embryonic epidermic

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35
Q

Where is hair not located?

A

Palmer surfaces, soles, and planter surfaces

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36
Q

What is the function of hair?

A

Hair on head guards scalp from injury and sun’s x-rays, eyebrows and eyelashes protect eyes from foreign particles, also functions in sensing light touch

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37
Q

What is the shaft of the hair?

A

Superficial portion above the surface

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38
Q

What is the root of the hair?

A

Penetrates into dermis and sometimes into the subcutaneous layer

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39
Q

The shaft and the root each consist of 3 layers of cells. What are these 3 layers?

A

1) Medulla (inner part. 2-3 rows of irregularly shaped cells that have parts of pigment granules in dark hair, small amounts in grey hair and a lack of pigment granules and presence of air bubbles in white hair). 2) Cortex (middle. Major part of the shaft and consists of elongated cells). 3) Cuticle of hair (Outermost layer. Single layer of thin flat cells that are very keratinized. Cuticle cells are arranged like shingles on the side of a house).

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40
Q

What is the hair follicle?

A

Surrounding the root of the hair. Made up of an external and internal root sheath (together they are referred to as epithelial root sheath)

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41
Q

What is the external and internal root sheath?

A

External root sheath is a downward continuation of epidermis. Internal root sheath is produced by the matrix. Forms a cellular tubular sheath by epithelium between the external root sheath and hair

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42
Q

What is the dermal root sheath?

A

Dense dermis surrounded by the hair follicle

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43
Q

What is the bulb of hair?

A

Base of each hair follicle and its surrounding dermal root sheath

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44
Q

What is the papilla of the hair?

A

It’s located in the bulb. It contains areolar connective tissue and many blood vessels to nourish the growing hair follicle

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45
Q

What is the hair matrix and where is it located?

A

Located in the bulb and is a germinal layer of cells. Arises from the stratum basale. Hair matrix cells responsible for the growth of existing hairs and producing new ones (ie replacement).

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46
Q

What is arrector pilli muscle?

A

Smooth muscle. Extends from the superficial dermis of the skin to the dermal root sheet at side of hair follicle. You get goose bumps because under physiological and emotional stress autonomic nerve endings stimulate the arrector pili muscles to contact

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47
Q

What is the hair root plexus?

A

Dendrites of neurons surrounding each hair follicle and is sensitive to touch

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48
Q

What are the stages in the hair follicle growth cycle?

A

Growth stage, regression stage, resting stage

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49
Q

What is the growth stage in the hair follicle cycle?

A

Cells of matrix divide. As new cells from hair matrix are added to the base of the hair root, existing cells are pushed upward (and keratinize and die) and the hair grows

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50
Q

What is the regression stage of the hair follicle cycle?

A

Cells of hair matrix stop dividing, hair follicle atrophies (shrinks) and hair stops growth

51
Q

What is the resting stage of the hair follicle cycle?

A

Following a resting stage, new growth begins, Old hair root falls out or is pushed out of the hair follicle and new hair begins to grow in its place

52
Q

What effects the rate of growth and replacement of hair?

A

Illness, radiation / chemo therapy, age, genetics, gender, severe emotional stress

53
Q

What is LANUGO hair?

A

Very fine, non-pigmented downy hairs that cover the body of the fetus

54
Q

What is TERMINAL hairs?

A

Replaces the lanugo of the eyebrows, eyelashes and scalp prior to birth. Long, coarse, heavily pigmented

55
Q

What are vellus hairs?

A

Replaces the lanugo on the rest of the body. Called “peach fuzz”, fine and pale. DUring puberty, terminal hairs replace vellus in the axillae (armpits) and pubic regions of boys and girls, and the vellus hairs on the face, limbs and chest of boys.

56
Q

Where does hair colour come from?

A

Melanin is synthesized by melanocytes scattered in the matrix of the bulb and passes into cells of the cortex and medulla

57
Q

What colour hair does eumelanin produce>?

A

Dark

58
Q

What colour of hair does pheomelanin produce?

A

Blond and red

59
Q

Why are permanent hair dyes permanent?

A

They penetrate deep into the hair shaft

60
Q

What are sebaceous glands and what are their functions?

A

Simple branched accinar. Connected to hair follicles usually. Secreting portion lies in the dermis and usually opens into the neck of a hair follicle. Small in most areas of the trunks and limbs. Large in the skin of the breasts, face, neck and superior chest.

61
Q

What is the sebum and what are the functions?

A

It’s an oily substance secreted by sebaceous glands. A mix of triglycerides, cholesterol, proteins and inorganic salts. Sebum coats the surface of hairs and prevents them from drying out, prevents excess evaportation from skin, keeps skin soft and pliable, inhibits growth of some bacteria

62
Q

What are subdoriforous glands?

A

3-4 million sweat glands. Two kinds (based on structure and type of secretion): Eccrine and apocrine

63
Q

What are eccrine sweat glands?

A

Simple coiled tubular. More common than apocrine. Distributed throughout the body but especially in forehead, palms and soles. Secretory portion deep in dermis. Sweat produced is mainly water with small amounts of ions (Na and Cl), rea, uric acid, ammonia, amino acids, glucose and lactic acid. Helps regulate body temp through THERMOREGULATION. Functions soon after birth.

64
Q

What is thermoregulatory sweating?

A

Sweat first fors in forehead and scalp and then extends to rest of body

65
Q

What is insensible perspiration and sensible perspiration?

A

Insensible —> Sweat that evaportates from skin BEFORE it’s perceived as moisture.

Sensible —> Sweat that evaporates from skin after it’s perceived as moisure

66
Q

What are apocrine sweat glands?

A

Simpl coiled tubular. In the skin of axilla (armpits), groin, areolae of breasts, bearded region of face. Secretion is via exocytosis (NOT aporine secretion). Secretory portion located in lower dermis or upper subcutneous layer. Sweat contains same components as eccrine but adds 2 additional things lipids and proteins. Only active when you hit puberty

67
Q

What are ceruminous glands?

A

Modified sweat glands in external ear. Produces waxy lubricating excretion. Secretory portions are in the subcutaneous layer deep into sebaceous glands. Either open direction to surface of external auditory canal or int ducts of sebaceous glands. CERUM is the combined secretion of sebaceous glands and ceruminous… sticky barrier that impedes the entrance of foreign bodies and insects. AKA EARWAX

68
Q

What are the 3 parts of a nail

A

Nail body, free edge and nail root

69
Q

What is the nail body?

A

Visible. Flattened keratinized cells with a hard type of keratin. Cells not shred.

70
Q

What are free edges in Nails?

A

Part of nail body that may extend past distal end of diget. White because no underlying capillaries.

71
Q

What is the nail root?

A

Buried under the feild of skin. Crescent… shaped area of the proximal end of the nail body is called LUNULA

72
Q

What is the hyponychium?

A

Beneath the free edge. Thick reagion. Secures nail to fingertip / toa nail

73
Q

What is a nail bed?

A

The skin beow the nail plate that extends from the lunula to hyponychium

74
Q

What is the eponychium (cutcle)?

A

Narrow band of epidermis… accumulates the border of the nail and consists of stratum corneum

75
Q

What is the nail matrix?

A

Epithelium proximal to the nail root. Cells divide mitotically to produce new nail cells. Rate of mitosis depends on: age, health, nutritional status, season, time of day and environmental changs in temp

76
Q

What are 3 functions of nails?

A

1) Protect distal end of digets
2) Provides support and counter pressure to the palmer surface of the fingers to enhance touh perception
3allows us to grasp and manipulate small objects and scratch and groom the body

77
Q

what are the two types of skin?

A

thin (hairy) and thick (hairless skin)

78
Q

what is thermoregulation?

A

homeostatic regulation of body temp

79
Q

What are the 2 ways skin contributes to thermoregulation?

A

liberating sweat at surface and adjusting blood flow in dermis

80
Q

How does skin respond to high envirnmentla temp?

A

evaporation to cool or dilation of blood gessels in dermis to let blood flow through dermis which increases heat loss

81
Q

how does skin respond to low environmental temp?

A

production of sweat from eccrine glands is decreased and blood vessels in the dermis constrict which decreases blood flow through skin and reduces heat loss

82
Q

what is a blood reservoir?

A

skin acts like one because the dermis houses an extensive network of blood vessels

83
Q

function of keratin

A

protects underlying tissue from microbes, abrasions, heat and chemics

84
Q

function of sebum from sebaceous glands

A

keeps skin and hair from drying out and contains bactericidal chemicals

85
Q

what benefit does the acidic ph of perspiration have?

A

slows growth of some microbes

86
Q

what is the benefit of pigment in melanin?

A

helps shield against the damaging effects of uv

87
Q

what do intraepidermal macrophages do?

A

alert immune system to the presence of potentially harmful microbial invaders

88
Q

what do macrophages in the skin do?

A

in the dermis and they phagocytize bacteria and viruses that bypass the intraepidermal macrophages of the epidermis

89
Q

name some cutaneous sensations

A

tactile, thermal and pain. many nerve endings are distributed in the skin: tactile discs, corpuscles of touch in the dermis and hair root plexus around each hair follicle

90
Q

what is excreted in the sweat?

A

small amounts of salt, co2, and 2 organic molecules that result from the breakdown of proteins (ammonia and urea)

91
Q

What is able to penetrate the skin?

A

certain lipid soluble materials like fat soluble vitamins (A, D, E, K), certain drugs, and gases O2 amd CO2

92
Q

what toxic materials can be absorbed through the skin?

A

organic solvents like acetone (in some nail polish removers), carbon tetrachloride (dry cleaning fluid), salts of heavy metals like lead, mercury, and arsenic, and substances in poison ivy and poison oak

93
Q

how do topical steroids like cortisone work?

A

they are lipid soluble as they move easily into the papillary region of the dermis where they exert their anti inflammatory properties by inhibiting histamine production by mast cells

94
Q

How is vitamin D synthesized?

A

Need small UV exposure. Enzymes in liver and kidneys modify the activated molecules, producing CALCITRIOL which is the most active form of vitamin D… Calcitriol is the horome that aids in the absorption of calcium from foods in the GI tract into the blood

95
Q

Functions of vitamin D

A

Vit D activated in response to an infection like the flu, may enhance activity, increas production of antimicrobial substances in phagocytes, regulate immune functions and help reduce inflammation

96
Q

what are the two types of wound healing?

A

epidermal wound healing (wounds affect epidermis only) and deep wound healing (wounds penetrate dermis)

97
Q

what happens during epidermal wound healing?

A

Basal cells of epidermis break contact with basement membrane. The cells then enlarge and migrate across the wound. When epidermal cells encounter one another they stop migrating due to a cellular response called CONTACT INHIBITION? Migration of epidermal cells stop completely when each is finally in contact with other epidermal cells on each side. A hormone called EPIDERMAL GROWTH FACTOR stimulates basal stem cells to divide and replace ones that have moved inward

98
Q

Describe deep wound healing

A

Injury extends to dermis and scar tissue is formed. Has 4 phases: inflammatory phase, migration phase, proliferative phase and maturation phase

99
Q

Describe the inflammatory phase of deep wound healing

A

A blood clot forms in the wound and loosely unites the wound edges. Inflammation occurs which is a vascular response that helps eliminate microbes, foreign materials and dying tissue in preparation for repair. Vasodilation and increased permeability of blood vessels associated with inflammation enhance the delivery of helpful cells (neutrophils, monocytes and mesenchymal cells which develop into fibroblasts)

100
Q

What is the migratory phase of deep wound healing?

A

Blood clot becomes a scab and epithelial cells migrate beneath the scab to bridge the wound. Fibroblasts begin synthesizing scar tissue and damaged blood vessels begin to regrow. Tissue filling the wound is GRANUALTION TISSUE

101
Q

What is the proliferative phase of deep wound healing?

A

Extensive growth of epithelial cells beneath the scab. Deposition of fibroblasts of collagen fibres in random patterns and continued growth of blood vessels

102
Q

What is the maturation phase of deep wound healing?

A

Scab sloughs off once epidermis is restored to normal thickness. Collagen fibres become more organized, fibroblasts decrease in number and blood vessels restored to normal

103
Q

What’s the difference between scar tissue and normal tissue?

A

Collagen fibres more densely arranged, decreased elasticity, fewer blood vessels and may or may not have same number of hairs, glands and sensory structures

103
Q

What happens with the integumentary system after the 4th week of development?

A

Epidermis consists of only a single layer of ectodermal cells

104
Q

What happens with the integumentary system after the 7th week of development?

A

The single layer (basal layer) divides and forms a superficial protected layer of flattened cells called the PERIDERM. Peridermal cells are always being sloughed off

105
Q

What happens with the integumentary system during 11th week of development?

A

Basal layers form an INTERMEDIATE LAYER of cells. Cells from the ectoderm migrate into the dermis and differentiate into MELANOBLASTS. These cells will soon enter the epidermis and differentiate into melanocytes. ALSO, mesenchymal cells differentiate into fibroblasts and begin to form collagen and elastic fibres. DERMAL PAPILLAE (containing capillary loops, corpuscles of touch and free nerve endings) also arise

106
Q

What happens with the integumentary system in late first trimester of development?

A

INTRAEPIDERMAL MACROPHAGES (arise from red bone marrow) invade the epidermis

107
Q

What happens with the integumentary system during month 5 of development?

A

Secretions from sebaceous glands mix with them and hairs to form a fatty substance called VERNIX

108
Q

What happens with the integumentary system during month 4-6 of development?

A

Tactile epithelial cells appear

109
Q

What happens with the integumentary system after the 12th week of development?

A

Hair follicles develop as downgrowths of the basal layer of the epidermis into the deeper dermis. The downgrowths are called HAIR BUDS (their distal ends called hair bulbs). Cells in the centre of the bulbs are the hair matrix. Peripheral cells of hair bulb form the epithelial root sheath. Mesenchyme in the surrounding dermis develops into the DERMAL ROOT SHEATH and errector pilli muscle.

110
Q

What happens with the integumentary system after the 5th month of development?

A

Hair follicles produce lanugo (delicate fetal hair)

111
Q

Where / when do sebaceous oil glands come from?

A

Develop at ~4 as outgrowths from sides of hair follicles

112
Q

Where to subdiferous (sweat) glands come from?

A

Derived from downgrowths (buds) of the stratum basale of the epidermis into the dermis. Appears at around 5 months on palms and soles and a little longer in other areas

113
Q

When do nails develop?

A

At around 10 weeks. Initially consists of a thick layer of epithelium called the PRIMARY NAIL FIELD. Ninth month is when nails actually reach tips of digits

114
Q

How does aging effect collagen fibres in skin?

A

Collagen fibres in the dermis decrease in number, stiffen, break apart, and disorganize into a matted tangle

115
Q

How does aging effect elastic fibres?

A

Elastic fibres lose some elasticity, thicken into clumps and fray… this is accelerated in smokers

116
Q

How does aging affect fibroblasts?

A

Fibroblasts produce collagen and elastic fibres. Aging decreases the number… results in wrinkles

117
Q

How does aging affect intraepidermal macrophages?

A

Decreases in number and becomes less efficient phagocytes

118
Q

How does aging affect sebaceous glands?

A

Aging decreases the size of sebaceous glands so broken skin means more infection

119
Q

Why does heat stroke increase in elders?

A

Production of sweat decreases

120
Q

Why do old people have gray hair?

A

Decreased number of melanocytes. Also balding because hair follicles stop producing hair

121
Q

What are age spots?

A

Increase in size of some melanocytes produces pigmented blotching

122
Q

What are some other results of aging?

A

Skin is thinner than in young, heals poorly so more susceptable to pathological conditions like skin cancer and pressure sores, nails brittle

123
Q

Several cosmetic anti-aging treatments are available to diminish effects of aging. What are these?

A

Topical products, microdermabrasion, chemical peel, laser resurfacing, dermal fillers, fat transplantation, botulinum toxin (botox), radio frequency nonsurgical face lift, and facelift/browlift/neck lift

BIOL235 Anatomy & Physiology (10 decks)

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