Lesson 5

Front 1

Protection

Back 1

Skin acts as a physical, chemical and biological barrier, to offer protection against damage & infection. Also a barrier to water, inhibiting the loss or absorption of water

Front 2

Thermoregulation

Back 2

Maintains body temperature through sweating or by increasing blood flow to skin, or increase temperature through decreasing blood flow & sweating.

Front 3

Cutaneous Sensations

Back 3

Sensations of heat, cold, itch, touch, pain etc via large amount of nerve endings & receptors in the skin

Front 4

Excretion and absorption

Back 4

Absorption of some lipid soluble materials, & excretion of waste materials from the skin’s glands.

Front 5

Vitamin D production

Back 5

Contains a vitamin d precursor molecule that changes when exposed to light to vitamin d. Vit D is necessary to absorb calcium from the digestive system. Vit D is activated by the kidneys and liver to become a form the body can use.

Front 6

Reservoir for blood

Back 6

8-10% of blood volume is found in the blood vessels of the dermis

Front 7

cutaneous membrane

Back 7

aka skin, 2 layers. Superficial, thinner portion composed of pithelial tissue=epidermis. Deeper thicker connective tissue part=dermis

Front 8

subcutaneous layer

Back 8

aka hypodermis, deep to the dermis not part of skin composed of areolar and adipose tissues. storage for fat and large blood vessels that supply the skin.

Front 9

Keratin

Back 9

tough, fibrous protein that helps protect the skin and underlying tissues from heat, microbes, and chemicals.

Front 10

Keratinocytes

Back 10

90% of epidermal cells, form the protective layer. produce the protein keratin and lamellar granules which release a water-repellent sealant.

Front 11

Melanocytes

Back 11

8% of epidermal cells, deep in epidermis. produce the pigment melanin which provides protection from ultraviolet light

Front 12

Langerhans cells

Back 12

arise from red bone marrow and migrate to the epidermis, special type of white blood cell, release hystamines. participate in immune responses against microbes

Front 13

Merkel cells

Back 13

least numerous epidermal cells, located in the deepest layer where they contact the flattened process of a sensory neuron called a tactile (merkel) disc.

Front 14

Layering of the epidermis-superficial to deep

Back 14

1)Stratum corneum 2)Stratum lucidum -thick skin only 3)Stratum granulosum 4)Stratum spinosum 5)Stratum basale

Front 15

Thick skin is found

Back 15

Palms, fingers, soles of feet. thick stratum spinosum and corneum, stratum lucidum is present, more dermal papillae (palm, finger,foot prints)

Front 16

Dermis

Back 16

2nd deeper part of the skin composed mainly of connective tissue, blood vessels, nerves, glands, and hair follicles.

Front 17

Papillary layer

Back 17

1/5 of total dermal layer. areolar connective tissue.

Front 18

Dermal Papillae

Back 18

fingerlike projection of the papillary region of the dermis that may contain capillary loops (blood capillaries) some contain touch receptors called corpuscles of touch and free nerve endings. blood vessels in the dp reduce the distance to each cell...nutrients can reach the cells and waste doesn't accumulate

Front 19

Reticular layer

Back 19

deep layer of the dermis that is attached to the subcutaneous layer. dense irregular connective tissue, a few adipose cells, hair follicles, nerves, sebaceous glands and sudoriferous (sweat)glands.

Front 20

Capillary loops

Back 20

smooth muscle sphincters regulate blood flow. Normal conserve heat, blushing lose heat.

Front 21

Color of skin

Back 21

Melanin, hemoglobin, and carotene 3 pigments that create wide variety of skin colors.

Front 22

Hair

Back 22

aka pili, offers some protectin from injury and sun (head) decreases heat loss, protects eyes, ears, nose from foreign particles, sensing light touch

Front 23

hair shaft

Back 23

superficial portion of the hair which projects above the surface of skin

Front 24

hair root

Back 24

portion of hair deep to the shaft that penetrates into the dermis and sometimes into the subcutaneous layer.

Front 25

3 concentric layers of hair

Back 25

shaft and root have inner medulla layer, middle cortex, and the cuticle.

Front 26

hair follicle

Back 26

surrounds the root of the hair made up of an external root sheath and and internal root sheath together reffered to as an epithelial root sheath.

Front 27

bulb

Back 27

base of each hair follicle. houss the papilla of the hair (contains areolar tissue and blood vessels that nourish the growing hair. also contains a germinal layer of cells called the matrix.

Front 28

hair growth

Back 28

eash follicle goes through a growth stage and a resting stage. during growth cells of the matrix differentiate, keratinize and die as new cells are added at the base of the hair root it grows longer. after resting hair falls out and new hair begins to grow in its place.

Front 29

Sebaceous glands

Back 29

usually connected to hair follicles, secrete oil onto cuticle of hair. strengthen hair

Front 30

eccrine sweat glands

Back 30

sweat on to surface of skin, more common. located in the deep dermis sometimes the upper subcutaneous layer

Front 31

apocrine sweat glands

Back 31

sweat onto hair, armpits and groin, begin to function at puberty.

Front 32

Nails

Back 32

plates of tightly packed, hard, dead, keratinized epidermal cells.

Front 33

nail matrix

Back 33

deep to the nail root were cells divide by mitosis to produce growth

Front 34

nail root

Back 34

portion that is buried in a fold of skin

Front 35

epinychium

Back 35

aka cuticle a narrow band of epidermis that extends from and adheres to the margin of the nail wall

Front 36

hyponychium

Back 36

secures nail to fingertip

Front 37

nail growth

Back 37

cells divide by mitosis in the matrix, specialize into nail cells.

Front 38

superficial wounds

Back 38

only damage to the epidermis, doesn't bleed. cells in the stratum basale divide and migrate to cover the wound and the other layers are replaced from the stratum basale, a little pain b/c nerve projections in epidermis.

Front 39

deep wound healing

Back 39

when a wound extends to the dermis and subcutantious layer. 4 stages.

Front 40

Inflammatory phase

Back 40

blood clot forms, inflammation helps eliminate microbes, foreign material and dead cells. WBC, phagocytes migrate into area, blood vessels open up to get more blood flow to area.

Front 41

Migratory phase

Back 41

scab forms, migration of stratum basale, fibroblasts migrate, blood vessels grow. begins process of healing.

Front 42

Proliferative phase

Back 42

epithelial growth, random collagen, blood vessels grow.

Front 43

Maturation phase

Back 43

scab sloughs off. organized collagen, normal circulation.

Front 44

neutrophils

Back 44

phagocytic white blood cells. come during inflammatory phase

Front 45

monocyte

Back 45

develop into macrophages that phagocytize microbes. come during inflammatory phase

Front 46

first degree burn

Back 46

damage to epidermis

Front 47

second degree burn

Back 47

damage to dermis

Front 48

third degree burn

Back 48

damage to hypodermis and deeper tissues

Front 49

accessory structures of the integumentary system

Back 49

hair nails and glands

Front 50

Two layers of the skin

Back 50

Epidermis and dermis

Front 51

Hypodermis

Back 51

Is associated but not part of the skin. It is composed largely of adipose and areolar tissue and it anchors the skin to its underlying structures, such as muscle.

Front 52

Stratum Basale

Back 52

The deepest layer of the skin. These cells rest on the basement membrane and are stem cells capable of dividing and replace lost skin cells. A scattering of cells in this area include keratinocytes, melanocytes, Langerhans and merkel cells. One row of cuboidal or columnar keratinocytes.

Front 53

Stratum Spinosum

Back 53

This layer is several cell layers (fitted closely together)thick and the cells are connected with desmosomes. Cells contain keratin protein fibers and lamellar bodies. Langerhan’s and melanocyte cells are found most often in this layer in small numbers. The thickest layer of the epidermis.

Front 54

Stratum Granulosum

Back 54

Found in the middle of the epidermal layer, it has up to five layers of flattened, dead keratinocytes . Cells become squamous, fill with keratin, produce lipids for waterproofing (lamellar granules)

Front 55

Stratum Lucidum:

Back 55

This layer is only found in only in thick skin and is lacking entirely in the thinner skin that covers most of your body. Areas of thick skin would be the palm of your hands & the soles of your feet(High friction areas).Three to five layers of dead, flattened keratinocytes, clear in appearance.

Front 56

Stratum Corneum:

Back 56

This is the most superficial layer of skin. Cells in this layer are cornified to protect against abrasion and penetration and are waterproofed by deeper lamellar granules present between the cells. Cells are constantly being sloughed off from this layer and replaced by cells produced in a deeper layer. Up to 30 layers of dead, flat keratinocytes.

Front 57

Dermis has two layers

Back 57

1) Papillary2) Reticular

Front 58

Papillary Layer

Back 58

This is the most superficial layer of the dermis. It is composed of loose areolar connective tissue and is highly vascularized with cutaneous receptors present. The dermal papillae of this region project into the epidermis to form a wavy border. Meissner’s Corpuscles which are light touch sensory receptors are found within this region.

Front 59

Reticular Layer

Back 59

This region accounts for the majority of the dermal area. It is composed of dense irregular connective tissue and is highly vascularized. Pacinian receptors that detect deep pressure are found within this layer along with sensory nerve endings. Hair follicles, arrector pili, and glands are also present within this layer.

Front 60

Skin color is determined by the presence of which three pigments

Back 60

Melanin,Carotene,Hemoglobin

Front 61

Melanin-description

Back 61

Only pigment found in the skin, comes from melanocytes. Its production depends on amino acid tyrosine in the presence of the enzyme tyrosinase. It is taken up by keratinocytes which make them shed their nuclei.Present in larger amounts in the tip of the penis, nipples, face and limbs. Freckles are an accumulation of melanin.

Front 62

Melanin-function

Back 62

Protects the skin from UV light, increase light-increased melanin-tan produced. Person’s skin colour is determined by how much melanin is produced, not by the amount of melanocytes which remains the same.

Front 63

Melanocytes

Back 63

Found in the stratum basale produce melanosomes full of melanin which are phagocytized by the keratinocytes in the upper layers of the epidermis. Melanocytes are activated to increase their production of melanin when they are exposed to ultraviolet radiation. This is why you tan. This increased melanin protects the DNA from damage.

Front 64

Carotene

Back 64

Yellow/orange to reddish pigments obtained from dietry fruits and vegetables. Some are precursors of Vit A, used to synthesis a pigment needed for vision.Found stored in the stratum corneum, fatty areas of the dermis, & subcutaneous area, excess intake will show up as a discolouration in the soles and palms.

Front 65

Hemoglobin

Back 65

Is the pigment found in red blood cells. This pigment is responsible for the red color of oxygenated blood(when deoxygenated it’s purple/blue). This pigment contributes to the 'rosiness' of skin. The lighter the color of melanin present, the greater influence hemoglobin has on overall coloration. Additionally, the closer blood vessels are to the skin, the more apparent this pigment is.

Front 66

Albinism

Back 66

An inherited condition of an inability to produce melanin, melanocytes are unable to synthesis tyrosinase. Melanin is missing from their eyes, skin and hair.

Front 67

Vitiligo

Back 67

Irregular white spots, from a partial or complete loss of melanocytes. Possibly due to immune system malfunction, where antibodies attack melanocytes.

Front 68

Two main types of glands

Back 68

Sweat and oil

Front 69

Sudoriferous (sweat) glands

Back 69

Sweat glands are extremely numerous, covering almost the entire body (except nipples and parts of the external genitalia). Sweat glands may be classified as either eccrine or apocrine, depending upon the substance they secrete.

Front 70

Eccrine sweat glands

Back 70

These are found over most of the body and are the most numerous type of sweat glands. They secrete a type of sweat which is largely composed of water (approximatley 99%) which is filtrated from the blood. In addition to water, minute amounts of salts, metabolic wastes, antibodies, lactic acid and vitamin C make up the other approximately 1% of sweat's composition. Heat activated or emotionally induced. Maintainance of body temperature.

Front 71

Apocrine sweat glands

Back 71

These sweat glands are found only in armpit & groin areas of the body. They secrete sweat into hair follicles & their sweat is similar in composition to that of the eccrine sweat glands except for added fatty substances and proteins. This makes this sweat more viscous with a slightly whitish tinge to it.

Front 72

Sebaceous (oil) glands

Back 72

These glands secrete sebum or oil either into a hair follicle or to the surface of the skin. Sebum helps maintain skin and hair textures by slowing water loss, and making it softer. Additionally, sebum is bactericidal.

Front 73

How is hair color determined?

Back 73

by the amount and kind of melanin pigment produced within the hair cortex by melanocytes and may change over time. White/gray hair has drastically decreased amounts of melanin or lacks melanin completely.

Front 74

Arrector pili muscle

Back 74

is a bundle of smooth muscle tissue that is associated with individual hair follicles. When stimulated, contraction of this muscle causes hair to elevate or 'stand up' and may dimple the skin forming 'goose bumps.'

Front 75

Two types of hair

Back 75

Vellus and terminal

Front 76

Vellus hair

Back 76

thinner, softer (body hair of children and adult females)

Front 77

Terminal hair

Back 77

Thicker, coarser hair, may be darker in color than vellus hair. Hair found on the axillary (underarm) and pubic regions of males and females. This hair type is also found on the face, chest, arms, and legs of males.

Front 78

Nails

Back 78

Nails are composed of a mass of keratinized cells. Nails contain the same type of hard keratin found in hair. The exposed nail is composed of dead cells, while cell division occurs in the underlying nail bed. Nails appear pink due to the hemoglobin in the capillaries of the underlying dermis. The white, moon-shaped portion of the nail is the lunula which lies over the thick nail matrix. The cuticle is the overgrowth of the stratum corneum layer of the skin which attaches to the proximal nail fold.

Front 79

Lanugo coat

Back 79

is a layers of delicate hairs that cover a fetus. These appear approximately in the fifth month of development and are shed in approximately the seventh month of development. At this point vellus hairs replace the lanugo coat.