BY 115 Integumentary System, Bone, and Cartilage

Skin

Epidermis + dermis

Epidermis

Superficial epithelial layer; keratinized stratified squamous epithelium; avascular; keratinization contributes to the protective, water-resistant barrier

Dermis

Deeper connective tissue layer

Subcutaneous layer/Hypodermis

Lies deep to the skin but is not part of it

Major functions of integument

Protection, prevention of water loss, temperature regulation, sensation, immune defense, secretion and metabolic functions

Epidermal Strata (Deep to Superficial)

Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

Stratum basale

Deepest epidermal layer; keratinocytes attached near the basement membrane; mitotically (copies of identical cells) active cells produce new keratinocytes

Stratum spinosum

Several layers of keratinocytes which undergo structural changes at they move toward the surface; contains many epidermal dendritic cells; keratinocytes move superficially and continue differentiating

Stratum granulosum

Keratinocytes become flatter, keratinization becomes prominent; nuclei and organelles begin to degenerate

Keratinization

Progressive accumulation of keratin and transformation of keratinocytes as they move toward the surface

Identify 1

Integument

Identify 2

Dermis

Identify 3

Subcutaneous layer

Identify 4

Epidermis

Identify 1

Stratum corneum

Identify 2

Stratum lucidum

Identify 3

Stratum granulosum

Identify 4

Stratum spinosum

Identify 5

Stratum basale

Identify 6

Dermis

Stratum lucidum

Present only in thick skin; thin, translucent layer; flattened anucleated keratinocytes

Stratum corneum

Most superficial epidermal layer; many laters of dead, keratinized cells that continuously shed; forms an important protective and water-resistant barrier

Thick epidermis

All five layers present; found on palms of hands and soles of feet

Thin epidermis

Have all epidermal layers except for stratum lucidum

Identify

Thick epidermis

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Thin epidermis

Keratinocytes

Throughout epidermis; produce keratin and act as a protective barrier

Melanocytes

Found in stratum basale; produces melanin

Epidermal dendritic cells

Primarily found in stratum spinosum; act as immune defense

Tactile cells

Found in stratum basale; serve as touch sensation

Dermis

Connective tissue layer deep to epidermis; consists of papillary layer and reticular layer; contains blood vessels, nerves, glands, and hair follicles

Papillary layer

Primarily areolar CT; superficial layer of dermis, contains dermal papillae, interdigitates with epidermis

Identify

Papillary dermis

Reticular layer

Primarily dense irregular CT; deeper and thicker dermal layer; contains blood vessels and nerves, glands, hair follicles

Identify

Reticular layer

Dermal fiber orientation

Collagen bundles in the reticular dermi have predominant orientations, which have tension/cleavage lines

Fiber organization

Affects how skin responds to mechanical stress

Perpendicular incisions

More likely to open due to cute elastic fibers

Parallel incisions

More likely to heal quickly

Identify

Perpendicular incision; more likely to open due to cut elastic fibers

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Parallel incision; more likely to heal quickly

Subcutaneous layer

Also hypodermis and superificial fascia; lies deep to skin but not part of it; primarily areolar and adipose CT; anchors skin, cushions, insulates, and stores energy

Identify

Subcutaneous layer

Nails

Composed of keratinized cells; protects and supports the distal digits; consists of nail plate/bodyl root, bed, and matrix

Nail plate/body

Visible, hardened portion of the nail

Nail root

Proximal portion hidden beneath the skin

Nail bed

Tissue directly beneath and supporting the nail plate

Nail matrix

Growth region that produces new nail cells

Hair shaft

Portion that projects above the skin surface

Hair root

Portion located below the skin surface

Hair bulb

Enlarged base of the root where hair growth occurs

Hair follicle

Epidermal sheath that surrounds the root

Arrector pili muscle

Smooth muscle attached to the follicle; contraction raises the hair; involuntary

Hair

Consists of hair shaft, root, bulb, follicle, and arrector pili muscle; protects and receives sensory information

Merocrine sweat

Goes to skin surface, acts as thermoregulation

Merocrine

Intact cell

Apocrine Sweat

Goes to hair follicle, thick regional secretion

Sebaceous

Secretes sebum that usually goes to hair follicle, acts as a lubricant for skin and hair

Major functions of skeletal system

Support and protection, movement, hemopoiesis, mineral storage, energy storage

Movement

Attachment sites for muscles

Hemopoiesis

Blood cell production in red bone marrow

Mineral storage

Calcium and phosphate

Energy storage

Lipids stored in yellow bone marrow

Flat bones

Thin, flat surfaces

Examples of flat bones

Frontal bone, scapula, sternum

Irregular bones

Complex shapes

Examples of irregular bones

Vertebrae, hip bones, sphenoid bone

Long bones

Longer than wide

Examples of long bones

Humerus, fibula, tibia, ulna, radius, phalanges, metacarpals, metatarsals

Short bones

Nearly equal in length and width

Examples of short bones

Carpals, tarsals

Bone markings’ functions

Articulation, passage/opening, muscle/ligament attachment, depression/groove

Articulation

Head, condyle, facet

Passage/opening

Foramen, canal, meatus

Depression/groove

Fossa, sulcus

Diaphysis

Cylindrical shaft

Medullary cavity

Hollow space within the diaphysis; contains primarily yellow bone marrow in adults

Identify

Diaphysis

Identify

Medullary cavity

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Hair shaft

Identify 2

Hair root

Identify 3

Hair follicle

Identify 4

Arrector pili muscle

Identify 5

Hair bulb

Identify 1

Dead keratinocytes

Identify 2

Living keratinocyte

Identify 3

Melanocyte

Identify 4

Epidermal dendritic cell

Identify 5

Basement membrane

Identify 6

Tactile cell

Identify 7

Sensory nerve ending

Identify 1

Nail matrix

Identify 2

Nail root

Identify 3

Nail bed

Identify 4

Nail plate

Identify 5

Dermis

Identify 6

Epidermis

Identify 7

Phalanx