Integument b

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Integument b

• Chapter 4

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sensory
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Dermis

• Tough supportive ct matrix
• Vascular
• Varies in thickness
• Eyelids- 0.6 mm
• Back, palms, soles 3.0 mm
• Houses accessory structures
• 70 collagen, loose array elastic
• 2 components
• Papillary region
• Reticular region

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Papillary vs Reticular Layers
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Papillary Region

• Loose connective- areolar
• Dermal papillae
• Papilla (cone)
• CT projections into epidermis
• Increase vascularization nervous supply
• Papillary plexus
• Cutaneous nerves
• Push epithelia into surface ridges
• Create epidermal ridges

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Dermal Papillae
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Papillary Plexus
Blood vessels extend up into dermal papilla
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Epidermal Ridges
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Reticular Region

• Dense irregular connective tissue
• Strong tensile support
• Support accessory structures
• No distinct separation between papillary
  reticular region

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Dense Irregular CT
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Accessory Structures
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Accessory Structures

• Embedded /or supported in dermis
• Most in close association or derived from
  epithelial tissue
• Ex Hair, nails, glands
• NOT all ex. Blood muscles
• Contribute the nervous muscular tissue
  components of the integument

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Sensory
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Nervous Supply

• Nerve types
• Merkel cells
• Pacinian corpuscle
• Meissners corpuscle
• General
• Thermoreceptors- dermis, hot cold
• Free nerve ending- pain, dermis
• Root hair plexus- hair follicle
• Varied distribution
• Face, hands, genitalia

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Merkel Nerves

• Merkel cells
• End in epidermis
• Pain, itch, temperature
• Found in higher concentrations in glabrous skin

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Pacinian Corpuscle

• Pacinian corpuscle
• End in dermis- reticular region
• Intense Pressure vibration

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Pacinian Corpuscle
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Pacinian Corpuscle
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Meissners Corpuscle

• Meissners corpuscle
• Dermal papillae
• Lt pressure Touch
• Hands feet

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Nervous Supply

• Autonomic nerves are automatic
• Supply vessels, sweat glands, arrector pilli

Root hair plexus nerves make hairs sensitive to
touch
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Glands

• Exocrine
• Open to surface
• Sebaceous
• Assoc with hair
• Sweat (Sudoriforus)
• Independent of hair
• Ceruminous
• Varied distribution activation

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Sebaceous Glands

• Secrete sebum into hair shaft
• Oil glands secrete sebum
• Holocrine secretion
• Close association with hair follicles
• Lubricates, conditions, inhibits bacteria
• Enlarge during puberty
• Androgen hormones stimulate
• Varied distribution
• Face, scalp, chest, back
• None on glabrous skin

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Sebaceous Glands
Look like eyeballs!
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Sebum
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Sebum coats and protects hair
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Sweat Glands

• Watery secretion
• 99
• Thermoregulation, communication
• Coiled tubular glands
• Dermis
• Merocrine secretion
• Two types
• Eccrine (Merocrine)
• Apocrine

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Eccrine Sweat Glands

• AKA merocrine
• 2.5 million
• Thermal control
• Varied distribution
• Axillae, palms, soles, throughout skin
• Thermal psychological control
• Open to surface of skin
• Watery secretion solution of water ions

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Eccrine Gland
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Apocrine

• Open into hair follicle
• Merocrine secretion mode
• Milky fluid
• Larger
• Sexual scent gland derived
• Symbiotic bacteria
• Varied distribution
• Axillae, perineum (anogenital), areolae

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Ceruminous Glands

• Cerumin
• Thick waxy substance
• Protective
• Apocrine mechanism of secretion

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Hair

• Hair cells
• invagination of epidermis
• Highly keratinized compacted kertatinocytes
• Papilla in dermis
• Blood vessels nerves
• Hair types
• Lanugo- baby
• Vellus- peach fuzz
• Terminal- pigmented
• Function in Communication, sensory, insulation,
  protection
• Varies in distribution
• High concentration in facial area
• Absent in glabrous skin

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Invagination of Epithelium
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Thermoregulation
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Protection
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Sensory
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Hair Structure

• Follicle
• Epidermis sheath into dermis
• houses hair
• Bulb
• Base of follicle
• Contains the germinative layer
• Hair papillae
• Projection into bulb
• Supplies blood nervous
• Root
• Immature living hair
• Not completely keratinized
• 1/2 length of follicle
• Shaft
• Mature exposed part of hair

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Hair Follicle Shaft
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Hair Root
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Hair Bulb
Hair papilla
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Arrector Pili Muscle
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Arrector Pili Muscle
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Nails

• Hardened, densely packed keratin
• Protects finger tips
• Facilitates grasping tactile sensitivity
• Nail plate 0.1 mm/ day

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Hypodermis

• Aka Sub-cutaneous layer, Superficial fascia,
  Sub-Q
• NOT a part of the integument system
• Structure-
• Areolar connective tissue Adipose tissue
• Interwoven fibers with surrounding tissue layers
• Firm attachment while still flexible
• Vary in thickness- 3cm abdomen
• Blood supply to dermis
• Cutaneous plexus
• Function-
• Attachment of CM
• Insulation
• Padding

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Hypodermis
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Hypodermis