Integument b Chapter 4

sensory

Dermis Tough supportive ct matrix Varies in thickness 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

Papillary vs Reticular Layers

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

Dermal Papillae

Papillary Plexus Blood vessels extend up into dermal papilla

Epidermal Ridges

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

Dense Irregular CT

Tatoo

Accessory Structures

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

Sensory

Nervous Supply Nerve types General Varied distribution Merkel cells Pacinian corpuscle Meissner’s corpuscle General Thermoreceptors- dermis, hot & cold Free nerve ending- pain, dermis Root hair plexus- hair follicle Varied distribution Face, hands, genitalia

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

Pacinian Corpuscle Pacinian corpuscle End in dermis- reticular region Intense Pressure & vibration

Pacinian Corpuscle

Pacinian Corpuscle

Meissner’s Corpuscle Meissner’s corpuscle Dermal papillae Lt pressure &Touch Hands & feet

Nervous Supply Autonomic nerves are “automatic” Supply vessels, sweat glands, arrector pilli Root hair plexus nerves make hairs sensitive to touch

Accessory Structures

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

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

Sebaceous Glands

Sebaceous Glands Look like eyeballs!

Sebum

Sebum coats and protects hair

Eyelash

Got Sebum?

Pimples

Propionibacterium acnes

Whitehead Trapped sebum & bacteria stay below skin surface

Blackhead Trapped sebum & bacteria partially open to surface & turn black due to melanin exposure

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

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

Eccrine Gland

Eccrine Gland

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

Symbiotic Bacteria

Ceruminous Glands Cerumin Thick waxy substance Protective Apocrine mechanism of secretion

Hair Hair cells Papilla in dermis Hair types 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

Invagination of Epithelium

Communication

Communication

Thermoregulation

Protection

Sensory

Hair Structure Follicle Bulb Hair papillae Root Shaft 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

Hair Follicle & Shaft

Hair Root

Hair Bulb Hair papilla

Arrector Pili Muscle

Arrector Pili Muscle

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

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

Hypodermis

Hypodermis

Chemical Peel

Cellulite Fat cells swollen & pinched by connective tissue Restricts blood circulation- reduces O supply Connective tissue bands become tougher & less elastic Trap fluids & wastes, pinch off nerves Resulting hardening of tissues

Causes Heredity Insufficient water Diet- toxins Smoking Medication Lack of exercise

Aging