Intergumentary System

Thermoregulation

Process of maintaining core body temperature at near constant value

Epidermis

Superficial epithelial tissue

Dermis

Underlies epidermis. Mostly fibrous connective tissue. Contains nerve fibres and epidermal hair follicles. Papillary and reticular layer

Hypodermis

Subcutenal layer. Deep to the skin and not part of it. Adipose CT to absorb shock and insulate. Anchors skin to underlying structures, mostly muscles

Papillary

________ layer: Composed of areolar CT with collagen, elastic fibres and blood vessels

• Loose tissue with phagocytes patrolling for microorganisms

Keratinized stratified squamous

___________ ________ ___________ epithelium: Type of tissue making up epidermis

Keratinocytes

Cell of epidermis. Numerous, keratin producing, and tightly connected by desmosomes

Melanocytes

Cells found in deepest epidermis. Produce melanin which is packaged into _________. Protects apical surface from UV damage

Dendritic cells

Cell of epidermis. Macrophages. Key activators of immune system

Tactile cells

Cells of epidermis. Sense light, touch, and discriminate shapes and textures

Basale

Stratum ___________: Deepest epidermal layer

• Firmly attached to dermis

• Contains melanoyctes

• Single row of actively mitotic stem cells. One cell journeys to surface, one remains in layer as stem cell

Spinosum

Stratum ________: Second deepest layer of skin.

• Several layers thick- thickest layer

• Abundant melanin granules

• Provides flexibility and protection to epidermis

• Prekaratin

Granulosum

Stratum _________ : Thin layer 1-5 cell layers thick

• Cells flatten, nuclei and organelles disintigrate

• Keratinization begins

• Cells above this layer die as too far from dermal capillaries and water barrier prevents nutrients from getting through

Lucidum

Stratum _________ : Seen only in thick skin of palms and soles

• A few rows of flat, dead keratinocytes

• Thin translucent bond superficial to stratum granulosum

Corneum

Stratum ______ : Apical layer of skin

• 20-30 rows of flat, dead keratinized membranous sacs

• ¾ of epidermal thickness

• Though dead, cells function to protect deeper cells from water loss, abrasion, and as a chemical and physical barrier

Stratum Corneum

Layer that cells are shed from

Derminal papillae

Superficial piglike projections located in papillary layer

Reticular layer

_________ layer: Dermal layer composing 80% of thickness

• Composed of dense irregular CT

• Attached to underlying organs

• Collagen fibers and cleavage lines

Collagen fibers

Located in reticular layer. Provide strength and residency and bind water

Cleavage lines

Located in reticular layer. Externally invisible. Parallel dense regions of collagen fibres. Surgical incisions cut along these lines as easier to heal

Melanin

• Only pigment made in skin

• Protection from sun exposure

• Freckles and moles local accumulation

Melanin, Carotene, and Hemoglobin

Pigments composing skin colour

Dead keratinized

______ ________ cells form hair. Hard and more durable than soft ______ of skin

Hair functions

• Warn of insects on skin

• Protection of head from physical trauma

• Prevention of heat loss

• Protection from sunlight

• Found everywhere except palms, soles, nipples, and portions of external genetalia

Grey

______ hair: Formed by decreased melanin and increased air bubbles in hair shaft

Lunago

Thin hair covering a fetus. Disappers except for scalp and eyebrows

Vellus hair

“Peach fuzz”. Pale, fine body hair of children and adult females

Terminal hair

Coarse long hair of eyebrows and scalp. At puberty, appears in axillary and pubic regions of both sexes and face and neck of males

Hair follicles

Dead keratinized cells. Extend from epidermal surface to dermis. Shaft and root

Nails

Scale like modifications of epidermis. Protective cover of distal, dorsal surface of fingers and toes. Contain hard keratin

Nail matrix

Portion of nail responsible for cell growth

Sudorferious glands

All sweat glands. Found on all skin surfaces except nipples and parts of external genetalia.

3 million

Approximate number of sudorferious glands per person

Myoepithelial

_______ cells: Found in sweat glands. Contract upon nervous system stimulation to force sweat into ducts

Eccrine

________ sweat glands: Abundant everywhere but especially palms and forehead

• Ducts connect to pores

• Secrete sweat for thermoregulation

• 99% water, salts, vitamin C, antibodies, and metabolic wastes

Apocrine

________ sweat glands: Larger glands confined to Axillary and anogenital areas. Ducts empty into hair follicles. Begin functioning at puberty

Ceruminous glands

Modified apocrine gland that produces earwax

Mammary glands

Modified apocrine gland that produces breast milk

Sebaceous

_________ glands: Widely distributed except of thick skin of palms and soles

• Most develop from and secrete into hair follices

• Relatively inactive until puberty

• Secrete sebum to soften hair and skin

Skin secretions

Chemical barrier of system: Low pH to decrease bacteria

Basic

Sweat is ________ solution

Corneum

Layer of skin that is physical barrier. Blocks most water and water soluble substances

500ml

Normal amount of daily insensible perspiration

Sensible perspiration

If body temp rises, dermal vessels dilate and increased sweat gland activity leads to _______ ________ cooling the body

Metabolic

______ functions: Synthesis of vitamin D from sunlight. Disarms cancer causing chemicals

Cutaneous

_________ sensations: Cutaneous sensory receptors detect temp, touch, and pain

5%

Intergumentary system holds up to 5% of blood volume

Nitrogenous wastes

Excretion of _______ _______ in salt and sweat

Alopecia

Hair thinning of both sexes after 40. Can occur due to stressors

True baldness

Genetically determined sex influenced condone. Caused in males by follicular response to dihydrotestosterone

CLGSB

Acronym for layers of skin