intergument Flashcards
Integument
the largest system of the body
The integument is made up of two parts
- Cutaneous membrane (skin)
- Accessory structures
2 parts of Cutaneous Membrane
- Epidermis (superficial)
- Dermis (deep to epidermis)
what type of tissue is the epidermis (superficial)?
Epithelial tissues (ectoderm)
-> stratified squamous epithelium (keratinized0
what type of tissue is the dermis (deep to epidermis)?
- Connective tissues (mesoderm)
- Superficial = papillary layer
- Deep = reticular layer
what type of tissues is the hypodermis?
- loose connective tissue
- Superficial Fascia or Subcutaneous Layer
Accessory Structures
Originate in the dermis extend through epidermis
ex: hair, nails, exocrine glands
function of integument
- protect (physical & chemically)
- thermoregulation
- immune defense
- water resistance
- metabolic regulation
- storage
- sensory
what is the function of integument help in metabolic regulation of body?
vitamin D3 production
specialized cells within epidermis
- keratinocytes
- melanocytes
- dendritic cells
- Markel cells
what type of cells is most abundant in epidermis to produce keratin?
keratinocyte
which types of specialized cell in epidermis create melanin?
melanocytes
which type of specialized cell in epidermis produce immune system?
dendritic (Langerhans cells)
which type of specialized cell in epidermis related to nervous system, detect touch/pressure?
Merkel cells
2 types of skin
- thin skin
- thick skin
thin skin
–Covers most of the body
–Has four layers of keratinocytes
thick skin
–Covers the palms of the hands and soles of the feet
–Has five layers of keratinocytes
five strata of keratinocytes (from basal lamina (deep) to free surface (superficial) )
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum*
- Stratum corneum
structure of stratum basale
- epidermal ridges (form fingerprint)
- dermal papillae
- many basal cells
- melanocytes
where does mitosis begin in stratum basale?
basal cells (germinative cells)
Stratum Spinosum
- continue to divide -> increase thickness of epithelium
- contain dendritic cells
Stratum Granulosum
–Cells stop dividing
–Start producing: Keratin and Keratohyalin
-eventually cells die
Stratum Lucidum
- “clear layer”
- Found only in thick skin
- Covers stratum granulosum
- 3-5 layers of dead keratinocytes
Stratum Corneum
-the “horn layer”
* Exposed surface of skin
* 15 to 30 layers of dead keratinized cells
* Water resistant
* Shed and replaced every 2 weeks
Keratinization (cornification)
The formation of a layer of dead, protective cells
filled with keratin
what surface do not get keratinization?
eyes
how long does it take for keratinized stratum basale to stratum corneum?
15- 30 days
two types of pigment influence skin color
- Carotene
- Melanin
Carotene
–Orange-yellow pigment
–Found in orange vegetables
–Nonpolar
–Converted to vitamin A
Melanin
–Yellow-brown or black pigment
–Produced by melanocytes in stratum basale
–Stored in vesicles - melanosomes
–Keratinocytes incorporate by endocytosis
Function of Melanocytes
Melanin protects skin from sun damage
consequence of UV radiation
Causes DNA mutations and burns that lead to cancer
and wrinkles
Skin color depends on ________ __________, not
number of melanocytes
melanin production
disease caused by UV damage
Actinic keratosis – scaley sun damaged areas
skin cancers
–Basal cell carcinoma – #1
–Squamous cell carcinoma – #2
–Malignant melanoma – cancerous melanocyte
Blood contributes to skin color (conditions)
- erythema
- cyanosis
- pallor
- hematoma
Erythema
blush/flush, reddish
cyanosis
low oxygenated blood, bluish tint
pallor
Pale, low blood flow to skin
Hematoma
Bruising, black->blue->green->yellow
disease and other skin color abnormalities
– Jaundice
– Pituitary tumor
– Addison’s disease
– Vitiligo
– Melasma etc.
– Albinism
Jaundice
Yellow, first in the eyes
Pituitary tumor
Excess MSH
Addison’s disease
Bronzing
Vitiligo
Autoimmune destruction of melanocytes
Melasma etc.
Mask of pregnancy”
Albinism
Lack of melanin production
Epidermal cells produce cholecalciferol (____________) in presence of _______ _______
vitamin D3; UV radiation
vitamin D3 is converted into ______
calcitriol
disease associate with lack of vitamin D3
rickets
Epidermal Growth Factor (EGF)
– Produced by glands (salivary and duodenum)
– Used to grow skin grafts
Functions of epidermal growth factor (EGF)
– Promotes division of germinative cells
– Accelerates keratin production
– Stimulates epidermal repair
– Stimulates glandular secretion
dermis located between ______ and __________ ______
epidermis and subcutaneous layer
where does the accesory structure anchor in skin?
dermis
2 components of dermis
- Outer papillary layer
- Deep reticular layer
which layer of dermis has dense irregular connective tissue?
recticular layer
which layer of dermis has areolar CT tissue?
papillary layer
Papillary Layer
–Contains smaller capillaries, lymphatics, and
sensory neurons
–Has dermal papillae projecting between
epidermal ridges
Reticular Layer
–Contains larger blood vessels, lymphatic vessels,
and nerve fibers
–Contains collagen and elastic fibers
–Contains CT proper
Dermatitis
inflammation of the papillary layer
what causes dermatitis? symptoms?
–Caused by infection, radiation, mechanical
irritation, or chemicals (e.g., poison ivy)
–Characterized by itch or pain
what factors contribute to dermal strength and elasticity?
- Collagen fibers- Provide flexibility
- Elastic fibers- Limit the flexibility to prevent damage to tissue
Skin Damage
Sagging and wrinkles (reduced skin elasticity)
what factors cause skin damage?
- Dehydration
- Age
- Hormonal changes
- UV exposure
stretch mark
- type of skin damage
- Thickened tissue resulting from excessive stretching of skin
what cause stretch mark?
– Pregnancy
– Weight gain
cleavage lines in dermis
collagen & elastic fiber in parallel arrangement, resist force in one direction
Cleavage (tension) lines establish important patterns
- A parallel cut remains shut, heals well
- A cut across (right angle) pulls open and scars
hypodermis (subcutaneous layer)
– Made of elastic areolar and adipose tissues
– The site of subcutaneous injections using hypodermic needles
Integumentary accessory structures
Hair, Hair Follicles, Sebaceous Glands, Sweat Glands, and Nails
The human body is covered with hair, except:
–Palms
–Soles
–Lips
–Portions of external genitalia
Functions of Hair
–Protects and insulates
–Guards openings against particles and insects
–Sensory
–Communication
Hair follicle
Surrounded by nerves
structure in hair follicle
- arrector pili
- sebaceous glands
arrector pili
- Involuntary smooth muscle
- Elevates hair - “goose bumps”
Sebaceous glands
- Lubricate the hair
- Control bacteria
Regions of the Hair
- hair root
- hair shaft
hair root
- Lower part of the hair
- Attached to the integument
hair shaft
- Upper part of the hair
- Not attached to the integument
what contribute to color of hair?
–Produced by melanocytes at the hair papilla
–Determined by genes
types of hair
–Lanugo
–Vellus hairs
–Terminal hairs
Lanugo
Fine hair covers fetus
Vellus hairs
- Soft, fine peach-fuzz
- Cover body surface
Terminal hairs
- Thick, Heavily pigmented
- Head, eyebrows, and eyelashes
- Other parts of body after puberty
Sebaceous Glands (oil glands)
- Holocrine glands
- Secrete sebum
Sweat Glands
- Apocrine glands
- Merocrine glands
apocrine sweat gland
– Found in armpits, around nipples, groin, and anus
– Secrete into hair follicles after puberty
– Break down causes odors
– Secretions in response to hormonal or nervous signals
Merocrine Sweat Glands
– Widely distributed on body surface
– Discharge directly onto skin surface
– 99% Water
function of merocrine sweat gland
- sensible perspiration
- Excretes water and electrolytes
- Flushes microorganisms and harmful chemicals from skin
Specialized Integumentary Glands
- Mammary glands
- Ceruminous glands
mammary glands
- Produce milk
- modified apocrine sweat glands
Ceruminous glands
- Produce cerumen (earwax)
- Protect the eardrum
which system have control over sebaceous and apocrine sweat gland?
nervous system
which factor control merocrine sweat gland?
- controlled independently
- sweating occur locally
how does integument repair injury?
Fibroblasts produce scar tissue -> raised keloid may form
where can you find dendritic cell in epidermis?
stratum spinosum layer
which layer of epidermis can you find melanocyte?
stratum basale layer
which layer of epidermis can you find tactile (Merkel) cell?
