#7 the integumentary system (hypodermis, epidermal derivatives, cutaneous sense receptors)

hypodermis / subcutaneous layer→

• where is it found

• what kind of tissue

• immediately below the dermis

• connective tissue

where is half of the bodies adipose tissue

hypodermis

• insulates the body

superficial fascia (hypodermis)

binds skin to the muscle beneath

melanin →

• what layers is it found in

• what are its cells

• what does it provide

• stratum basale & spinosum of the epidermis

• melanocytes

• variation in skin color

what two forms are melanin found as

range in color

• yellow to tan

• reddish brown to black

melanin →

• who is unable to make it

• what stimulates its production

• what does the pinkish tinge come from

• albinos

• sun exposure (suntan)

• hemoglobin found in vascular dermal layer

structures derived from the epidermis

1. hair (follicle)

2. nails

3. exocrine glands

exocrine glands derived from epidermis

1. sebaceous → oil

2. sudoriferous → sweat

3. ceruminous → ear wax

4. mammary → milk

hair →

• what is it composed of

• what projects above the skin surface

• what is found below the skin surface

• dead keratinized cells

• shaft

• root

hair →

• where is keratinization complete

• where is it ongoing

• shaft

• root

hair follicle →

• where does it come from

folds down from the epidermal surface into the dermis

hair bulb

expended region at the deepest point of hair follicle

hair papilla →

• what is it

• what does it contain

• small piece of dermal tissue that protrudes into the hair bulb

• knot of capillaries that supply nutrients, signals growth

hair matrix

actively dividing area of hair bulb. produces hair

what is the hair follicle associated with (3)

1. root hair plexus (nerve ending)

2. sebaceous gland (opens hair follicle)

3. arrector pili muscle

nails →

• what are its cells and where are they found

• what forms the nail bed

• what is responsible for nail growth

1. heavily keratinized epidermal cells found within stratum corneum

2. epidermal layers

3. nail matrix

each nail is composed of a

1. free edge

2. nail body (visible portion of the nail)

3. proximal root (embedded in the root)

sebaceous glands →

• what is sebum composed of

• what is it connected to

• what is its function

• fats, salts, and proteins

• connected to hair follicle

• lubricates hair and skin, preventing desiccation & softening hair. also has antibiotic function

sudoriferous glands →

• what does it function in

• produces sweat to cool the body

• also contains antibiotic function (lysozyme breaks apart bacterial structures)

• remove wastes (eg. urea)

how does sweat cool the body

• sweat evaporates

• heat from body breaks hydrogen bonds

• heat no longer available to warm the body

cutaneous sense receptors →

• what is it

• where is it found

• what does it respond to

• nerve endings form from end of sensory neurons

• in the skin

• stimuli such as touch

4 varieties of cutaneous cell receptors

1. touch receptors

2. pressure receptors

3. thermoreceptors

4. nociceptors

touch receptors →

• what is it

• where is it founds

• root hair plexus wraps around the hair follicle

• free nerve endings found in the epidermis

meissner’s corpuscles

touch receptors found in the dermal papillae

pressure receptors

free nerve endings respond to changes in pressure

pacinian corpuscles

pressure receptors located within the deep dermis or the hypodermis

thermoreceptors

• what are they

• what do they detect

• temperature receptors

• free nerve endings detect hot and cold (more detect cold than hot)

nociceptors →

• what do they detect

• what are they

• what do they function in

• receptors that detect pain

• free nerve endings

• functions in protection, makes you aware (eg. putting hand on stove)