dermis

dermis

located between epidermis and subcutaneous layer. anchors epidermal accessory structures; consists of outer papillary layer and deeper reticular layer

papillary layer

upper ~1/3 of dermis that consists of loose areolar connective tissue and contains capillaries, lymphatic vessels, and sensory neurons. becomes inflamed in dermatitis

dermatitis

inflammation of the dermis due to infection, radiation, mechanical irritation, or chemicals

reticular layer

lower ~2/3 of dermis consisting of dense irregular connective tissue (contains collagen) and elastic fibers (stretch and recoil)

what contributes to dermal strength and elasticity?

collagen fibers, elastic fibers, skin turgor, and tension lines

collagen fibers

very strong and stretch-resistant fibers that can be easily bent or twisted. limit flexibility to prevent tissue damage

elastic fibers

fibers that can stretch then recoil to original length; provide flexibility

skin turgor

flexibility and resilience provided by fibers and water content of the skin. loss of ___ is caused by dehydration, aging, hormonal changes, and UV radiation

tension lines

“cleavage line” produced by parallel bundles of collagen and elastic fibers in the dermis; resist forces applied to skin.

a parallel cut will heal, while a perpendicular cut will scar

what makes up the dermal blood supply?

cutaneous plexus and subpapillary plexus

cutaneous plexus

deep network of arteries along the reticular layer

subpapillary plexus

network of small arteries in the papillary layer. capillaries drain into small veins that lead to larger veins in the subcutaneous layer

contusion

bruising caused by damage to blood vessels in the dermis

nerve fibers in skin …

control blood flow, adjust gland secretion rates, and monitor sensory receptors

sensory receptors respond to…

• free nerve endings- pain and temperature

• light touch- tactile (meissner) corpuscles in dermal papillae

• deep pressure and vibration- lamellar (pacinian) corpuscles in reticular layer

meissner (tactile) corpuscles

mechanoreceptors that detect fine, subtle touch in hairless skin. located in dermal papillae

pacinian (lamellar) corpuscles

mechanoreceptors that detect vibration and pressure in hairy and hairless skin. located in reticular layer

subcutaneous layer (hypodermis)

deepest layer of skin primarily composed of adipose tissue. large arteries and veins located in superficial region. distribution of ___ fat is determined by sex hormones