Unit 9 - Integumentary System

skin, hair, nails, glands, some muscles (like pili), sense receptors (nervous), hypodermis

3rd isnt a skin layer

Stratified squamous epithelium and avascular

Stratum Basale, Stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

- a single row of cells of two cell types

- keratinocytes (90%), this goes through mitosis, makes keratin (a tough protein), pushes cells towards surface as more are produced by mytosis

- melanocytes (10%), produces pigment (melanin) for UV protection. everyone has same amount, but diff amounts of melanin produced and shades of it

- blood (hemoglobin) in dermis can give pink tinge to pale skin

low levels of mitosis

- no mitosis, last layer of living cells

- contains granules that help produce keratin (strength) and start to produce waterproofing glycolipids (prevents water loss)

- dead layer, not visible in thin skin, only thick

- no mitosis, flat cells

- many layers of flat dead cells filled with keratin (tough protein)

- glycolipids between cells creates waterproof layer (prevents water loss)

- shed on this layer, then replaced from below

- vascular

- has two sublayers (CT): papillary & reticular layer

- contains blood vessels, nerves, glands, hair follicles, arrector polo muscles

- areolar connective tissue

- vascular

- projects into the epidermis (dermal papillae),

which in thick skin forms the epidermal ridges (fingerprints)

- between papillary layer and hypodermis

- forms most of dermis

- dense regular connective tissue

The papillary layer of the dermis

the reticular layer of the dermis

- thick vs thin refers to epidermis, not the dermis

- thin skin: lucidum absent, hair follicles, glands, arrector pilli muscles

- thick skin: palms and soles, lucidum present, no hair, glands, or pilli

hair, nails, skin exocrine glands

- hair is all dead skin cells

- root, part of hair embedded in skin

- shaft, visible out of skin surface

- hair follicle, surrounds root (made of up pieces)

- epithelial root sheath (several epidermal layers extend into the dermis)

- bulb (expanded region of base of root)

- matrix (single layer of cells derived from basale cells, site of hair growth and melanin for hair colour)

- outer CT sheath (formed in dermis, holds follicle in place)

- hair papilla (formed in dermis, contains blood for growing hair, extends up from beneath matrix)

- root hair plexus (free nerve endings sensors)

- sebaceous oil gland (opens into follicle)

- arrector pili muscle (smooth muscle, goosebumps)

- very keratinized epidermal cells

- consists of: nail root (under skin), body (visible), free edge

sebaceous glands, sudoriferous glands, ceruminous glands, mammary glands

- connects to hair follicles

- secretes sebum (oily, mix of fats, salts, and proteins)

- lubricates hair and skin, antibiotic

- sweat glands

- secretory portions in dermis of thick and thin skin

- ducts open onto skin surface

- fcns: temp regulation, waste removal, antibiotic action

- modified sweat glands

- in ear canal

- produces ear wax

- modified sweat glands

- produce milk

- sensory receptors are a sensory neuron (part of nervous system)

- specialized cell that responds to stimuli (touch, temp, pain, etc)

- 4 types: touch receptors, pressure receptors, thermoreceptors, nociceptors

- free nerve endings in epidermis

- root hair plexuses (nerve endings in end of hair follicle)

- tactile (meissners) corpuscles (sensitive to small touch, CT capsule around nerve ending)

- in dermal papillae

- free nerve endings in dermis

- Lamellar (pacinian) corpuscles, CT wrapped nerve endings, deep in dermis or hypodermis

- free nerve endings for temperature

- free nerve endings for pain

- in the dermis and epidermis, 3rd degree burns take them all out

- adipose connective tissue below skin that stores (1/2) of bodys adipose tissue (insulation)

- NOT part of the skin

- also called the subcutaneous layer and superficial fascia

Lack of melanin production by melanocytes

- Autoimmune disorder that causes accelerated mitosis or keratinocytes in the stratum basale.

- immature keratinocytes accumulate in the epidermis and the stratum corneum fails to shed, resulting in a thick scaley area of the surface of the skin