Practical 2 Integumentary System

Function Protection & connect it to structure (Integumentary System)

Epidermis (keratinocytes and epidermal water barrier)

Function Thermoregulation & connect it to structure (Integumentary System)

sweat glands (produce sweat to cool down) & dermal blood vessels (change blood flow to control heat loss)

Function Sensation & connect it to structure (Integumentary System)

feel touch, pressure, pain, temp, structure: sensory receptors/ nerve endings in dermis

Function vitamin D Synthesis & connect it to structure (Integumentary System)

Begins in epidermis on exposure to ultraviolet light, structure: Epidermis & UV light

Function Excretion & connect it to structure (Integumentary System)

gets rid of tiny amounts of wastes w/in sweat: water, salts, nitrogenous wastes, structures: sweat glands

List all functions of Functions Integumentary System

Protection, Thermoregulation, Sensation, Vitamin D Synthesis, Excretion of water, salts, nitrogenous wastes in sweat

Layers of skin

epidermis, dermis, hypodermis (subcutaneous layer, superficial fascia)

What is the epidermis made of

keratinized stratified squamous epithelium

What is the dermis made of

dense irregular connective tissue containing: blood vessels, nerves, glands, hair follicles

What is the hypodermis made of (subcutaneous layer, superficial fascia)

areolar tissue (loose connective tissue) and adipose tissue (connective tissue that stores fat)

Name all strata of the epidermis from deep to superficial

stratum basale (germinativum), stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

what happens in the stratum basale (germinativum)

depeest layer, a single row of cells resting on the basement of the membrane, site of mitosis and location of the melanocytes

what happens in the stratum spinosum

several cell layers thick, cells appear spiny in prepared slides and begin producing keratin

what happens in the stratum granulosum

cells flatten and fill with granules, keratinization proceeds and the cells begin to die

what happens in the stratum lucidum

a clear layer of dead, flattened cells, present only in thick skin (palms/soles)

what happens in the stratum corneum

the most superficial layer, many layers of dead keratinized cells that are cont shed

Thick Skin

has all 5 strata (includes the stratum lucidum) and occurs on the palms and soles

Thin Skin

lacks the stratum lucidum and covers the rest of the body

Describe the protection function of the integument

serves as physical , chemical and biological barrier

Describe the thermoregulation function of the integument

through sweat production and changes in dermal blood flow

Describe the sensation function of the integument

through receptors located at diff depths within the dermis

Describe the vitmamin D synthesis function of the integument

begins in epidermis on exposure to UV light

Describe the excretion function of the integument

excretion of small amounts of water, salts, and nitrogenous wastes in sweat

facts about epidermis

avascular and regenerates from its deepest layer made off keratinized stratified squamous epithelium

facts about dermis

gives skin its strength and flexibility , made of dense irregular connective tissue containing blood vessels, nerves, glands, and hair follicles

facts about hypodermis (subcutaneous layer, superficial fascia)

anchors the skin to underlying structures, insulates, and cushions. not part of the skin. made of areolar and adipose connective tissue

Keratinocyte

The most abundant epidermal cell. It produces keratin, the tough fibrous protein that waterproofs and toughens the skin

Melanocyte

located in the stratum basale. It produces melanin, the pigment that shields underlying cells from ultraviolet radiation

Name both layers of dermis from top to bottom

Papillary layer, Reticular layer

What is Papillary Layer Made of

The thin superficial layer made of areolar connective tissue (loose connective tissue that provides support and flexibility) thrown into dermal papillae

Dermal Papillae

small upward projections of the dermis into the epidermis

What does the Papillary Layer carry

capillary loops (tiny blood vessels that deliver oxygen and nutrients to the epidermis)

Touch receptors ( sensory structures that detect light touch)

Produce the epidermal ridges (raised patterns on the epidermis that form fingerprints)

What is reticular layer made of

dense irregular connective tissue (connective tissue w thick fibers arranged in multiple directions, allowing the skin to resist pulling from different directions)

What does the Reticular Layer carry/do

Collagen fibers that give skin strength (strong protein fibers that resist stretching and tearing)

Elastic Fibers (stretchy protein fibers that allow the skin to return to its original shape) —→ gives skin recoil

Hair Shaft

the portion projecting above the skin surface

Hair Root

the portion embedded within the skin

Hair Follicle

the sheath that surrounds the root and extends into the dermis

Hair bulb

the expanded deep end of the follicle where hair growth occurs

Hair Matrix

A group of cells inside the hair bulb that undergo mitosis to produce new hair cells (inside hair bulb)

Dermal Papilla

A projection of connective tissue containing blood capillaries that supplies nutrients to the growing hair matrix cells. (inside hair bulb)

Arrector Pili Muscle

a small band of smooth muscle attached to the follicle. Its contraction pulls the hair upright and produces goose bumps

Nail Body / Nail Plate

The visible attached portion of the nail (the hard part you can see), made of dead, tightly packed keratinized cells, rests/attached on top of the nail bed

Free Ridge

the portion extending beyond the fingertip, no longer attached to nail bed underneath (what you cut when trimming nails)

Nail Root

the proximal portion embedded in the skin (the hidden portion of the nail underneath the skin at its base) is cont w the nail body

Nail Bed

the epidermis lying beneath the nail body (the nail bed is the layer of living epidermal tissue directly underneath the nail plate)

Nail Matrix

The thickened proximal portion of the nail bed responsible for nail growth (The nail matrix contains living cells that undergo mitosis (cell division) to produce new nail cells. As new nail cells form and become keratinized, older cells are pushed forward, causing the nail to grow.)

Lunule

the white crescent at the proximal end of the nail (represents the visible portion of the nail matrix beneath the nail plate) (The lunule looks white because the tissue underneath prevents you from clearly seeing the pink blood vessels)

Cuticle (Eponychium)

The fold of skin projecting over the proximal nail (It helps form a protective seal between the skin and nail, preventing bacteria and other microorganisms from entering the area where the nail grows)