Integumentary anatomy bold terms

Integument (skin)

Functions include protection, prevention of water loss, temperature regulation, metabolic regulation, immune defense, sensory reception, excretion by secretion

How many layers does the epidermis have?

4-5 specific layers (thick skin - 5; thin skin - 4)

What is the epidermis?

A keratinized stratified squamous epithelium (also composed of dead cells). Thicker in the areas of the body like palms and soles of feet.

What is the Stratum Corneum?

Most superficial layer of the epidermis, composed of dead cells (keratinocytes) on the surface of the epithelium

What does the Stratum Corneum look like?

What is the Straum Lucidum?

Seen only in thick skin (palms, soles, digits), appears clear or white and is superficial to the stratum granulosum

What does the Stratum Lucidum look like?

What is the Stratum Granulosum

three to five layers of thin flattened cells which contain numerous dark granules. Acts as a transition zone where living skin cells turn into tough waterproof barrier by secreting lameller bodies filled with lipids to create spaces between cells hence creating a hydrophobic seal.

What does the Stratum Granulosum look like?

What is the Stratum Spinosum

several layers of cells which at high magnification look like spines on their surface connecting to cells. Provides strength and flexibility (to prevent tearing and blistering under physical stress) to the skin while supporting immune defense.

What does the Stratum Spinosum look like?

What is the Stratum Basale

deepest stratum, consists of layer of dark stained cells. continuously produce new skin cells and regenerate the epidermis. These cells constantly divide through mitosis to create new keratinocytes that push towards surface.

What does the Stratum Basale look like

What is the dermis?

Mostly Made up of dense irregular connective tissue; some areolar connective tissue, split up into 2 layers, vascular

Two layers of dermis

Papillary layer, Reticular layer

What is the papillary layer?

Deep to the stratum basale of the epidermis; most superficial layer of dermis. Named after the structures that protude from this layer.

What tissue type is the papillary layer?

areolar connective tissue

What is the dermal papillae and what layer is it in?

Finger like projections that lock epidermis to strengthen the skin. Contain nerve endings that allow detection of light touch, texture, and pressure. Also creates our fingerprints. In the papillary layer of dermis.

What is the Reticular layer

Deep in the papillary layer and thicker, contains large coarse bundles of collagen fibers, usually dark staining

What is in the Reticular layer

This layer contains secretory portion of sweat glands, oil glands, and hair follicles

What is the subcutaneous layer?

The layer that stores fat and anchors integument to underlying tissue.

What cells does areolar connective tissues have?

fibroblasts, with lots of ground stubstance

is areolar connective tissue vascular?

true

what cells do dense irregular connective tissue have?

fibroblasts, collage protein fibers, little ground substance

functions of areolar connective tissue

This tissue acts as the body's packaging material, connecting skin to underlying muscles and holding organs in place. Its fluid-filled, gel-like matrix stores water and salts, allowing nearby cells to absorb nutrients and release wastes. Loosely arranged collagen and elastic fibers let tissues stretch and return to their original shape while cushioning organs against impact and it has white blood cells (like macrophages and mast cells) to fight off bacteria, and fibroblasts to repair damaged

functions of dense irregular connective tissue

this tissue allows strength because it is interwoven, random collagen fibers let the tissue withstand tension from any angle. It stabilizes organs, anchors skin layers, and resists tearing. Tough capsules shield delicate internal structures from excessive stretching or distension

What cells are adipose tissue made out from?

adipocytes

is dense irregular tissue vascular?

poorly vascularized

is adipose tissue vascular

true

which layer is the dense irregular tissue found in?

dermis

which layer is adipose found in?

subcutaneous layer

Where is the nuclei pushed to in adipose connective tissue?

the periphery of the cell by fat droplet

functions of adipose tissue

energy storage, temperature regulation, cushion, hormone regulation by releasing adipokines to signal hunger/appetite

what tissues does the subcutaneous layer consists of?

areolar connective tissue and adipose connective tissue.

hair follicle

a tunnel-shaped skin organ that anchors and grows an individual strand of hair, found deep in epidermis, dermis, and subcutaneous layer

arrector pili muscle

pulls on hair follicle to shift how hair stands “arrector" = to straighten, aka goosebumps

Where are nails formed?

Stratum corneum

Nail functions

protects tips of fingers and toes, to help grasp objects

epidermal accessory organs are formed by what?

epidermis and invaginate deeper (dermis, sub)

sebaceous gland function

produce and secrete sebum

where are sebaceous glands located

located in the dermis (the second layer of the skin) and are found all over the body except on the palms of the hands and soles of the feet

hair function

protection against UV rays, sensory receptors, heat retention.

exocrine gland location

located in secretory portion in reticular layer of dermis

where do exocrine glands release their secretions

through ducts that open onto the surface of the epidermis

sebaceous oil gland’s two types

holocrine glands and sweat glands

holocrine gland

assoicated with hair follicles, secrete sebum, lubrication/waterproofing of epidermis, prevents hair from becomin brittle

sweat glands

excrete water products (sodium/urea), release perspiration to cool body

what is the immune defense of the integument?

epidermal dendritic cells

epidermal dendritic cell functions

also known as Langerhans cells, detects foreign invaders, capture antigens, and trigger body’s immune response. they phagocytize bacteria/debris

The integument system consists of

skin, exocrine glands in the skin, hair, nails

Functions of the integument

Protection to keep pathogens out and act as barrier to UV rays

to lose/dissipate heat

blood vessels dilate and sweat glands secrete

to conserve heat

blood vessels in dermis constrict and blood is shunted deeper

What tissues are found in the epidermis

keratinized stratified squamous epithelium, thicker in parts like soles of feet/palms, superficial

what tissues make up the dermis?

mostly dense irregular CT and some areolar connective tissue, deep

which layer has nerve endings, hair follicles, and glands?

dermis

what tissues make up the subcutaneous layer?

adiposes CT and areolar connective tissue

Which layer of epidermis is found in thick skin only?

Stratum Lucidum

What is keratinization?

The process by which cells form fibrils of keratin and harden, begins in deepest layer (basal), then as new keratinocytes form they move upward then as these cells rise, they fill with a tough protein called keratin, flatten out, and lose their internal cell parts, The cells die and form a hard, protective outer layer known as the stratum corneum in completion

epidendritic cells location

stratum spinosum

what kind of cells reside in the epidermis

keratinocytes, melanocytes, Langerhans cells, and Merkel cells

keratinocyte function

produce keratin, form a protective barrier against environmental damage, germs, and water loss, found throughout all layers, most abundant

melanocytes function

produce melanin, pigmentation is result of melanocyte activity as pigment is transferred to keratinocytes

melanocytes is found in what layer

stratum basal only

langerhan’s cells

epidermal dendritic cells

Tactile cells AKA Merkel cells function

connect to nerve endings, tactile (touch) sensation, located in stratum basal only

Reticular layer function

provides structural strength , elasticity, and support to skin while housing important glands, hair follicles, and nerve receptors while housing important glands, hair follicles, and nerve receptors

papillary layer function

It features finger-like projections (dermal papillae) that interlock with the epidermis to anchor the skin layers, house capillaries to feed the avascular epidermis, and contain Meissner's corpuscles for light touch sensation. supplies the outer layer of skin (epidermis) with vital nutrients and oxygen while firmly connecting the two layers together