INTEGUMENTARY SYSTEM

Single-Celled Protozoa

• plasma membrane as external covering

• Contains Pellicle: thick protein coat

Multicellular Invertebrates

Single layer of columnar epithelial cells

Cuticle

waxy substance in epidermis of rotifers, crustaceans, arachnids, insects, nematodes, and annelids

Mostly common in Anthropods

Shell

CaCO3 in cnidarians and Echinoderms

Mostly found in Molluses

Tegument

In parasitic flatworms

For nutrient absorption against digestion by hose enzymes

Common in Anthropoids

Integumentary System

• Protection of underlying tissues and against microbes and chemical agents

• Regulation of body temperature

• Synthesis of Vitamin D

Epidermis

Outermost layer of the epithelial tissue (squamous)

one to several cells think

Dermis

Thicker layer of connective tissue beneath the epidermis

composed of loose connective tissue and blood vessels

Has Glands and Nerves

• keratinocytes

• dendritic cells

• basal cells

• melanocytes

4 primary types of cells found in the epidermis

Keratinocytes

cells that undergo keratinization and produce vitamin D

Makes up about 99% of the cell population

Dendritic Cells

• traps unwanted debris through phagocytosis

• located in the middle layer of the epidermis

Basal Cells

Undergoes cell division

deepest layer of the epidermis

Melanocytes

Produces the pigment in skin color

• Stratum Corneum

• Stratum Lucidum

• Stratum Granulosum

• Stratum Spinosum

• Stratum Basale

Epidermis Layers

Stratum Corneum

Dead keratinized cells

Stratum Lucidum

Translucent layer parts of the body with thick skin

present only in the palms and soles

Stratum Granulosum

Partially flattened keratinocytes containing small granules in the cytoplasm

the granules are proteins that are in the process of transforming into the water proofing protein, keratin.

Stratum Spinosum

• Spiny layer

• the nuclei of the cells closer to the skin surface are often darkened, which is an early sign of cell death

Stratum Basale

• Cells that undergo cell division (Mitosis)

• They newly produced cells are pushed toward the skin surface as more are manufactured

• Papillary Layer

• Reticular Layer

Layer of the dermis

Papillary Layer

• below the basale and comped of loose connective tissues

• Has friction ridges that occur in patterns that are genetically determined and are therefore unique to the individual, making it possible to use ‘‘Fingerprints’’ and Footprints

Reticular Layer

Composed of dense connective tissue

gives strength elasticity and extensibility

• Free nerve endings

• Pacinian Corpuscle

• Meissner’s Corpuscles

• Ruffni’s End Organs

• Merkel’s Dics

Different Skin Receptors

Free nerve endings

responsible for pain sensation

Pacinian Corpuscle

Responsible for Deep Pressure

Meissner’s Corpuscle

Responsible for light touch

Ruffini’s end organs

responsible for pressure

Merkel’s Disc

responsible for continuous fine touch

• melanocytes

• xanthophores

• iridophores

• photophores

• Erythrophores

5 Chromatophores

Melanocytes

Has melanin (brown to black pigment)

Xanthophores

Xanthin (yellow pigment)

Iridophores

silvery appearance

Erythrophores

red pigment

Hairs

Derived from the epidermis

Hypodermis

is not part of the skin, but a region deep to the dermis that connects the skin to underlying body structures.

the connection is by way of strands of collagen that extend from the dermis through the hypodermis

is composed of adipose tissue and loose connective tissues

Sudoriferous Glands

• also known as ‘‘Sweat Glands’’

• The secretion of sweat helps maintain body temperature by cooling the body as the sweat evaporates

• Eccrine Glands

• Apocrine Glands

2 types of sweat glands

Eccrine Glands

They secrete a watery sweat in response to elevated body temperature providing a cooling effect on the skin.

Apocrine Glands

Begins functioning during puberty in response to sex hormones

sweat from these glands may have a pungent odor.

Sebaceous Glands

Secretes sebum oil

for moisturizing the skin

connected to the hair follicle

Ceruminous Glands

Secretes cerumen on the outer ear canal

they make the earwax (cerumen), helps protect the ear from drying out

Meibomian Glands

Moistening of conjunctiva

found in your eyelids

they make an oily substance to stop your eyes from drying out

Mammary Glands

Compound alveolar glands derived from the sebaceous gland.

found in breast and makes milk

Hair Shaft

projecting from the epidermis

dead keratinized cells

hair root

embedded in the dermis

Hair follicle

surrounding the hair root

Hair bulb

the base

receives a tiny cluster of blood vessels from the dermis

Nail plate

the hard, visible part of the nail made of keratin

Free Edge

The white tip of the nail that extends beyond the fingertip

Lunula

the whitish, crescent-shared area at the base of the nail plate (mostly visible on thumbs)

Nail Bed

The skin beneath the nail plate that supplies nutrient and support

Nail Root

Located under the skin at the base of the nail; it produces new nail cells

Eponychium (Cuticle)

Thin layer of skin overlapping the nail plate at the base, protects new nail cells

Nail Folds

The skin around the sides and base of the nail that frames and supports the nail plate

Filo Plume

Hair- like feather

looks like hair

• mainly sensory- helps birds detect movement of other feathers and aids in flight adjustments

Plumae

Vane feather/ Contour feather

Includes flight feathers (wings and tales) and contour feathers (body covering)

Plumule

Down feather

found beneath contour feathers, especially in chicks and on adults for insulation

Placoid scales

found in cartilaginous fishes like sharks, rays, and skates

• reduces water resistance

• helps in streamlined swimming

• provide protection from injury and parasites

Cycloid

provides flexibility and smooth movement in water

Ctenoid

extra protection and reduce drag while swimming

Horns

core: bony projection from the skull

covering: tough keratin sheath (derived from the epidermis)

Antlers

entirely made of bone (no keratin sheath once mature)

covered with soft skin called velvet

Baleen

Broad sheets of the epithelium in whalles

Rattles

rings of stratum corneum

Ischial Callosities

made of thickened epidermis with underlying fibrous tissue

Tori

epidermal pads in mammals

provides grip and traction

Corns and Calluses

localized, thickened epidermis with hard center often caused by friction of pressure

Beaks

Composed of a bony core covered by keratinized epidermis

Combs

Fleshy, vascularized, keratinized structure on the head

Contact Dermatitis

Exposures cause allergic reaction

produce symptoms of swelling and redness to the affected are of the skin

Boil

Carbuncles

• a local infection of hair follicle

• several boils developing from adjacent follicles and joining to form a single mass

Impetigo

caused by bacterial infection

Athletes foot

caused by fungal infection

Psoriasis

an inherited disease of the skin

result of an accelerated rate of mitosis in epidermal cells

Cancer

an abnormal cell mass

cells grow and divide uncontrollably, losing the normal regulation that keeps cell growth in check .

these abnormal cells can form a mass called a tumor

Benign

Does not spread

Malignant

metastasized to other parts

Rule of nines

A Way to determine the extent of burns

Skin burns

tissue damage and cell death caused by heat, electricity, UV radiation, or chemical burns

First degree burns

only epidermis is damages

skin is red and swollen

Second degree burns

epidermis and upper dermis are damaged

skin is red with blisters

Third degree burns

destroy entire skin later