The Integumentary System

External covering of an animal

Integument

Single-celled Protozoa

Plasma membrane as external covering

The integument is the

external covering of an animal

The skin is the largest organ with respect to

surface area

Which is NOT a function of the integument?

digestion of food

The external covering of single-celled protozoa is the

plasma membrane

The thick protein coat of Paramecium and Euglena is the

pellicle

In most multicellular invertebrates, the epidermis is the outer layer made of

a single layer of columnar epithelial cells

The epidermis of Hydra is

a few cell layers thick

Nematodes and annelids have an epidermis that is

one cell thick and secretes a multilayered cuticle

The waxy cuticle in the epidermis is found in

rotifers, crustaceans, arachnids, insects, nematodes, and annelids

The CaCO3 shell is found in

cnidarians (corals) and echinoderms (starfish, sea urchins)

The tegument of parasitic flatworms is used for

nutrient absorption and protection against host enzymes

Echinoderms have an epidermis that is

ciliated, with a dermis containing CaCO3

Arthropods are the most complex invertebrates because their integument is a

specialized chitinous exoskeleton

The two main layers of vertebrate skin are the

epidermis and dermis

The epidermis is the outermost layer made of

squamous epithelial tissue, one to several cells thick

Jawless fishes (lampreys and hagfishes) have thick skin due to

a multilayered epidermis with glandular cells and fat storage cells in the hypodermis

Denticles, bony structures resembling teeth, are found in the skin of

cartilaginous fishes (sharks)

Bony fishes (teleosts) have skin that contains

scales

Which vertebrates have stratified skin with mucous and poison glands plus pigmentation?

amphibians

The warts of toads are

special sensory structures with sensory cells

Which vertebrates have a thick epidermis with keratinized scales and no integumentary glands, resulting in dry skin?

reptiles

Birds have a soft, thin epidermis with no epidermal glands and

feathers

Which tough coiled protein waterproofs the skin and provides strength and flexibility?

keratin

Melanin, which protects the skin from UV, is produced by

melanocytes

Skin pigmentation in frogs is due to

chromatophores

The uppermost thin layer of flat dead cells that is constantly shed off is the stratum

corneum

The stratum germinativum is a thick inner layer of stratified squamous epithelium that is

actively dividing

The stratum germinativum is composed of

S. granulosum, S. spinosum, and S. basale

The stratum lucidum is found only in

thick skin such as palms, soles, and digits

Which is NOT a characteristic of epidermal cells?

they remain alive and permanent in the stratum corneum

The dermis is composed of dense/fibrous connective tissue made of collagen, which imparts

strength and flexibility

Which dermal layer is loose connective tissue with blood vessels, nerves, and cutaneous glands?

papillary layer (stratum spongiosum)

Which dermal layer is a thick lower layer of dense irregular connective tissue with mostly collagen fibers?

reticular layer (stratum compactum)

Hairs are derived from the

epidermis

When the hair muscle (arrector pili) contracts, it

pulls the hair erect

Nails are made of

keratin

Sweat (sudoriferous) glands in the deeper dermis function in

sweating for cooling

Which gland secretes sebum, an oily substance that lubricates and softens?

oil (sebaceous) gland

The hypodermis (subcutaneous layer)

is not part of the skin itself, is abundant in adipose, and binds the skin to the body

Whats the part of the black bracket called?

Papillary layer

Whats the maroon line pointing to?

Stratum corneum

whats the red line pointing to?

Stratum lucidum

whats the yellow pointing to?

Stratum granulosum

whats the orange line pointing to?

Stratum spinosum

whats the light green line pointing to?

Stratum basale

whats the dark green line pointing to?

Melanocyte

Whats the light blue pointing to?

Dermis

Whats the dark blue pointing to?

Sensory neuron

whats the brown line pointing to ?

Merkell cell

whats the purple line pointing to?

Keratinocyte

whats the pink line pointing to?

Lamellar granules

whats the pink line pointing to?

Merkel’s discs

whats the purple line pointing to?

skin surface

whats the brown line pointing to?

Ruffini’s corpuscles

whats the green line pointing to?

Pacinian corpuscles

whats the blue line pointing to?

Meissner’s corpuscles

whats the red line pointing to?

epidermis

whats the orange line pointing to?

dermis

whats the blue line pointing to?

hypodermis

whats the black line pointing to?

Nociceptors

whats the brown line pointing to?

Meissner’s corpuscles

whats the purple line pointing to?

Thermoreceptors

whats the dark blue line pointing to?

Pacinian corpuscles