Integumentary system

melanin protects the keratinocyte nuclei from the damaging effects of ...

UV radiation

A nail is

a scalelike modification of the epidermis that covers the dorsum of a finger. the actively growing region is the nail matrix

arrector pili

a smooth muscle that is attached to the hair follicle. when the muscle contracts, the hair becomes erect (goosebumps).

reticular layer

a thick layer of dense irregular connective tissue. It lies deep to the papillary layer and makes up most of the dermis.

papillary layer

a thin outer layer of areolar connective tissue with fingerlike projections called dermal papillae that protrude into the epidermis. In the hands and feet, the dermal papillae generate epidermal ridges. ( sweat from the epidermal ridges leaves fingerprints).

the hypodermis consists of mostly ___________ tissue and is the the storage site of most body _______.

adipose, fat

hairs

are elongated filaments of keratinized epithelial cells that arise and emerge from the skin of mammals

Melanoma

cancer of melanocytes, is less common but dangerous

stratum basale (stratum germinativum)

contains a single layer of columnar cells actively dividing by mitosis to produce cells that migrate into the upper epidermal layers and ultimately to the surface of the skin.

stratum spinosum

contains eight to ten layers of cells connected by desmosomes. These cells are moderately active in mitosis.

stratum corneum

contains many layers of dead, anucleate keratinocytes completely filled with keratin. the outermost layers are constantly shed.

stratum granulosum

contains two to four layers of cells held together by desmosomes. these cells contain keratohyaline granules, which contribute to the formation of keratin in the upper layers of the epidermis.

stratum lucidum

contains two to three layers of anucleate cells; only found in thick skin. e.g: palms of hand and sole of foot

the hypodermis lies between the ___________ and underlying __________ and _________.

dermis,tissues, organs

sweat (sudoriferous) glands include

eccrine (merocrine) sweat glands, apocrine sweat glands, ceruminous glands, mammary glands

the epidermis develops from ________ ________.

embryonic ectoderm

function of dermis

fasten the skin to the underlying surface, provides thermal insulation, and absorbs shocks from impacts to the skin.

what kind of connective tissue is found in the dermis?

fibroblasts and macrophages within a gelatinous matrix containing collagen, elastic, and reticular fibers.

the severity of burns is indicated by the terms...

first degree, second degree, and third degree. third degree burns require grafting for successful recovery

The epidermis has __________ layers

five; thick skin has 5 and thin skin has 4

skin appendages, which derive from the epidermis include...

hair and hair follicles, nails, and glands

hair is composed of

hair shaft, hair root, hair follicle, bulb, matrix, and arrector pili

The integumentary system plays a vital role in

homeostasis by maintaining a constant body temperature via the act of sweating or shivering and by making you aware of external stimuli through information perceived within the touch receptors .

Major blood vessels are found in the _____________.

hypodermis

the most common skin disorders result from _________.

infections

The dermis function

its structure provides strength, extensibility (ability to be stretched), and elasticity (ability to return to its original form).

The epidermis consists of

keratinized stratified squamous epithelium (4 types).

The four types of cells in the epidermis include

keratinocytes, melanocytes, langerhans cells, and merkel cells

In severe burns, the initial threat is...

loss of protein and electrolyte-rich body fluids, which may lead to circulatory collapse

function of sebum

lubricates the skin and hair, prevents water loss from the skin, and acts as a bactericidal agent.

melanin, is produced by ________________ and transferred to _______________.

melanocytes, keratinocytes

the dermis and hypodermis develop from __________.

mesoderm

basal cell carcinoma and squamous cell carcinoma are cured if they are removed before ___________.

metastasis

The extent of a burn may be evaluated by using the rule of ________.

nines

Sebaceous glands

occur all over the body except for the palms and soles. they are simple alveolar glands; their oily holocrine secretion is called sebum. Sebaceous gland ducts usually empty into hair follicles

Merkel cells

occur deep in the epidermis at the epidermal-dermal boundary. They form Merkel discs, which in association with nerve endings, serve sensory function.

eccrine (merocrine) sweat glands

occur under most skin surfaces and secrete a watery salt solution through pores, which serve to cool the skin as it evaporates. Their primary function is thermoregulation. They are simple coiled tubular glands.

apocrine sweat glands

occur under skin surfaces of the armpits and pubic regions and, beginning with puberty , secrete a solution in response to stress or sexual excitement. Their secretion contains proteins and fatty substance on which bacteria thrive.

The dermis consists of two layers:

papillary layer and reticular layer

Langerhans cells

phagocytic macrophages that interact with white blood cells during an immune response

________________ is a major cause of skin aging

photodamage

skin color reflects the amount of _______________ in the skin and the ________________ level of hemoglobin in the blood.

pigments (melanin and carotene), oxygenation

keratinocytes

produce keratin, a protein that hardens and waterproofs the skin.

Melanocytes

produce melanin, a pigment that protects cells from ultraviolet radiation. Melanin from the melanocytes is transferred to the keratinocytes.

Mammary gland

produce milk

Functions of skins include

protection, sensation, thermoregulation, synthesis of vitamin D, moving blood, excretion of salts and wastes

ceruminous glands

secrete earwax into the external ear canal which helps impede the entrance of foreign bodies

the layers of the epidermis include (upper to deeper)

stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale

the types of glands in the dermis include

sweat (sudoriferous glands) and sebaceous (oil) glands

bulb

the base of the hair follicle

matrix

the bottom of the hair folliclehere, cells are actively dividing, producing new hair cells.

hair shaft

the portion of the hair that is visible on the surface of the skin

hair root

the portion of the hair that penetrates the skin (epidermis and dermis).

hair follicle

the sheath that surrounds the hair in the skin . richly vascularized and well supplied with nerve fibers

true or false? the dermis contains capillaries and many nerve endings

true

The skin, or integument is composed of

two discrete tissue layers, an outer epidermis and a deeper dermis, resting on subcutaneous tissue, the hypodermis.

melanin production is stimulated by exposure to _________ _________.

ultraviolet radiation

fetal sebaceous glands produce _________ _____, which helps protect the fetus's skin from its watery environment

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