a&p ch. 5

where is vitamin d synthesized

epidermal layer of skin

what are the two main layers of skin?

epidermis and dermis

Langerhans cell

functions as a macrophage by engulfing bacteria, foreign particles, and damaged cells

How many layers are in the epidermis?

4 layers in thin skin 5 layers in thick skin (palms of hands and soles of feet)

dermal papilla

A finger-like projection, or fold; increase the strength of the connection between the epidermis and dermis; the greater the folding, the stronger the connections made

what is vitamin d essential for?

Calcium and phosphorus absorption (healthy bones) and homeostasis

. Sebaceous glands ________. a. are a type of sweat gland b. are associated with hair follicles c. may function in response to touch d. release a watery solution of salt and metabolic waste

B. Are associated with hair folliclesThey secrete sebum into the hair and skin

Eccrine sweat glands ________. a. are present on hair b. are present in the skin throughout the body and produce watery sweat c. produce sebum d. act as a moisturizer

B. Are present in the skin throughout the body and produce watery sweat

melanocyte

cell that produces melanin

eleiden

clear protein rich in lipids, derived from keratohyalin, which gives these cells their transparent appearance and provides a barrier to water.

Where are keratinocytes found?

in all layers except the stratum basale

reticular layer

composed of dense irregular connective tissue; rich sensory and sympathetic nerve supply;

The hair matrix contains ________. a. the hair follicle b. the hair shaft c. the glassy membrane d. a layer of basal cells

d. a layer of basale cells

two layers of dermis

papillary layer and reticular layer

melanosome

transfers melanin into keratinocytes

eccrine sweat gland

type of gland that produces a hypotonic sweat for thermoregulation. These glands are found all over the skin's surface, but are especially abundant on the palms of the hand, the soles of the feet, and the forehead

sebaceous gland

type of oil gland that is found all over the body and helps to lubricate and waterproof the skin and hair

what is a keratinocyte?

a cell that manufactures and stores the protein keratin

The papillary and reticular layers of the dermis are composed mainly of ________. a. melanocytes b. keratinocytes c. connective tissue d. adipose tissue

c. connective tissue

what is the fifth layer of skin called?

stratum lucidum

what are the layers of skin in order from deep to superficial?

stratum basale, stratum spinosum, stratum granulosum, and stratum corneum.

third phase of hair growth

telogen phase, the hair follicle is at rest and no new growth occurs. At the end of this phase, which lasts about 2 to 4 months, another anagen phase begins

stratum basale

the deepest epidermal layer and attaches the epidermis to the basal lamina, below which lie the layers of the dermis

apocrine sweat gland

usually associated with hair follicles in densely hairy areas, such as armpits and genital regions. Apocrine sweat glands are larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching the hypodermis, with the duct normally emptying into the hair follicle. In addition to water and salts, apocrine sweat includes organic compounds that make the sweat thicker and subject to bacterial decomposition and subsequent smell. The release of this sweat is under both nervous and hormonal control,

. Similar to the hair, nails grow continuously throughout our lives. Which of the following is furthest from the nail growth center? a. nail bed b. hyponychium c. nail root d. eponychium

B. Hyponychium

basal cell

a cuboidal-shaped stem cell that is a precursor of the keratinocytes of the epidermis

stratum lucidum

a smooth, seemingly translucent layer of the epidermis located just above the stratum granulosum and below the stratum corneum. This thin layer of cells is found only in the thick skin of the palms, soles, and digits

desmosome

a structure by which two adjacent cells are attached, formed from protein plaques in the cell membranes linked by filaments.

As you are walking down the beach, you see a dead, dry, shriveled-up fish. Which layer of your epidermis keeps you from drying out? a. stratum corneum b. stratum basale c. stratum spinosum d. stratum granulosum

a. stratum corneum

Collagen lends ________ to the skin. a. elasticity b. structure c. color d. UV protection

b. structure

. Bedsores ________. a. can be treated with topical moisturizers b. can result from deep massages c. are preventable by eliminating pressure points d. are caused by dry skin

c. are preventable by eliminating pressure points

Which of the following is not a function of the hypodermis? a. protects underlying organs b. helps maintain body temperature c. source of blood vessels in the epidermis d. a site to long-term energy storage

c. source of blood vessels in the epidermis

second phase of hair growth

catagen phase lasts only 2 to 3 weeks, and marks a transition from the hair follicle's active growth

hair

compressed, keratinized cells that arise from hair follicles, the sacs that enclose the hair fibers

Hypodermis (subcutaneous layer)

connect the skin to the underlying fascia (fibrous tissue) of the bones and muscles; vascularized, loose, areolar connective tissue and adipose tissue, which functions as a mode of fat storage and provides insulation and cushioning

dermis

contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands; made of two layers of connective tissue that compose an interconnected mesh of elastin and collagenous fibers, produced by fibroblasts

After a skin injury, the body initiates a wound-healing response. The first step of this response is the formation of a blood clot to stop bleeding. Which of the following would be the next response? a. increased production of melanin by melanocytes b. increased production of connective tissue c. an increase in Pacinian corpuscles around the wound d. an increased activity in the stratum lucidum

b. increased production of connective tissue

In response to stimuli from the sympathetic nervous system, the arrector pili ________. a. are glands on the skin surface b. can lead to excessive sweating c. are responsible for goose bumps d. secrete sebum

c. are responsible for goose bumps

In general, skin cancers ________. a. are easily treatable and not a major health concern b. occur due to poor hygiene c. can be reduced by limiting exposure to the sun d. affect only the epidermis

c. can be reduced by limiting exposure to the sun

One of the functions of the integumentary system is protection. Which of the following does not directly contribute to that function? a. stratum lucidum b. desmosomes c. folic acid synthesis d. Merkel cells

c. folic acid synthesis

24. Squamous cell carcinomas are the second most common of the skin cancers and are capable of metastasizing if not treated. This cancer affects which cells? a. basal cells of the stratum basale b. melanocytes of the stratum basale c. keratinocytes of the stratum spinosum d. Langerhans cells of the stratum lucidum

c. keratinocytes of the stratum spinosum

If you cut yourself and bacteria enter the wound, which of the following cells would help get rid of the bacteria? a. Merkel cells b. keratinocytes c. Langerhans cells d. melanocytes

c. langerhans cells

An individual using a sharp knife notices a small amount of blood where he just cut himself. Which of the following layers of skin did he have to cut into in order to bleed? a. stratum corneum b. stratum basale c. papillary dermis d. stratum granulosum

c. papillary dermis

An individual has spent too much time sun bathing. Not only is his skin painful to touch, but small blisters have appeared in the affected area. This indicates that he has damaged which layers of his skin? a. epidermis only b. hypodermis only c. epidermis and hypodermis d. epidermis and dermis

d. epidermis and dermis

The papillary layer of the dermis is most closely associated with which layer of the epidermis? a. stratum spinosum b. stratum corneum c. stratum granulosum d. stratum basale

d. stratum basale

Merkel cell

functions as a receptor and is responsible for stimulating sensory nerves that the brain perceives as touch

stratum granulosum

grainy appearance due to further changes to the keratinocytes as they are pushed from the stratum spinosum. The cells (three to five layers deep) become flatter, their cell membranes thicken, and they generate large amounts of the proteins keratin, which is fibrous, and keratohyalin

Where is the stratum lucidum located?

in between the stratum corneum and the stratum granulosum

what is the basement membrane?

intertwining collagen fibers that allows the stratum basale to bond to the dermis

what is the epidermis composed of?

keratinized stratified squamous epithelium

papillary layer

made of loose, areolar connective tissue, which means the collagen and elastin fibers of this layer form a loose mesh; projects into the stratum basale of the epidermis to form finger-like dermal papillae

stratum corneum

most superficial layer of the epidermis and is the layer exposed to the outside environment; dry, dead layer helps prevent the penetration of microbes and the dehydration of underlying tissues, and provides a mechanical protection against abrasion for the more delicate, underlying layers. Cells in this layer are shed periodically and are replaced by cells pushed up from the stratum granulosum (or stratum lucidum in the case of the palms and soles of feet). The entire layer is replaced during a period of about 4 weeks

sudoriferous glands

produce sweat to cool the body

Functions of the Integumentary System

protection, thermoregulation, sensory

elastin fibers

provide some elasticity to the skin, enabling movement

collagen fibers

provide structure and tensile strength; binds water to keep the skin hydrated

sebum

secreted by sebaceous glands; a mixture of lipids, onto the skin surface, thereby naturally lubricating the dry and dead layer of keratinized cells of the stratum corneum, keeping it pliable

stratum spinosum

spiny in appearance due to the protruding cell processes that join the cells via a structure called a desmosome

what is keratin?

an intracellular fibrous protein that gives hair, nails, and skin their hardness and water-resistant properties

first phase of hair growth

anagen phase, during which cells divide rapidly at the root of the hair, pushing the hair shaft up and out. The length of this phase is measured in years, typically from 2 to 7 years

. Langerhans cells are commonly found in the ________. a. stratum spinosum b. stratum corneum c. stratum granulosum d. stratum basale

a. stratum spinosum

In humans, exposure of the skin to sunlight is required for ________.A. Vitamin D synthesis B. Arteriole constriction C. Folate production D. Thermoregulation

a. vitamin d synthesis