BIOL 2403 Ch.6

What does integumentary mean?

covering

What are the components of the integumentary system?

skin and its derivatives

What are other words for "skin"

integument, cutaneous

what are skin derivatives?

hair, nails, sweat glands, sebaceous glands

what does sebaceous mean?

oily

What is the largest organ?

skin

Skin contains ________ tissue types

all four

How many layers of skin are there and what are they called?

1. epidermis

2. dermis

What type of cells make up the epidermis?

stratified squamous epithelium

What type of tissue makes up the dermis?

connective

What does epi mean?

above

What does hypo mean?

below

What is the fatty area underneath the dermis called?

hypodermis or subcutaneous

What are the layers of the epidermis called?

strata

What is the first layer (bottom layer) of the epidermis called?

stratum basale

What is the second layer of the epidermis called?

stratum spinosum

What is the third layer of the epidermis called?

stratum granulosum

What is the fourth layer of the epidermis called?

stratum lucidum

What is the fifth layer (top layer) of the epidermis called?

stratum corneum

What three cell types does the basale layer contain?

keratinocytes, melanocytes, and tactile cells

What are keratinocytes?

-most abundant

-synthesize the tough protein keratin (STRENGTH).

-keratinocytes STEM CELLS constantly DIVIDE to produce cells

What are melanocytes?

-produce protein PIGMENT (melanin) in response to UV light

-transfers pigment granules into the keratinocytes to SHIELD the nucleus

What are tactile cells?

-sensitive to TOUCH

-when compressed, release chemicals that stimulate sensory nerve endings

Stratum spinosum contains which two types of cells?

keratinocytes and epidermal dendritic cells

in stratum spinosum, keratinocytes are interconnected by junctions called _________

desmosomes

What do epidermal dentritic cells do?

help INITIATE IMMUNE RESPONSE in case of invasion of pathogens or development of cancer

What does "dendra" mean?

branches

What happens to keratinocytes in the stratum granulosum?

keratinocytes undergoing keratinization: cells fill with keratin - causing nucleus and organelles to disintegrate

The properties of stratum corneum originate from which strata?

strata lucidum

What composed the stratum corneum?

20-30 layers of dead, flat, interlocking keratinocytes

How does the stratum corneum develop?

dead skin cells are pushed through various strata for about 4 weeks while undergoing structural changes and are eventually shed

Which protein can be found in certain areas of the skin? (palms and soles) and why?

eledin; to create callouses

What is the difference between thick and thin skin?

thick skin has 5 layers, thin skin has 4 layers. THIN SKIN DOES NOT HAVE LUCIDUM

red pigment in skin is a result of...

hemoglobin

black, brown, tan, yellow-brown, reddish pigment is skin is due to...

melanin - the specific color depends on age, heredity, and light exposure

_______ pigment is aquired from yellow-orange veggies

carotene

carotene is converted to ______ within the body

vitamin A

what is the medically scientific term for moles and birthmarks?

nevus

What are friction ridges

fingerprints - increases friction on contact (think of grip)

How thick is the dermis?

0.5mm - 3.0mm

What type of tissue composes the dermis

connective

What two layers make up the dermis?

papillary and reticular

papillary means

nipples

dermal papilae contain what?

capillaries and nerve endings

What are epidermal ridges?

the nipple looking protrusions

What is the function of epidermal ridges?

interlock and increase the area of contact between the layers

What is the reticular layer (in the dermis)

deeper, major portion of the dermis

What does the reticular layer mostly consist of?

dense irregular connective tissue with bundles of collagen fibers and elastic fibers with other stuff (blood vessels, nerve endings, glands, hair follicles)

What are the two types of dermal nerves?

sensory and motor

What do sensory nerve fibers do?

collect info (about your surroundings), senses pain, temp, touch, and pressure (think TOUCH)

What do motor nerve fibers do?

regulate blood flow and gland secretions

What are the functions of dermal blood vessels?

1. supply nutrients and O2, while removing waste

2. regulate body temp and blood pressure

What are the two process that regulate body temp and BP in dermal blood vessels?

vasocontriction and vasodilation

The subcutaneous layer ________ part of the integument

is NOT

What types of CT is in the subcutaneous layer

areolar and adipose

What are the functions of the subcutaneous layer?

1. stabilize and bind the body

2. energy reservoir

3. thermal insulation

4. rich in blood vessels

WHat are the funtions of the integument

1. protection

2. prevention of water loos and gain

3. metabolic regulation

4. secretion (ex: sebum)

5. absorption (ex: nicotine patch)

6. immune function (epidermal dendritic cells)

7. temp regulation

8. sensory reception

What are the three epidermal derivatives?

nails, hair, and exocrine glands

Nails are ______ of tightly packed _______________________________

plates; keratinized epidermal cells

What are the function of nails?

1. protect the tips (of fingers and toes)

2. assist in grabbing objects

What is the structure of the nail?

Nail plate (the nail itself)

nail bed (below the plate)

nail matrix (where the nail plate comes out)

Hair strands are _______ packed _________________________

tightly; karatinized epidermal cells (KERATINOCYTES)

where is hair located

everywhere except palms, soles, and lips

What are the two types of hair?

vellus and terminal

What is vellus hair

short, fine, and unpigmented (almost everywhere)

What is terminal hair?

coarser, pigmented, longer (scalp, brows, pubes)

What are the three zones of hair?

Shaft (the exposed hair)

root (the hair below the skin surface)

hair bulb (swelling at the base)

What two things does the hair bulb contain?

hair papilla (vessels and nerves)

hair matrix (actively dividing cells)

What are the structures that are associated with hair?

hair follicle (tube surrounding hair root)

arrector pili (smooth muscle that elevates hair)

sebaceous gland (sebum)

Functions of hair

protection (physical or chemical damage)

visual identification

chemical dispersal (pheromones)

What are the two types of exocrine glands?

merocrine sweat glands and apocrine sweat glands

Merocrine sweat glands are the ________ numerous and ______ distributed

most; widely

What is the shape of merocrine sweat glands?

simple coiled shape

merocrine discharge

discharges sweat through sweat PORES

What are the functions of merocrine sweat glands?

1. thermoregulation

2. removal of waste

3. antibacterial activity (creates acidic envrionment)

Where are apocrine sweat glands found?

axillae, around nipples, genital region

What is the shape of apocrine sweat glands

simple coiled shape

When do apocrine sweat glands activate?

puberty

apocrine sweat gland secretion

exocytosis; viscous and cloudy; contains proteins and lipids that produce odor when acted on bacteria; secretes through hair follicles

What is the function of apocrine sweat glands

attract sexual partners

What is the difference between apocrine and merocrine sweat glands?

apocrine is attached to a hair follicle while merocrine is attached to a pore

sebaceous glands produce _____

sebum

Sebaceous glands discharge into ______

a hair follicle

What are the functions of sebaceous glands?

lubricant for skin and hair, bactericidal properties

where are ceruminous glands located

external ear canal (meatus)

What do ceruminous glands secrete?

cerumen (ear wax)

What is the function of cerumen (ear wax)

trap foreign material

mammory glands are located in the _______ and are only activated during ________. They secrete ________

breast, pregnancy, milk