combined lab exam set

what is the hair shaft

filamentous strands of dead keratinized cells produced by hair follicles; above skin

what kind of keratin is hair made up of

dead, hard keratin which is more durable than soft keratin found in skin

what are the parts of hair?

the Shaft which projects from skin surface, the Root which is embedded in the Follicle, a core called the medulla, a cortex, and an outer cuticle

what is the hair follicle

an internal root sheath of cells surrounding root of hair; extends from the dermis into the epidermal surface

what is a hair bulb

the base of a hair follicle, wrapped in a knot of sensory nerve endings (hair receptors), goes over dermal papillae

what is the piloerector or arrector pili muscle

a muscle that contracts to raise hair follicle and give you goose bumps in response to stimuli; made of smooth muscle cells

how do sudoriferous glands (sweat) secrete

exocytosis, or onto the surface

what are the two types of suderiferous glands?

sweat glands; merocrine sweat glands and apocrine sweat glands

where are merocrine sweat glands found (also called eccrine)

palms of hands, soles of feet, and forehead (exocrine onto skin)

what is the function of merocrine sweat glands

thermoregulation

what are ceruminous glands

modified apocrine glands in ear canal that secrete cerumen

what are apocrine sweat glands

source of sex pheromones; exocrine into hair follicles

where are apocrine sweat glands found

axillary and anogenital areas, areola, and beard on mature men

what is the difference in consistency between eccrine and apocrine sweat? why?

apocrine is more milky because it has more fatty acids

what are mammary glands

specialized type of apocrine gland to secrete milk

what are sebaceous glands

simple alveolar glands that soften skin and secrete and sebum into hair follicles; also make cerumen (ear wax) in ears

what are sebaceous glands made up of

epithelial tissue

what is the function of hair in humans

maintains warmth, alerts body to what is on skin, guards the scalp against physical trauma, heat loss, and sunlight

where is hair NOT on the body?

palms, soles, lips, nipples, and portions of external genitalia

three layers that make up skin

epidermis, dermis, hypodermis

what is the dermis layer made up of

connective tissue; fibroblasts, macrophages, mast cells and white blood cells

what are the layers of the epidermis?

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

what are the two dermal layers

papillary and reticular

what is the papillary region made up of

areolar CT, collagen and elastic fibers; projections called dermal papillae that contain capillary loops, Meissner’s corpuscles, and free nerve endings

what are dermal ridges and what do they do

they are larger mounds of papillae on palms and soles, and they make up our fingerprints

what is the reticular layer of the dermis made out of?

dense irregular tissue, collagen fibers, elastin fibers, and a network of blood vessels

what is the function of the reticular layer of the dermis

add strength and resilience to skin, allowing for stretch/recoil; makes up about 80% of skin thickness

what is the hypodermis made up of

adipose and areolar tissue, mostly adipose

what is the primary function of the hypodermis

shock absorption and insulation

what three pigments contribute to skin color

melanin, carotene, and hemoglobin

what is melanin

a reddish-brown to black pigment, can be yellow too, responsible for darker skin

what is carotene

yellow to orange pigment; acquired through diet (egg yolks, carrots) and most obvious in thick skin

what is hemoglobin

a reddish pigment responsible for pink hue through skin; made up of blood cells

what is collagen

fiber; made up of collagen protein, tough, provides high tensile strength

what is an elastic fiber

fiber; made up of protein elastin, long, thin, and allow for stretch and recoil

what is a reticular fiber

fiber; short, thin, branched collagenous fibers that form sponge-like framework for some organs such as spleen and lymph nodes

types of fibers

collagen, elastic, reticular

types of cells

fibroblasts, chondroblasts, osteoblasts, hematopoietic stem cells

what are fibroblasts

their own type of cell; support connective tissue proper

where are fibroblasts found

fibrous connective tissue

in which tissue would you find white blood cells and macrophages

loose CT

where are chondroblasts

cartilage

where are osteoblasts

bone

where are hematopoietic stem cells

bone marrow

what are stem cells

undifferentiated cells that divide and give rise to keratinocytes

where are stem cells in the epidermis

the stratum basale

what is a keratinocyte

cells that produce the fibrous protein keratin; make up most epidermal cells, connected by desmosomes

how frequently do you have a totally new epidermis and why?

25-45 days, due to continuous mitosis of cells

where are melanocytes in the epidermis

stratum basale and spinosum

what are the functions of melanocytes?

produce melanin, protect nucleus from UV radiation

what are the three tactile cells?

meissner’s corpuscles, pacinian (or lamellated) corpuscles, merkel cells

where/what are meissner’s corpuscles?

little “balloons” in the dermal papillae area; detect lighter touch

where are merkel cells and what do they look like

all epidermal-dermal junctions; spiky

what do merkel cells do

function as medium touch receptors with the sensory nerve endings

where are pacinian corpuscles (lamellated) located?

lower dermis or hypodermis

what do the pacinian corpuscles detect?

deep pressure

where are dendritic cells? (Langerhans’)

the stratum granulosum and the stratum spinosum; arise from bone marrow and migrate to epidermis

what are dendritic cells? how many are there?

epidermal macrophages that help to activate the immune system; as many as 800 per sq/mm

what are the 5 layers of the epidermis?

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

what layer is the stratum corneum, and how thick?

the outermost layer, keratinized cells; 20-30 layers thick, ¾ of epidermal thickness

what is the function of the stratum corneum?

waterproofing, protects from abrasions and penetration, provides barrier to biological, chemical and physical assaults

what is stratum granulosum made up of?

keratohyalin, lamellated granules, and waterproofing glycolipids

how thick is the stratum granulosum?

thin, 3-5 cell layers thick; drastic change in keratinocyte appearance occurs

what is the stratum lucidum made up of?

flat, dead keratinocytes

where/what is the stratum lucidum?

a thin transparent band of dead keratinocytes found right above the granulosum, found only in thick skin

what is the stratum spinosum made up of?

melanin granules and Langerhans’ cells; a weblike system of intermediate filaments attached to desmosomes

where is the stratum basale

the deepest layer of the epidermis; firmly attached to basement membrane that attaches to the dermis

what is the stratum basale made up of?

a single row of the youngest keratinocytes; 10-25% of cells are melanocytes, with the occasional merkel cell

why is the stratum basale also called the stratum germinativum?

the cells undergo rapid division

simple squamous epithelium location

kidney glomerular capsule, lining of heart, lining of blood vessels, lining of lymphatic vessels, air sacs of lungs, and outer lining of digestive tract (or serosae)

simple cuboidal epithelium location

kidney tubules, ovary surface, and ducts and secretory portion of small glands

simple squamous epithelium functions

diffusion and filtration; provide a friction reducing lining to the cardiovascular and lymphatic systems

simple cuboidal epithelium functions

secretion and absorption

simple columnar epithelium location

noncilliated line gallbladder and digestive tract, ciliated line small bronchi, uterine tubes, and regions of uterus

simple columnar epithelium functions

absorption and secretion; cilia help facilitate movement in internal passageways

pseudostratified columnar (ciliated) function

secretion and propulsion of mucus

goblet cells location and function

columnar epithelium; mucus production

pseudostratified columnar location ciliated and nonciliated

male sperm carrying ducts when nonciliated; trachea when ciliated

stratified squamous epithelium location

areas of wear and tear; external part of skin, non-keratinized found in body openings

stratified squamous epithelium functions

protects against damage/abrasion to tissue and regenerates as needed; keratinized acts as waterproofing layer

stratified cuboidal epithelium location

ducts of large glands like sweat and mammary

stratified cuboidal epithelium function

aids in secretion of sweat glands

stratified columnar epithelium location

ducts of salivary glands

stratified columnar epithelium functions

protects underlying tissue and maintains moist environment; aids in secretion

transitional epithelium location

lines the urinary bladder, ureters, and part of the urethra

transitional epithelium function

stretches to permit the distention of the urinary bladder

mucous membrane function/location

lines body cavities that are open to the exterior (digestive and respiratory)

serous membrane function/location

moist membranes found in closed body cavities; parietal and visceral peritoneum, pericardium and pleura

parietal vs visceral membrane function

parietal lines the outer layer or is the outer layer of the cavity, while visceral covers the organ

types of dense connective tissue

dense regular and dense irregular

types of loose connective tissue

areolar, reticular, adipose

all types of connective tissue

loose, dense, cartilage, bone, and blood

functions of connective tissue

binds organs, supports framework of organs/bones, protects bones, facilitates movement, stores fat, produces heat, and transports nutrients, waste, and blood

what is ground substance

the unstructured material that fills in the space between cells and contains fibers; found in connective tissue

what is loose areolar connective tissue made up of

fibroblasts, macrophages, mast cells, white blood cells; all three CT fibers

where can loose areolar CT be found?

in dermal papillary layer; widely distributed throughout the body; wraps and cushions organs

what is reticular loose connective tissue made up of

leukocytes and reticular fibers; very loose/open ground substance

where is loose reticular CT found?

forms compartments in the lymph nodes, bone marrow, and the spleen

how does loose reticular CT function?

forms a soft internal skeleton that supports other cell types (stroma)

where is dense regular connective tissue found

tendons, ligaments, and aponeuroses; attaches muscle to bone, muscle to muscle, and bone to bone