a&p test 2

integument

skin

sweat glands

eccrine and apocrine glands

functions of the integumentary system

protecting the internal environment from the external environment (actively and passively), thermoregulation, sensory reception, and homeostatic functions

ways that skin helps thermoregulation

sweat (evaporative cooling), shuttles blood away/towards skin, and adipose tissue (insulation)

sensory receptors in skin

mechanoreceptors, thermoreceptors, and nociceptors

nociceptors

pain receptors

what are skins homeostatic functions

reservoir of blood for blood pressure, prevents water loss, synthesis of vitamin D necessary for calcium absorption

regions of skin

epidermis and dermis

epidermis

stratified squamous epithelium (keratinized), superficial to dermis, regenerating sacrificial protective layer, avascular

cell in epidermis

keratinocytes, melanocytes, langerham cells, merkel cells

keratinocytes

produce keratin fibers, anchored together via desmosomes, provides epidermis with toughness and durability, millions slough off per day

hypodermis

made of adipose tissue, helps connect skin to body and absorb shock, not technically skin but its associated

melanocytes

produces melanin, package pigments into melanosomes, exported to the epidermis (where keratinocytes pick them up)

melanin

pigment that protects DNA from damage from UV radiation exposure

Langerhans cells

type of macrophage, further excites adaptive immune system, contain lots of lysosomes, example of active barrier

macrophages

engulf and digest bacteria and pathogens, part of immune system, in epidermis and papillary layer

Merkel cells

tactile receptors

what are the layers of epidermis (interior to exterior)

stratum Basale, spinosum, granulosum, lucidum, corneum

stratum Basale

bottom single layer of cells in epidermis, in contact with underlying dermis, mitotically active, daughter cells take 25-45 days to migrate to the surface, 75-90% are keratinocytes, 10-25% melanocytes

stratum spinosum

superficial to Basale, several cell layers thick, pre-keratin fibers anchored to desmosomes (keratinocytes appear spiny), melanosomes and Langerhans cells are found here

stratum granulosum

in between spinosum (inferior) and lucidum/corneum, 4-6 layers thick, cells are flattened, nuclei and organelles disintegrate, keratinization begins, lamellar granules (glycolipids resist water loss),

stratum lucidum

2-3 rows of clear, flat, dead, keratinocytes. found only in thick skin (palms of hand and plantar feet), inferior to corneum

stratum corneum

20-30 layers of flat, dead, keratinocytes, ¾ of epidermis, prevents abrasions and penetration, physical barrier, prevents water loss, protects deeper cells and tissue

what regions is the dermis made of

papillary and reticular regions

papillary region

part of dermis, areolar connective tissue, vasculature (supports avascular epidermis), and immune system support

what makes up the papillary region

macrophages, mast cells, Meissner’s corpuscles, dermal papillae

mast cells

mediate inflammation, releases histamine, immune system, in papillary layer

Meissner corpuscles

tactical sensory receptor in papillary region, does NOT help immunity

dermal papillae

part of papillary layer, enhance surface area and increase adhesion to epidermis

reticular region

dense irregular connective tissue (provides strength), hair follicles, exocrine glands are found and anchored here, lamellar corpuscles

lamellar corpuscles

deep tactile receptors in reticular region

hair/pili

flexible strand of dead keratinized cells

root

portion of hair housed within follicle

neldula

a part of the root, central core of larger cells

cortex

part of root, intermediate layer

cuticle

part of root, flattened overlapping cells

what is the follicle made of

epithelial root sheath, glassy membrane, peripheral C.T sheath (areolar C.T)

internal root sheath

sheath that is against the cuticle of hair root

external root sheath

against the areolar CT of the follicle

glassy membrane

basement membrane adhering to external epithelial root seath

what is the base of the follicle made of

hair matrix and hair papillae

hair matrix

part of base of follicle, mitotically active epithelium, similar to stratum Basle

hair papillae

part of base follicle, areolar C.T, high density of capillaries

nails anatomy are analogous to?

hair/follicle (is analogous to?)

nail bed is analogous to?

epithelial root sheath (is analogous to?)

nail bed

dead, tough (from more disulfide bonds) keratinocytes

eccrine

most numerous exocrine gland, involved in thermoregulation, exocytosis sweat (water, salts, vitamin c)

apocrine

found in axillary and pubic region, sweat is rich with proteins and lipids, odorless but bacteria metabolize the sweat and create an odor. distal ¼ or 1/3 pinches off into the lumen of gland

what are the modified apocrine glands

mammary glands and ceruminous glands

mammary glands

apocrine glands that produce milk

ceruminous glands

apocrine glands tha are in ear canal and produce wax

sebaceous oil glands

secretes oil that helps keep hair more supple and flexible, softens stratum corneum of the epidermis

holocrine gland

apical cells pinching of small cell fragments, lots of lipids from plasma membrane

skeletal system

consist of bone organ and cartilage organs

cartilage

produces flexibility and resiliency. skeleton develops from its scaffold, grows from its tissue, gets repaired with it

where is hyaline cartilage

respiratory cartilage, costal (ribcage) cartilage, articular cartilage, epiphyseal plate of long bone

epiphyseal plate

growth plate

where is elastic cartilage

epiglottis, external ear,

where is fibrocartilage

pubic symphysis, intervertebral disk, menisci of knees and tmj

what is the cartilage matrix made of

80% H2O and 20% collagen, elastic fibers, hyaluronic acid, and chondroitin

cartilage cells

chondrocytes and chondroblast

chondrocytes

mature form of cartilage cell, maintain the matrix

chondroblast

produces cartilage matrix

perichondrium

surrounds cartilage, dense irregular C.T

appositional growth

growth of cartilage from the outside

luterstitial growth

growth of the cartilage from within

calcification

calcium phosphate replacing cartilage matrix, makes cartilage less resilient and more rigid

when is calcification normal

during endochondral ossification (bone development)

examples of bone development

epiphyseal plate during bone growth, repair of bone fractures, and in old age

bone functions

support, protection, movement, mineral storage, blood cell formation, triglycine storage, and hormone production

osteocalcin

helps regulate insulin and glucose

cancellous

compact

trabecular

spongy bone

periosteum

fibrous layer, irregular C.T near tendons, becomes regular C.T near tendons, tissue in bone

osteolytic layer

mesenchymal cell, stem cell precursor, tissue in bone

fibrocartilage

between hyaline cartilage (lacks collagen) and tendons (collagen rich), is transitional cartilage

hematopoiesis

red blood cell formation, red marrow

yellow marrow

triglyceride storage, in adipose tissue

tissues associated with vasculature

smooth muscle and simple squamous epithelium

long bone

short bone

flat bone

irregular bone

ectasis

enlargements that form articulations, upon growth, proximal and distal

diaphysis

shaft, apart growth, medullary cavity

medullary cavity

makes bones hollow

outside to inside of long bone

periosteum and articular cartilage (fibrous layer and osteogenic layer) compact bone, spongy bone, endosteum

endosteum

most interior in long bone, has trabeculae, osteogenic layer

bone cells

osteoblast, osteocytes, and osteoclast

osteoblast

produce bone matrix, derived from mesenchymal cells

osteocytes

maintain matrix, derived from mesenchymal cells

osteoclast

dissolve bone matrix, derived from macrophages, lysomal products (acid hydrolase) exocytosis onto the bone matrix

organic matrix of bone

osteoid, 1/3 volume of bone matrix, chemicals that promote precipitation and calcification of inorganic matrix (alkane phosphate)

osteoid

ground substance and collagen fibers, part of bone matrix

inorganic matrix of bone

hydroxyapatites (mineral salts), 2/3 of bone matrix, calcium phosphate, precipitates around collagen fibers

bone matrix is strong in ___, good in ___, and okay in ___

compression, tension, and strain

osteocytes

were once osteoblast, support osseus tissue, trapped in lacunae

how does osteoblast turn into osteocytes

laid down osteoid and other matrix, eventually surrounding themselves with calcified osseus tissue, were no longer able to secrete any additional

central canal

the center of osteon, contains nerve and blood vessel that supply nutrients and respiratory gases

canaliculi

branch from the lacunae, allow parts of cell membrane of each osteon to spread the across the lamella