A&P I
osteocytes
mature bone cells; regulate the composition of bone matrix
condrocytes
mature cartilage cells
Layers of the epidermis
(superficial to deep) Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale "Come, Let's Get Some Beer"
Ossification contributing to bone length is usually complete by _____________ years of age
18-21
bone matrix composition
25% water 25% collagen 50% calcium
Hypodermis
AKA subcutaneous not part of the skin!
Partial or complete lack of hair
Alopecia
Dermis
Dense irregular connective tissue ; collagen and elastic connective tissue papillary region (superficial) reticular region (deep) contains hair follicles, vessels, nerves, etc.
What are the four cells types that make up the keratinized stratified squamous epithelium of the epidermis?
Keratinocytes Melanocytes Langerhans Merkel
What pigments influence skin color?
Melanin Carotene Hemoglobin *All expression based on genetics except for hemoglobin, which has its coloration based on O2 levels
Keratinocytes
Most abundant Waterproofs the skin and helps protect the skin and tissues from heat, microbes, and chemicals
Hemoglobin
Oxygen carrying pigment in red blood cells
osteoporosis
Porous bones caused by bone resorption outpacing bone deposition due in large part to depletion of calcium from the body. Bone mass becomes so depleted that bones fracture
In this condition, keratinocytes divide and move quickly from the stratum basale to the stratum corneum and are shed prematurely (immature keratinocytes)
Psoriasis
osteoarthritis
The degeneration of articular cartilage such that bony ends touch, resulting in bone against bone which results in friction that worsens the condition
blister
a collection of serous fluid within the epidermis or between the epidermis and dermis, due to short-term but severe friction
athlete's foot
a superficial fungal infection of the skin of the foot
bone desposition
addition of minerals and collagen fibers to bone by osteoblasts
Melanocytes are unable to synthesize tyrosinase
albinism
callus
an area of skin that is thick or hard from continual pressure or friction (as the sole of the foot)
abrasion
an area where skin has been scraped away
Subcutaneous layer (hypodermis)
areolar and adipose tissues
apocrine sweat glands
associated with hair developed post-puberty
epiphyseal plate
at the metaphysis of a growing bone
What are the three common forms of skin cancer?
basal cell carcinomas (most common, most benign) squamous cell carcinomas malignant melanomas (least common, most dangerous)
diaphysis
body of long bone
What supports calcium homeostatis
bone remodeling
Ricket's disease
bones are too soft also osteomalacia
small channels filled with extracellular fluid connecting the lacunae
canaliculi
endochondral ossification
cartilage is replaced by bone (both compact and spongy) for most bones, especially long bones one primary and two secondary centers of growth
blood and lymphatic vessels are found in the osteon's ________________
central canal
elastic cartilage
chondrocytes located in a threadlike network of elastic fibers malleable part of the external ear and the epiglottis
terminal hairs
coarse, heavily pigmented hair; includes hair of the head, eyebrows, eyelashes, and hair that develops as a secondary characteristic
Two types of bone
compact bone (cortical bone) spongy bone (cancellous, trabecular bone)
hirsutism
condition of excessive body hair
cartilaginous joints
connected by cartilage fibrocartilage or hyaline cartilage no synovial cavity little to no movement (synchondroses, symphyses) Ex: ribs
cartilage
consists of a dense network of collagen fibers and elastic fibers embedded in a jelly-like ground substance of chondroitin sulfate (plasticity comes from this)
Fibrocartilage
consists of thick bundles of collagen fibers disc-shaped segment of cartilage between bones
Skin inflammation caused by exposure of the skin to chemicals that bring about an allergic reaction
contact dermatitis
Melanocytes
contains melanosomes that produce melanin from tyrosine in the presence of tyrosinase projections from melanocytes extend between keratinocytes and transfer melanin granules to them melanin granules cluster over nucleus on the side towards skin surface to shield DNA from UV light
Stratum basale
deepest epidermal layer mostly keratinocytes keratinocytes have intermediate filaments called tonofilaments composed of a protein that will later form keratin continuously undergo mitosis
periosteum
dense irregular connective tissue that covers the bone (except for the articular cartilage)
Rickets Disease
disease of children in which growing bones become "soft" and are easily deformed. New bone formed at the epiphyseal plates fails to ossify, resulting in bowed legs and deformities of the skull, rib cage, and pelvis
epiphyses
distal and proximal ends of a long bone
What are the layers of the skin?
epidermis and dermis
third degree burns (full thickness)
epidermis, dermis, and associated structures marble-white to mahogany to charred, dry wounds numbness
redness of the skin caused by engorgement of capillaries
erythema
epidermal ridges
fingerprints develop in fetal months as epidermis conforms to contours of the dermal papillae of papillary region
Stratum granulosum
flattened keratinocytes transition between the deeper living cells and the more superficial dead cells filled with granules of keratin lamellar granules release a waterproofing lipid solution
Rule of 9's
for 2nd and 3rd degree burns accurate for adults, not kids
Fracture and repair steps of bone
formation of fracture hematoma formation of a spongy bone callus remodeling (spongy replaced by compact bone)
Hair root plexuses
groups of dendrites and nerve fiber endings that form a network around a hair follicle generate nerve impulses when hair is moved
what occurs exclusively in spongy bone?
hematopoiesis (blood cell production)
what are the types of cartilage?
hyaline cartilage elastic cartilage fibrocartilage
articular cartilage
hyaline cartilage covering the epiphyses
Langerhans cells
immune response cells type of dendritic cell
Eczema
inflammation of the skin characterized by patches of red, blistering, dry itchy skin
encircle the medullary cavity
inner circumferential lamellae
where is spongy bone found?
interior of long bones
_______________ between osteons are left over fragments of older osteons
interstitial lamellae
Buildup in the blood of the yellow pigment bilirubin, indicative of liver disease
jaundice
Stratum spinosum
just superficial to the stratum basale layers of keratinocytes cells are still alive; some divide older cells start to flatten
small spaces between the lamellae which house osteocytes
lacunae
where are condrocytes found?
lacunae
fibrous joints
little movement (sutures, syndesmoses, gomphoses)
What is the white crescent-shaped area on a nail called?
lunula
wart
mass produced by uncontrolled growth of epithelial skin cells; caused by a papillomavirus
topical
medication applied to the skin surface, rather than ingested or injected
Hair shaft/root layers
medulla, cortex, and cuticle *root is in dermis
endosteum
membrane lining the marrow cavity
hyaline cartilage
most abundant type of cartilage covers ends of long bones covers parts of ribs, nose, trachea, bronchi, and larynx
eccrine sweat glands (merocrine)
most common found on skin thermoregulation
synovial joints
most moveable articular capsule synovial membrane synovial fluid articular cartilage/discs
Stratum corneum
most superficial layer mostly keratin between cells, lipids from lamellar granules provide water-proofing
Osteomalacia ("adult Rickets")
new bone formed during remodeling fails to calcify
epidermal wound healing
occurs following superficial wounds that affect only the epidermis (returns to normal function)
deep wound healing
occurs when an injury extends to the dermis and subcutaneous layer (loss of some function and scarring from collagen fibers) Stages: inflammatory phase migratory phase proliferative phase maturation phase
sebaceous gland
oil glands that keep hair from drying out, prevents excess evaporation, and inhibits bacterial growth
first degree burns (superficial)
only epidermis, function intact
Stratum lucidum
only found in fingertips, palms, soles dead keratinocytes filled with keratin
process of forming new bone
ossification (osteogenesis)
compact bone contains units called ______________ formed from _____________
osteons (Haversian systems) concentric lamellae (rings of calcified matrix)
encircle the bone beneath the periosteum
outer circumferential lamellae
allows transit of these vessels to the outer cortex of the bone
perforating (Volkmann's canals)
most cartilage is covered by a dense, irregular connective tissue called ________________.
perichondrium
The growth of hair occurs at the base of the follicle, which pushes the growing hair through the ______________________.
pilary canal
second degree burns (partial thickness)
portion of epidermis and part of dermis blisters, some functions lost associated structures usually not injured scarring may result
calcitonin
produced by parafollicular cells of the thyroid gland, lowers blood Ca levels by inhibiting bone resorption
Intra-membranous ossification
produces spongy bone and flat bones (simpler method) from mesenchymal cells that develop within a membrane - without going through a cartilage stage many ossification centers
Vitamin D
promotes calcium absorption
Calcitriol (vitamin D)
promotes intestinal absorption of Ca
parathyroid hormone
promotes resorption of bone matrix prevents loss of Ca in urine promotes vitamin D (calcitriol) formation
osteoclasts
release enzymes that digest bone matrix for remodeling of bone
bone resorption
removal of minerals and collagen fibers from bone by osteoclasts
Merkel cells
reside in deepest layer of epidermis contact flattened processes of tactile discs (Merkel discs - a type of sensory neuron)
Striae
scarring of the skin caused by tearing of the dermis (stretch marks)
What structures are associated with hair?
sebaceous (oil) glands arrector pili muscles hair root plexuses
osteoblasts
secrete bone matrix; become osteocytes
Pacinian corpuscles (lamellated corpuscles)
sensory receptors for pressure found in the subcutaneous layer
vellus hairs
short, fine, pale hairs that develop on most of the body during childhood
medullary (marrow) cavity
space inside the diaphysis
osteogenic cells
stem cells that can divide and differentiate into osteoblasts
Vitamin A
stimulates osteoblast activity
functions of bone tissue
storage of calcium and phosphorus red bone marrow for RBC production triglyceride storage - yellow bone marrow is adipose connective tissue
sudoriferous glands
sweat glands two types: eccrine and apocrine
calcium
synaptic transmission, muscle contraction, blood clotting, etc bone stores 99%
Vitamin K and B12
synthesis of bone proteins
Vitamin C
synthesis of collagen
lanugo
the fine, nonpigmented, downy hairs that cover the fetus
Meissner's corpuscles
touch/light touch receptors in dermis
in spongy bone lamellae are arranged in a lattice of thin columns called _______________
trabeculae
autoimmune disorder in which the melanocytes are attacked and killed (also a genetic link)
vitiligo
metaphyses
where the diaphysis and epiphyses meet
Carotene
yellow-orange pigment that is a precursor to vitamin A, which is used to synthesize pigments needed for vision
Melanin
§amount of pigment the melanocytes produce and distribute, since the number of melanocytes is about the same in all races §Exposure to UV light increases the enzymatic activity of melanosomes, leading to increased melanin production, which gives the skin a tanned appearance and further protects the body against UV radiation