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