A&P Test 2

Skin, it makes up 16% of body weight

One of the major componenets of integument system, skin

Loose connective tissue, below dermis, location of hypodermic injections

Protects underlying tissue and organs; excretes salts, water and organic wastes; maintains body temp

Has many germinative (stem) cells or basal cells
Attached to basal lamina by hemidesmosomes
Forms strong band between epidermis and dermis
Has epidermal ridges and dermal papillae
Has merkel cells and melanocytes

Produced by division of stratum germinousum
8-10 layers of keratinocytes bound by desmosomes
Cell shrunk until cytoskeletons stick out (spiny)
Continue to divide, increasing epithelium thickness
Contain langerhans cells (active in immune response)

Stops dividing and starts producing
Has keratin and keratohyalin
Cells: Produce protein fibers
dehydrate and die
create tightly interlocked layer of keratin surrounded by keratohyalin

Only found in thick skin
Covers stratum granulosum
Cells: flat; dense; filled w/ keratin

Exposed surface of skin
15-30 layers of keratinized cells
water resistant
shed and replaced every 2 weeks

bodys most abundant epitheilal cell

formation of a layer of dead, protective cells filled w/ keratin
occurs on all exposed skin except eyes

insensible- interstitial fluid lost by evaporation through stratum corneum
sensible- water excreted by sweat glands

from immersion in hypertonic solution

bluish skin- caused by reduction in blood flow or oxygenation

build up of bile produced by liver

pituitary gland, skin darkening

loss of melanocytes, loss of color

protects skin from sun damage skin color depends on melanin production, not number of melanocytes

causes DNA mutations and burns which lead to cancer and skin wrinkles

epidermal cells produce cholecalciferol (Vitamin D3) in presence of UV radiaiton liver & kidneys convert vitamin D into calcitriol to aid absorption of calcium & phosphorus

Between epidermis & subcutaneous layer
anchors epidermal accessory structures (hair follicles & sweat glands)

in the dermis
consists of dense irregular connective tissue
contains large blood vessels, lymph vessels & nerve fibers
contains connective tissue proper

in the dermis
consist of dense irregular connective tissue
contains large blood vessels, lymph vessels & nerve fibers
contains connective tissue properties

collagen & elastic fibers in dermis
establish important patterns
parallel cut remains shut, heals well
cut across (right angle) pulls open & scars

cutaneous plexus
network of arteries along reticular layer
papillary plexus- capillary network
from small arteries in papillary layer

venous plexus- capillary return deep into the papillary plexus
contusion- damage to blood vessels resulting in "black & blue" bruising

lies below integument
stabilizes skin & allows seperate movement
made of elastic areolar & adipose tissue
connected to reticular layer of integument by connective tissue fibers

capillary malformation
-angel's kiss
-stork bite
-infantile hemangioma
-capillary inalformation

nevus

deposits of subcutaneous fat
have distribution pattern determined by horomones
are reduced by cosmitic liposuction

exocrine glands- sebaceous glands (oil glands)
simple branched alveolar glands: associated w/ hair follicles
sebaceous follicles: discharged directly onto skins surface
holocrine glands

everywhere except palms, soles of feet, lips and portions of external genitalia

hair root: lower part of hair attached to integument
hair shaft: upper part of hair not attached to integument
arrector pili: -involuntary smooth muscle
-causes hairs to stand up
-produces "goose bumps"
sebaceous glands: -lubricate hair
-control bacteria

begins deep in dermis
hair papilla contains capillaries & nerves
hair bulb produces hair matrix

layer of dividing base cells
produce hair structures
push hair up and out of skin

Lanugo- fetal hair follicles
Vellus Hairs- soft, fine; cover body surface
Terminal Hairs- heavy pigmented; head & eyebrows & genitalia area

nail root- deep epidermal fold near the bone
nail body- visable portion of the nail covers nail bed
lunula- pale crescent at the base of the nail

damage due to heat, electricity, radiation or chemicals
catastrophic loss of body fluids
-dehydration & electrolyte imbalance
rule of nine

1st degree- epidermis is damaged
2nd degree- epi and upper dermis is damaged
3rd degree- entire thickness of skin is damaged

fluid filled cavity encircled by muscle fibers; soft-bodied invertebrates

body encased in hard shell chitin most be shed for growth
limits body size as exoskeleton has to grow increasingly thicker and heavier

rigid internal skeleton of bone

1. support
2. storage of minerals (calcium)
3. storage of lipids (yellow marrow)
4. blood cell production (red marrow)
5. protection (ribs, skull)
6. Leverage (force of motion)

long & thin; found in arms, legs, hands, feet, fingers and toes

thin w/ parallelsurfaces; are found in skull, sternum, ribs and scapula

small, irregular bones; found between the flat bones of the skull

have complex shapes
ex. spinal vertebrae & pelvic bones

small & thick
ex. ankle & wrist bones

small & flat
ex. joints of knees, hands & feet

depressions or groves along bone surface
-projections where tendons & ligaments attach at a articulation w/ other bones
-tunnels where blood & nerves enter bone

-mature bonecells that maintain the bone matrix
-live in lacunae
-between layers of matrix
-connect by cytoplasmic extensions through canaliculi in lamellae
-do NOT divide
2 functions: -maintain protein & mineral content of matrix
-helps repair damaged bone

-immature bone cells that secrete matrix compounds (osteogenesis)
osteoid- matrix produced by osteoblasts, but not yet calcified to form bone
osteoblasts- surrounded by bone becomes osteocytes

-secrete acids & protein digesting enzymes
-giant, multinucleate cells
-dissolve bone matrix & release stored minerals (osteolysis)
-derived from stem cells thatproduce macrophages

-mesenchymal cells that divide to produce osteoblasts
-located in inner, cellular lyaer of periosteum (endosteum)
-assist in fracture repair

osteon is teh basic unit of mature compact bone
-osteocytes are arraanged in concentric lamellae
-around a central canal containing blood vessels

basic unit of mature compact bone

perforating canal- perpendicular to the central canal
-carry blood vessels into bone & marrow

circumferential lamelle- wrapped around the long bone
-binds osteons together

covers all bones except parts enclosed in joint capsules
-made up of an outer, fibrous layer & inner, cellular layer

1. isolate bone from surrounding tissues
2. provide a route for circulatory & nervous supply
3. participate in bone growth & repair

-an imcomplete cellular layer
-lines marrow cavity
-covers trabeculae of spongy bone
-lines central canal
-contains osteoblasts, osteoprogenitor cells & osteoclasts
-active in bone growth & repair

-does not have osteons
-matrix forms an open network of trabeculae
-trabeculae have no blood vessels
-in some bones, spongy bone holds yellow marrow

1. mesenchymal cells aggregate differentiate into soteoblasts, begin ossification at ossification center, develop spicules
2. blood vessels grow into the area to supply the osteoblasts & spicules connect trapping blood vessels inside bone
3. spongy bone develops & remodeled into osteons of compact bone

-ossifies bones that originate as hyaline cartilage (most bone)
-long bones
1. chondrocytes in the center of hyaline cartilage
2. blood vessels grow around the edges of the cartilage & cell in the perichondrium change to osteoblasts
3. blood vessels enter the cartilage bringing fibroblasts that become osteoblasts & spongy bones develops @ primary ossification center
4. remodeling creates a marrow cavity
5. capillaries & osteoblasts enter the epiphyses creating secondary ossification centers
6. epiphyses fill w/ spongy bone:
-cartilage w/ in joint cavity is articulation  cartilage
-cartilage at metaphysis is epiphyseal cartilage

when long bones stop growing after puberty epiphyseal cartilage disappears & visible on x-rays

-single pair of large blood vessels
-enter diaphysis through nutrient foramen
-femur has more than one pair

-supply the epiphyseal cartilage
-where bone growth occurs

-blood to superficial osteons
-secondary ossification centers

recycles & renews bone matrix
*involves osteocytes, osteoblasts & osteoclasts

dietary source of calcium & phosphate salts:
-plus small amts of magnesium, fluoride, ion & manganse

Vitamin C: required for collagen synthesis & stimulates differentiation
Vitamin A: stimulates osteoblast activity
Vitamin K&B12: help synthesize bone proteins

-made in kidneys & helps absorb calcium & phosphorus from digestive tract
-synthesis required vitamin D3 (cholecalciferol)
-growth hormone & throxine stimulate osteoblasts
-calcitonin & parathyroid hormone regulate calcium & phosphate levels

produced by parathyroid glands in the neck
increases calcium ion levels by:
-stimulating osteoclasts
-increasing intestinal absroption of calcium
-decrease calcium excretion at kidneys

secreted by C cells (parafollicular cells) in thyroid
decreases calcium ion levels by:
-inhibiting osteoclast activity
-increasing calcium excretion at kidneys

contacts w/ other bones

areas of muscle & ligament attachment

openings for nerves & blood vessels

longitudinal axis
supports & protects organs in body cavities
attaches to muscles of:
-head, neck & trunk
-respiration
-appendicular skeleton

protects:
-brain
-entrances to respiratory system
-entrance to digestive system
-has 22 bones
  -8 cranial bones

encloses cranial cavity
which contains the brain
-and its fluids, blood vessels, nerves & membranes

superficial facial bones for muscle attachment:
-maxillary, lacrimal, nasal, zygomatic, mandible
deep facial bones seperate oral & nasal cavity from nasal septum:
-palatine bones, inferior nasal conchae, vomer

seperates occipital from parietal ones

attaches frontal one to parietal bones

between parietal bones, lambdoid suture to coronal suture

form boundaries between temporal & panetal bones