CIS Hu Phys: Osseus

humerus

long bone in upper arms

marrow cavity

space within hollow shaft in bone; filled with vascular marrow

red bone marrow

produces red blood cells

yellow bone marrow

primarily adipose tissue, serves as an energy reserve

compact bone

thick and dense, makes up diaphysis

articular cartilage

covers portions of epiphysis; avascular, relies on diffusion from synovial fluid to obtain nutrients and oxygen

epiphysis

expanded area found at the ends of bone (think of of the rounded shelf where your femur meets your tibia, etc.)

diaphysis

the shaft of the bone; long and tubular

spongy bone

composes epiphysis; network of struts and plates; has a thin covering of compact bone everywhere other than joint cavities

periosteum

sheath of connective tissue that covers compact bone

what are functions of the periosteum?

• isolates bone from surrounding tissue

• provides route for blood/nerves to access bone

• helps with growth and repair

osteocytes

mature bone cells that maintain protein content in the bone

lamellae

layers of bone matrix

lacuna (pl. lacunae)

the pocket between lamellae occupied by an osteocyte

canaliculli

passageways penetrating the bone matrix; provide route for nutrient diffusion

osteoblasts

produce new bone matrix through process known as ossification

osteoclasts

remove and recycle bone

osteolysis

process through which stored minerals in bone are released to the interstitial fluid

osteon

basic functional unit of compact bone (not included in spongy bone)

what is another name for osteon?

Haversian System

central canal

runs parallel to the bone surface; hollow canal in the center through which veins pass through (bone builds around it; think of it as the bullseye)

calcium

important in most bodily functions; requires vitamin D₃ to synthesize; bones, kidneys, and intestines involved in homeostatic regulation

trabeculae

struts/plates in spongy bone matrix

appositional growth

how diameter of the bone enlarges; cells in inner periosteum differentiate and add bone matrix

perforating fibers

collagen from tendons/ligaments/joint capsules cement into lamellae of bone; very sturdy, bones are more likely to break than the fibers

endosteum

incomplete cellular layer lining marrow cavity; has roles in bone growth/repair/remodeling, covers trabeculae

parathyroid gland

two pairs embedded in thyroid; regulates blood calcium

parathyroid cells

one of two types of cell populations in parathyroid gland; produces PTH

oxyphils

one of two types of cell populations in parathyroid gland; no known function

parathyroid hormone (PTH)

secretion of this hormone raises calcium concentration in blood

calcitonin

released by thyroid; increases calcium deposited into bones and excreted by kidneys

calcitriol

increases amount of calcium absorbed in digestive system

fontanelle

large fibrous areas between cranial bones in infants; enables distortion of the skull without damage to brain

sphenoidal fontanelle

on each side, lies between squamous/coronal suture (above ears)

mastoid fontanelle

on each side, lies between squamous and lambdoid sutures (further back on head but aligned with ear)

occipital fontanelle

junction between lambdoid and sagittal sutures (back of head)

anterior fontanelle

“soft spot” on newborns, persists up to two years old (on top of head)

kyphosis

causes a humpback, results from:

1. osteoporosis with compression fractures along anterior vertebral bodies

2. chronic contractions in muscles upon the vertebrae, or

3. abnormal vertebral growth

scoliosis

abnormal lateral (horizontal) curvature of spine; develops due to developmental issues, damage, or paralysis of one side of the back

lordosis

abdomen and butt protrude; can occur because of pregnancy, abdominal obesity, or weak muscles in the abdominal wall