UNIT 2 ANATOMY EXAM

Cartilage functions

Supports soft tissue

Provides a gliding and/or cushioning surface at joints

Flexibility in bone structures

Provides a model for bone growth

Interstitial growth

from inside of cartilage

Appositional growth

along opposite edge and stem cells to become chondrocytes

Bone functions

structural support, protection, movement, mineral storage, blood cell production in red bone marrow, and storage of lipids

Long bones

greater length than width, diaphysis, epiphyses, metaphyses, humerus

Short bones

nearly equal length and width

Flat bones

flat and thin surfaces, skull

Irregular bones

complex shapes like vertebrae

Sesamoid bones

formed in tendons

Bone constituents: Cells

1% of bone weight, osteoprogenitors, osteoblasts, osteocytes, and osteoclasts

Osteoprogenitors

mesenchymal stem cells which are found in deep endosteum and peristeum

Osteoblasts

secrete organic form of bone matrix called osteoid (mostly collage)

Osteocytes

mature osteoblasts that have become trapped inside lacunae and maintain matrix

Osteoclasts

large, multinucleted phagocytes that dissolve bone, releasing minerals

Matrix

Inorganic and organic components

Inorganic

makes up 2/3, calcium phosphate and calcium hydroxide interact to form crystals of hydroxyapatite (hardens bone matrix)

Organic

makes up 1/3, collagen fibers and ground substance

Head

bony expansion of a narrow neck, head of femur

Condyle

rounded articular projection, later condyle of femur

Facet

smooth, nearly flat articular surface, superior articular facet

Ramus

angular extension of bone, mandibular ramus

Tuberosity

a large, rough, and rounded bump on a bone where muscles, tendons, and ligaments attach, ischial tuberosity

Crest

narrow, prominent ridge of bone

Trochanter

a prominent, bony projection on the upper part of the thighbone (femur) that serves as an attachment site for hip and thigh muscles, greater trochanter

Line

subtle, narrow, and faint raised ridge or narrow stripe on a bone that serves as an attachment point for muscles, tendons, or ligaments, linea aspera

Tubercle

small, rounded projection, bump, or eminence on a bone that usually serves as an attachment site for muscles, tendons, or ligaments, greater tubercle

Epicondyle

a raised bump or projection on a long bone, located just above or on the articular surface of a joint, that serves as a vital attachment point for muscles, tendons, and ligaments, medial epicondyle

Spine

thin bone projection, scapula

Process

any bone prominence, styloid process

Sinus

cavity within a bone, frontal sinus

Fossa

shallow, basin line depression, olecranon fossa

Groove

narrow depression

Fissure

narrow, slit-like opening through bone, superior orbital fissure

Foramen

round oval opening through bone, foramen magnum

Canal

passageway through bone, meatus is the same

Spongy bone

porous, consists of lattice of narrow plates (trabecular), forms internal structures, red bone marrow

Compact bone

dense and cortical bone, solid, forms external portions of flat and long bones

Compact bone constituent

osteon, central canal, lamellae, lacunae, canaliculi, perforating canals, interstitial lamellae, circumferential lamellae

Osteons

basic structural and functional units of bone

Central canal

carries blood vessels through center of osteons, haverisans

Lamellae

concentric: rings of bone around a central canal (osteocytes sit in here)

Lacunae

small, spindle-shaped cavities or spaces located between the lamellae (concentric rings) of bone matrix that house mature bone cells called osteocyte

Canaliculi

small cnals between lacunae, allowing interactions between osteocytes

Perforating canals

perpendicular connections between central canals

Interstitial lamellae

leftover pieces of old osteons

Circumferential

along endosteum and periosteum

Spongy bone: trabeculae

basic structure and functional units of spongy bone

Ossification type: Endochondral

hyaline cartilage model forms and then is replaced by bone

Ossification type: intramembranous

thickened deposits of mesenchyme become mineralized

Bone growth: interstitial

from inside of cartilage, increases in length

Bone growth: appositional

along opposite edge of cartilage, increases in thickness or diameter

Zone of Resting cartilage

farthest from diaphysis, chondrocytes in hyaline cartilage

Zone of proliferating cartilage

large chondrocytes undergoing rapid miotic cell division

Zone of hypertrophic cartilage

chondrocytes become enlarged

Zone of calcified cartilage

deposited minerals kill chondrocytes

Zone of ossification

Resorption/Bone Deposition Zone, closest to diaphysis

What type of bone growth is occurring at the ephiphyseal plate?

Interstitial growth

Why is bone continuously remodeled?

In response to mechanical stress, repair microdamage, maintain bone strength, and regulate mineral levels

Which cells build bone?

osteoblasts

Which cells resorb bone?

Osteoclasts

Why does growth in length of long bones cease?

The growth plates will completely ossify and fuse to solid bone

Wolff’s law

Bone is deposited where it is needed and resorbed where it is not needed

How does the balance between growth and resorption of bone change as an individual ages?

As a person ages bone resorption increases and bone deposition decreases

Germ cell layer that derives bone

Mesoderm

When does ossification occur?

Between sixth and seventh weeks of embryonic development

Axial skeleton

skull, hyoid, vertebrae, thoracic cage

Appendicular skeleton

shoulder girdle, arms, pelvic girdle, legs

Paired neurocranial bone

Parietals and temprals

Unpaired neurocranial bones

frontal, occipital, sphenoid, ethmoid

Paired Facial bones

zygomatic, lacrimals, nasals, inferior nasal, concnae, palatine, maxilla

Unpaired facial bones

vomer and mandible

Foramen magnum

in the occipital and bone, passageway for the spinal cord from skull to vertebral column

Cribriform plate

ethmoid bone, passageway of olfactory nerve endings

External acoustic meatus

temporal bone, opening in skull to ear

Orbits

bony cavities that encase eyes and fatty tissued, formed by: sphenoid, ethmoid, zygomatic, lacrimal, etc

Optic canals

sphenoid bone, passgeway of optic nerves from brain to eye

Nasal cavity

regulates air temps, humidifies air, formed by the ethmoid, sphenoid, nasal, and maxilla

Nasal conchae

scrolled spongy bones that portrudes into nasal passageway

Paranasal sinuses

connected to nasal cavities, mucosa lined and filled, decreases weight of skull, moistens air, provide resonance to voice

Sutural bones

coronal suture, sagittal suture, lambdoid suture, squamous suture

Jaws and teeth

maxillae and mandible, form upper and lower jaws, house teeth

Intervertebral disks

fibrocartilage, shock absorbers, between vertebrae

Annulus fibrosus

encloses nucleus pulposus

Nucleus pulposus

he soft, jelly-like center of the intervertebral disc that acts as a shock absorber between the bones of the spine

Body of vertebrae

to support and bear the heavy weight of the upper body and torso

Spinous process

pointy and thin

Superior articular facet

an upward-facing bony surface on a vertebra that connects with the inferior (downward-facing) facet of the vertebra directly above it

Inferior articular facet

guides spinal movement and supports body weight

Vertebral foramen

the large, central hole in each individual vertebra that allows the spinal cord to pass through

Atlas (c1)

no body; superior articular facets allow head nodding

Axis (C2)

dens of axis inserts into atlas and allows head rotation

Dens axis

a prominent tooth-like vertical projection rising from the body of the second cervical vertebra (C2 axis

Cervical

7, concave, secondar

Thoracic

12, convex, primary

Lumbar

5, concave, secondary

Sacral

5, convex, primary

Coccyx

2-4