AP - Exam 2

Long bones

are those that has a greater length than width. Examples are the femur (thigh) and

humerus (upper arm).

Diaphysis

the central shaft of the bone.

Epiphyses

The distal and proximal ends of the bone.

Metaphyses

regions where the diaphysis meets the epiphyses.

epiphyseal plate

is a layer of hyaline cartilage that is responsible for the growth of the bone/metaphysis of long bones.

Articular cartilage

thin layer of hyaline cartilage covering the epiphysis, that reduces friction and absorbs shock in the joint.

Periosteum

dense irregular tissue that surrounds the bone surface wherever it is not covered by articular cartilage.

Sharpy’s (perforating) fibers

are collagen fibers that attach the periosteum to the bone.

Medullary cavity

space in the diaphysis that contain fatty yellow bone marrow in adult long bones and red marrow in flat bones.

Endosteum

thin membrane of bone forming cells that lines the medullary cavity.

Osteogenic cells

unspecialized stem cells that undergo mitosis and differentiation and become osteoblasts.

Osteoblasts

bone-building cells that synthesize collagen to build the extracellular matrix and initiate calcification.

Osteocytes

mature bone cells that maintain the bone

metabolism and nutrient/waste exchange with the blood.

Osteoclasts

Large cells produced from the fusion of approximately 50 monocytes (type of WBC) found in the endosteum. These cells are responsible for resorption of bone.

concentric lamellae

In the osteon, each haversian canal is surrounded by rings of calcified extracellular matrix called

lacunae

Is between the lamellae are small spaces and house the osteocytes

canaliculi

Radiating in all directions from the lacunae are small canals called

Spongy bone

is abundant in flat and irregularly shaped bones (sternum, ribs, pelvis, scapulae, vertebrae).

is much lighter and also because it contains and protects the majority of red bone marrow in the body.

is located in bones that are not heavily stressed (i.e., where there is minimal body force or pressure applied).

Ossification or osteogenesis

are the terms for bone formation and it involves either the replacement of preexisting connective tissue with bone or the replacement of cartilage with bone.

Intramembranous Ossification

Seen in flat bone, mandible (jaw bone) and skull formation.

Endochondral Ossification

This is the replacement of cartilage by bone that forms the long bones.

Interstitial Growth

Zone of resting cartilage: layer of small chondrocytes that is closest to the epiphysis

Zone of proliferating cartilage: layer of larger chondrocytes that divide to replace dead chondrocytes

Zone of hypertrophic cartilage: Layer of large, maturing chondrocytes arranged in columns.

Zone of calcified cartilage: layer of mostly dead, calcified chondrocytes.

Appositional Growth

The osteoblasts secrete collagen and extracellular matrix until they become surrounded by it. This process forms bone ridges on either sides of a periosteal blood vessel. Eventually the ridges fold over the vessel and fuse, causing the groove to become a tunnel that encloses the blood vessel.

osteoclasts

Bone remodeling involves bone resorption by

osteoblasts

Bone remodeling involves bone deposition by

Remodeling

is essential to allow for the increased growth of a bone. But it also removes injured bone, replacing it with new, stronger and thicker bone, that is more fracture resistant than old bone.

Minerals

dietary mineral intake of calcium and phosphorus. And to a lesser extent fluoride, magnesium, iron, and manganese.

Vitamin C

is essential for collagen formation.

Vitamins K and B12

are needed for bone protein synthesis.

Vitamin A

stimulates osteoblastic activity.

Vitamin D

allows calcium to be absorbed from the GI tract into the blood.

Hormones

bone growth is especially controlled by insulin like growth factors (IGFs). They are produced by the liver and the bone tissue in response to human growth hormone secreted by the anterior lobe of the pituitary lobe.

fracture

is any break of the bone.

Fracture repair

-These vessels leak blood and form a clot around the site of the fracture, 6-8 hours post injury.

This is called the fracture hematoma.

-Leads to the formation of a fibrocartilage callus, which is a tissue mass connecting the broken ends of the bone. Formation of the callus takes 3 weeks.

-Osteoblasts also start converting the fibrocartilage callus into spongy bone, forming the

bony callus. This bony callus lasts 3-4 months.

-The final phase is the remodeling of the bony callus. This is achieved by resorption of dead bone by the osteoclasts

Calcium

is essential for other bodily processes, such as muscle contraction, nerve conduction, blood clotting, and heart function.

Wolff's Law

"Remodeling of bone ... occurs in response to physical stresses - or to the lack of them - in that bone is deposited in sites subjected to stress and is resorbed from sites where there is little stress“

-that weight bearing exercise is the best way to prevent osteoporosis (decreased bone

mineralization and density) and osteopenia (decrease in bone)

osteoporosis

decreased bone mineralization and density

osteopenia

decrease in bone mass

206

The human skeleton is composed of how many bones?

Axial skeleton.

the bones that lie around the longitudinal axis (imaginary line that runs from the body’s center of gravity from the head to the space between the feet).

Consists of 80 bones

composed of flat bones and irregular bones

Appendicular skeleton

bones that form the upper and lower limbs. Consists of 126 bones

Skull

08 cranial bones; 14 facial bones

Hyoid bone

1 bone

Auditory ossicles

6 bones

Vertebrae

total of 26 bones; 1 sacrum; 1 coccyx; 24 vertebrae

thorax

1 sternum and 24 ribs

Long bones

those with a greater length than width (femur, humerus).

Short bones

usually cube shaped and nearly equal in length and width (carpal and tarsal bones).

Flat bones

thin bones that function mainly to protect (sternum, ribs, scapulae).

Irregular bones

complex shaped bones (vertebrae, calcaneus).

Sesamoid bone

bones formed within tendons to improve the mechanical efficiency of a joint (patella).

Depressions and openings

grooves, holes or pits in bone that allow the passage of nerves, vessels, ligaments, tendons, or muscle, as well as contribute to the shape of the joint.

Processes

projections or outgrowths on bone that form joints, or are attachment points for ligaments or tendons.

Fissure

slits in bone that house vessels (superior orbital fissure).

Foramen

holes in bone where nerves, vessels, or ligaments pass (optic foramen)

Fossa

shallow depression/pit that house muscle (infraspinatus fossa).

Sulcus

groove on the bone surface that contains nerve, vessels, or tendon (intertubercular sulcus of the humerus)

Meatus

tube-like opening or tunnel (external auditory meatus).

Frontal bone

forms the forehead and roofs of the eye sockets (orbits).

frontal sinus

is a membrane lined hollow space in the center of the frontal bone.

Parietal bones

the two bones that form the greater portion of the right and left sides and roof of the skull (cranium).

Temporal bones

two bones that form the right and left lateral sides of the skull. Contains the mandibular fossa and articular tubercle that articulates with the mandible forming the temporomandibular joint (TMJ).

Occipital bone

single bone that forms the posterior skull and most of the base

Sphenoid bone

located at the middle part of the base of the skull. This bone articulates with and holds all the other cranial bones together. Contains the sella turcica which is a space that contains the pituitary gland. Also contains the sphenoidal sinus.

Ethmoid bone

located between the orbits and form the medial walls of the eye sockets, parts of the nasal septum and nasal cavity. Contains the cribriform plate that is the roof of the nasal cavity

Nasal bones

two bones that form the right and left side of the bridge of the nose.

Maxillae

two paired bones that form the right and left upper jaw bone. Each bone contains a maxillary sinus, the alveolar process that holds the upper teeth (alveoli), and palatine process which is the anterior ¾ of the hard palate.

Zygomatic bones

two right and left sided bones that, with the articulation with the temporal bones, form the zygomatic arch (cheek bone).

Lacrimal bones

two small, thin paired bones (smallest of the face), that contribute to the medial walls of the orbits. Contains the lacrimal fossa which houses the lacrimal sac that stores tears.

Palatine bones

two “L” shaped bones that form part of the floor and lateral wall of the nasal cavity and the posterior portion of the hard palate

Inferior nasal conchae

two scroll-like bones inferior to the middle nasal conchae of the ethmoid bone. Also functions to warm, moisten and filter inhaled air before it passes to the lungs.

Vomer

single triangular bone that forms the inferior portion of the nasal septum.

Mandible

the lower jaw bone which is the only movable skull bone. The horizontal portion is the body, the right and left perpendicular portions are the rami which have a posterior condylar process that articulates with the mandibular fossa and articular tubercle of the temporal bone forming the temporomandibular joint (TMJ).

Nasal septum

the vertical partition that divides the nasal cavity into right and left halves. Contains bone and cartilage.

suture

is an immovable joint in an adult that is found between the skull bones.

Coronal

unites the frontal and parietal bones.

Sagittal

unites the two parietal bones

Lambdoid

unites the parietal and occipital bones.

Squamous

unites the parietal and temporal bones.

Paranasal Sinuses

These are cavities in certain cranial or facial bones that are lined with mucous membrane and are continuous with the nasal cavity.

They are found in the frontal, sphenoid, ethmoid, and maxillary bones.

They function to produce mucus as well as being resonating chambers for sound when we speak or sing.

Fontanelles

These are the “soft spots” on a baby’s head found between the cranial bones.

They are areas of unossified mesenchyme that will eventually be replaced with bone by intramembranous ossification and form the sutures (up to 24 months after birth).

The fontenelles function to allow the fetal head to be flexible in order to pass through the birth canal.

The names are the anterior, posterior, anterolateral and posterolateral fontenelles.

7 cervical vertebrae

How many vertebrae are found in the neck?

12 thoracic vertebrae

How many vertebrae are found in the middle and upper back?

5 lumbar vertebrae

How many vertebrae are found in the lower back

5 fused vertebrae in the base of the spine

In sacrum, how many fused vertebrae does it consist?

4 fused vertebrae that forms the tailbone

In coccyx, how many vertebrae does it consists?

lordosis

In the adult, a “C” curve with its concavity posterior is called? and is found in the cervical and lumbar regions of the spine.

kyphosis

A “C” curve with its concavity anterior is called? and is found in the thoracic and sacral regions of the spine.

Intervertebral disc

In the vertebral column, each vertebrae is separated by what discs?

annulus fibrosus and nucleus pulposus

The outside layer is called? and is composed of tough fibrocartilage;

The inside “jelly” is called?

cervical spine

has the largest vertebral foramen in the spine because it has to accommodate the widest portion of the spinal cord.

Composed of 7 vertebrae (C1-C7)

atlas

The first cervical vertebra (C1) is commonly called? This is a very unique vertebra because it has no body and no spinous process.

axis/C2

What makes this vertebrae unique is that the body extends superiorly forming a peg-like projection called the dens or odontoid process.

vertebra prominens

Other unique features of the cervical spine are that the spinous processes of C2-C5 are bifid, meaning that the spinous processes are split into two parts; and that C7, because it has such a large single spinous process that can be seen and felt at the base of the neck, is called

Thoracic Spine

There are 12 thoracic vertebrae (T1-T12)

These are larger and stronger than the cervical vertebrae but are restricted in spinal motion.

facets or demifacets

The lateral thoracic bodies and transverse processes contain small areas for articulations with the ribs. These are called?

Lumbar Vertebrae

There are 5 vertebrae (L1-L5).

These are the largest and strongest in the spine because they support the majority of the body weight.

Sacrum

is an up-side-down triangular bone formed by the union of five sacral vertebrae (S1-S5)

sacral ala

The lateral portions of the sacrum are called?

Sternum

is a flat narrow bone located in the center of the anterior thoracic wall.