Skeletal System Flashcards
joints, car- tilages, and ligaments
fibrous cords that bind the bones together at joints
The skeleton is divided into two parts what are these?
the AXIAL skeleton, the bones that form the longitudinal axis of the body and APPENDICULAR skeleton, the bones of the limbs and girdles that attach them to the axial skeleton.
what is hematopoiesis?
Blood cell formation, or hematopoiesis (hem′′ah-to-poi-e′sis), occurs within the marrow cavities of certain bones.
The adult skeleton is composed of 206 bones. There are two basic types of osseous, or bone, tis- sue: what are these?
Compact bone is dense and looks smooth and homogeneous, whereas
Spongy bone has a spiky, open appearance like a sponge
Long bones are mostly compact bone but also contain spongy bone at the ends. All the bones of the limbs, except.
the patella (kneecap) and the wrist and ankle bones, are long bones
Bones that are thin, flattened, and usually curved. They have two thin layers of compact bone sandwiching a layer of spongy bone between
them. Most bones of the skull, the ribs, and the sternum (breastbone) are
Flat bones.
Bones that are generally cube-shaped and contain mostly spongy bone with an outer layer of compact bone. The bones of the wrist and ankle are?
Short bones
The vertebrae, which make up the spinal column, fall into this group. Like short bones, they are mainly spongy bone with an outer layer of compact bone.
Irregular bones
In a long bone ______ or shaft, makes up most of the bone’s length and is composed of compact bone
the diaphysis (di-af′ ̆ı-sis),
The diaphysis is covered and protected by a fibrous connective tissue membrane, what is it called?
the perios- teum (per-e-os′te-um).
Hundreds of connective tissue fibers, called __________ secure the periosteum to the underlying bone.
perforating fibers, or Sharpey’s fibers,
The _______ are the ends of long bones. Each epiphysis consists of a thin layer of compact bone enclosing an area filled with spongy bone.
epiphyses (e ̆-pif′ ̆ı-seˉz)
Instead of a periosteum, articular cartilage covers its external surface. Because the articular cartilage is glassy hyaline cartilage, it pro- vides a smooth surface that decreases friction at the joint when covered by lubricating fluid. Imagine how slick a marble floor (the articular cartilage) is when wet; this is analogous to the lubrication of a joint
articular cartilage has it’s own lubrication
In adult bones, there is a thin line of bony tissue spanning the epiphysis that looks a bit differ- ent from the rest of the bone in that area.
This is the epiphyseal line.
The inner bony surface of the shaft is covered by a delicate connective tissue called
endosteum
In infants, the cavity of the shaft, called the med- ullary cavity, is a storage area for ________ , which produces blood cells.
red marrow
Children’s bones contain red marrow until the age of 6 or 7, when it is gradually replaced by ______ which stores adipose (fat) tissue.
yellow marrow,
There are two categories of bone markings:
(a) projections, or processes, which grow out from the bone surface, and
(b) depressions, or cavities, which are indentations in the bone.
There is a lit- tle trick for remembering some of the bone mark- ings listed in the table: All the terms beginning with T are “projections”, and the terms beginning with F (except facet) are depressions.
that spongy bone is composed of small needlelike pieces of bone called _______ and lots of “open” space filled by marrow, blood vessels and nerves
trabeculae
In compact bone, the mature bone cells, osteocytes (os′te-o-sˉıtz′′), are found within the bone matrix in tiny cavities called
lacunae (lah- ku′ne).
Tiny canals are called _____ radiate outward from the central canals to all lacunae. The canaliculi form a transportation sys- tem that connects all the bone cells to the nutrient
supply and waste removal services through the hard bone matrix.
canaliculi (kan′′ah- lik′u-li),
most bones develop using hyaline car- tilage structures as their “models.” This process of bone formation,is called?
ossification
(os′′ ̆ı-f ̆ı-ka′shun), involves two major phases
First, the hyaline cartilage model is completely covered with bone matrix (a bone “collar”) by bone-building cells called OSTEOBLAST. So, as the embryo develops into a fetus, for a short period it has cartilage “bones” enclosed by actual bone matrix.
When the blood calcium ion level drops below its homeostatic level, the parathyroid glands (located in the throat) are stimulated to release parathyroid hormone (PTH) into the blood. PTH activates OSTEOCLAST, giant bone-destroying cells in bones, to break down bone matrix and release calcium ions into the blood. When the blood cal- cium ion level is too high (hypercalcemia [hi′′per- kal-se′me-ah]), calcium is deposited in bone matrix as hard calcium salts by osteoblasts.
A fracture type that Bone breaks into three or more fragments - Particularly common in older people, whose bones are more brittle
Comminuted
a fracture type that is Bone is crushed- Common in porous bones (i.e., osteoporotic bones of older people)
Compression
Fracture type that is Broken bone portion is pressed inward - Typical of skull fracture
Depressed
Broken bone ends are forced into each other - Commonly occurs when someone attempts to break a fall with outstretched arms
Impacted
Ragged break occurs when excessive twisting forces are applied to a bone - Common sports fracture
Spiral
Bone breaks incompletely, much in the way a green twig breaks - Common in children, whose bones are more flexible than those of adults
Greenstick
Blood vessels are rup- tured when the bone breaks. As a result, there is a blood-filled swelling, or bruise, called a
__________forms.
hematoma (he-mah-to′mah)
Two early
events of tissue repair are the growth of new capillaries (granulation tissue) into the clottedblood at the site of the damage and disposal of
dead tissue by phagocytes.
A fibrocartilage callus forms.
As more osteoblasts 2 and osteoclasts migrate into the area and multi- 4 ply, the fibrocartilage callus is gradually replaced by the _______ made of spongy bone.
bony callus
Over the next few 6 weeks to months, depending on the bone’s size and site of the break, the bony callus is
remodeled in response to the mechanical
stresses placed on it, so that it forms a strong, permanent “patch” at the fracture site.
Bone remodeling occurs
Axial skeleton can be divided into three parts—
the skull, the vertebral column, and the thoracic cage.
The skull is formed by two sets of bones. what are these?
The cranium encloses and protects the fragile brain tissue.
The facial bones form a cradle for the eyes that is open to the anterior and allow the facial muscles to show our feelings through smiles or frowns.
All but one of the bones of the skull are
joined together by sutures, which are interlocking, immovable joints.
Only the _______ is attached to the rest of the skull by a freely movable joint.
mandible (jawbone)
Cranium
The boxlike cranium is composed of eight large flat bones. Except for two sets of paired bones (the parietal and temporal), they are all single bones.
Cranium
The _______ forms the forehead, the bony projections under the eye- brows, and the superior part of each eye’s orbit
Frontal Bone
The _________ form most of the superior and lateral walls of the cra- nium. The sagittal suture is formed at the midline where the two ______ meet and the coronal suture is formed where the paired _______ meet the frontal bone.
Parietal Bones
The ________ lie inferior to the parietal bones and join them at the squamous sutures.
temporal bones
Several important bone markings appear on the temporal bones - dont answet justs study
• The external acoustic meatus is a canal that leads to the eardrum and the middle ear. It is the route by which sound enters the ear.
• The styloid process, a sharp, needlelike pro- jection, is just inferior to the external auditory meatus. Many neck muscles use the styloid process as an attachment point.
• The zygomatic (zi′′go-mat′ik) process is a thin bridge of bone that joins with the cheek- bone (zygomatic bone) anteriorly.
• The mastoid (mas′toid) process, which is full of air cavities (the mastoid sinuses), is a rough projection posterior and inferior to the external acoustic meatus. It provides an attachment site for some muscles of the neck.
The mastoid sinuses are so close to the middle ear—a high-risk spot for infections— that they may become infected too, a condi- tion called mastoiditis. Also, this area is so close to the brain that mastoiditis may spread to the brain.
