Skeletal System

Question 1

joints, car- tilages, and ligaments

Answer 1

fibrous cords that bind the bones together at joints

Question 2

The skeleton is divided into two parts what are these?

Answer 2

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.

Question 3

what is hematopoiesis?

Answer 3

Blood cell formation, or hematopoiesis (hem′′ah-to-poi-e′sis), occurs within the marrow cavities of certain bones.

Question 4

The adult skeleton is composed of 206 bones. There are two basic types of osseous, or bone, tis- sue: what are these?

Answer 4

Compact bone is dense and looks smooth and homogeneous, whereas

Spongy bone has a spiky, open appearance like a sponge

Question 5

Long bones are mostly compact bone but also contain spongy bone at the ends. All the bones of the limbs, except.

Answer 5

the patella (kneecap) and the wrist and ankle bones, are long bones

Question 6

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

Answer 6

Flat bones.

Question 7

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?

Answer 7

Short bones

Question 8

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.

Answer 8

Irregular bones

Question 9

In a long bone ______ or shaft, makes up most of the bone’s length and is composed of compact bone

Answer 9

the diaphysis (di-af′ ̆ı-sis),

Question 10

The diaphysis is covered and protected by a fibrous connective tissue membrane, what is it called?

Answer 10

the perios- teum (per-e-os′te-um).

Question 11

Hundreds of connective tissue fibers, called __________ secure the periosteum to the underlying bone.

Answer 11

perforating fibers, or Sharpey’s fibers,

Question 12

The _______ are the ends of long bones. Each epiphysis consists of a thin layer of compact bone enclosing an area filled with spongy bone.

Answer 12

epiphyses (e ̆-pif′ ̆ı-seˉz)

Question 13

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

Answer 13

articular cartilage has it’s own lubrication

Question 14

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.

Answer 14

This is the epiphyseal line.

Question 15

The inner bony surface of the shaft is covered by a delicate connective tissue called

Answer 15

endosteum

Question 16

In infants, the cavity of the shaft, called the med- ullary cavity, is a storage area for ________ , which produces blood cells.

Answer 16

red marrow

Question 17

Children’s bones contain red marrow until the age of 6 or 7, when it is gradually replaced by ______ which stores adipose (fat) tissue.

Answer 17

yellow marrow,

Question 18

There are two categories of bone markings:

Answer 18

(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.

Question 19

that spongy bone is composed of small needlelike pieces of bone called _______ and lots of “open” space filled by marrow, blood vessels and nerves

Answer 19

trabeculae

Question 20

In compact bone, the mature bone cells, osteocytes (os′te-o-sˉıtz′′), are found within the bone matrix in tiny cavities called

Answer 20

lacunae (lah- ku′ne).

Question 21

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.

Answer 21

canaliculi (kan′′ah- lik′u-li),

Question 22

most bones develop using hyaline car- tilage structures as their “models.” This process of bone formation,is called?

Answer 22

ossification

Question 23

(os′′ ̆ı-f ̆ı-ka′shun), involves two major phases

Answer 23

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.

Question 24

A fracture type that Bone breaks into three or more fragments - Particularly common in older people, whose bones are more brittle

Answer 24

Comminuted

Question 25

a fracture type that is Bone is crushed- Common in porous bones (i.e., osteoporotic bones of older people)

Answer 25

Compression

Question 26

Fracture type that is Broken bone portion is pressed inward - Typical of skull fracture

Answer 26

Depressed

Question 27

Broken bone ends are forced into each other - Commonly occurs when someone attempts to break a fall with outstretched arms

Answer 27

Impacted

Question 28

Ragged break occurs when excessive twisting forces are applied to a bone - Common sports fracture

Answer 28

Spiral

Question 29

Bone breaks incompletely, much in the way a green twig breaks - Common in children, whose bones are more flexible than those of adults

Answer 29

Greenstick

Question 30

Blood vessels are rup- tured when the bone breaks. As a result, there is a blood-filled swelling, or bruise, called a __________forms.

Answer 30

hematoma (he-mah-to′mah)

Question 31

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.

Answer 31

A fibrocartilage callus forms.

Question 32

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.

Answer 32

bony callus

Question 33

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.

Answer 33

Bone remodeling occurs

Question 34

Axial skeleton can be divided into three parts—

Answer 34

the skull, the vertebral column, and the thoracic cage.

Question 35

The skull is formed by two sets of bones. what are these?

Answer 35

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.

Question 36

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.

Answer 36

mandible (jawbone)

Question 37

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.

Answer 37

Cranium

Question 38

The _______ forms the forehead, the bony projections under the eye- brows, and the superior part of each eye’s orbit

Answer 38

Frontal Bone

Question 39

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.

Answer 39

Parietal Bones

Question 40

The ________ lie inferior to the parietal bones and join them at the squamous sutures.

Answer 40

temporal bones

Question 41

Several important bone markings appear on the temporal bones - dont answet justs study

Answer 41

• 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.

Question 42

The ________ is the most posterior bone of the cranium. It forms the base and back wall of the skull. This joins the parietal bones anteriorly at the lambdoid (lam′doyd) suture. In the base of it is a large opening, the foramen magnum

Answer 42

occipital (ok-sip′ ̆ı-tal) bone

Question 43

The butterfly-shaped _______ spans the width of the skull and forms part of the floor of the cranial cavity

Answer 43

sphe- noid (sfe′noid) bone

Question 44

In the midline of the sphenoid is a small depression, ________ ,or Turk’s saddle, which forms a snug enclosure for the pituitary gland.

Answer 44

sellaturcica(sel′ahtur′s ̆ı-kah)

Question 45

The _________, a large oval opening in line with the posterior end of the sella turcica

Answer 45

foramen ovale

Question 46

the optic canal, which allows the optic nerve to pass to the eye, and the slitlike superior orbital fissure, through which the cranial nerves controlling eye movements - dont answer just study

Answer 46

the optic canal, which allows the optic nerve to pass to the eye, and the slitlike superior orbital fissure, through which the cranial nerves controlling eye movements

Question 47

The______bone is very irregularly shaped and lies anterior to the sphenoid. It forms the roof of the nasal cavity and part of the medial walls of the orbits.

Answer 47

Ethmoid Bone

Question 48

The two _______ fuse to form the upper jaw. All facial bones except the mandible join the ______ ; thus they are the main, or “keystone,” bones of the face.

Answer 48

maxillae (mak-s ̆ı′le), or maxillary bones,

Question 49

The maxillae carry the upper teeth in the

Answer 49

alveolar process.

Question 50

Extensions of the maxillae called the ________ processes form the anterior part of the hard palate of the mouth

Answer 50

palatine (pal′ah-tˉın)

Question 51

The ________ are commonly referred to as the cheekbones. They also form a good-sized portion of the lateral walls of the orbit

Answer 51

Zygomatic Bones

Question 52

The _______ are fingernail-sized bones forming part of the medial, wall of each orbit.

Answer 52

lacrimal (lak′r ̆ı-mal) bones

Question 53

The small rectangular bones forming the bridge of the nose are the nasal bones. (The lower part of the skeleton of the nose is made up of hyaline cartilage.)

Answer 53

Nasal Bones

Question 54

The single bone in the median line of the nasal cavity . (means “plow,” which refers to the bone’s shape.) The ___ the inferior part of the bony nasal septum, which separates the two nostrils.

Answer 54

Vomer Bone

Question 55

The _________ are thin, curved bones projecting medially from the lateral walls of the nasal cavity

Answer 55

inferior nasal con- chae (kon′ke)

Question 56

The ______, is the largest and strongest bone of the face. It joins the temporal bones on each side of the face, forming the only freely movable joints in the skull.

Answer 56

mandible, or lower jaw

Question 57

Though not really part of the skull, is closely related to the mandible and temporal bones. The ______ is unique in that it is the only bone of the body that does not articulate (form a joint) with any other bone. Instead, it is suspended in the midneck region

Answer 57

the hyoid (hi′oid) bone

Question 58

Serving as the axial support of the body, the _______extends from the skull, which it supports, to the pelvis, where it transmits the weight of the body to the lower limbs. Instead, the ___ is formed from 26 irregular bones connected and reinforced by ligaments in such a way that a flexible, curved structure results

Answer 58

verte- bral column, or spine,

Question 59

Before birth, the spine consists of 33 separate bones called ______, but 9 of these eventually fuse to form the two composite bones, the sacrum and the coccyx,

Answer 59

vertebrae

Question 60

The individual vertebrae are separated by pads of flexible fibrocartilage—

Answer 60

intervertebral discs

Question 61

▪ Bones grow in width ▪ Osteoblasts in the periosteum add bone matrix to the outside of the diaphysis ▪ Osteoclasts in the endosteum remove bone from the inner surface of the diaphysis

Answer 61

Appositional growth

Question 62

▪Bones are remodeled throughout life in response to two factors STUDY ONLY

Answer 62

1. Calcium ion level in the blood determines when bone matrix is to be broken down or formed 2. Pull of gravity and muscles on the skeleton determines where bone matrix is to be broken down or formed

Question 63

(high blood calcium levels) prompts calcium storage to bones by osteoblasts

Answer 63

Hypercalcemia

Question 64

▪ Released when calcium ion levels in blood are low ▪ Activates osteoclasts (bone-destroying cells) ▪ Osteoclasts break down bone and release calcium ions into the blood

Answer 64

Parathyroid hormone

Question 65

Bone fractures are treated by reduction and immobilization eeks

Answer 65

▪ Closed reduction: bones are manually coaxed into position by physician’s hands ▪ Open reduction: bones are secured with pins or wires during surgery ▪Healing time is 6–8 w

Question 66

Repair of bone fractures involves four major events STUDY ONLY

Answer 66

▪ Hematoma (blood-filled swelling, or bruise) is formed ▪ Fibrocartilage callus forms ▪ Cartilage matrix, bony matrix, collagen fibers splint the broken bone ▪ Bony callus replaces the fibrocartilage callus ▪ Osteoblasts and osteoclasts migrate in ▪ Bone remodeling occurs in response to mechanical stresses

Question 67

▪Forms the longitudinal axis of the body ▪Divided into three parts 1. Skull 2. Vertebralcolumn 3. Bonythorax

Answer 67

Axial Skeleton

Question 68

Two sets of bones form the skull

Answer 68

1. Cranium bones enclose the brain 2. Facialbones ▪ Hold eyes in anterior position ▪ Allow facial muscles to express feelings

Question 69

▪Bones are joined by sutures ▪Only the mandible is attached by a freely movable joint STUDY ONLY

Answer 69

▪Bones are joined by sutures ▪Only the mandible is attached by a freely movable joint STUDY ONLY

Question 70

▪8 cranial bones protect the brain

Answer 70

1 Frontal bone 2 Occipital 3 Ethmoid 4 Sphenoid 5, 6 Parietal bones 7, 8 Temporal bones

Question 71

Outside covering of the diaphysis

Answer 71

Periosteum

Question 72

▪ Covers the external surface of the epiphyses ▪ Made of hyaline cartilage ▪ Decreases friction at joint surfaces

Answer 72

Articular cartilage

Question 73

▪ Remnant of the epiphyseal plate ▪ Seen in adult bones

Answer 73

Epiphyseal line

Question 74

▪ Flat plate of hyaline cartilage seen in young, growing bone ▪ Causes lengthwise growth of a long bone

Answer 74

Epiphyseal plate

Question 75

▪ Lines the inner surface of the shaft ▪ Made of connective tissue

Answer 75

Endosteum

Question 76

▪ Cavity inside the shaft ▪ Contains yellow marrow (mostly fat) in adults ▪ Contains red marrow for blood cell formation in infants until age 6 or 7

Answer 76

Medullary cavity

Question 77

▪ Mature bone cells situated in bone matrix

Answer 77

Osteocytes

Question 78

▪ Cavities in bone matrix that house osteocytes

Answer 78

Lacunae

Question 79

▪ Concentric circles of lacunae situated around the central (Haversian) canal

Answer 79

Lamellae

Question 80

▪ A unit of bone containing central canal and matrix rings ▪ Structural and functional unit of compact bone

Answer 80

Osteon (Haversian system)

Question 81

▪By birth, most cartilage is converted to bone except for two regions in a long bone

Answer 81

1. Articularcartilages 2. Epiphysealplates

Question 82

▪ Hollow portions of bones surrounding the nasal cavity ▪ Functions of paranasal sinuses

Answer 82

Paranasal sinuses

Question 83

26 vertebral bones are separated by intervertebral discs: STUDY ONLY ▪ 7 cervical vertebrae are in the neck ▪ 12 thoracic vertebrae are in the chest region ▪ 5 lumbar vertebrae are associated with the lower back ▪ Sacrum (formed by fusion of 5 vertebrae) ▪ Coccyx (formed by fusion of 3–5 vertebrae

Answer 83

study only

Question 84

▪ Spinal curvatures of the thoracic and sacral regions ▪ Present from birth ▪ Form a C-shaped curvature in newborns

Answer 84

Primary curvatures

Question 85

▪ Spinal curvatures of the cervical and lumbar regions ▪Develop after birth ▪ Form an S-shaped curvature in adults

Answer 85

Secondary curvatures

Question 86

Bony thorax, or thoracic cage, protects organs of the thoracic cavity ▪Consists of three parts

Answer 86

1. Sternum 2. Ribs ▪ True ribs (pairs 1–7) ▪ False ribs (pairs 8–12) ▪ Floating ribs (pairs 11–12) 3. Thoracicvertebrae

Question 87

Appendicular Skeleton

Answer 87

▪Composed of 126 bones ▪ Limbs (appendages) ▪ Pectoral girdle ▪Pelvic girdle

Question 88

▪Also called pectoral girdle ▪Composed of two bones that attach the upper limb to the axial skeletal 1. Clavicle 2. Scapula ▪Light, poorly reinforced girdle ▪Allows the upper limb a exceptional flexibility

Answer 88

Bones of the Shoulder Girdle

Question 89

▪Composed of 126 bones ▪ Limbs (appendages) ▪ Pectoral girdle ▪Pelvic girdle

Answer 89

Appendicular Skeleton

Question 90

▪Also called pectoral girdle ▪Composed of two bones that attach the upper limb to the axial skeletal 1. Clavicle 2. Scapula ▪Light, poorly reinforced girdle ▪Allows the upper limb a exceptional flexibility

Answer 90

Bones of the Shoulder Girdle

Question 91

▪ Humerus ▪ Forms the arm ▪ Single bone ▪ Proximal end articulation ▪ Head articulates with the glenoid cavity of the scapula ▪Distal end articulation ▪ Trochlea and capitulum articulate with the bones of the forearm

Answer 91

Bones of the Upper Limbs

Question 92

▪The forearm has two bones

Answer 92

1. Ulna—medial bone in anatomical position ▪ Proximal end articulation ▪ Coronoid process and olecranon articulate with the humerus 2. Radius—lateral bone in anatomical position ▪ Proximal end articulation ▪ Head articulates with the capitulum of the humerus

Question 93

Bones in Hand

Answer 93

▪ Carpals—wrist bones 8 bones arranged in two rows of 4 bones in each hand ▪ Metacarpals—palm bones 5 per hand ▪ Phalanges—fingers and thumb 14 phalanges in each hand In each finger, there are 3 bones In the thumb, there are only 2 bones

Question 94

Bones of the Pelvic Girdle Formed by two coxal (ossa coxae) bones

Answer 94

▪Composed of three pairs of fused bones 1. Ilium 2. Ischium 3. Pubis ▪Pelvic girdle = two coxal bones, sacrum ▪Pelvis = two coxal bones, sacrum, coccyx

Question 95

▪ The heaviest, strongest bone in the body ▪ Proximal end articulation ▪ Head articulates with the acetabulum of the coxal (hip) bone ▪Distal end articulation ▪ Lateral and medial condyles articulate with the tibia in the lower leg

Answer 95

Femur—thigh bone

Question 96

The lower leg has two bones

Answer 96

1. Tibia—shinbone; larger and medially oriented ▪ Proximal end articulation ▪ Medial and lateral condyles articulate with the femur to form the knee joint ▪ Distal end articulation ▪ Medial malleolus forms the inner part of the ankle 2. Fibula—thin and sticklike; lateral to the tibia ▪ Has no role in forming the knee joint ▪ Distal end articulation ▪ Lateral malleolus forms the outer part of the ankle

Question 97

▪Tarsals—7 bones ▪ Two largest tarsals are the: ▪ Calcaneus (heel bone) ▪Talus ▪ Metatarsals—5 bones form the sole of the foot ▪ Phalanges—14 bones form the toes

Answer 97

Bones of Foot

Question 98

Two ways joints are classified

Answer 98

▪ Functionally ▪ Structurally

Question 99

Functional joint classifications

Answer 99

▪ Synarthroses-Immovable joints ▪ Amphiarthroses -Slightly movable joints ▪ Diarthroses - Freely movable joints

Question 100

Structural joint classifications

Answer 100

▪ Fibrous joints - Generally immovable ▪ Cartilaginous joints-Immovable or slightly movable ▪Synovial joints - Freely movable

Question 101

Study only Birth to adulthood ▪ First “long bones” of a fetus are hyaline cartilage ▪ Earliest “flat bones” of the fetal skull are fibrous membranes ▪ As fetus grows, all bone models are converted to bone

Answer 101

Birth to adulthood ▪ First “long bones” of a fetus are hyaline cartilage ▪ Earliest “flat bones” of the fetal skull are fibrous membranes ▪ As fetus grows, all bone models are converted to bone

Question 102

▪ Fontanels are fibrous membranes connecting the cranial bones ▪ Known as “soft spots” ▪ Allow skull compression during birth ▪ Allow the brain to grow during later pregnancy and infancy ▪ Usually ossify by 2 years of age

Answer 102

Fetal skull

Question 103

Study Only ▪Size of cranium in relationship to body ▪ 2 years old—skull is three-fourths the size of adult skull ▪ 8 or 9 years old—skull is near adult in size and proportion ▪ Between ages 6 and 11, the face grows out from the skull

Answer 103

▪Size of cranium in relationship to body ▪ 2 years old—skull is three-fourths the size of adult skull ▪ 8 or 9 years old—skull is near adult in size and proportion ▪ Between ages 6 and 11, the face grows out from the skull

Question 104

STUDY ONLY Older adults ▪ Osteoporosis ▪ Bone-thinning disease afflicting: ▪ 50 percent of women over age 65 ▪ 20 percent of men over age 70 ▪ Disease makes bones fragile, and bones can easily fracture ▪ Vertebral collapse results in kyphosis (also known as “dowager’s hump”) ▪ Estrogen aids in health and normal density of a female skeleton

Answer 104

▪Older adults ▪ Osteoporosis ▪ Bone-thinning disease afflicting: ▪ 50 percent of women over age 65 ▪ 20 percent of men over age 70 ▪ Disease makes bones fragile, and bones can easily fracture ▪ Vertebral collapse results in kyphosis (also known as “dowager’s hump”) ▪ Estrogen aids in health and normal density of a female skeleton