Chapter 7 - Skeletal System Flashcards
1
Q
acetabulum
acetabul-
A
vinegar cup
2
Q
axial skeleton
ax-
A
axis
3
Q
osteoblast
-blast
A
bud, a growing organism in early stages
4
Q
canaliculus
canal-
A
channel
5
Q
carpals
carp-
A
wrist
6
Q
osteoclast
-clast
A
break
7
Q
clavicle
clav-
A
bar
8
Q
condyle
condyl-
A
knob, knuckle
9
Q
coracoid process
corac-
A
a crow’s beak
10
Q
cribriform plate
cribr-
A
sieve
11
Q
crista galli
crist-
A
crest
12
Q
fovea capitis
fov-
A
pit
13
Q
glenoid cavity
glen-
A
joint socket
14
Q
intervertebral disc
inter-
A
among, between
15
Q
intramembranous bone
intra-
A
inside
16
Q
lamella
lamell-
A
thin plate
17
Q
external acoustic meatus
meat-
A
passage
18
Q
odontoid process
odont-
A
tooth
19
Q
hematopoiesis
poie-
A
make, produce
20
Q
skeletal system
A
- made up of bones, cartilages, and ligaments
- provides framework, protects soft tissues, provides attachments for muscles, produces blood cells, store inorganic salts
21
Q
Name the four types (and one subtype) of bones and where they’re found.
A
- long: arms and legs
- short: carpals and tarsals
- sesamoid: patella
- flat: skull bones
- irregular: vertebrae, facial bones
22
Q
long bones
A
bones with long longitudinal axes and expanded ends (humerus, femur, tibia, fibula, radius, ulna)
23
Q
short bones
A
cubelike, with roughly equal lengths and widths (e.g. carpals and tarsals)
24
Q
sesamoid bone
A
small, nodular and embedded in a tendon adjacent to a joint, where the tendon is compressed (e.g. patella)
25
flat bones
platelike structures with broad surfaces (e.g. ribs, scapulae, and some skull bones)
26
irregular bones
have a variety of shapes, and most are connected to several other bones (e.g. vertebrae and many facial bones)
27
Name the major parts of long bones.
* epiphysis
* articular cartilage
* diaphysis
* metaphysis
* periosteum
* compact bone
* spongy bone
* trabeculae
* medullary cavity
* endosteum
* marrow
28
epiphysis
expanded portion at each end (proximal or distal) of a long bone that articulates with another bone
29
articular cartilage
layer of hyaline cartilage coating the articulating portion of the epiphysis
30
diaphysis
the shaft of a long bone
31
metaphysis
the widening part of a bone between the diaphysis and epiphysis
32
periosteum
a tough, vascular covering of dense connective tissue that encloses a bone
33
compact bone (cortical bone)
dense bone tissue in which cells are organized in osteons without apparent spaces
34
spongy bone
bone that consists of bars and plates separated by irregular spaces; cancellous bone
35
trabeculae
branching bony plate that separates irregular spaces within spongy bone
36
medullary cavity
cavity containing marrow in the diaphysis of a long bone
37
endosteum
tissue lining the medullary cavity in a bone
38
marrow
connective tissue in bones that includes hematopoietic stem cells
39
Name the microscopic parts of bone.
* osteocyte
* lacuna
* central canal
* canaliculi
* osteon
* perforating canal
40
osteocyte
bone cell
41
lacuna
small chamber or cavity
42
central (Haversian) canal
* canal through the center of an osteon, surrounded by concentric circles of osteocytes in lacunae; extends longitudinally through bone tissue
* each contains blood vessels and nerve fibers surrounded by loose connective tissue
* blood nourishes osteocytes via their gap junctions
43
perforating canal
* openings that connect central canals of osteons
* contain larger blood vessels and nerves to provide communication between the osteons, medullary cavity, and surface of bone
44
canaliculi
* microscopic canal that connects lacunae of bone tissue, extend inward from the surface of trabeculae
* osteocytes in spongy bone get nutrients from substances that diffuse into caniculi
45
osteon
* cylinder-shaped unit of bone consisting of osteocytes in lacune in concentric circles around a central canal
* runs longitudinally through bone to provide strength
46
How do bones form?
when bony tissue replaces existing connective tissue
47
Where does intramembranous bone originate? What bones form this way? How do they form?
* originates within sheetlike layers of unspecialized connective tissue
* includes flat bones of the skull, clavicles, sternum, mandible, maxillae, and zygomatic bones
1. dense networks of blood vessels supply the connective tissue, whose cells further differentiate into osteoblasts
2. these deposit bony matrix around themselves, forming spongy bone in all directions until isolated in lacunae (osteocytes)
3. some spongy bone becomes compact later as spaces fill with bony matrix
4. connective tissue cells outside the bony matrix become the periosteum
48
Where does endochondral bone originate? What bones start this way? How does it form? What's different about long bones?
* develop from masses of hyaline cartilage shaped like future bony structures (endochondral ossification)
* most human bones are endochondral
1. cartilage cells enlarge and their lacunae grow until surrounding matrix breaks down and cells die
2. periosteum forms around decomposing cartilage, and blood vessels and partially differentiated connective tissue cells invade
3. some invading cells become osteoblasts and form spongy bone, then osteoblasts deposit compact bone around the spongy bone
* in long bones, ossification occurs from the diaphysis toward the epiphyses, and cartilage bands called epiphyseal plates form
49
What is an epiphyseal plate? Describe its layers (4) and their functions.
* band of cartilage between the epiphysis and diaphysis that is the site of active growth
1. zone of resting cartilage: not active in growth process; anchors epiphyseal plate to epiphysis
2. zone of proliferating cartilage: rows of young cells in mitosis; as new cells appear and matrix forms around them, the plate thickens
3. zone of hypertrophic cartilage: older cells left behind when new ones form; oldest cells are calcified and die
4. zone of calcified cartilage: thin layer composed of dead cells and calcified matrix; broken down by osteoclasts so osteoblasts can deposit bone tissue
50
bone remodeling
* process by which osteoclasts resorb bone tissue and osteoblasts deposit new bone over time on the surfaces of the periosteum and endosteum
* spongy bone is remodeled more quickly than compact bone
* 10-20% of the skeleton is replaced each year
51
ossification timetable
1. third month prenatal: ossification in long bones begins
2. fourth month prenatal: most primary ossification centers have appeared in diaphyses
3. birth to 5 yrs: secondary ossification centers appear in epiphyses
4. 5-12 yrs (female) and 5-14 yrs (male): ossification rapidly spreads from ossification centers
5. 15-18 yrs (female) and 17-20 yrs (male): upper limb bones and scapulae ossified
6. 16-21 (female) and 18-23 (male): lower limb and hip bones ossified
7. 21-23 (female) and 23-25 (male): sternum, clavicles, vertebrae ossified
8. by 23 (female) and by 25 (male): nearly all bones ossified
52
How does vitamin D affect bone development and growth? What does deficiency do?
* it is necessary for the absorption of calcium in the small intestine
* inorganic salt portion of bony matrix lacks calcium, making bones soft and deformed; called rickets in children and osteomalacia in adults
53
vitamin D
* scarce in foods except eggs
* inactive form produced in skin when dehydrocholesterol is exposed to UV light; activated by liver and kidneys
54
What roles do vitamins A and C play in bone development and growth? What happens without them?
* vitamin A is necessary for osteoblast activity and deficiency can retard bone development
* vitamin C is required for collagen synthesis, and deficiency makes bones abnormally slender and fragile
55
Name other bone proteins less abundant than collagen and their functions.
* osteocalcin: activated by vitamin K to bind calcium
* osteonectin: binds hydroxyapatite and collagen and stimulates mineral crystal deposition
* osteopontin speeds bone remodeling
* bone morphogenetic proteins include growth factors that induce bone and cartilage formation
56
What hormones affect bone growth and development? How?
* growth hormone (pituitary gland): stimulates division of cartilage cells in epiphyseal plates; too much means pituitary gigantism and too little means pituitary dwarfism
* thyroxine (thyroid): stimulates replacement of cartilage in epiphyseal plates with bone tissue by increasing cellular metabolism and thus osteoblast activity
* parathyroid hormone (parathyroid glands): stimulates increase in number and activity of osteoclasts
* testosterone and estrogen: promote formation of bone tissue and stimulate ossification in epiphyseal plates; estrogen works more better for this
57
How does physical stress affect bone growth?
it stimulates hardening and thickening, and lack of physical stress (exercise) allows bone tissue to waste
58
What do bones do?
* support, protect, move
* form blood cells
* store inorganic salts
59
What is hematopoiesis (hemopoiesis)? Where is it carried out in various stages of life?
* blood cell formation
1. starts in yolk sac outside the embryo
2. later happens in liver and spleen
3. eventually done in bone marrow
60
Describe bone marrow.
* a soft, netlike mass of connective tissue in medulllary cavities of long bones, irregular spaces of spongy bone, and larger central canals of compact bone
* two types: red and yellow
* red marrow forms erythrocytes, leukocytes and platelets; the color comes from oxygen-carrying pigment hemoglobin
* yellow marrow replaces some red marrow with age; stores fat and does not produce blood cells; can become red marrow if blood is deficient
61
What's important about bones' storage of inorganic salts?
* account for about 70% of extracellular matrix of bone by weight
* mostly crystals of calcium phosphate (hydroxyapatite)
* parathyroid hormone releases calcium from bones when body is deficient
* bone tissue also contains magnesium, sodium, potassium, and carbonate ions
62
List and describe the types and classifications of bone fractures.
* greenstick: incomplete; break occurs on convex surface of bend in bone
* fissured: involves incomplete longitudinal break
* comminuted: complete and fragments bone
* transverse: complete, at right angle to axis of bone
* oblique: at an angle other than a right angle to axis of bone
* spiral: caused by twisting a bone excessively
* compound (open): broken bone exposed to the outside by an opening in the skin
* closed: break protected by uninjured skin
* traumatic: break due to injury
* spontaneous or pathologic: break resulting from disease
63
Describe the body's reaction to a broken bone and the healing process.
Healing process:
1. Blood escapes from broken blood vessels and forms a hematoma. Vessels in surrounding tissues dilate, swelling and inflaming tissues.
2. Spongy bone forms close to developing blood vessels, and fibrocartilage forms in more distant regions (cartilaginous callus). Phagocytic cells begin to remove blood clot and dead or damaged cells.
3. A bony callus replaces fibrocartilage.
4. Osteoclasts remove excess bony tissue, restoring new bone structure much like the original.
64
How many bones do humans have on average?
206
65
axial skeleton
bony and cartilaginous parts that support and protect the head, neck, and trunk
66
What makes up the skull?
composed of the cranium (brain case):
* frontal
* temporal (2)
* parietal (2)
* occipital
* sphenoid
* ethmoid
and facial bones:
* maxillae (2)
* palatine (2)
* zygomatic (2)
* lacrimal (2)
* nasal (2)
* vomer
* inferior nasal conchae (2)
* mandible
67
What are fontanels, how many are there, and at what ages do they close?
* also called soft spots
* six membranous areas of incomplete intramembranous ossification present in the skull at birth
* they close in this order: posterior (2 mos), sphenoidal (3 mos), mastoid (1 yr), anterior (2 yrs)
68
Where is the vertebral column and what is it made of? What does it do?
* extends from the skull to the pelvis and forms the vertical axis of the skeleton
* composed of many bony parts called vertebrae separated by masses of fibrocartilage called intervertebral discs and connected by ligaments
* supports head and body but is flexible enough for bending forward, backward or side to side and turning or rotating on the central axis; also protects the spinal cord
69
How are vertebrae divided?
* cervical (7):
* atlas (C1): supports the head by articulation with occipital condyles and has nearly no body or spine
* axis (C2): has dens (odontoid process) that projects into atlas, which pivots around it
* vertebra prominens (C7): spinous process is longer and can be felt through the skin
* thoracic (12): articulate with ribs; increasing in size inferiorly
* lumbar (5): larger and with shorter spinous processes
* sacrum (5 fused vertebrae)
* coccyx (4 fused vertebrae)
70
spondylolisthesis
condition in which vertebra slips out of place over the vertebra below, most commonly L5 and sacrum
71
Name the bones of the thoracic cage.
* ribs (24)
* true ribs (vertebrosternal): first seven pairs; join sternum directly by costal cartilages
* false ribs: next five pairs' cartilages do not reach sternum directly; upper three (vertebrochondral ribs) join the cartilages of the seventh rib; the lower two pairs do not join the sternum
* sternum
* manubrium
* body
* xiphoid process
72
Name the bones of the pectoral (shoulder) girdle.
* clavicle (2)
* scapula (2)
73
Name the bones of the upper limb.
* humerus (2)
* radius (2)
* ulna (2)
* carpal (16)
* scaphoid
* capitate
* trapezoid
* trapezium
* lunate
* hamate
* triquetrum
* pisiform
* metacarpal (10)
* phalanx (28)
74
carpus
compact mass formed by carpal bones
75
metacarpus
framework of the palm created by the five metatarsals
76
polydactyly
* "many digits"
* a condition in which a child is born with one or more extra fingers
77
Name the bones of the pelvic girdle.
* hip bone (2)
* pelvic bones (2)
along with the sacrum, these form the pelvis
78
Name the bones of the lower limb.
* femur (2)
* tibia (2)
* fibula (2)
* patella (2)
* tarsal (14)
* metatarsal (10)
* calcaneous
* talus
* navicular
* cuboid
* lateral cuneiform
* intermediate cuneiform
* medial cuneiform
* phalanx (28)
79
tarsus
ankle
80
metatarsus
part of the foot made up of metatarsals
81
What are the effects of aging on bones?
* height begins to decrease at age 30 (about 1/16 inch per year)
* bone mass begins to decline at 35
* compact bone loss begins around 40
* women have about half the bone mass in very old age as they did in their 20s
* bone loss steady in men, but markedly faster in women with hormone changes
* vertebral compression fractures contribute to loss of height
* femur most commonly broken in elderly; other common breaks are wrist, hip, leg, and pelvis
* bones become brittle, with less calcium and bone material
* osteoclasts begin to outnumber osteoblasts, leaving more spaces in bone during remodeling
* ratio of mineral to protein increases, making them brittle
