anatomy chapter 7
Which of the following best describes osseous tissue?
A connective tissue with a hardened matrix that makes up bone
Which of these about spongey bone is true? Few osteons and no central canals Provides strength with minimal weight Slivers of bone called spicules Thin plates of bone called trabeculae
All are true
______________ steroids cause growth to stop
Anabolic
growth occurs at bone surface Continual growth in diameter and thickness Intramembranous ossification
Appositional growth
Calcium homeostasis is regulated by three hormones:
Calcitriol, calcitonin, and parathyroid hormone
Hypocalcemia causes
Caused by vitamin D deficiency, diarrhea, thyroid tumors, underactive parathyroid glands
where do cells reside in osteoclasts?
Cells often reside in resorption bays (pits in bone surface)
surround a central (haversian) canal running longitudinally fill outer region of dense bone
Circumferential lamellae
area of hyaline cartilage that separates epiphyses and diaphyses of children's bones
Epiphyseal plate
long bone structure
Epiphyses and diaphysis - Compact and spongy bone - Marrow cavity - Articular cartilage - Periosteum
What is the calcium-phosphate salt deposited within bone called?
Hydroxyapatite
deficient calcium in blood
Hypocalcemia
Which type of bone growth occurs within cartilage and results in bone elongation?
Interstitial
The bones of the skull form by which type of ossification?
Intramembranous
In the human fetus and infant, bone develops by two methods
Intramembranous ossification, Endochondral ossification
what does hypercalcemia do?
Makes ion channels less responsive and thus nerve and muscle are less excitable
branch of medicine dealing with prevention and correction of injuries and disorders of bones, joints, and muscles
Orthopedics
what happen in mineral deposition?
Osteoblasts produce collagen fibers that spiral the length of the osteon Fibers become encrusted with minerals
When is PTH released?
PTH released when calcium levels low in blood
secreted by parathyroid glands on posterior surface of thyroid
Parathyroid hormone (PTH)
where does mineral resorption take place?
Performed by osteoclasts at ruffled border
Place the following terms in order moving from superficial to deep.
Periosteum, Circumferential lamellae, Central canal, endosteum, medullay canal.
who is at a greater risk of Osteoporosis
Postmenopausal white women at greatest risk
are osteoclasts small or large cells?
Very large cells formed from fusion of several stem cells Have multiple nuclei in each cell
architecture of bone determined by mechanical stresses placed on it
Wolff's law of bone
formation of a calculus (calcified mass) in an otherwise soft organ such as a lung, brain, eye, muscle, tendon, or artery (arteriosclerosis)
abnormal calcification
The skeletal system helps maintain acid-base balance by __________.
absorbing or releasing alkaline phosphate and carbonate salts
connective tissue with the matrix hardened by calcium phosphate and other minerals
bone
soft tissue occupying marrow cavities of long bones and small spaces of spongy bone
bone marrow
how does calcitriol raise phosphate levels ?
by promoting its absorption by small intestine
The most active form of vitamin D, hormone that raises blood calcium level, produced mainly by the kidneys, is _____
calcitriol
Which mineral is most important throughout life to assist in maintaining strong bones?
calcium
Osseous tissue matrix is composed of __________.
calcium phosphate
Mineralization is a process that extracts __________ and __________ from the blood plasma and deposits it into bone.
calcium; phosphate
little channels that connect lacunae
canaliculi
A __________ fracture is one in which the bone is broken into three or more pieces.
comminuted
dense outer shell of bone
compact bone
shaft that provides leverage • Medullary cavity (marrow cavity)—space in the diaphysis of a long bone that contains bone marrow
diaphysis of long bone
thin layer of reticular connective tissue lining marrow cavity
endosteum
in adults, a bony scar that marks where growth plate used to be
epiphyseal line
Functions as growth zone where bone elongates - Has typical hyaline cartilage in the middle with transition zones on each side where cartilage is replaced by bone - Metaphysis is zone of transition facing the marrow cavity
epiphyseal plate
enlarged ends of a long bone -enlarged to strengthen joint and attach ligaments and tendons
epiphyses
t/f: PTH raises calcium blood level by three mechanisms
false, PTH raises calcium blood level by four mechanisms
t/f By late teens to early 20s, all remaining cartilage in the epiphyseal plate is generally still there
false, it is consumed
t/f: Calcitriol is not necessary for bone deposition— helping provide adequate calcium and phosphate
false, it is necessary
T/F During infancy and childhood, the epiphyses fill with COMPACT bone
false, spongy
Sandwich-like construction - Two layers of compact bone enclosing a middle layer of spongy bone • Both surfaces covered with periosteum Diploe—spongy middle layer
flat bone
- Thin, curved plates - Protect soft organs
flat bones
excessive calcium levels
hypercalcemia
85% hydroxyapatite (crystallized calcium phosphate salt) - 10% calcium carbonate - Other minerals (fluoride, sodium, potassium, magnesium)
inorganic matter
growth from within
interstitial growth
fill irregular regions between osteons
interstitial lamellae
Elaborate shapes that do not fit into other categories
irregular bones
deformity of spine due to vertebral bone loss
kyphosis
tiny cavities where osteocytes reside
lacunae
Bones grow in two directions
length and width
hold bones together at joints
ligaments
Longer than wide Rigid levers acted upon by muscles; crucial for movement
long bones
of osseous tissue is, by dry weight, about one- third organic and two-thirds inorganic matter
matrix
process in which calcium, phosphate, and other ions are taken from blood and deposited in bone
mineral deposition
process of dissolving bone and releasing minerals into blood
mineral resorption
the hardening process of bone
mineralization or calcification
minute holes in bone surface that allows blood vessels to penetrate
nutrient foramina
involves surgical exposure of the bone and the use of plates, screws, or pins to realign the fragments
open reduction
synthesized by osteoblasts, Collagen, carbohydrate
organic matter
Form single layer of cells under endosteum and periosteum - Nonmitotic - Synthesize soft organic matter of matrix which then hardens by mineral deposition - Stress stimulates osteogenic cells to multiply rapidly and increase the number of osteoblasts which reinforce bone - Secrete hormone osteocalcin
osteoblasts
Stimulates insulin secretion of pancreas • Increases insulin sensitivity in adipocytes which limits the growth of adipose tissue
osteocalcin
bone-dissolving cells found on bone surface
osteoclasts
former osteoblasts that have become trapped in the matrix they deposited
osteocytes
stem cells found in endosteum and inner layer of periosteum
osteogenic cells
Four principal types of bone cells
osteogenic cells, osteoblasts, osteocytes, osteoclasts
Osteoblasts of inner periosteum deposit _________
osteoid tissue
the most common bone disease
osteoporosis
break in a bone weakened by disease
pathological fracture
transverse or diagonal passages
perforating canals
penetrate into bone matrix
perforating fibers
external sheath covering most of bone
periosteum
what gives bones some flexibility
polymer
What is the function of red bone marrow?
produce blood cells
How does PTH lower blood phosphate levels?
promoting its urinary excretion
Contains hemopoietic tissue—produces blood cells - In nearly every bone in a child - In adults, found in skull, vertebrae, ribs, sternum, part of pelvic girdle, and proximal heads of humerus and femur
red marrow
what kind of border do osteoclasts have?
ruffled
Approximately equal in length and width - Glide across one another in multiple directions
short bones
composed of bones, cartilages, and ligaments
skeletal system
Bones lose mass and become brittle affects what the most?
spongey bone
lattice of bone covered with endosteum and spaces filled with red bone marrow
spongey bone
loosely organized bone tissue Found in center of ends and center of shafts of long bones and in middle of nearly all others Covered by more durable compact bone
spongey bone
break caused by abnormal trauma to a bone
stress fracture
Functions of the skeleton
support, protection, movement, electrolyte balance, acid-base balance, blood formation
Which of the following is not considered a weight bearing activity?
swimming
attach muscle to bone
tendons
Skeleton _________-fourths compact and _______-fourth spongy bone by weight
three; one
Trusses and arches, which help form an internal scaffolding network, are found in __________.
trabecular bone
t/f Bone elongation is a result of cartilage growth within the epiphyseal plate
true
t/f Dissolving bone is part of bone remodeling
true
t/f Osteoclasts develop from same bone marrow stem cells that give rise to blood cells
true
t/f Some osteocytes reabsorb bone matrix while others deposit it
true
t/f: At least 20 or more hormones, vitamins, and growth factors affect osseous tissue
true
t/f: Total of about 1,100 g of calcium in adult body with 99% of it in bones
true
t/f: the normal calcium concentration in blood plasma is 9.2-10.4 mg/dL
true
what happens when osteocytes are stressed?
when stressed, produce biochemical signals that regulate bone remodeling (shape and density changes that are adaptive)
Fatty marrow that does not produce blood - Can transform back to red marrow in the event of chronic anemia
yellow marrow (ADULTS)
Place the following stages into the correct spaces to represent the chronological order of intramembranous ossification.
1. Deposition of osteoid tissue into embryonic mesenchyme. 2. Calcification of osteoid tissue and entrapment of osteocytes. 3. Honeycomb of spongy bone with developing periosteum. 4. Filling of space to form compact boneat surface, leaving spongy bone in middle.
Bone remodeling (absorption and deposition) occurs throughout life—_____ of skeleton per year
10%
normal plasma concentration
3.5-4.0 mg/dL
At which of the following ages would calcium loss from bone be more than calcium deposits into bone, even when a high calcium diet is eaten?
50
layer of hyaline cartilage that covers joint surface; allows joint to move more freely
articular cartilage
Bones in the legs, arms, spine and pelvis grow __________.
at different rates
forerunner of most bones
cartilage
___________ ___________allows the bone to support body weight without sagging
ceramic portion
procedure in which bone fragments are manipulated into their normal positions without surgery
closed reduction