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