Ch 7 Saladin A&P

What is endochondral ossification? Most bones of the body develop in this way, and the process includes six stages, what are the six stages and can you briefly describe each one?

"bones develop from pre-existing hyaline CARTILAGE;

Intramembranous ossification produces what bones? Development includes four stages, what are the four stages and can you briefly describe each one?

"flat (cranial) and clavicle; TISSUE

An uncomplicated fracture heals in ____ to ____ weeks, but complex fractures and fractures in the elderly take longer; the healing process occurs in four stages. What are those four stages? Can you briefly describe them?

8-12 weeks; 1. formation of hematoma 2. formation of soft callus 3. conversion to hard callus 4. remodeling

In adults, red marrow is limited to where?

skull, vertebrae, ribs, sternum, hip girdle, humerus/femur heads

When bones are deficient in calcium salts (the ceramic component), they are what?

soft and bend easily

Define diploe. How does the diploe handle a moderate blow?

spongy layer in the cranium; can handle a moderate blow by absorbing the impact

What does a cast do?

stabilizes a bone during healing

What are osteogenic cells and where are they found?

stem cells; endosteum & inner layer of periosteum

Spongy bone imparts ________ while adding a minimum of weight; its trabeculae are arranged along the bone's lines of stress.

strength

Define osteology. What is the skeletal system is composed of?

study of bone; bones, cartilages, and ligaments

What happens to the bone in an open reduction?

surgical exposure of bone - use plates, screws, or pins to realign fragments

Some collagen fibers of the outer layer are continuous with ________ that bind muscle to bone.

tendons

Describe flat bones and give some examples.

thin curved plate; cranial bones, sternum, scapula, ribs, hip bones

Define lacunae and canaliculi.

tiny cavities that have osteocytes within; channels that connect lacunae

Spongy bone consists of a lattice of delicate slivers of bone called spicules and thin plates called __________; the term spongy refers to its appearance, not its hardness.

trabeculae

Bones continually grow throughout life in diameter and thickness through a process called _____________ growth that deposits new tissue at the surface.

appositional

The joint surface where bones meet is covered with a layer of hyaline cartilage called the __________ cartilage, which enables a joint to move easily.

articular

Yellow marrow no longer produces _______, although in cases of severe or chronic anemia it can do what?

blood

How does nutrients and waste enter and leave bone?

blood vessels

Osteoclasts are ______-____________ cells found on the bone surface.

bone dissolving

What are osteoblasts and where are they found?

bone forming cells; endosteum & periosteum

Wolff's law of bone states what?

bone structure is determined by the stress placed on it

What causes a stress fracture?

break caused by abnormal trauma

What is a pathologic fracture and what is it due to?

break in bone weakened by some other disease

Mineral deposition is a crystallization process in which _______, __________, and other ions are taken from the blood plasma and deposited in bone tissue, mainly as crystals of hydroxyapatite.

calcium, phosphate

They lay down matrix in layers parallel to the surface, not in cylindrical osteons; this process produces ________________ lamellae.

circumfrential

The organic matter includes what?

collagen, various protein-carbohydrate complexes

The polymer is __________, and the ceramic component is the ______________ and other minerals.

collagen; hydroxyapatite

The cranium is a typical flat bone, describe the sandwich-like arrangement seen in it.

compact, spongy, compact

Bone is in a class of materials called a ____________, a combination of two structural materials—in this case, a ceramic and a polymer.

composite

What type of tissue is bone, or osseous tissue? What is mineralization and what's another name for it? What other tissue types are present in bone?

connective tissue; hardening of the tissue, calcification; blood, bone marrow, cartilage, adipose tissue, nervous tissue, fibrous connnective tissue

How are they collagen fibers arranged in the matrix? What does the arrangement enhance?

corkscrew down the matrix; enhances the strength

What is the periosteum? What are the two layers?

covers bone - tough outer fibrous layer, inner osteogenic layer

The protein component gives bone what? Describe how a bone would be without it.

flexibility; would be excessively brittle

This phenomenon is an example of the complementarity of _____ and __________.

form and function

Define osteogenesis. What are the two methods of bone development?

formation of bone: intramembranous & endochondral

Neighboring osteocytes are connected by ______ junctions, allowing the passage of nutrients, wastes, and chemical signals.

gap

What is the epiphyseal plate?

growth zone in children's bones

What is arteriosclerosis?

hardening of the arteries/calcification of arterial walls

Why is the osteogenic layer important for?

has bone forming cells

In children and adolescents, an epiphyseal plate of ________ cartilage separates the marrow spaces of the epiphysis and diaphysis.

hyaline

The epiphyseal plate consists of _________ cartilage in the middle, with a _________ zone on each side.

hyaline; transitional

The inorganic matter is mostly made up of?

hydroxyapatite, calcium carbonate, other minerals

The side of the cell facing the bone surface has a ruffled border, what does this help with?

increase surface area and efficiency of bone resporption

The growth of cartilage from within the metaphyses is called ____________ growth; _________ can result from a failure of cartilage to grow in the long bones.

interstitial; dwarfism

Describe irregular bones and give some examples.

irregular shape; vertebrae, some skull bones

These histological sections show onion-like concentric _________ arranged around a _________ (haversian or osteonic) canal and connected to each other by ____________.

lamellae; central; canaliculi

What is circumferential lamellae?

layers of bone matrix that go all the way around the bone

The epiphyseal plate is the region in which bone ___________ takes place.

length

Describe perforating (Volkmann) canals.

link central canals, allowing blood vessels and nerves to travel across bone

The general anatomy of bones can be observed in a _______ bone; flat bones have variations due to their shape.

long bones

Describe long bones and give some examples.

longer than it is wide; femur, humerus

What does calcitonin do?

lowers blood calcium levels

On average, how are the bones of athletes and people engaged in manual labor different from the bones in sedentary people?

manual labor has greater density

Red bone marrow (myeloid tissue) fills what?

marrow cavities?

The transitional zone, facing the marrow cavity, is called the __________.

metaphysis

Red marrow is often termed ___________ tissue because it produces blood cells, but it is actually composed of multiple tissues and acts as an organ unto itself.

myeloid

Central canals are not needed, why is this?

no osteocyte is far from the marrow

Osteoblasts are ______________ (do not divide), so differentiation of osteogenic cells is the only way new osteoblasts are generated.

nonmitotic

Treatment of fractures involves reducing the _____________ of broken bones and ______________ the bone during healing.

number; stabilize

Blood vessels penetrate into the bone through minute holes called?

nutrient foramina

Osteoblasts synthesize what? What stimulate osteogenic cells to multiply rapidly and generate increased numbers of osteoblasts?

organic matter of the bone; stress and fractures

Osteocytes are former ____________ that have become trapped in the bone matrix they deposited.

osteoblasts

Bone remodeling results from the action of osteo_____ and osteo______.

osteoblasts and osteoclasts

Bone remodeling results from the combined action of _____________ and ______________.

osteoblasts and osteoclasts

How does this process happen?

osteoblasts lay down collagen fibers along osteon. Fibers become encrusted with minerals which attract more minerals.

Osteoblasts secrete what hormone and what does it stimulate?

osteocalcin stimulates insulin secretion by pancreas

Osteoclasts develop from bone marrow stem cells that give rise to ________ cells; thus, they have an independent origin from osteogenic cells, osteoblasts, and osteocytes.

osteoclast

Several other bone disorders exist, the most common of which is ________________.

osteoporosis

Osteocytes have slender, fingerlike cytoplasmic processes that reach into the canaliculi, what do these processes do?

pass nutrients and other chemical signals to one another

Other collagen fibers of the outer layer penetrate into the bone matrix as ___________ fibers.

perforating

Both surfaces of a flat bone are covered with ____________, and the marrow spaces are lined with _____________.

periosteum; endosteum

The skeleton has at least six functions. What are those six?

protection, support, movement, acid-base balance, electrolyte balance, blood formation

What does parathyroid hormone do?

raises blood calcium levels

Some osteocytes _______ bone matrix and others _______ it, contributing to the homeostasis of both bone density and blood concentrations of calcium and phosphate ions.

reabsorb; deposit

Bone marrow is a general term for soft tissue that occupies the marrow cavity of a long bone, the spaces in spongy bone, and larger central canals; the two kinds are ______ marrow and ___________ marrow.

red; yellow

How does this process happen?

releases minerals into blood to make them available for other uses by osteoclasts

What is interstitial lamellae?

remains of old osteons that were broken down, between osteons

Osteoclasts often reside in pits called?

resorption bays

Osteocytes are also strain sensors—what does this mean?

sends signals to regulate bone remodeling

What is the diaphysis and the epiphysis refer to? What are their purposes?

shaft provides leverage; ends stregnthen joint and give more surface area for tendons and ligaments

As a bone increases in diameter, its marrow cavity does what?

widens

In closed reduction, the bone fragments are manipulated how?

without surgery - by hand

Describe short bones and give some examples.

wrist, ankle; cube shaped

In adults, most red marrow turns to ______ __________ bone marrow.

yellow

What is a calculus?

a calcified mass in an otherwise soft organ

What constitutes an osteon?

a central canal and its lamellae

Define ectopic ossification.

abnormal calcification of tissues - lungs, brain, eyes, muscles, tendons, arteries

Bones are continually remodeled throughout life by the ___________ of old bone and ___________ of new, replacing about _____% of skeletal tissue per year.

absorption; deposition; 10%

Mineral resorption is the process of what?

dissolving bone

A thin layer of reticular connective tissue called the _____________ lines the internal marrow cavity, covers all surfaces of the spongy bone, and lines the canal system.

endosteum

Spongy bone is covered with ___________ and permeated by spaces filled with bone marrow.

endosteum

Growth stops when all the __________ is depleted; the site of the original epiphyseal plate is marked with a line of spongy bone called the epiphyseal ______.

epiphyseal plate; line