Chapter 6 Bones and Skeletal Tissue (Bone Markings, etc)

The cell responsible for secreting the matrix of bone is the ______.

osteoblast

Common Types of Fractures

1. Comminuted Bone fragments into three or more pieces 2. Compression: Bone is crushed (usually vertebrae) 3. Spiral: Ragged/twisted break occurs when excessive twisting forces applied to bone 4. Epiphyseal: Epiphysis separates from diaphysis along epiphyseal (hyaline cartilage) plate

4 STEPS OF BONE REPAIR

1. Hematoma Forms 2. Fibrocartilaginous callus forms 3. Bony Callus forms 4. Bone Remodeling occurs Fig. 6.14 STAGES in the healing of a bone fracture Ch. 6 Slide: 79

5 STAGES OF ENDOCHONDRIAL OSSIFICATION (1 Type of Bone Formation)

1. Hyaline Cartilage model with primary ossification center in middle of diaphysis. Bone collar on sides 2. Medullary cavity forming from middle primary ossification center 3. Nutrient Artery invades diaphysis. Spongy bone forms 4. Diaphysis and medullary cavity elongates. Secondary ossification center appears on both ends (epiphyses) 5. Entire bone ossified except for epiphyseal (hyaline cartilage) plates between epiphyses (ends) and diaphysis (shaft). Articular Cartilage at ends

4 STAGES OF INTRAMEMBRANOUS OSSIFICATION (1 Type of Bone Formation)

1. Ossification center appears in fibrous connective tissue membrane 2. Osteoid secreted within fibrous membrane and calcifies 3. Woven Bone and periosteum form 4. Lamellar bone replaces woven bone, just deep to the periosteum. Red Marrow appears BONE FORMATION FOR ONLY -CRANIAL BONES (skull) -Clavicle (collar bone)

The blood vessels and nerve in the figure are found within which type of space? A) central (Haversian) canal B) perforating (Volkmann's) canal C) canaliculi D) marrow cavity

A) central (Haversian) canal A central (or Haversian) canal runs lengthwise at the center of each osteon. Canaliculi: hairlike canals that connect lacunae to each other and to central canal

Which of the following are correctly matched? A) compound fracture; the fractured bone ends penetrate the skin B) incomplete fracture; the bone is broken through C) linear fracture; the break is perpendicular to the bone's long axis D) nondisplaced fracture; the fractured bone ends are misaligned

A) compound fracture In a compound (open) fracture, the fractured bone ends penetrate the skin. Such open injuries carry a higher risk of infection.

Yellow bone marrow contains a large percentage of ________. A) fat B) elastic tissue C) Sharpey's fibers D) blood-forming cells

A) fat (adipose tissue)

Osteoblasts __________. A) form new bone B) maintain bone matrix C) form skeletal cartilage D) break down bone

A) form new bone 5 TYPES OF CELLS IN BONE TISSUE 1. Osteogenic (osteoprogenitor) cells: active stem cells in periosteum and endosteum (differentiate into osteoblasts or bone-lining cells) 2. Osteoblasts: Mitotically active, Bone-forming cells secrete unmineralized bone matrix (osteoid) 3. Osteocytes: Mature bone cells in lacunae that no longer divide. MAINTAIN bone matrix, act as stress or strain sensors. Communicate info to osteoblasts or osteoclasts (cells that destroy bone) so bone remodeling can occur 4. Bone-Lining cells: Flat cells on bone surfaces -On external COMPACT bone surface PERIOSTEAL CELLS -On internal medullary cavity surface ENDOSTEAL Cells 5. Osteoclasts: Giant multinucleate cells function in bone resorption (breakdown of bone) -active cells located in depressions called RESORPTION BAYS

What is the structural unit of compact bone? A) osteon B) Haversian canal C) osteoid D) canaliculus

A) osteon The structural unit of compact bone is the osteon, an elongated cylinder oriented parallel to the long axis of the bone. Canaliculi: hairlike canals that connect lacunae to each other and to central canal Osteoid: unmineralized bone matrix secreted by bone-forming cells (osteoblasts)

Select the bone disorder in which bone resorption outpaces bone deposit, leaving the person with thin and often very fragile bones? A) osteoporosis B) Paget's disease C) rickets D) osteomalacia

A) osteoporosis

Which of the following refers to a bone disorder found most often in the aged and resulting in the bones becoming porous and light? A) osteoporosis B) Paget's disease C) osteomalacia D) rickets

A) osteoporosis Osteoporosis refers to groups of diseases in which bone resorption outpaces bone deposit. The bones become fragile and easily fractured. The composition of the matrix remains normal, but bone mass declines, and the bones become porous and light.

The resilience of bone is thought to come from which of the following? A) sacrificial bonds in or between collagen molecules B) amount of mineral salt and protein in the bone C) amount of mineral salts in the bone D) presence of osteoblasts in the bone

A) sacrificial bonds in or between collagen molecules Organic Components of Bone (Collagen Fibers) -Resilience of bone is due to "sacrificial bonds" in or between collagen molecules that stretch and break to dissipate energy and prevent fractures -If no additional trauma, bonds re-form

Which of the following best describes the process shown in the figure? A) the formation of bone in a membrane B) bone remodeling in response to changes in mechanical stress C) bone repair at a site of fracture D) the formation of bone in a preexisting cartilage model

A) the formation of bone in a membrane The figure illustrates the formation of new bones within a fibrous membrane ("intramembranous") during embryonic development. 2 Types of Bone Formation 1. Intramembranous Ossification (Cranial Bones, Clavicle, primary ossification center in fibrous membrane) 2. Endochondral Ossification (all other bones, primary ossification center in hyaline cartilage model)

What is the structural unit of compact bone? A) the osteon B) osseous matrix C) spongy bone D) lamellar bone

A) the osteon

Choose which bone marking type would likely increase in size when a weight lifter repeatedly exercises muscles that attach to it. A) trochanter B) foramen C) meatus D) fossa

A) trochanter Bone Marking: Trochanter: very large, blunt, irregularly shaped process (the only examples are on the femur) DEDUCTIVE REASONING. Which answer is not like the others? TROCHANTER: -Projection: outward bulge of bone, usually sites of muscle attachments. May be due to increased stress from muscle pull or is modification for joint OTHER ANSWERS ARE Depressions and Openings (not usually for muscle attachments) -meatus: canal-like passageway -fossa: shallow basinlike depression in a bone, often serving as an articular surface (makes normal direct contact with another skeletal structure as part of a synovial joint) -foramen: round or oval opening, hole or passage through a bone

Which of the following is a characteristic of the bone material at D but NOT of the material at B? A) vascularity B) an origin in mesenchyme C) osteocytes D) lamellae

A) vascularity The compact bone at D would contain blood vessels as well as nerves in the central canals of its osteons. The spongy bone at B would be nourished by the surrounding fluids.

In which of the labeled parts of the adult long bone would hematopoietic tissue be located? A B C D E

B Hematopoietic tissue is found in the spaces within the red bone marrow found within certain body locations consisting of spongy bone. Examples include the diploe of flat bones and the proximal epiphyses of the femur and humerus (pictured). RED MARROW = Found within cavities of spongy bone and DIPLOE (thin plates of spongy bone) of FLAT BONES 4 Bone Type Classifications -Flat bones: thin, flat, slightly curved, sternum, scapulae, ribs, and most skull bones. -Irregular bones: vertebrae and hip bone -Long bones: limb bones (LONGER compared to wide) -Short Bones: cube-shaped, sesamoid bones

Which of the following statements is true? A) Endochondral ossification leads to the formation of the clavicles and cranial bones. B) Endochondral ossification converts hyaline cartilage "bone" models into true bones (i.e., hyaline cartilage serves as a template for bone formation). C) Most bones in the body are formed by intramembranous ossification. D) Endochondral ossification occurs within fibrous connective tissue membranes.

B) Endochondral ossification converts hyaline cartilage "bone" models into true bones (i.e., hyaline cartilage serves as a template for bone formation). Endochondral ossification is the formation of bone within hyaline cartilage. Hyaline cartilage "bones" are used as templates for the formation of true bone. Most bones below the base of the skull form by endochondral ossification. Intramembranous Ossification -Formation of clavicles and cranial bones -Occurs within fibrous connective tissue membranes Endochondral Ossification -Converts hyaline cartilage "bone" models into true bones (i.e., hyaline cartilage serves as a template for bone formation). -Most bones in the body are formed by endochondral ossification

The central (Haversian) canal that runs through the core of each osteon is the site of ________. A) cartilage and interstitial lamellae B) blood vessels and nerve fibers C) yellow marrow and spicules D) adipose tissue and nerve fibers

B) blood vessels and nerve fibers Yellow marrow = Fat, adipose tissue, stored in medullary cavity of bones (usually long bones)

The structure of bone tissue suits the function. Which of the following bone tissues is adapted to support weight and withstand tension stress? A) trabecular bone B) compact bone C) spongy bone D) irregular bone

B) compact bone

Which of the following is the single most important stimulus for epiphyseal plate activity during infancy and childhood? A) thyroid hormone B) growth hormone C) parathyroid hormone D) calcium

B) growth hormone

What material makes up most of the structure at A? A) fibrocartilage B) hyaline cartilage C) elastic cartilage D) dense irregular connective tissue

B) hyaline cartilage The articular cartilage at the ends of long bones is formed from hyaline cartilage.

The term diploë refers to the ________. A) fact that most bones are formed of two types of bone tissue B) internal layer of spongy bone in flat bones C) two types of marrow found within most bones D) double-layered nature of the connective tissue covering the bone

B) internal layer of spongy bone in flat bones

Bones are constantly undergoing resorption (breaking bone down) for various reasons. Which of the following cells accomplishes this process? A) osteocyte B) osteoclast C) stem cell D) osteoblast

B) osteoclast (clasts = CLEAVE/CHEW bone, multinucleated, release it from bone storage layer back to blood as Ca2+ ions)

Skeletal remains are discovered at an archeological site. X-rays of the femur show evidence of a thin epiphyseal plate. This bone likely belonged to which of the following? A) 25 year old female B) 60 year old male C) 18 year old male D) 8 year old female

C) 18 year old male 20 years or younger = epiphyseal plate (with hyaline cartilage) not yet fused Closer to 20 = cartilage of plate ossifies and becomes bone.

Which event has to precede all others during endochondral ossification? A) Bone trabeculae appear in the epiphyses. B) An epiphyseal plate is trapped between the diaphysis and either epiphysis. C) A cartilage model is formed. D) A nutrient artery invades the diaphysis.

C) A cartilage model is formed.

Which of the following statements best describes interstitial growth of cartilage? A) Unspecialized cells from mesenchyme develop into chondrocytes, which divide and form cartilage. B) Growth occurs in the lining of the long bones. C) Chondrocytes in the lacunae divide and secrete matrix, allowing the cartilage to grow from within. D) Fibroblasts give rise to chondrocytes that differentiate and form cartilage.

C) Chondrocytes in the lacunae divide and secrete matrix, allowing the cartilage to grow from within.

For intramembranous ossification to take place, which of the following is necessary? A) The cartilage matrix begins to deteriorate. B) A medullary cavity forms. C) Ossification centers form in the fibrous connective tissue membrane. D) A bone collar forms around the cartilage model.

C) Ossification centers form in the fibrous connective tissue membrane.

The structures in the figure collectively form which structural unit of compact bone? A) diploë B) trabeculae C) an osteon D) central canal

C) an osteon The circular structural unit found within compact bone is termed the osteon, and consists of a central canal surrounded by layers of bone. Diploe: thin plates of spongy bone Trabeculae: rods of bone tissue in spongy bone

A fracture in the shaft of a bone would be a break in the ________. A) epiphysis B) articular cartilage C) diaphysis D) metaphysis

C) diaphysis

Choose the best location for obtaining a red bone marrow sample from a patient. A) medullary cavity of femur B) frontal bone C) hip bone D) head of humerus

C) hip bone (Red marrow found in spongy bone cavities of hip bone) also in the spongy bone cavities at the end of long bones, but LARGER the bone = more red marrow HIP BONE would be better

What is the term for the layers of bony matrix surrounding the cell at A? A) periosteum B) endosteum C) lamellae D) lacunae

C) lamellae Lamellae are layers of bony matrix synthesized by osteoblasts during bone growth and maintenance.

At an archeological site you discover a bone that is cylindrical in shape, about one inch long and a quarter of an inch wide. Choose the correct classification. A) irregular B) short C) long D) sesamoid

C) long (longer than they are wide, LIMB BONES)

The periosteum is secured to the underlying bone by ________. A) the struts of bone known as spicules B) a bony matrix with hyaline cartilage C) perforating (Sharpey's) fibers D) Volkmann's canals

C) perforating (Sharpey's) fibers

Which of the following correctly pairs the structure at C with its primary component? A) endosteum; dense regular connective tissue B) periosteum; cuboidal epithelium C) periosteum; dense irregular connective tissue D) endosteum; areolar tissue

C) periosteum; dense irregular connective tissue The periosteum (connective tissue membrane on the surface of bone) is composed of dense irregular connective tissue along with a layer of simple squamous epithelium. HELD ON TO THE SURFACE by Sharpey's Fibers (tacks) Periosteum: covers the outside of compact bone Endosteum: covers inside portion (medullary cavity)

Osteoid-producing osteoblasts must rely upon this organelle to produce primary structures leading to the formation of collagen and calcium-binding proteins. A) peroxisomes B) centrioles C) ribosomes D) mitochondria

C) ribosomes

Cranial bones develop ________. A) from cartilage models B) within osseous membranes C) within fibrous membranes D) from a tendon

C) within fibrous membranes (Intramembranous Ossification: Type of bone formation) Cranial + Clavicle (collar) bones use this type of bone formation Endochondral Ossification: bone formation using hyaline cartilage model. Forms all other bones besides Cranial + clavicle 2 Types of Bone Formation 1. Intramembranous Ossification (Cranial Bones, Clavicle, primary ossification center in fibrous membrane) 2. Endochondral Ossification (all other bones, primary ossification center in hyaline cartilage model)

Choose the structures that most directly provide nutrients and remove wastes from osteocytes in compact bone.

Canaliculi (small passage ways connecting osteocytes together, nutrients and wastes travel through as well)

Which of the following statements is FALSE? A) The sternum is an example of a flat bone. B) Sesamoid bones form within certain tendons. C) Irregular bones include the vertebrae and hip bones. D) Long bones include all limb bones except the patella.

D) Long bones include all limb bones except the patella. This is false; long bones include all limb bones except the patella, tarsals, and carpals.

Which of the following is the major component of the part of the bone labeled E? A) dense connective tissue B) hyaline cartilage C) osseous tissue D) adipose tissue

D) adipose tissue Yellow bone marrow within the medullary cavity is composed primarily of adipose tissue (fat).

Prevention of osteoporosis includes adequate intake of ________. A) vitamin D and chloride B) calcium, and vitamin E C) potassium and vitamin D D) calcium and vitamin D

D) calcium and vitamin D (calcium absorption)

Which of the following is not a function of the skeletal system and bone tissue? A) houses the bone marrow which produces blood B) cells (hematopoiesis) C) storage of minerals D) communication E) support

D) communication HOUSES RED MARROW = Found within cavities of spongy bone and DIPLOE (thin plates of spongy bone) of FLAT BONES. Creates blood (hematopoiesis) Storage of calcium salts and minerals (layers of bone) Structural support and levers for muscles

Which bone-forming process is shown in the figure? A) intramembranous ossification B) bone remodeling C) bone fracture repair D) endochondral ossification

D) endochondral ossification

Which of the following is impacted in osteoporosis in older women? A) poor posture B) heritage such as African or Mediterranean C) abnormal PTH receptors D) estrogen deficiency due to menopause

D) estrogen deficiency due to menopause

Which of the following pairs is MISMATCHED? A) femur: long bone B) tarsals: short bones C) skull bones: flat bones D) sternum: long bone

D) sternum: long bone sternum is a flat bone

What can a deficiency of growth hormone during bone formation cause?

Decreased epiphyseal plate activity

Which of the following is a bone marking that indicates an armlike bar of bone? A) epicondyle B) meatus C) fossa D) foramen E) ramus

E) ramus

At what age to bones reach their peak density?

Early adulthood

In some cases the epiphyseal plate of the long bones of children closes too early. What might be the cause?

Elevated levels of sex hormones (androgen levels such as testosterone) have been proven to cause early, premature fusion of epiphyseal plates.

Which structure allows the diaphysis of the bone to increase in length until early childhood?

Epiphyseal plate

The pubic symphysis connects the two hip bones anteriorly and provides a little movement during childbirth. Choose the most appropriate tissue for this structure that is subjected to both pressure and stretch.

Fibrocartilage

Growth of bones is controlled by a symphony of hormones. Which hormone is important for bone growth during infancy and childhood?

Growth hormone

What tissue forms the model for Endochondrial ossification?

Hyaline Cartilage

Which hormone increases osteoclast activity to release more calcium ions into the bloodstream?

Parathyroid hormone

Cartilage grows in two ways, appositional and interstitial. What is appositional growth?

The secretion of new matrix against the external face of existing cartilage Cartilage Growth (2 ways) Appositional Growth: Cartilage forming cells in the perichondrium secrete new matrix against external face of existing cartilage -New matrix laid down on surface of cartilage Interstitial growth: Chondrocytes within lacune divide and secrete new matrix, expanding cartilage from within -New matrix made within cartilage

Which bone would likely take the longest to heal?

Thigh bone of an elderly individual

The process of bones increasing in thickness is known as ________.

appositional growth

Ossification (Osteogenesis) is the process of ____.

bone formation

In the epiphyseal plate, cartilage grows _____.

by pushing the epiphysis (ends) away from the diaphysis (shaft)

What kind of tissue is the forerunner of long bones in the embryo?

hyaline cartilage Endochondral Ossification: Hyaline Cartilage Model replaced by Bone

Lengthwise, long bone growth during infancy and youth is exclusively through ________.

interstitial growth (longitudinal) of the epiphyseal plates (hyaline cartilage plates separating epiphyses/ends of bones from diaphysis/shaft

Ossification of the ends of long bones _____.

is produced by secondary ossification centers

When an osteoblast (immature) becomes completely surrounded by its own matrix secretions it is referred to as an ________.

osteocyte (mature) bone cell sits in a hole (lacunae) of the osteon (structural unit of compact bone)

Bones are covered and lined by a protective tissue called periosteum. The inner (osteogenic) layer consists primarily of ________.

osteogenic cells

The periosteum is secured to the underlying bone by ________.

perforating (Sharpey's) fibers

In humans, the effect of the hormone calcitonin is to ________.

temporarily decrease blood calcium levels when administered in large doses CALCITONIN: TONES DOWN CALCIUM in the blood

Wolff's law is concerned with ________.

the thickness and shape of a bone being dependent on stresses placed upon it

Spongy bone contains ____.

trabeculae (long rod bone tissue)