ANATOMY AND PHYS

Lesson 4 - ch 6

T/F: hematopoesis refers to the formation of blood cells within the red marrow cavities of certain bones

TRUE

T/F: Compact bone is replaced faster than spongy bone

False

T/F: Bones are classified by whether they are weight-bearing or protective in function

False

T/F: The periosteum is a tissue that serves only to protect the bone because it is not supplied with nerves or blood vessels

False

T/F: Short, irregular, and flat bones have large marrow cavities in order to keep the weight of the bones light

False

T/F: In newborn infants, the medullary cavity and all areas of spongy bone contain yellow bone marrow.

False

T/F: The structural unit of compact bone (osteon) resembles the growth rings of a tree

True

T/F: The term osteoid refers to the organic part of the matrix of compact bones.

True

T/F: Sixty-five percent of the mass of bone is an organic compound called hydroxyapatite

False

T/F: All bones are formed by intramembranous ossification are irregular bones

False

T/F: An osteon contains osteocytes, lamellae, and a central canal, and is found in compact bone only.

True

T/F: The trabeculae of spongy bone are oriented towards lines of stress

True

T/F: bone tissue in the skeleton of a human embryo is completely formed at six months’ gestation

False

T/F: Each bone lamella has collagen fibers that wrap in opposite directions

True

A fracture in the shaft of a bone would be a break in which structure?

Diaphysis

Which of the following choices is the most abundant skeletal cartilage type?

Hyaline

Is strength a function of the skeletal system?

No

What is the structural unit of compact bone?

The osteon

What are the small spaces in the bone tissue that are holes in which osteocytes live?

Lacunae

What cells accomplish resorption of bone?

Osteoclast

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

Parathyroid hormone

Vertebrae are considered what type of bones?

Irregular

A bone fracture perpendicular to the bone’s axis is called what kind of fracture?

Transverse

Which gland produces hormones that tend to decrease blood calcium levels?

Thyroid

Spongy bones are made up of what kind of framework?

Trabeculae

Osteogenesis is which kind of process?

Bone formation and bone remodeling

Which hormone is important for bone growth during infancy and childhood?

Growth (factor)

Which type of fracture is not likely in a 92-year-old?

Greenstick

Appositional Growth

The growth pattern of bone in which matrix is laid down on the surface.

Chondrocytes

The cells responsible for endochondral ossification

Diaphysis

The area of long bones where cartilage cells are replaced by bone cells

Epiphyseal line

The appearance of this line signals the end of bone growth.

Epiphyseal plate

Area where bone growth takes place

Greenstick fx

An incomplete fracture or cracking of the bone without actual separation of the parts. Common in children.

Comminuted fx

Bone fragments into many pieces

Spiral fx

Common sports fx resulting from a twisting force

Osteomalacia

Bone formed is poorly mineralized and soft. Deforms on weight bearing.

Osteoporosis

Bones ae porous and thin but bone composition is normal.

Paget’s Disease

Abnormal bone formation and reabsorption.

Which of the following describes blood cell formation?

1. Hematopoiesis

2. Fissure

3. Appositional

4. Comminuted

1) Hemaopoiesis

What type of ossification forms a long bone?

Endochondral

What is a narrow slit-like opening generally between two bones?

Fissure

What type of bone is embedded in a tendon?

Sesamoid

Which multinucleated cells destroy bones?

Osteoclasts

Which of the following is a disease of the bone in which bone reabsorption outpaces bone deposit, leaving the person with thin and often very fragile bones?

Osteoporosis

What is pain in the bone called?

Ostealgia

What is growth in the diameter of long bones called?

Appositional growth

What type of fibers may have a Haversian canal contain, along with arteries, veins, capillaries, and lymph vessels?

Nerve

What is a round or oval hole through a bone that contains blood vessels and/or nerves?

Foramen

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

Hyaline cartilage

Bone growth (lengthwise) during infancy and youth is exclusively through which of the following?

Interstitial growth of the epiphyseal plates

The canal that runs through the core of each osteon (Haversian canal) is the site of what?

Blood vessels and nerve fibers

Normal bone formation and growth are dependent on the adequate intake of what nutrients?

Calcium, phosphate, vitamin D

Factors in preventing (or delaying) osteoporosis include what

Drinking fluoridated water

The term dipole refers to what? (BONES, NOT CHEM)

The internal layer of spongy bone in flat bones

It is thought that remodeling or bone growth is in response to the forces placed on it. What hypothesis may explain how mechanical forces communicate with cells responsible for bone remodeling?

Electrical signals direct the remodeling process.

How do cranial bones develop?

Within fibrous membranes

For intramembranous ossification to take place, what is necessary?

An ossification center forms in the fibrous connective tissue.

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

Osteoblasts and osteoclasts.

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

Elevated levels of sex hormones.

Which of the following describes ossification of the ends of long bones?

1. It is a characteristic of intramembranous bone formation.

2. It is characterized by secondary ossification.

3. It involves medullary cavity formation.

4. It twice as long as diaphysis.

1. It is characterized by secondary ossification.

Yellow bone marrow contains a large percentage of which what?

Fat

What describes the universal loss of mass seen in the skeleton and begins about the age of 40?

It reflects an inbalance in the bone remodeling process.

What best describes interstitial growth?

Chondrocytes in the lacunae divide and secrete matrix, allowing the cartilage to grow.

In the epiphyseal plate, how does cartilage grow?

From the epiphysis to the diaphysis

T/F: There is blood-forming marrow in the vertebrae, cranial, and pelvic bones of an adult.

Correct

The periosteum is secured to the underlying bone by dense connective tissue called what?

Sharpey’s fibers

In bone formation, a deficiency of growth hormone will cause what?

Decreased proliferation of the epiphyseal plate cartilage.

The process of bones increasing in width is known as what?

Appositional growth

The structure of bones suits the functions. Which bones are adapted to withstand stress?

Compact bone

What cell is responsible for secreting the matrix of bone?

Osteoblast

Wolff’s law is concerned with what?

The thickness and shape of a long bone being dependent on stresses placed upon it.