Human Anatomy Notes Chapter 6

Briefly describe the processes involved in healing a bone fracture.
(1) A fracture hematoma forms at the injury site. (2) An internal callus forms as spongy bone unites the inner surfaces. An external callus of toughened connective tissue stabilizes the outer edges. (3) The external callus ossifies, and trabecular bone unites the broken ends. Dead bone closest to the break is removed and replaced. (4) The initial swelling of the external callus is eventually remodeled so that the repair site is only slightly thicker than the original bone.
Compare osteoporosis and osteopenia.
Osteoporosis and osteopenia both involve weakening of bone. The first is a disorder; the second is a normal occurrence. Both osteoporosis and osteopenia are most commonly associated with aging, the former more prevalent in women. Osteopenia is caused by a reduction in osteoblast activity.
What are canaliculi, and why are they important?
Canaliculi, the hollow channels that penetrate the lamellae of both compact and spongy bone, are essential for the survival of the osteocytes. By interconnecting the lacunae with the blood supply, they allow the transfer of nutrients and wastes through an otherwise impenetrable solid matrix.
Don thinks his left arm is weaker than his right because he broke his left humerus a few years ago. Is he likely correct? Why or why not?
The humerus that was broken is probably stronger than the one that never was broken. When completely healed, fracture sites typically withstand comparable stresses better than original bone.
Describe the trabeculae in spongy bone, and explain their functional significance.
Trabeculae are thin, often branching struts or plates composed of the concentric lamellae of spongy bone. They form an open, cross-braced framework that is light in weight but can resist stress from many directions. In addition, this framework protects and supports the cells of bone marrow.
How do bones grow in length?
Metaphyseal cartilage at each end of a long bone grows lengthwise toward the epiphyses and diaphyses while osteoblasts convert the inner (diaphyseal) surface of the epiphyseal plate to bone.
How does the “growth spurt” at puberty ultimately cause a person to stop growing taller?
The increase in sex hormones at puberty dramatically accelerates bone growth by stimulating osteoblasts. As the osteoblasts produce bone faster than the metaphyseal chondroblasts produce cartilage, the epiphyseal plates eventually ossify, and lengthwise growth ceases.
What vitamins most directly affect normal bone growth?
Vitamins A and C are essential for normal bone growth, and vitamin D is essential for enabling the digestive system to absorb calcium ions from the diet.
Name and describe the five types of nonarticulating processes found on bone surfaces.
(1) A trochanter is a large, rough projection. (2) A tuberosity is a smaller rough projection. (3) A tubercle is a small, rounded projection. (4) A crest is a prominent ridge. (5) A line is a low ridge. All of these are formed in places where tendons or ligaments attach to the periosteum of the bone.
Flat bone is composed of outer layers of compact bone known as inner and outer tables which sandwich a layer of spongy bone.
C A. True
X B. False

Flat bones are thin and composed f two nearly parallel plates of compact bone exposing a layer of spongy bone. Spony bones in the head are called diploe. They provide a lot of muscle attachment. Ex. cranial bones, sternum, ribs, scapulae.

The sternum is an example of a __________ bone.
O A. long
X B. short
C C. flat
O D. irregular
Compact bone has a regular arrangement of circular plates or layers arranged around a central canal. This concentric ring unit is called a(n):
C A. osteon
X B. lacunae
O C. canaliculi
O D. osteocytes
Compact bone has cells so tightly packed that there is no room for blood vessels.
X A. True
C B. False
Bones have a bit of flexibility to them due to the organic collagen fibers.
C A. True
X B. False
Strength of the area at the arrow is largely due to the arrangement of _______________ of the bone tissue making up this region.
O A. osteocytes
X B. lamellae
C C. trabeculae
O D. lacunae
Endochondral ossification begins with the formation of ossification centers in a(n)
O A. fibrocartilage callus
O B. epiphyseal plate
C C. hyaline cartilage model
X D. layer of spongy bone
Flat bones are formed by which type of osteogenesis?
O A. intrachondral ossification
X B. endochondral osteogenesis
O C. endomembranous osteogenesis
C D. intramembranous ossification

Intramembranous Ossification: Flatbones, facial bones, mandible, medial part of clavicle.

Exdochondrral: the rest of the  bones in the body

In the skeletal system, spongy bone is located:

Your Answer: in lining the canaliculi of bones.
Correct Answer: where stresses arrive from many directions.

A long bone increases in length by means of:

Your Answer: growth and ossification at the epiphyseal cartilage.

During intramembranous ossification, osteoblasts leave the area as bone is formed, leaving it exclusively as matrix.

Your Answer: False
Correct Answer: True

Small bones found in tendons: sesamoid bones

The periosteum:

Your Answer: lines the marrow cavity.
Correct Answer: contains an inner osteogenic layer.

Immovable fibrous joint that joins skull bones: suture

In a long bone, the epiphyseal plate functions to ensure that:

Your Answer: the bone can continue to increase in length.

Nasal septum = Perpendicular plate of ethmoid bone + Vomer

Osteopenia is a:

Your Answer: thickening of bone under the influence of unusual and heavy stresses.
Correct Answer: result of insufficient weight-bearing exercise, too little Vitamin D, and not enough calcium.

Membrane that covers cartilage: Perichondrium

Canal by which nerves and blood vessels penetrate into compact bone: Perforating canal.

Osteoporosis most severely reduces the ability of a bone to:

Your Answer: provide structural support for the body.

Processes that form where ligaments or tendons attach to a bone include:

Your Answer: trochanters, tuberosities and tubercles.

Mesenchyme-filled space where bone formation is not yet complete, especially between the cranial bones of an infant’s skull: fontanel

Depositon of mineral salts in a frameword formed by collagen fibers in which the tissue hardens: calcification.

A load that stresses a bone by pulling it in two different directions is __________.

Your Answer: tensile
Correct Answer: tension

The basic unit of structure in adult compact bone, consisting of a central (haversian) canal with its concentrically arranged lamellae, lacunae, osteocytes, and canaliculi. AKA Haversian system: Osteon

Small, hollow space, such as that found in bones in which the osteocytes lie: lacuna

Because they are strong and relatively inflexible, calcium phosphate crystals enable bone to withstand the stress of compression.

Ossification is the developmental process wherein mesenchyme or cartilage is replaced by bone.

Your Answer: False
Correct Answer: True
Your Answer: True

Mucus-lined air cavity in a skull bone that communicates with the nasal cavity. Paranasal sinuses are located in the frontal, maxillary, ethmoid, and sphenoid bones: paranasal sinus

Bone tissue consisting of trabeculae; found inside short, flat, and irregular bones and in the epiphyses (ends) of long bones.

7 bones of the ankle: Tarsals.

In the correct order, what are the steps involved in repair of a fracture in a bone?

Your Answer: An internal callus forms; it is remodeled, and once this is complete, the outer surface of the bone is remodeled.
Correct Answer: Blood forms a clot; a callus forms; its cartilage is replaced by new bone, and the old callus swelling is remodeled.

Microscopic tube running hte length of the spinal cord. Runs longitudinally in the center of an osteon of mature compact bone, containing blood and lymphatic vessels and nervesL Central canal.

Membrane that lines the medullary (marrow) cavity of bones, consisting of osteogenic cells and scattered osteoclasts.

A suture is a very complex junction between two bones of the skull that maximizes the area of ligamentous connection between the bones.

Your Answer: False
Correct Answer: True

Exaggeration of the thoracic curve of the vertebral column, resulting in a hunchback: kyphosis

A major difference between compact and spongy bone is that:

Your Answer: spongy bone lacks concentric lamellae.
Correct Answer: spongy bone lacks osteons.

Method of bone formation in which the bone is formed directly in messenchyme arranged sheet like layers that resemble membranes: Intramembranous ossification.

Stem cell derived from mesenchyme that has mitotic potential and the ability to differentiate into an osteoblast. Osteogenic cell.

8 bones of the wrist: Carpals.

Fused bones at the inferior end of the vertebral column: coccyx

Frontal plane = coronal plane

What are the four major sets of blood vessels in a typical bone?

Your Answer: Haversian artery, Volkmann’s artery and vein, and connecting capillaries
Correct Answer: nutrient artery and vein, epiphyseal vessels, metaphyseal vessels, and periosteal vessels

Slightly movable cartilaginous joint between the anterior surfaces of the hip bones. Pubic symphysis.

Joint in the skull between the parietal bones and the occipital bone, sometimes contains sutural bones: lambdoid suture.

Replacement of cartilage by bone. AKA intracartilaginous ossification: endochondral ossification

Small, irregularly shaped bones that sometimes form between bones of the skull are called ____________ bones.

Your Answer: sutural

7 bones of the ankle: tarsus

Exaggeration of the lumbar curve of the vertebral column. AKA hollow back: lordosis

Hyaline cartilage plate in the metaphysis of the long bone; site of lengthwise growth of long bones: epiphyseal plate

Space within the diaphysis of a bone that contains yellow bone marrow. AKA marrow cavity: Medullary cavity.

Growth due to surface deposition of material, as in the growth in diameter of cartilage and bone. AKA exogenous growth. Appositional growth.

8 bones of wrist: Carpals

A small channel or canal where they connect lacunae.

Which type of bone has an internal and external table of compact bone with a layer of spongy bone called the diploe in between?

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