NOVA BIO 141

What do chondroblasts do?

(chondros = grit or gristle) they produce cartilage matrix and become chondrocytes after being encased by this substance. They occupy small spaces called lacunae.

What are the two types of ossification?

1) Endochondral (endo = within, chondral = cartilage) ossification; and 2) intramembranous ossification.

What are the two types of bone marrow and where are they found?

1) Red bone marrow (also called myeloid tissue or hemopoietic tissue), found in adults in the flat bones of the skull, the vertebrae, the ribs, the sternum, the ossa coxae (hip bone), and in the proximal epiphyses of each humerus and femur. The proximal epiphysis is closest to the body trunk. 2) Yellow bone marrow (fat)

What are the stages of fracture repair?

1) fracture hematoma; 2) fibrocartilaginous callus; 3) bony callus; and 4) bone is remodeled.

Explain the two types of cartilage growth.

1) interstitial growth (growth in length from within 5 zones of the epiphyseal plate where cartilage grows and eventually is replaced by bone), and 2) appositional growth (growth in diameter around the periphery of cartilage formed within the periosteum).

What are the "zones" of an epiphyseal plate called?

1) resting cartilage; 2) proliferating cartilage; 3) hypertrophic cartilage; 4) calcified cartilage; and 5) ossified cartilage.

Ribs _____ are true ribs, and ribs _____ are called false ribs; the last two false ribs are also called _____ _____.

1-7, 8-12, floating ribs

The arm and thigh each contain one bone, the forearm and leg contain two bones that pivot against one another, there are multiple short bones in the wrist and proximal foot, and both the hand and foot contain _____ phalanges each.

14

The adult skeleton is typically composed of _____ bones.

206

The vertebral column is composed of ___ vertebrae: ___ cervical vertebrae, ___ thoracic, ___ lumbar, the sacrum and the coccyx.

26, 7, 12, 5; A typical vertebra has a body and a vertebral arch. Together they enclose a vertebral foramen, which houses the spinal cord.

Each lower limb is composed of the femur, patella, tibia, fibula, ___ tarsals, ___ metatarsals and ___ phalanges.

7, 5, 14

Each upper limb contains a humerus, radius, ulna, ___ carpals, ___ metacarpals and ___ phalanges.

8, 5, 14

In intramembranous ossification, ossification centers appear around the _____ week of development.

8th

What function does the thyroid grand serve in the bone formation process?

A major role of thyroid hormone in bone remodeling is to stimulate bone growth by influencing the basal metabolic rate of bone cells. Its C-cells produce calcitonin which inhibits osteoclast activity and stimulates osteoblast activity. Alternatively, parathyroid hormone and calcitriol produced there will stimulate osteoclast activity.

_____ _____ house the teeth in both the maxillae and mandible.

Alveolar processes

What's ground substance?

An extracellular gelatinous material that is transparent, colorless, and fills the spaces between fibers and cells. It actually consists of large molecules called glycosoaminoglycans (GAGs) which link together to form even larger molecules like proteoglycans, glycoproteins, and hydroxyapatite cells.

_____ _____ (malleus, incus, stapes) are tiny ear bones housed in each temporal bone.

Auditory ossicles

How is bone formed?

Bone formation begins when osteoblasts secret the initial semisolid organic (un-mineralized) form of the bone matrix called osteoid. Calcification, or mineralization, subsequently occurs to the osteoid when hydroxyapatite crystals deposit in the bone matrix.

What happens during intramembranous ossification?

Bone forms from a thin layer of mesenchyme (sometimes called a membrane). It occurs without a cartilage model in embryonic flat bone formation (skull, maxilla, mandible, pelvis, clavicle, subperiosteal surface of long bone) as well as during fracture healing in bones throughout the body (commonly known as contact healing and Haversian remodeling). At first woven bone is formed, however, it is not well organized and is replaced later by stronger lamellar bone, also called secondary bone.

What is bone matrix and what is it made up of?

Bone matrix is the "concrete poured along the rebar". It has both organic and inorganic components. The organic component is osteoid, which is produced by osteoblasts; it gives the bone tensile strength. The inorganic portion is made up of salt crystals that are primarily calcium phosphate and calcium hydroxide; this part gives rigidity to the bone.

What is calcitonin?

Calcitonin is a hormone released from the thyroid gland in response to increased blood calcium levels. In regulating blood calcium, it is thought to be less significant than parathyroid hormone and calcitriol, at least in adults.

How are calcium levels maintained?

Calcium homeostasis requires precise controls over calcium uptake, calcium loss, and calcium storage.

How does cartilage receive its nutrition?

Cartilage receives its nutrients via diffusion through the matrix.

Where are chondrocytes found and what do they do?

Chondrocytes are found within a long bone's central cavity's primary ossification center. They deposit cartilage at the ends of the medullary cavity to make bone longer. They then enlarge, causing the matrix to calcify, which makes internal matrix impermeable to nutrients. When the matrix dies, it forms the internal tube of long bones.

_____ bone forms the dense outer, solid region of bone, whereas _____ bone is located internally.

Compact, spongy

What is an osteon?

Concentric lamellae of osteons, also known as a Haversian system, are rings of bone tissue that contain collagen fibers.

_____ bones enclose the cranial cavity

Cranial

What happens to bones during the aging process?

During the aging process, the tensile strength of bone decreases, and bone loses calcium and other minerals (demineralization).

_____ bones support the entrances to the digestive and respiratory systems.

Facial

Describe characteristics of typical female skulls.

Female skulls tend to be more gracile, have more pointed (versus squared-off) chins, and have sharper supraorbital margins.

_____ permit the skulls of infants to distort during birth as well as expand as the brain grows.

Fontanelles

Which hormones stimulate gone growth by increasing osteoblast activity?

Growth hormone, thyroid hormone, and sex hormones

Which hormones interfere with normal bone remodeling?

High doses of glucocorticoids and serotonin.

What happens during endochondral ossification?

It begins with a hyaline cartilage model where newly-formed osteoblasts gather at the diaphysis wall to form a bone collar. Most bones of the skeleton are produced this way at the primary ossification center in the diaphysis.

_____ vertebrae are more massive than cervical and thoracic vertebrae. They lack costal facets and transverse foramina.

Lumbar

Describe characteristics of typical male skulls.

Male skulls tend to be more robust, have more prominent bone markings - such as muchal lines and external occipital protuberance - and have squared-off chins and angles of the mandible.

What happens during bone remodeling?

New bone tissue is continually deposited by osteoblasts and "resorbed" by osteoclasts

How is spongy bone formed?

Osteoclasts degrade cartilage so it can become spongy bone.

Osteitis deformans, also called _____, involves which type of abnormalities?

Paget disease; its caused by increased osteoblast and osteoclast activity.

_____ _____ function to lighten the skull and give resonance to the voice.

Paranasal sinuses

How is spongy bone different that compact bone?

Spongy bone contains no osteons. Instead, its structure is an open lattice of narrow rods and plates of bone, called, trabeculae.

_____are immobile joints between skull bones.

Sutures They allow for growth of the skull bones during childhood.

The cranial bones include which individual bones?

The frontal bone, paired parietal bones, occipital bone, paired temporal bones, sphenoid bone, and the ethmoid bone.

What are the parts of the sternum?

The manubrium, body and xiphoid process.

Which seven bones form the orbital complex?

The maxilla, frontal, lacrimal, ethmoid, sphenoid, palatine and zygomatic bones.

The facial bones include which individual bones?

The paired zygomatic bones, lacrimal bones, nasal bones, inferior nasal conchae, palatine bones, maxillae, a single vomer bone and a single mandible.

What does the appendicular skeleton include?

The pectoral and pelvic girdles, the bones of the upper limb, and the bones of the lower limb

Which micronutrients are required for bone formation?

The process requires vitamin D (which enhances calcium absorption) and vitamin C (which is required for collagen formation) as well as calcium and phosphate for calcification.

What does the axial skeleton include?

The skull, vertebral column, and thoracic cage it does not include the pelvic and pectoral girdles.

What are the components of the thoracic cage?

The thoracic vertebrae, the ribs and the sternum.

What are canaliculi, where are they found and what do they do?

They contain osteocyte cytoplasmic extensions, they extend from lacunae to lacunae and nutrients pass through them.

_____ vertebrae have coastal facets on their bodies and on most of their transverse processes.

Thoracic

How do bones obtain their nutrition?

Typically, a "periosteal bud" containing one nutrient artery , which delivers nutrients to osteogenic cells (osteoblasts and osteoclasts), and one vein enter the bone via a small opening in the bone called a nutrient foramen.

What is Vitamin D and how is it formed?

Vitamin D is a pre-hormone that is activated to calcitriol through several enzymatic steps. Parathyroid hormone is released from the parathyroid gland in response to decreased blood calcium levels, and its release increases the final step in the synthesis of calcitriol. The combined actions of parathyroid hormone and calcitriol increase blood calcium levels to within the normal range.

When is long bone growth considered complete?

When an epiphyseal line replaces the epiphyseal plate in mature bone.

The _____ of the os coxae articulates with the head of the femur.

acetabulum

What is abnormal conversion of hyaline cartilage to bone called?

achondroplasia

Each os coxae forms through the fusion of _____.

an ilium, an ischium and a pubis

What is the most abundant tissue type found in bones?

bone (osseous) connective tissue

Osteoprogenitor cells are _____ _____ cells; they are located in both the _____ and the _____.

bone stem, periosteum and endosteum

The 8 _____ bones form the wrist, the 5 _____ form the bones of the palm, and the 14 _____ form the bones of the fingers.

carpal, metacarpals, phalanges

What are the components of hyaline cartilage?

chondrocytes in lacunae within a semi rigid matrix.

The _____ is the S-shaped bone that articulates with the sternum. It forms the "shoulder blade."

clavicle

Four small coccygeal vertebrae fuse to form the _____.

coccyx

A _____ fracture occurs at the _____ end of the radius?

colles, distal

The _____ suture connects the frontal and parietal bones.

coronal

The _____ _____ along the floor of the cranial cavity contain depressions for parts of the brain, grooves for blood vessels, and numerous foramina.

cranial fossae

What are the regions of a typical long bone called?

diaphysis, epiphysis, metaphysis, articular cartilage, and medullary cavity

What are the components of the skeletal system?

dynamic living tissue: bones, cartilage, ligaments, and other connective tissue that stabilize or connect bones

What are rings of bone directly internal to the periosteum of a bone called?

external circumferential lamellae

The _____ is the laterally-located, more slender bone, and its _____ _____forms the lateral bump of the ankle.

fibula, lateral malleolus

The clavicle's _____ _____ articulates with the head of the _____.

glenoid cavity, humerus

Skeletal features can be used to determine which characteristics at death?

height, age at death, sex and general health

The _____ is the bone of the upper arm. It articulates distally with the bones of the forearm, the radius and ulna, at the elbow.

humerus

The _____ bone does not articulate with any other bone but serves as an attachment site for several muscles and ligaments.

hyoid

osteoblasts produce ...

initial semisolid organic form of the bone matrix called osteoid

What are leftover parts of osteons that have been partially resorbed?

interstitial lamellae.

The _____ suture forms the boundary between the parietal and occipital bones.

lambdoid

Where can you find endosteum and what does it do?

lines medullary cavities, contains osteoblasts and is active during bone repair

How are bones classified by shape?

long, short, flat, or irregular.

What happens during bone resorption?

lysosomes dissolve the organic parts of bone matrix and hydrochloric acids dissolves minerals of bone

osteocytes ...

maintain the bone matrix

The _____ of the femur articulate with the _____ on the tibia.

medial and lateral condyles, condyles

The _____ _____ are the most sexually dimorphic bones of the body; how do they differ between the sexes?

ossa coxae; The female pelvis is wider, has a broader greater sciatic notch, and a more rectangular-shaped pubis than the male pelvis.

The pelvic girdle consists of two _____, while the pelvis is composed of _____.

ossa coxae; the ossa coxae, sacrum and the coccyx

Insufficient ossification is a condition known as _____?

osteopenia

The _____ is the kneecap and inserts within the quadriceps femoris tendon.

patella

Each limb is held in place by a girdle (_____ girdle for the upper limbs, _____ girdle for the lower limbs).

pectoral, pelvic

The _____ _____ is an oval ridge of bone that divides the pelvis into a true pelvis and a false pelvis.

pelvic brim

A long bone is covered externally by the _____ and lined internally by the _____.

periosteum, endosteum.

In fracture repair, the fracture hematoma becomes a _____, then a _____.

procallus, fibrocartilaginous callus.

The tarsal bones form the _____, the 5 metatarsals form the _____ of the foot and the 14 _____ form the bones of the toes.

proximal foot, bones of the arch, phalanges

osteoclasts ...

resorb bone

The _____ is a triangular-shaped bone with five fused vertebrae.

sacrum

What are the functions of bone?

support and protection, movement, hemopoiesis, and storage of minerals and energy reserves

What are the components of the pectoral girdle and what is its function?

the clavicle and scapula; it articulates with the axial skeleton and supports the upper limb

Where is donor bone marrow most commonly harvested from?

the iliac crest

What is the region of a mature bone between the diaphysis and epiphysis called?

the metaphysis

The _____ is the medially located thick and strong bone of the leg, and its _____ _____ forms the medial bump of the ankle.

tibia, medial malleolus

Cervical vertebrae typically have both a _____ _____ and a _____ _____ _____.

transverse foramina, bifid spinous processes