CH. 6 Bones and Skeletal tissue

soft callus

"Kalus; Hard skin" Splints the broken bone

Your patient is returning for follow-up 6 weeks after sustaining a nondisplaced fracture of his radius. He tells you that his forearm is no longer painful, but he is concerned that he can palpate a "lump" in the bone at the site of the healing fracture. What is your response?

"That bump is a normal part of bone healing at this stage. As your body completes the process, the cells in your bone will gradually remodel it to its previous shape."

Cleidocranial dysostosis

-partially/completely missing coller bone, top of head frontal failed to close, bones and joints are under developed. -Pushing to hard during labor can increase pressure in the abdomen of baby causing the clavicle to break

Stages of healing bone

1. Hematoma formation 2. Fibrocartilage callus formation 3. Bony callus forms 4. Bone Remodeling occurs

4 classifications of Bones

1. Long bones 2. Short bones 3. Flat bones 4. Irregular bones

epiphyseal plate consists of five zones

1. Resting ( quiescent) 2. Proliferation (growth) 3. Hypertrophic 4. Calcification 5. Ossification (osteogenic)

Seven important functions of bone

1. Support 2. Protection 3. Movement 4. Mineral growth and factor storage 5. Blood cell formation 6. Tryglyceride (fat) storage 7. Hormone Production

Five major cell types populate bone tissue

1. osteogenic cells 2. osteoblasts 3. osteocytes 4.bone lining cells 5. osteoclasts

Calcitriol

A hormone produced from vitamin D that acts in essentially the same manner as parathyroid hormone.

Ramus

Arm like bar of bone. An extension of a bone making an angle with the rest of the structure

Why are bones considered organs?

Because they are made up of different types of tissues

FACT:

Bone lining cells are flat cells found on bone surfaces where bone remodeling is not going on.

Osteon

Bone. contains osteocytes, lamellae, and a central canal, and is found in compact bone only.

Bone Function: Mineral growth and factor storage

Calcium and phosphorus, and growth factor reservoir

What fibers are found in this type of cartilage?

Collagen Fibers

The structure of bone tissue suits the function. Which of the following bone tissues is adapted to support weight and withstand torsion stresses?

Compact Bone

Epiphysis

End of a long bone compact bone externally spongy bone internally

Canaliculi

Hairlike canals that connect lacunae to each other and the central canal

Identify the cells required for fibrocartilaginous callus formation and list their functions.

Fibroblasts - produce of collagen fibers to connect the broken bone ends chondroblast- secrete a cartilaginous matrix that later calcifies that spans the break and connects the broken ends

What are the tree levels of structure for a bone

Gross Microscopic Chemical

epiphyseal plate

Growth plate, made of cartilage, gradually ossifies

canaliculi

Hairlike canals that connect lacunae to each other and the central canal provide nutrients and remove wastes from osteocytes in compact bone.

Bone Function: Blood cell formation

Hematopoiesis Occurs in red bone marrow cavities of certain bones.

which of the labeled parts of the adult long bone would hematopoietic tissue be located?

Hematopoietic tissue is found in the red bone marrow 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).

Three types of cartilage

Hyaline Elastic Fibrocartilage

ossification with Hyaline Caartilage

In this type of ossification, the bone is first modeled from cartilage and then replaced by bone as blood vessels invade the model.

What physiological processes allow growing bones to acquire their unique features such as processes, tuberosities, condyles, and fossae?

It results from mechanical stress and remodeling. Bones develop their specific features according to the stresses placed on them as they grow and fit together, and as they are pulled on by muscles.

Long bones are for what

Limbs

calcitonin.

Lowers blood calcium levels in pregnant women and children

Hyaline cartilage

Most common type of cartilage; it is found on the ends of long bones, ribs, and nose Collagen fibers ONLY provides support, flexibility and resilience

FACT:

Osteoblasts secrete collagen and calcium-binding proteins.

Bone Function: Hormone production

Osteocalcin secreted by bones helps to regulate insulin secretion, glucose levels, and metabolism

Osteoclasts

Osteoclasts are the bone cells that break down bone. If they were activated more than normal, you should expect to see bone loss.

FACT:

Osteoclasts secrete digestive enzymes and hydrogen ions.

Osteoporosis

Osteoporosis refers to a group of diseases in which bone resorption outpaces bone deposit. The composition of the matrix remains normal but bone mass declines, and the bones become porous and light. The bones become so fragile that they can break from something as simple as stepping off a curb or a hearty sneeze.

PTH function in bone

PTH; indirectly stimulates osteoclast activity

Old Norse stories tell of a famous Viking named Egil, who lived around 900 AD. His skull was greatly enlarged and misshapen, and the cranial bones were thickened (6 cm, more than 2 inches, thick). He had headaches from the pressure exerted by enlarged vertebrae on his spinal cord. So much blood was diverted to his bones to support their extensive remodeling that his fingers and toes always felt cold and his heart was damaged through overexertion. What bone disorder did Egil probably have?

Paget's disease is characterized by excessive and abnormal bone remodeling. It results in irregular thickening of bone tissue and often affects the skull and spine, causing pain and deformity.

Which anatomical structures in compact bone house blood vessels?

Perforating and Central canal

endochondral ossification

Process of transforming cartilage into bone.

Foramen

Round or oval opening through a bone

Elastic Cartilage

Similar to hyaline, contains elastic fibers External ear and epiglottis

What is the weakest part of a developing, adolescent long bone?

The epiphyseal plate is a weak point because of the lack of calcification.

Fibrocartilage

Thick collagen fibers great tensile strength Menisci of knee vertebral disks

achondroplasia

This genetic disease can lead to shortening of the long bones due to premature closure of the epiphyseal plate.

periosteum

What covers and lines the bone by this protective tissue

Short bones are for

Wrist and ankle

Trochanter

a site for a muscle or ligament attachment Very large, blunt, irregularly shaped process..

Yellow bone marrow within the medullary cavity is composed primarily of

adipose tissue (fat).

bone process

any part of a bone that protrudes

In bone remodeling the release of minerals into the bloodstream called

blood resorption

compound fracture

bone breaks through the skin

Bone remodeling involves the process of storing minerals in bone tissue called

bone deposition

fossa

bone depression into which a condyle might fit.

displaced fractures,

bone ends are out of normal alignment

Osteoblasts

bone forming cells secrete bone matrix

During bone growth, which significant event occurs at the surface indicated by the letter D?

bone resorption

sesamoid bones

bones embedded in tendons example: patella Vary in size

Cells responsible for ossification

cells responsible are osteoclast and osteoblast

Osteoclasts are

cells that break down bone matrix (Bone destroying cells)

Three types of fibers

collagen, elastic, reticular

osteomalacia

disease marked by softening of the bone caused by calcium and vitamin D deficiency

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

Paget's disease

excessive and haphazard bone deposition and resorption

interstitial growth of cartilage

growth in length

epiphyseal line

growth plate

red marrow in adults is only found in the cavities between trabeculae of spongy bones in:

he flat bones of the skull, as well as the sternum, ribs, clavicles, scapulae, hip bones, and vertebrae The heads of the femur (thigh bone) and humerus (long bone of the arm)

cartilage forms what

he model for endochondral ossification?

What controls bone remodeling?

hormones and mechanical stress

Perforating (Sharpey's) fibers

hundreds of connective tissue fibers that secure the periosteum to the underlying bone

The articular cartilage at the ends of long bones is formed from

hyaline cartilage

FACT:

hyaline cartilage This tissue persists within the epiphyseal plate at the boundary between primary and secondary ossification centers until early adulthood.

appositional growth

increase in bone thickness

appositional growth?

increase in bone thickness the secretion of new matrix against the external face of existing cartilage

parathyroid hormone increases osteoclast for what

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

Ossification of the ends of long bones ________.

is produced by secondary ossification centers

Bone Function: Movement

levers for muscle action

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.

long

Bones are classified as

long, short, flat, or irregular on the basis of their shape, and as axial or appendicular based on their body location.

Proteoglycan

major component of the ground substance secreted by bone-forming cells. Provide Feedback

Osteosarcoma

malignant tumor of the bone

Endosteum

membranous lining of the hollow cavity of the bone

What does a bone contain other than osseous tissue?

nervous tissue, cartilage, fibrous connective tissue, muscle cells, epithelial cells in its blood vessel

central (Haversian) canal

opening in the center of an osteon, carries blood vessels and nerves

bone tissue is also called

osseous tissue

What term is used to describe the addition of new bone tissue?

ossification

Bone deposition is accomplished by cellular activity of

osteblasts

Bone resorption is accomplished by the cellular activity of

osteoclasts

What is the structural unit of compact bone?

osteon, an elongated cylinder oriented parallel to the long axis of the bone.

The periosteum is secured to the underlying bone by ______

perforating (Sharpey's) fibers

secondary ossification center

region of bone development in the epiphyses

bone markings

reveal where muscles, tendons, and ligaments were attached and where blood vessels and nerves passed

Lamellae

rings around the central canal, sites of lacunae. layers of bony matrix synthesized by osteoblasts during bone growth and maintenance. bony matrix surrounding the vessels and nerve

condyle

rounded part of a bone that articulates with another bone

Diaphysis

shaft of long bone, composed of compact bone filled with yellow bone marrow (adults)

spine

sharp, slender, often pointed projection

tuberosity

site of muscle attachment that is large and rough

Lacunae

small cavities in bone that contain osteocytes

facet

smooth, nearly flat articular surface

Flat bones located in

sternum, scapulae, ribs and most skull bones

trabeculae

supporting bundles of bony fibers in cancellous (spongy) bone

nondisplaced fractures,

the bone ends retain their normal position.

Osteomyelitis

the medical term for an infection in a bone; it can occur if an injury exposes the bone to germs.

Hematopoietic (blood-forming) tissue found in infants is located where

the medullary cavity of the diaphysis and all areas of spongy bone contain red bone marrow

bone resorption

the removal of minerals and collagen fibers from bone by osteoclasts

Wolff's law is concerned with ________.

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

Blood resorption occurs when

there is a decrease of blood calcium and mechanical stress and an increase of parathyroid hormone

Bone deposition specifically occur when

there is an increase of blood calcium and mechanical stress decrease of parathyroid hormone

Diploe

thin plates in spongy bone

osteoid

unmineralized bone matrix

Irregular bones located in

vertebrae, hip bones.