Chapter 6 The Skeletal System: Bone Tissue

Compact bone tissue is composed of repeating structural units called

Osteons, or harversian system.

________ fracture of distal end of fibula and serious injury of distal tibia articulation.

Pott's

What is the function of periosteum?

Protects bone Assist in fracture repair Helps nourish bone tissue Serves as attachment point for ligaments and tendons

Fracture Reduction is

Realigning fragments into normal anatomical position.

Blood cell production occurs in which type of bone marrow?

Red Bone Marrow

In bones, blood supply is most abundant where?

Red Bone Marrow

What is found in the space between each trabeculae?

Red bone marrow.

_____________ bone, Lightweight Provides tissue support Site of red bone marrow Location: Interior of bone protected by compact bone

Spongy

(True or False) Compact bone tissue contains few spaces and is the strongest form of bone tissue

TRUE

Bone is richly supplied with blood vessels (True or False)

TRUE

Estrogens and ______________ stimulate osteoblast activity and synthesis of bone matrix.

Testosterone

In calcification, the crystals that are formed are called_____________?

Hydroxyapatite

Which two arteries supply ends of longs bones?

Metaphyseal and Epiphyseal

What are the factors effecting bone growth and bone remolding?

Adequate dietary intake of vitamins and minerals and well as sufficient levels of several hormones.

When bones throughout the body grow in thickness

Appositional Growth

A Long bone is covered by ____________cartilage at the articular surfaces of its proximal and distal epiphyses and by periosteum around all other parts of the bone.

Articular

In calcification, mineral salts are deposited in a framework formed by which type of fibers?

Collagen

Osteoblasts synthesize and secrete

Collagen fibers , Organic components needed to build extracellular matrix

A Break at distal ends of the radius where distal fragment is displaced posteriorly.

Colles Fracture ("broken wrist")

______________ bone, provides protection and support Makes up bulk of diaphysis of long bones Location: Beneath Periosteum

Compact

The ______________is a thin membrane that lines the medullary cavity.

Endosteum

Thin membrane lining medullary cavity

Endosteum

What type of tissue is found in the epiphyseal plate?

Hyaline Cartilage

In a ____________ fracture, the bone breaks into multiple fragments which are driven into each other.

Impacted

Location of osteoprogenitor cells

Inner portion of periosteum, endosteum, in bone canals that contain blood vessels.

What is the space around the osteocytes called

MATRIX

What is another name for bone tissue?

Osseous Tissue

The entire framework of bones and their cartilages, along with ligaments and tendons, constitutes the

Skeletal System

Bones are composed of several different tissues working together, what are they?

bone or osseous tissue, cartilage, dense connective tissue, epithelium, adipose and nervous tissue.

Bone remodeling still occurs in adults, _% total bone mass in being replaced at any given time.

5%

Osteoporosis affects more women than men. ____% who suffer are older women.

80%

What percent of the skeleton is compact vs. spongy bone?

80% compact / 20% spongy

Maintaining the levels of minerals is known as

Mineral Homeostasis ( Storage and Release)

Bones need both _______salts and __________fibers for calcification.

Mineral Salts and Collagen Fibers.

What are the functions of nerves in bones?

Nerves accompany the blood vessels that supply bones. The Periosteum is rich in sensory nerves, some of which carry pain sensations.

Osteon (AKA Haversian System) = basic unit Components:

Nerves and Blood Vessels Lacunae Canaliculi

What is a bone scan?

Nuclear imaging test that helps diagnose and track bone abnormalities.

Near the center of the diaphysis, a large __________ artery passes through a hole in compact bone called nutrient foramen.

Nutrient

In a Open (Compound) fracture the broken bone

Protrudes through the skin (higher risk of infection)

Articular cartilage does what?

Reduces friction and absorbs shock at a freely movable joint.

Bone tissue, a complex and dynamic living tissue, continually engages in a process called

Remolding-Construction of new bone tissue and breaking down of old bone tissue.

The breakdown of bone extracellular matrix is, termed______________.

Resorption.

Red bone marrow consist of developing blood cells, adipocytes, fibroblasts, and macrophages within a network of ___________fibers

Reticular

How is spongy bone different from compact? How is it similar?

Spongy is lighter and lacks osteons, trabecula support and project red bone marrow. Similarities: contain osteoblasts, osteocytes, lacunae, and canaliculi

Is bone vascular or avascular?

Vascular

Describe the role of bones of bones in blood cell production?

Within certain bones, a connective tissue called red bone marrow produces red blood cells, white blood cells, and platelets, a process called hemopoiesis.

______________ bone marrow Minimizes weight of bone and reduces dense bony material where it is least needed

Yellow

_______________ bone marrow is found in central cavities of long bones and consists of mostly fat

Yellow

______________bone marrow mainly consist of ______ cells, which store triglycerides. The stored Triglycerides are a potential chemical energy reserve.

Yellow Adipose

Medullary Cavity (hollow space within diaphysis) Contains:

Yellow bone marrow Blood vessels (Adults)

How do "blasts" and "cytes" differ?

-"blast" = immature cells that secrete extracellular matrix - "cytes" = mature cells that maintain and monitor tissue

Ossification is the process of bone formation, this occurs in 4 situations. What are they?

1. During embryological and fetal development 2. Growth before adulthood 3. Bone Remodeling (replacement of old bone by new bone) 4. Repair of fractures

2 Major events in Interstitial growth

1. Interstitial growth of cartilage on epiphyseal side of the epiphyseal plate 2. Endochondral ossification, which is a replacement of cartilage on diaphyseal side of epiphyseal plate with bone.

Periosteum has ____Layers

1. Outer Fibrous Layer Composition: Irregular DWFCT Contains fibroblasts 2. Inner Cambium/Estrogenic Layer Composition: Cells Osteogenic cells = progenitor cells develop into osteoblasts Increase width of long bone Increase overall size of other bone types

What are the 3 healing phases in a bone fracture.

1. Reactive Phase-Early Inflammation 2. Reparative Phase-Formation of fibro cartilaginous & bony callus 3. Bone Remolding Phase- bony callus is remodeled.

What are the 3 benefits of bones remolding?

1. Stronger Bone 2. Proper Support 3. More resistant to fractures.

What are the 6 functions of bone tissue?

1. Support soft tissue and provides attachment to skeletal muscles 2. Protects Internal Organs6. 3.Asissts in movement 4. Stores and Releases Minerals 5. Contains Red Bone Marrow, which produces blood cells 6. Contains Yellow Bone Marrow, which stores triglycerides (fats).

The epiphyseal (growth)plate is a layer of hyaline cartilage in the metaphysis of a growing bone that consist of 4 zones, what re they?

1. Zone of resting cartilage 2. Zone of proliferating cartilage 3. Zone of hypertonic cartilage 4. Zone of calcified cartilage

Bone ceases to grow in length at about what ages

14-24 years of age

Bone tissue makes up about _____% of the weight of the human body.

18%

The epiphyseal plate closes when adolescence comes to an end, at about what ages?

18-Females 21-Males

Renewal rate for spongy bone in adults

20% Per Year

Renewal rate for compact bone in adults

4% Per year

Why is bone tissue classified as a connective tissue?

Bone (osseous tissue) consists of extracellular matrix. 15% water, 30% collagen fibers, and 55% crystalized mineral salts.

Collagen fibers WITHIN concentric lamellae run parallel, while they run in different directions in ADJACENT systems? Why?

Bone Strength

The most abundant mineral salt in bone tissue is

Calcium Phosphate [Ca3(PO4)2].

Bone tissues stores several minerals, especially _______&_______, which contributes to the strength of bones.

Calcium and Phosphorus. Bone tissue stores about 99% of the body's calcium.

A typical long bone consist of which 7 parts?

Diaphysis Epiphyses Metaphyses Articular Cartilage Periosteum Medullary cavity Endosteum

In a long bone the diaphysis is which part of the bone?

Diaphysis (growing between) is the bone's shaft or body--the long, cylindrical, main portion of the bone.

The Articular cartilage is a thin layer of hyaline cartilage covering part of the___________, where the bone forms an articulation (joint) with another bone.

Epiphyses

In a long bone the epiphyses is which part of the bone?

Epiphyses (growing over) are the proximal and distal ends of the bone.

Bone remolding has different rates in different regions of the body: Distal portion of the femur is replaced

Every 4 months.

Define Achondroplasia (AKA dwarfism)

Failure of proliferation and column formation of epiphyseal cartilage cells.

In a _________________ fracture, partial fracture in which one side of the bone is broken ad the other bends. Most common in children.

Greenstick

when long bones lengthen by addition of bone material on the diaphyseal side of the epiphyseal plate.

Interstitial Growth

Ossification takes place in 2 forms, what are they?

Intramembranous Endochondral

Because articular cartilage lacks perichondrium and blood vessels, repair of damage is?

Limited

Which is Red Bone Marrow found in the body?

Medullary Cavities of flat and short bones, articular ends of long bones.

The epiphyseal (growth) plate is layer of hyaline cartilage, located in which region in a growing bone?

Metaphyses (Between), regions between the diaphysis and the epiphyses.

What are the functions of spongy bone?

Orientated along lines of stress or where stress applied from multiple directions. Helps bones resist stresses. Transfers force without breaking bone. Form as infant begins to walk

Bone-Building cells that do not go under cell division, forms bone extracellular matrix, initiate calcification.

Osteoblasts

Calcification is initiated by bone-building cells called

Osteoblasts.

large, motile, multinucleated bone-resorbing cells Derived from fusion 50+ monocytes (WBC) Found in endosteum Cell face that contacts bone surface has ruffled border Serve to break down tissue

Osteoclast

Mature bone cells (main cell in bones) Maintains bone tissue, do not undergo cell division, maintains daily metabolism.

Osteocyte

Four types of cells that are present in bone tissue.

Osteogenic cells, Osteoblasts, Osteocytes, and Osteoclasts.

The study of bone structures and the treatment of bone disorders is called

Osteology

Mesenchymal stem cells, found in bone marrow of bones, only bone cells that undergo cell division, develop into osteoblast.

Osteoprogenitor cells

Endosteum contains

Osteoprogenitor cells Osteoblasts = bone building cells Osteoclasts = breakdown bone Small amount connective tissue, clasts carve out bone.

What examples are bone scans used for?

P has unexplained skeletal pains, cancer detections.

What are the 2 hormones that aid in the body's calcium homeostasis and where do they secrete from?

Parathyroid Hormone (PTH) secreted by parathyroid gland. Calcitonin (CT) Secreted by thyroid

______________ arteries, small arteries accompanied by nerves, enter the diaphysis through many perforating (Volkmann's) canals and supply the periosteum and outer part of compact bone.

Periosteal

The Skeletal system contains 4 types arteries in bones.... what are they?

Periosteal Arteries Nutrient Arteries Metaphyseal Arteries Epiphyseal Arteries

What are sharpey's fibers?

Thick bundles of collagen fibers that extend from periosteum into bone extracellular matrix Attaches periosteum to bone

What is periosteum?

Tough CT sheath, blood supply that surrounds bone surface that is not covered by articular cartilage.

How are trabeculae different from osteons?

Trabecula are more organized, precisely oriented along lines if stress.

Bone DIFFERS from other CT because matrix is

calcified (calcification)