A&P Chapter 6 - Bones & Skeletal Tissues

2 Ways cartilage can grow

Appositional growth (new matrix secreted on the external face of existing cartilage), and Interstitial growth (lacunae-bound chondrocytes divide and secrete new matrix, expanding cartilage from within)

What is the functional relationship between skeletal muscles and bones?

Skeletal muscles use bones as levers to cause movement of the body and its parts.

avascular

without blood vessels

trabeculae

"little beams"....honeycomb of small needle-like or flat pieces; Any of the fibrous bands extending from the capsule into the interior of an organ; (2) strut or thin plate of bone in spongy bone. (also see the term, capsule, involving this) In living bones the open spaces between ____________________are filled with red or yellow bone marrow. each of a series or group of partitions formed by bands or columns of connective tissue, especially a plate of the calcareous (mostly or partly composed of calcium carbonate; in other words, containing lime or being chalky) tissue forming cancellous bone.

resorption

Bone ____________________is __________________of bone tissue, that is, the process by which osteoclasts break down the tissue in bones and release the minerals, resulting in a transfer of calcium from bone tissue to the blood. The osteoclasts are multi-nucleated cells that contain numerous mitochondria and lysosomes.

Chemical Composition of Bone

Bone contains both organic and inorganic substances. Organic components include bone cells and osteoid. Its inorganic components are mineral salts. When organic and inorganic components are present in the right proportions, bone is extremely strong and durable without being brittle.

Are crests, tubercles, and spines bony projections or depressions?

Crests, tubercles, and spines are bony projections.

periosteum (peri = around, osteo = bone)

Double-layered connective tissue that covers and nourishes the bone. covers the external surface of the entire bone except the joint surfaces. The outer fibrous layer of the periosteum is dense irregular connective tissue. The inner osteogenic layer, next to the bone surface, consists primarily of primitive stem cells, osteogenic cells, that give rise to all bone cells except bone-destroying cells. It is richly supplied with nerve fibers and blood vessels, which pass through the shaft to enter the marrow cavity via a nutrient foramen

spongy bone

Internal layer of skeletal bone. Also called cancellous bone. also known as cancellous bone or trabecular bone, is a very porous type of bone found in animals. It is highly vascularized and contains red bone marrow. _______________ bone is usually located at the ends of the long bones (the epiphyses), with the harder compact bone surrounding it.

Interstitial Lamellae

Not all the lamellae in compact bone are part of complete osteons. Lying between intact osteons are incomplete lamellae called _________________. They either fill the gaps between forming osteons or are remnants of osteons that have been cut through by bone remodeling (discussed later).

osteogenic cell

Stem cell; undergoes mitosis: 1 remains stem, 1 gets specified. relating to the formation of bone.

True or False: The gross structure of ALL bones consists of compact bone sandwiching spongy bone

True

Projections

bone markings that bulge outward from the surface—include heads, trochanters, spines, and others. Each has distinguishing features and functions. In most cases, bone projections indicate the stresses created by muscles attached to and pulling on them or are modified surfaces where bones meet and form joints.

Elastic Cartilage

cartilage with abundant elastic fibers; more flexible than hyaline cartilage ______________________ or yellow cartilage is a type of cartilage present in the outer ear, Eustachian tube and epiglottis. It contains elastic fiber networks and collagen type II fibers. The principal protein is elastin.

typical flat bone arrangement

compact bone-spongy bone-compact bone, which resembles a stiffened sandwich

Foramen

hole or opening in bone or between body cavities

cartilage

firm, whitish, flexible connective tissue found in various forms in the larynx and respiratory tract, in structures such as the external ear, and in the articulating surfaces of joints. It is more widespread in the infant skeleton, being replaced by bone during growth.

cartilage

firm, whitish, flexible connective tissue found in various forms in the larynx and respiratory tract, in structures such as the external ear, and in the articulating surfaces of joints. It is more widespread in the infant skeleton, being replaced by bone during growth. "his knees failed and the cartilages were removed"

metaphysis (meta = between)

flared portion of the bone where the diaphysis and epiphysis meet, whether it is the epiphyseal plate or line

Bone lining cells

flat cells found on bone surfaces where bone remodeling is not going on. Like osteocytes, they are thought to help maintain the matrix. __________________________ on the external bone surface are also called periosteal cells, and those lining internal surfaces are called endosteal cells.

red bone marrow

found mainly in the flat bones such as hip bone, breast bone, skull, ribs, vertebrae and shoulder blades, and in the cancellous ("spongy") material at the proximal ends of the long bones femur and humerus. Pink Marrow is found in the hollow interior of the middle portion of long bones.

epiphyseal line

found on the long bones where the epiphyseal plate use to be. Between the diaphysis and each epiphysis of an adult long bone; a disc of hyaline cartilage that grows during childhood to lengthen the bone.

Where short, irregular and flat bones form movable joints with their neighbors, this covers their surfaces

hyaline cartilage

Yellow bone marrow

involved in the storage of fats. The fats in ________________________ are stored in cells called adipocytes. This fat can be used as an energy source as needed. __________________________ marrow also contains mesenchymal stem cells. These are cells that can develop into bone, fat, cartilage, or muscle cells.

Epiphysis/Epiphyses

the bone ends (epi = upon). In many cases, they are broader than the diaphysis. An outer shell of compact bone forms the ___________________exterior and the interior contains spongy bone. A thin layer of articular (hyaline) cartilage covers the joint surface of each epiphysis, cushioning the opposing bone ends during movement and absorbing stress.

synovial membrane

the connective tissue membrane that lines the cavity of a synovial joint and produces the synovial fluid; it lines all internal surfaces of the cavity except for the articular cartilage of the bones.

epiphysis

the end part of a long bone, initially growing separately from the shaft.

hematopoiesis=hemapoeisis

the production of blood cells and platelets, which occurs in the bone marrow. Origin

How does the structure of compact bone differ from that of spongy bone when viewed with the naked eye?

Compact bone looks fairly solid and homogeneous whereas spongy bone has an open network of bone trabeculae.

depressions and openings

Bone markings that include fossae (singular: fossa), sinuses, foramina (singular: foramen), and grooves. They usually allow nerves and blood vessels to pass.

List at least 2 types of substances stored in bone and state where each is stored.

Bone matrix stores minerals (Ca and Phosphate) and growth factors. Bone marrow cavities serve as sites for triglyceride (fat) storage (and blood cell formation!).

Which component of bone—organic or inorganic—makes it hard?

Bone's inorganic component (bone salts) makes it hard.

Canals

Running through the core of each osteon is the central ___________, or Haversian _____________, containing small blood vessels and nerve fibers that serve the osteon's cells. ______________of a second type called perforating ______________, or Volkmann's ______________(folk′mahnz), lie at right angles to the long axis of the bone and connect the blood and nerve supply of the medullary cavity to the central ______________(Figure 6.7a). Unlike the central ______________of osteons, the perforating _____________are not surrounded by concentric lamellae, but like all other internal bone cavities, these _______________are lined with endosteum.

irregular bone

The spine is the place in the human body where the most of these bones can be found. There are, in all, 33 of these bones found here. These bones are: the vertebrae, sacrum, coccyx, temporal, sphenoid, ethmoid, zygomatic, maxilla, mandible, palatine, inferior nasal concha, and hyoid.

Circumferential lamellae

located just deep to the periosteum and just superficial to the endosteum, extend around the entire circumference of the diaphysis (Figure 6.7a) and effectively resist twisting of the long bone.

osteogenic layer

"The periosteum consists of dense irregular connective tissue. It is divided into an outer "fibrous layer" and inner "cambium layer" (or "_____________________"). The fibrous layer contains fibroblasts, while the cambium layer contains progenitor cells that develop into osteoblasts."

medullary cavity

(innermost part) is the central cavity of bone shafts where red bone marrow and/or yellow bone marrow (adipose tissue) is stored; hence, the _____________________ is also known as the marrow cavity. A thick collar of compact bone surrounds it.

ossification

(or osteogenesis) in bone remodeling is the process of laying down new bone material by cells called osteoblasts. It is synonymous with bone tissue formation. * Natural process of bone formation * The hardening (as of muscular tissue) into a bony substance * The simplest type arise from mesenchyme

canaliculi

small channels or ducts microscopic canals between the lacunae of ossified bone. The radiating processes of the osteocytes (called filopodia) project into these canals. These cytoplasmic processes are joined together by gap junctions. Osteocytes do not entirely fill them up.

osteogenesis

the formation of bone; the development of the bones. ________________________ imperfec´ta is an inherited condition marked by abnormally brittle bones that are subject to fracture.

periosteum

A dense membrane composed of fibrous connective tissue that closely wraps all bone except that of the articulating surfaces in joints, which is covered by a synovial membrane.

Ossification Centers

A primary _______________________ is the first area of a bone to start ossifying. It usually appears during prenatal development in the central part of each developing bone. In long bones the primary centers occur in the diaphysis/shaft and in irregular bones the primary centers occur usually in the body of the bone.

Woven bone

Bony tissue characteristic of the embryonic skeleton in which the collagen fibers of the matrix are arranged irregularly in the form of interlacing networks. e.g. Intramembranous Ossification: After ossification centers appear in the fibrous CT membrane, bone matrix (osteoid) is secreted within the fibrous membrane and calcifies. ______________________________ and periosteum form: * Accumulating osteoid is laid down between embryonic blood vessels in a random manner. The result is a network (instead of lamellae) of trabeculae called ______________________). * Vascularized mesenchyme condenses on the external face of the woven bone and becomes the periosteum. Then lamellar bone replaces woven bone, just deep to the periosteum. Red marrow appears.

chondroblasts vs chondrocytes

Chondroblasts are a type of immature cells whereas chondrocytes are a type of mature cells. Chondroblasts secrete the extracellular matrix of the cartilage whereas chondrocytes are involved in the maintenance of the cartilage.

Which membrane lines the internal canals and covers the trabeculae of a bone?

Endosteum lines the internal canals and covers the trabeculae.

canaliculi

Spider-shaped osteocytes occupy lacunae (lac = hollow; una = little) at the junctions of the lamellae. Hairlike canals called ________________________ connect the lacunae to each other and to the central canal. The manner in which __________________are formed is interesting. When bone is forming, the osteoblasts secreting bone matrix surround blood vessels and maintain contact with one another and local osteocytes by tentacle-like projections containing gap junctions. Then, as the newly secreted matrix hardens and the maturing cells become trapped within it, a system of tiny canals—the _________________________filled with tissue fluid and containing the osteocyte extensions—is formed. The ______________________tie all the osteocytes in a mature osteon together, allowing them to communicate and permitting nutrients and wastes to be relayed from one osteocyte to the next throughout the osteon. Although bone matrix is hard and impermeable to nutrients, its ________________________and gap junctions allow bone cells to be well nourished.Hairlike canals that connect lacunae to each other and the central canal

Spongy Bone

In contrast to compact bone, ___________________bone looks like a poorly organized, even haphazard, tissue (see Figure 6.4b and Figure 6.3). However, the trabeculae in ____________________bone align precisely along lines of stress and help the bone resist stress. These tiny bone struts are as carefully positioned as the cables on a suspension bridge. Only a few cells thick, trabeculae contain irregularly arranged lamellae and osteocytes interconnected by canaliculi. No osteons are present. Nutrients reach the osteocytes of _______________bone by diffusing through the canaliculi from capillaries in the endosteum surrounding the trabeculae.

osteoid

In histology, __________________is the unmineralized, organic portion of the bone matrix that forms prior to the maturation of bone tissue. Osteoblasts begin the process of forming bone tissue by secreting the osteoid as several specific proteins. e.g. Intramembranous Ossification: Bone matrix (osteoid) is secreted within the fibrous membrane and calcifies. Osteoblasts begin to secrete osteoid which is calcified within a few days.

intramembranous ossification vs endochondral ossification

In intramembranous ossification, bone develops directly from sheets of mesenchymal connective tissue. In endochondral ossification, bone develops by replacing hyaline cartilage. Activity in the epiphyseal plate enables bones to grow in length. Modeling allows bones to grow in diameter.

compact bone

also known as cortical bone, is a denser material used to create much of the hard structure of the skeleton. Although it looks solid, a microscope reveals that it is riddled with passageways that serve as conduits for nerves and blood vessels. (Remember the concentric rings of hard matrix that allowed you to identify bone tissue) _______________________ forms the cortex, or hard outer shell of most bones in the body. The remainder of the bone is formed by cancellous or spongy bone. __________________________(or cortical bone), forming the hard external layer of all bones, surrounds the medullary cavity (innermost part or bone marrow). It provides protection and strength to bones. _____________________________ tissue consists of units called osteons or Haversian systems.

cancellous bone

also known as spongy or trabecular bone, is one of the two types of bone tissue found in the human body. _______________________bone is found at the ends of long bones, as well as in the pelvic bones, ribs, skull, and the vertebrae in the spinal column.

short bone

as wide as they are long. Their primary function is to provide support and stability with little to no movement. They are one of five types of bones: short, long, flat, irregular and sesamoid.

Intramembranous ossification

bone develops directly from sheets of mesenchymal connective tissue.

Osteoblasts

bone-forming cells that secrete the bone matrix. Like their close relatives, the fibroblasts and chondroblasts, they are actively mitotic. The unmineralized bone matrix they secrete includes collagen (90% of bone protein) and calcium-binding proteins that make up the initial unmineralized bone, or osteoid. As described later, ______________________also play a role in matrix calcification. When actively depositing matrix, ______________________ are cube shaped. When inactive, they resemble the flattened osteogenic cells or may differentiate into bone lining cells. When the _______________________become completely surrounded by the matrix being secreted, they become osteocytes.

flat bone

bones whose principal function is either extensive protection or the provision of broad surfaces for muscular attachment. These bones are expanded into broad, flat plates, as in the cranium (skull), the ilium (pelvis), sternum and the rib cage.

Organic compounds - Sacrificial Bonds

bones' resilience is thought to come from sacrificial bonds in or between: collagen molecules. These bonds stretch and break easily on impact, dissipating energy to prevent the force from rising to a fracture value. In the absence of continued or additional trauma, most of the sacrificial bonds re-form.

intramembranous ossification

The direct conversion of mesenchymal tissue into bone. occurs primarily in the bones of the skull. In other cases, the mesenchymal cells differentiate into cartilage, and this cartilage is later replaced by bone.

Contrast the general function of the axial skeleton to that of the appendicular skeleton.

The major function of the axial skeleton is to establish the long axis of the body and to protect structures that it encloses. The general function of the appendicular skeleton is to allow us mobility for propulsion and manipulation of our environment.

Endochondral ossification

The process of bone development from hyaline cartilage. The periosteum is the connective tissue on the outside of bone that acts as the interface between bone, blood vessels, tendons, and ligaments. bone develops by replacing hyaline cartilage. Activity in the epiphyseal plate enables bones to grow in length. Modeling allows bones to grow in diameter. ______________________________________________is one of the two essential processes during fetal development of the mammalian skeletal system by which bone tissue is created. Unlike intramembranous ossification, which is the other process by which bone tissue is created, CARTILAGE is present during endochondral ossification. https://courses.lumenlearning.com/wm-biology2/chapter/bone-growth-and-development/

What bone class do the ribs and skull bones fall into?

The ribs and skull bones are flat bones.

Osteon (Haversian System)

The structural unit of compact bone is called either the __________________, or ________________ _________________. Each ________________is an elongated cylinder oriented parallel to the long axis of the bone. Functionally, osteons are tiny weight-bearing pillars. a group of hollow tubes of bone matrix, one placed outside the next like the growth rings of a tree trunk. Each matrix tube is a lamella (lah-mel′ah; "little plate"), and for this reason compact bone is often called lamellar bone. Although all of the collagen fibers in a particular lamella run in a single direction, the collagen fibers in adjacent lamellae always run in different directions. This alternating pattern is beautifully designed to withstand torsion stresses—the adjacent lamellae reinforce one another to resist twisting. You can think of the _________________'s design as a "twister resister." Collagen fibers are not the only part of bone lamellae that are beautifully ordered. The tiny crystals of bone salts align between the collagen fibers and thus also alternate their direction in adjacent lamellae.

True or False: Bones are organs.

True. Because they contain different types of tissue, bones are organs Although bone (osseous) tissue dominates bones, they also contain nervous tissue in their nerves, cartilage in their articular cartilages, dense connective tissue covering their external surface, and muscle and epithelial tissues in their blood vessels.

lamellar vs woven

Woven bone can be found in the embryonic skeleton and in cortical and cancellous bone in states of rapid bone growth, bone replacement, or high bone turnover. It is replaced in the normal skeleton by lamellar bone after completion of growth.

lamellar bone

Woven bone, (also known as fibrous bone) which is characterized by a haphazard organization of collagen fibers and is mechanically weak. _____________________bone, which has a regular parallel alignment of collagen into sheets and is mechanically strong. "Woven bone can be found in the embryonic skeleton and in cortical and cancellous bone in states of rapid bone growth, bone replacement, or high bone turnover. It is replaced in the normal skeleton by ________________________bone after completion of growth."

osteocyte

a bone cell, formed when an osteoblast becomes embedded in the matrix it has secreted. Mature bone cell that maintains the bone matrix. Some are completely incased in bone. They send out projections in the caniculea. The MONITOR STRESS like when the person "works out", and say "osteoclasts and osteoblasts need to come here". They monitor BONE HEALTH. They line bone surfaces in areas bone remodeling is NOT occurring.

sesamoid bone

a bone embedded in a tendon. Sesamoids are found in several joints in the body. In the normal foot, the ________________s are two pea-shaped bones located in the ball of the foot, beneath the big toe joint.

lacuna

a cavity or depression, especially in bone. a small cavity within the bone matrix, containing an osteocyte, and from which slender canaliculi radiate and penetrate the adjacent lamellae to anastomose with the canaliculi of neighboring lacunae, thus forming a system of cavities interconnected by minute canals.

fibroblasts

a cell in connective tissue which produces collagen and other fibers.

osteoblast

a cell that secretes the matrix for bone formation. Matrix-synthesizing cell responsible for bone growth. Bone Builders. cells with a single nucleus that synthesize bone. However, in the process of bone formation, ______________________function in groups of connected cells. Individual cells cannot make bone.

chondrocyte

a cell which has secreted the matrix of cartilage and become embedded in it.

synovial joint

a connection between two bones consisting of a cartilage lined cavity filled with fluid, which is known as a diarthrosis joint. Diarthrosis joints are the most flexible type of joint between bones, because the bones are not physically connected and can move more freely in relation to each other.

anastomosis

a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. a connection made surgically between adjacent blood vessels, parts of the intestine, or other channels of the body, or the operation in which this is constructed. "The lacuna is a small cavity within the bone matrix, containing an osteocyte, and from which slender canaliculi radiate and penetrate the adjacent lamellae to anastomose with the canaliculi of neighboring lacunae, thus forming a system of cavities interconnected by minute canals."

osteoclast

a large multinucleate bone cell which absorbs bone tissue during growth and healing. Arose from bone marrow. Specialized WBC's. Specialized macrophages, so arise from monocytes in bone marrow, travel via cardiovascular system to the bone area. Bone destroyers. (The oseoblasts follow behind and put down new bone matrix.) Why multiple nuclei? The function of ________________is to digest the calcified bone matrix. ... Finally, our data indicate that the resorption pit surface is linearly related to the nuclei number per _____________, strongly suggesting that functional advantage of _______________________multinucleation is to improve resorption efficiency. oseo (bone) + klastes (breaker)

bone remodeling

a lifelong process where mature bone tissue is removed from the skeleton (a process called bone resorption) and new bone tissue is formed (a process called ossification or new bone formation).

mesenchyme

a loosely organized, mainly mesodermal embryonic tissue which develops into connective and skeletal tissues, including blood and lymph.

The 5 Bone shapes

long (humerus), short (talus), flat (sternum), or irregular (vertebrae), and sesamoid ("shaped like a sesame seed") they form and are embedded in a tendon like the 2 pea shaped bones in the ball of the foot, beneath the big toe joint)

Long bone

longer than they are wide. The end is the epiphysis and the shaft is the diaphysis.

Osteocytes

mature bone cells that occupy spaces (lacunae) that conform to their shape. ________________________monitor and maintain the bone matrix. If they die, the surrounding matrix is resorbed. ____________________________also act as stress or strain "sensors" and respond to mechanical stimuli (bone loading, bone deformation, weightlessness). They communicate this information to the cells responsible for bone remodeling (osteoblasts and osteoclasts) so that bone matrix can be made or degraded as necessary to preserve calcium homeostasis.

Osteogenic Cells

mitotically active stem cells found in the membranous periosteum and endosteum. In growing bones they are flattened or squamous cells. When stimulated, these cells differentiate into osteoblasts or bone lining cells (see below), while others persist as _______________________cells.

Organic Components of the cell

organic components of bone include its cells (osteogenic cells, osteoblasts, osteocytes, bone-lining cells, and osteoclasts) and osteoid, the organic part of the matrix.

5 major cell types that populate bone tissue

osteogenic cells, osteoblasts, osteocytes, bone lining cells, and osteoclasts All of these except for the osteoclasts originate from embryonic connective tissue cells

Bone markings

projections, depressions, and openings; sites of muscle, ligament, and tendon attachment, as joint surfaces, or as conduits for blood vessels and nerves

Joint Capsule

resembles a sac-like envelope that forms a sleeve around the synovial joint and encloses its cavity. The joint capsule is a dense fibrous connective tissue that is attached to the bones via specialized attachment zones at the end of each involved bone. (see the term, Trabecula, which involves this)

5 types of bone

short, long, flat, irregular and sesamoid.

axial skeleton components

skull, the vertebral column, and the rib cage

diploe

spongy bone; the spongy cancellous bone separating the inner and outer layers of the cortical bone of the skull.

Osteoclasts

stem cells that differentiate into macrophages, osteoclasts (Figure 6.5d) are giant multinucleate cells located at sites of bone resorption. When actively resorbing (breaking down) bone, the _______________________rest in a shallow depression called a resorption bay and exhibit a distinctive ruffled border that directly contacts the bone. The deep plasma membrane infoldings of the ruffled border tremendously increase the surface area for enzymatically degrading the bones and seal off that area from the surrounding matrix.

perichondrium

the connective tissue that envelops cartilage where it is not at a joint. peri (around) + khondros (cartilage)

bone matrix

the intercellular substance of bone, consisting of collagenous fibers, ground substance, and inorganic salts. Bones consist of living cells embedded in a mineralized organic matrix. This matrix consists of organic components, mainly type I collagen - "organic" referring to materials produced as a result of the human body - and inorganic components, primarily hydroxyapatite and other salts of calcium and phosphate.

Organic component - osteoid

the organic part of the matrix. __________________, which makes up approximately one-third of the matrix, includes ground substance (composed of proteoglycans and glycoproteins) and collagen fibers, both of which are secreted by osteoblasts. These organic substances, particularly collagen, contribute both to a bone's structure and to the flexibility and tensile strength that allow it to resist stretch and twisting.

Perforating (Sharpey's) fibers

tufts of collagen fibers that extend from its fibrous layer into the bone matrix—secure the periosteum to the underlying bone (bone fibres, or perforating fibres) are a matrix of connective tissue consisting of bundles of strong predominantly type I collagen fibres connecting periosteum to bone. ... Each fibre is accompanied by an arteriole and one or more nerve fibres. Bundles of collagenous fibers that pass into the outer circumferential lamellae of bone, alveolar bone proper of the alveolus of teeth, or the cementum of teeth.

osteogenic cell

undifferentiated with high mitotic activity; they are the only bone cells that divide. Immature _________________________ are found in the deep layers of the periosteum and the marrow. When they differentiate, they develop into osteoblasts. These cells differentiate and develop into osteoblasts which, in turn, are responsible for forming new bones. Osteoblasts synthesize and secrete a collagen matrix and calcium salts.

Hydroxyapatites

INorganic portion of bone (65% by mass) consists of inorganic ____________________________________, or mineral salts, largely calcium phosphates present as tiny, tightly packed, needle-like crystals in and around collagen fibers in the extracellular matrix. The crystals account for the most notable characteristic of bone—its exceptional hardness, which allows it to resist compression. Healthy bone is half as strong as steel in resisting compression and fully as strong as steel in resisting tension. Because of the mineral salts they contain, bones last long after death and provide an enduring "monument." In fact, skeletal remains many centuries old reveal the shapes and sizes of ancient peoples, the kinds of work they did, and many of the ailments they suffered, such as arthritis.

Which cell has a ruffled border and acts to break down bone matrix? From your knowledge of organelles (Chapter 3), state which organelle would be the likely source of the enzymes that can digest bone matrix.

The osteoclast fits this description. The lysosomes would contain the matrix-digesting enzymes.

Formation of the Bony Skeleton: The 5 Stages of Endochondral Ossification

1. Bone collar forms around hyaline cartilage model. 2. Cartilage in the center of the diaphysis calcifies and then develops cavities. 3. The periosteal bud invades the internal cavities and spongy bone begins to form. 4. The diaphysis elongates and a medullary cavity forms as ossification continues. Secondary ossification centers appear in the epiphyses in preparation for stage 5. 5. The epiphyses ossify. When completed, hyaline cartilage remains only in the epiphyseal plates and articular cartilages.

What are the 7 functions bones perform?

1. Support a. Lower limbs act as pillars to support the body trunk when we stand. b. Rib cage supports the thoracic wall. 2. Protection a. the fused bones of the skull protect the brain b. the vertebrae protect the spinal cord 3. Anchorage a. skeletal muscles, which attach to bones by tendons, use bones as levers to move the body and its parts b. As a result we can walk, grasp objects and breathe 4. Mineral Storage a. Ca & Phosphate b. Released into the bloodstream in their ionic form as needed. Withdrawals and deposits going on continually. 5. Blood Cell Formation (hematopoiesis) * Most occurs in the red marrow of certain bones 6. Tryglyceride (fat) Storage a. Source of energy for the body b. Most stored as yellow marrow in long bones 7. Hormone Production a. Bones produce osteocalcin, a hormone that helps to regulate insulin secretion, glucose homeostasis, and energy expenditure.

Diaphysis

A tubular ___________________, or shaft, forms the long axis of the bone. It is constructed of a relatively thick collar of compact bone that surrounds a central medullary cavity (med′u-lar-e; "middle"), or marrow cavity. In adults, the medullary cavity contains fat (yellow marrow) and is called the yellow marrow cavity. (dia = through, physis = growth)

Hyaline Cartilage

The most abundant cartilage type in the body; provides firm support with some pliability. ________________ is the glass-like (hyaline) but translucent cartilage found on * many joint surfaces *ribs, nose, larynx, and trachea. _______________________ is pearl-grey in color, with a firm consistency and has a considerable amount of collagen. Formation of the bony skeleton - - Endochondral ossification: Bone collar forms around _______________________________model.

Fibrocartilage

The most compressible type of cartilage; resistant to stretch. Forms vertebral discs and knee joint cartilages. cartilage that contains fibrous bundles of collagen (such as that of the intervertebral disks in the spinal cord) _________________is the tough, very strong tissue found predominantly in the intervertebral disks and at the insertions of ligaments and tendons; it is similar to other fibrous tissues but contains cartilage ground substance and chondrocytes.

Long Bone - typical structure

a shaft, bone ends, and membranes

endostium (pl. endostea)

a thin vascular membrane of connective tissue that lines the inner surface of the bony tissue that forms the medullary cavity of long bones. This surface is usually resorbed during long periods of malnutrition, resulting in less cortical thickness. a thin, soft, connective tissue, lining the cavity of long bones like Humerus and Femur. It acts as a coating for the inner compact bone and the trabeculae of the spongy tissue.

Hematopoietic Tissue

aka red marrow, is typically found within the trabecular cavities of spongy bone of long bones and in the diploë of flat bones. For this reason, both these cavities are often called red marrow cavities. In newborn infants, the medullary cavity of the diaphysis and all areas of spongy bone contain red bone marrow. In most adult long bones, the fat-containing yellow marrow extends well into the epiphysis, and little red marrow is present in the spongy bone cavities. For this reason, blood cell production in adult long bones routinely occurs only in the heads of the femur and humerus NOTE! red marrow found in the diploë of flat bones (such as the sternum) and in some irregular bones (such as the hip bone) is much more active in hematopoiesis. When clinicians suspect problems with the blood-forming tissue, they obtain red marrow samples from these sites. However, yellow marrow in the medullary cavity can revert to red marrow if a person becomes very anemic and needs more red blood cells.

diaphysis (dia = through, physis = growth)

the shaft/long axis or central part of a long bone. relatively thick collar of compact bone that surrounds a central medullary cavity (med′u-lar-e; "middle"), or marrow cavity. In adults, the medullary cavity contains fat (yellow marrow) and is called the yellow marrow cavity.

articular cartilage

the smooth, white tissue that covers the ends of bones where they come together to form joints. Healthy cartilage in our joints makes it easier to move. It allows the bones to glide over each other with very little friction. __________________________________can be damaged by injury or normal wear and tear.