Ch 6: THE SKELETAL SYSTEM: Bone Tissue
Red Bone Marrow
Produces red blood cells, white blood cells, and platelets in a process called Hemopoiesis
Tensile Strength
Provided by collagen fibers and other organic molecules. Resistance to being stretched or torn apart.
Spongy Bone
Short, flat, and irregular bones and the interior of the epiphyses in long bones
Support
Skeletal Structural Framework: supports soft tissues, provide attachment points for the tendons of most skeletal muscles
Protection
Skeletal function that protects most important internal organs from injury
The ending -clasts
in a bone cell means that the cell breaks down extracellular matrices
Medullary Cavity /Marrow Cavity
A hollow, cylindrical space within the diaphysis that contains fatty yellow bone marrow in adults
Periosteal Arteries
Accompanied by nerves enter the diaphysis through many perforating (Volkmann's) canals. Supply the periosteum and outer parts of the compact bone.
Metaphyseal and Epihyseal Arteries
BOTH supply the ends of long bones, which arise from arteries that supply the associated joint
Metaphyses of a long bone and Nutrient Artery
BOTH supply the red bone marrow and bone tissue of the metaphyses.
Osteoclasts
Bone-destroying cells that contain lysosomes and phagocytic vacuoles that demineralize bone tissue. Help regulate blood calcium level. Target cells for drug therapy to treat osteoporosis. Ruffled border.
Bone Tissue
Bone (Osseous tissue), Cartilage, dense connective tissues, epithelium, adipose tissue, and nervous tissue. Makes up 18% of weight of the human body.
Calcium & Phosphorus (Minerals)
Bone Tissue mineral storage: calcium & phosphorus (strengthens bones), Stores 99% of the body's calcium
Two types of Bone Tissue
Compact Bone Tissue and Spongy Bone tissue
Skeletal System
Composed of Bones and their cartilages, ligaments and tendons
Yellow Bone Marrow
Consists mainly of adipose cells, which store triglycerides.
Lacunae
Contain osteocytes. Small spaces between lamellae.
Bone Flexibility
Depends on its collagen fibers.
Spongy Bone Tissue
Does not contain osteons, Consists of lamellae trabeculae surrounding many red bone marrow-filled spaces.
Epiphyseal Arteries
Enter the Epiphyses of long bone and supply the red bone marrow and bone tissue of the epiphyses
Metaphyseal Arteries
Enter the metaphyses of a long bone
Intramembranous (dermal) Ossification
Forming directly as a bone. (Facial bones, most cranial bones, and the clavicle)
Bone Tissue Functions
Homeostatic Contributions: Provide Support, Protection, Production of blood cells, Storage of Minerals and Triglycerides
Endosteum
Is a thin membrane that lines the internal bone surface facing the medullary cavity. Contains a single layer of cells and a small amount of connective tissue.
Blood Supply of Bone
Long bones are supplied by periosteal, nutrient, metaphyseal, and epiphyseal arteries; veins accompany the arteries.
Long Bones
Longer than they are wide, Act as levers and shock absorbers, mostly compact bone with spongy bone at the ends.
Spongy Bone tissue Trabeculae
Offer resistance along lines of stress, support and protect red bone marrow, and make bones lighter for easier movement
Mineral Storage and Release
On demand, bone releases minerals in to the blood to maintain critical mineral balances (homeostasis) and distribute the minerals to other parts of the body
Endochrondral Osssification
Ossification from primary centers occurs before birth; from secondary centers in the epiphyses, it occurs during the first 5 years.
Circumferential Lamellae
Rings of hard calcified matrix found just beneath the periosteum and in the medullary cavity
Central or Haversian Canals
Run longitudinally through the bone
Compact Bone
Strongest form of one tissue. Provide protection and support and resists the stresses produced by weight and movement. Found beneath the periosteum of all bones and make up the bulk of the diaphyses of long bones
Periosteum
Surrounds the external bone surface wherever it is not covered by articular cartilage. Protects the bone, assists in fracture repair, helps nourish bone tissue, and serves as an attachment point for ligaments and tendons
Diaphysis
The bone's shaft or body (Long, cylindrical, main portion of the bone) Contains the Medullary (Marrow) Cavity
Remodeling
The construction of new bone tissue and breaking down of old bone tissue.
Osteogenic Cells
Unspecialized stem cells derived from mesenchyme. Found along the inner portion of the periosteum, in the endosteum, and in the canals within the bone that contain blood vessels. The only bone cells that goes through cell division. Give rise to all bone cells
Epiphyseal Line
When the bone ceases to grow in length (ages 18-24), this is the replacement of the Epiphyseal Plate. Boney structure.
Blood cell production
Red bone marrow consist of developing blood cells, adipocytes, fibroblasts, and macrophages within a network of reticular fibers.
Assistance in Movement
Skeletal muscles attach to bones; upon muscle contraction they pull on bones to produce movement
Haversian Systems
perforating canals: allow blood vessels and nerves into bone tissue; Cicumferential Lamellae : layers of bone next to periosteum and endosteum
Endochrondral Ossification
Bone development first through a cartilaginous stage. Begins in a primary center in the shaft of the cartilage model with hypertrophy of chondrocytes (cartilage cells) and calcification of the cartilage matrix. The cartilage model is then vascularized, osteogenic cells form a bony collar around the mode, and osteoblasts lay down bony matrix around the calcareous spicules. The formation of most bones
Ossification
Bone formation develops by either ENDOCHRONDRAL ossification or INTRAMEMBRANOUS (dermal) ossification begins during the fourth week of prenatal development.
Osteoblasts
Bone-building cells, Synthesize and secrete collagen fibers and other organic components needed to build the extracellular matrix of bone tissue, initiates calcification, surrounds themselves within their own extracellular matrix, become osteocytes.
Periosteum Composition
Outer fibrous layer of dense irregular connective tissue Inner osteogenic layer consists of cells (Some cells enable bone growth in thickness, but not in length)
Resorption
Part of normal development, maintenance, and repair of bone
Triglyceride storage
Potential chemical energy reserve. With increasing age, much of the red bone marrow turn yellow
Types of Cells present in Bone Tissue
Osteogenic Cells, Osteoblasts, Osteocytes, and Osteoclasts
Components of Compact Bone
Osteons/ Haversian systems: Repeating structural unitis
Osteons
(resembles a stack of logs) Consists of a central (haversian) canal, with arranged lamellae, lacunae, osteocytes, and canaliculi. they are aligned in the same direction along lines of stress which helps the long bone resist bending or fracture. Changes over time in response to the physical demands placed on the skeleton
Extracellular Matrix of Bone Tissue
25% water, 25% collagen fibers, and 50% crystallized mineral salts.
Epiphyseal Growth Plate
A layer of hyaline cartilage that allows the diaphysis of the bone to grow in length.
Perforating or Volkmann's Canals
Allows blood vessels, lymphatic vessels, and nerves from the periosteum to penetrate compact bones
Nutrient Foreman
An opening in the shaft of the bone allowing an artery to pass into the one
Interstitial Lamellae
Area between osteons. Fragments of older osteons that have been partially destroyed during bone rebuilding or growth
Concentric lamellae
Around the central canals are rings of calcified extracellular matrix much like the rings of a tree trunk
Bone (Osseous) Tissue
Contains an abundant extracellular matrix that surounds widely separated cells.
Bone Hardness
Depends on the crystallized inorganic mineral salts.
Red Bone Marrow Locations
Developing fetus. Adult bones: hip bones, ribs, breastbone, vertebrae, skull, ends of bones of the arm and thigh.
Parts of a Long Bone
Diaphysis, Epiphyses, Metaphyses, Articular Cartilage, Periosteum, Medullary Cavity, Endosteum
Osteocytes
Mature bone cells, the main cells in bone tissue and MAINTAIN its daily metabolism such as the exchange of nutrients and wastes with blood
Nutrient Artery
Near the center of the diaphysis; Divides in the medullary cavity into proximal and distal branches. Supplies both the inner part of the compact bone tissue of the diaphysis and the spongy bone tissue and red marrow as far as the epiphyseal plats
Nerve Supply of Bone
Nerves accompany blood vessels in bone; the periosteum is rich in sensory neurons. Some of which carry pain sensations.
Canaliculi
Small channels filled with extracellular fluid. Inside contains slender fingerlike processes of osteocytes. Connects lacunae with one another and with the central canals, provides routes for nutrients and oxygen to reach the osteocytes and for the removal of wastes
Epiphyses
The proximal and distal ends of the bone
Metaphyses
The regions between the diaphysis and the epiphyses. Contains Epiphyseal (growth) plate (or) Epiphyseal Line
Osteology
The study of bone structure and the treatment of bone disorders.
Mesenchyme
The tissue from which almost all connective tissues are formed
Perforating (Sharpey's) Fibers
Thick bundles of collagen fibers that extend from the periosteum into the extracellular bone matrix. Provide attachment of the periosteum to the underlying bone.
Long Bones
Thighs, Legs, Toes, Upper arms, Forearms, and Fingers
Articular Cartilage
Thin layer of hyaline cartilage that covers the part of the epiphysis where the bone forms an articulation (joint) with another bone. Reduces friction and absorbs shock at freely movable joints
Osteoprogenitor Cells
bone stem cells, periosteum and endosteum
Genic
genic= producing
The ending -blasts
in the name of a bone cell or any other connective tissue cell means that the cell secretes extracellular matrix
The ending -cytes
in the name of a bone cell or any other tissue cell means that the cell maintains the tissue