Chapter 6 Study Skills: Key Terms
A structure made of some variety of cartilage tissue molded to fit its body location and function
Layer of dense irregular connective tissue surrounding cartilage in a skeletal cartilage structure
What are the functions of the perichondrium?
Act as a girdle to resist outward expansion when cartilage is compressed, contains blood vessels from which nutrients diffuse through the matrix to reach the cartilage cells internally
What are the three types of cartilage tissue?
Hyaline, Elastic, and Fibrocartilage
Most abundant skeletal cartilages; provide support with flexibility and resilience
What shape are chondrocytes in hyaline cartilage?
What cartilages are included under the category skeletal hyaline cartilages?
Articular, Costal, Respiratory, and Nasal Cartilages
Type of hyaline cartilage that cover the ends of most bones at movable joints
Type of hyaline cartilage that connects the ribs to the sternum (breastbone)
Type of hyaline cartilage which forms the skeleton of the larynx and reinforces other respiratory passageways
Type of hyaline cartilage which support the external nose
Type of cartilage that resembles hyaline cartilage except that they contain more stretchy elastic fibers; can stand up to repeat bending
Where are elastic cartilages found in the body?
In the external ear and the epiglottis
Type of cartilage that is composed of roughly parallel rows of chondrocytes alternating with thick collagen fibers; highly compressible with great tensile strength; occur in areas that are subjected to both pressure and stretching
Where are fibrocartilages found in the body?
Menisci of the knees, discs between vertebrae, pubic symphysis
How does cartilage differ from bone in terms of growth?
Bone has a hard matrix, while cartilage has a flexible matrix that can accommodate mitosis
What are the two types of cartilage growth?
Appositional growth and Interstitial growth
Cartilage growth in which cartilage-forming cells in the surrounding perichondrium secrete new matrix against the external face of the existing cartilage tissue
Cartilage growth in which the the lacunae-bound chondrocytes divide and secrete new matrix, expanding the cartilage from within
When does cartilage growth typically end?
During adolescence when the skeleton stops growing
Which type of cartilage is most plentiful in the body?
What two body structures contain flexible elastic cartilage?
The external ear and the epiglottis
Cartilage grows by interstitial growth. What does this mean?
This means that cartilage grows from within
What are the seven important functions of the bones?
Support, Protection, Anchorage, Mineral and Growth Factor Storage, Blood Cell Formation, Triglyceride (Fat) Storage, and Hormone Production
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.
What two types of substances are stored in the bone matrix?
Bone matrix stores minerals and growth factors
Describe two functions of a bone's marrow cavities.
Bone marrow cavities serve as sites for blood cell formation and fat storage
Section of the skeleton that forms the long axis of the body
What bones are included in the Axial Skeleton?
The bones of the skull, vertebral column, and rib cage
What are the general functions of the axial skeleton?
Protect, support, or carry other body parts
Part of the skeleton that consists of the upper and lower limbs and the girdles (shoulder and hip bones) that attach the limbs to the axial skeleton
What are the functions of limb bones?
Limb bones help us move from place to place (locomotion) and manipulate our environment
What are the four shape classifications of bones?
Long, Short, Flat, or Irregular
Bones that are considerably longer than they are wide; have a shaft plus two ends, which are often expanded; named for their elongated shape, NOT their overall size
Which bones are long bones?
All limb bones except the patella (kneecap) and the wrist and ankle bones
Bones that are roughly cube-shaped
Which bones are short bones?
the bones of the wrist and ankle
Short bones that form in a tendon; vary in size and number in different individuals
What is an example of a sesamoid bone?
Bones that are thin, flattened, and usually a bit curved
What bones are flat bones?
The sternum, scapulae (shoulder blades), ribs, and most skull bones
Bones that have complicated shapes that do not fit the long, short, or flat classes
What bones are irregular bones?
The bones of the vertebrae and the hip bones
What are the components of the axial skeleton?
The components of the axial skeleton are the skull, the vertebral column, and the ribcage
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 the structures that it encloses. The general function of the appendicular skeleton is to allow us mobility for propulsion and manipulation of our environment
What bone class to the ribs and skull bones fall into?
Why are bones considered organs?
Because they contain different types of tissues
What types of tissues are contained in bones?
Bone tissue, nervous tissue (nerves), cartilage (articular cartilage), dense connective tissue (external surfaces), and epithelial tissues (blood vessels)
Dense external layer on bones that looks smooth and solid to the naked eye
Internal to the compact bone, a honeycomb of small, needle-like or flat pieces
Small, needle-like or flat pieces that compose spongy bone
What is the structure of short, irregular, and flat bones?
Thin plates of spongy bone covered by compact bone, which is covered inside adn outside by connective tissue membranes (the periosteum and endosteum, respectively); do not contain a shaft or expanded ends, nor do they contain well-defined marrow cavities
What is the structure of typical long bones?
Shaft, bone ends, and membranes
Shaft that forms the long axis of a long bone
Marrow cavity that is present in the shaft of long bones; surrounded by a relatively thick collar of compact bone
Yellow Marrow Cavity
Medullary cavity in adults that contains fat (yellow marrow)
Bone ends; usually broader than the diaphysis; exterior composed of compact bone and interior composed of spongy bone; joint surface of each epiphysis is covered with a thin layer of articular (hyaline) cartilage to cushion the opposing bone ends during movement and absorbing stress
Separates the diaphysis and the epiphysis of each adult long bone; remnant of the epiphyseal plate
Disc of hyaline cartilage that grows during childhood to lengthen the bone
Glistening white, double-layered membrane that covers the external surface of the entire bone in long bones except the joint surfaces; outer fibrous layer is dense irregular connective tissue, inner osteogenic layer consists primarily of stem cells that give rise to all bone cells except bone-destroying cells
opening through which nerve fibers and blood vessels pass through the shaft to enter the marrow cavity
Tufts of collagen fibers that extend from the fibrous layer of the periosteum into the bone matrix and secure the periosteum to the underlying bones
A delicate connective tissue membrane that covers the internal bone surfaces, including the trabeculae of the spongy bone and lines the canals that pass through the compact bone; contains osteogenic cells that can differentiate into other bone cells
Hematopoietic tissue that is typically found within the trabecular cavities of spongy bone of long bones and in the diploe (thin plates of spongy bone) of flat bones
Red Marrow Cavities
Trabecular cavities within long bones and flat bones that contain red marrow
Projections, depressions, and openings on the external surfaces of bones that serve as sites of muscle, ligament, and tendon attachment, as joint surfaces, or as conduits for blood vessels and nerves.
Mitotically active stem cells found in the membranous periosteum and endosteum; when stimulated, these cells differentiate into osteoblasts or bone lining cells
Bone-forming cells that secrete the bone matrix; actively mitotic
Mature bone cells that occupy spaces (lacunae) that conform to their shape; monitor and maintain the bone matrix
Bone Lining Cells
Flat cells found on bone surfaces where bone remodeling is not going on; thought to help maintain the matrix
Giant multinucleate cells derived from the same hematopoietic stem cells that differentiate into macrophages, located at sites of bone resorption
Structural unit of compact bone; elongated cylinder oriented parallel to the long axis of the bone
Hollow tubes that compose osteons in compact bone like the growth rings of a tree trunk
Bone composed of lamellae
Central Canal (Haversian Canal)
canal that runs through the core of each osteon and contains small blood vessels and nerve fibers taht serve the osteon's cells
Perforating Canal (Volkmann's Canals)
Canals that 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 canals
Hairlike canals that connect the lacunae to each other and to the central canal
incomplete lamellae that lie between intact osteons that either fill teh gaps between forming osteons or are remnants of osteons that have been cut through by bone remodeling
Located just deep to the periosteum and just superficial to the endosteum, extend around the entire circumference of the diaphysis and effectively resist twisting of the long bone
Organic part of the matrix
"mineral salts"; inorganic component of bone tissue; tiny, packed, needle-like crystals in and around collagen fibers in the extracellular matrix
Are crests, tubercles, and spines bony projections or depressions?
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
Which membrane lines the internal canals and covers the trabeculae of the bone?
Which component of bone - organic or inorganic - makes it hard?
Which cell has a ruffled border and acts to break down bone matrix?
Process of bone formation
Cartilage bone; formed through bone development by replacing hyaline cartilage with bone
Bone formed from a fibrous membrane
Bone development in which bone is formed by replacing hyaline cartilage
Bone development in which bone is developed from a fibrous membrane
Bones don't begin with bone tissue. What do they begin with?
Bones begin as fibrous membranes or hyaline cartilages
When describing endochondral ossification, some say "bone chases cartilage". what does this mean?
The cartilage model grows, then breaks down and is replaced by bone.
Where is the primary ossification center located in a long bone? Where is (are) the secondary ossification center(s) located?
Primary ossification center in a long bone is in the center of the shaft. the secondary ossification centers are in the epiphyses (bone ends)
As a long bone grows in length, what is happening in the hypertrophic zone of the epiphyseal plate?
The chondrocytes are enlarging and their lacunae are breaking down and leaving holes in the cartilage matrix.
Unmineralized band of gauzy-looking bone matrix that is 10-12 micrometers wide and marks areas of new matrix deposits by osteoblasts
Parathyroid Hormone (PTH)
Primary hormonal controls produced by the parathyroid glands to control bone remodeling
If osteoclasts in a long bone are more active than osteoblasts, how will bone mass change?
If bone-destroying cells are more active than bone-forming cells, then bone mass will decrease
Which stimulus - PTH or mechanical forces acting on the skeleton - is more important in maintaining homeostatic blood calcium levels?
The hormonal stimulus maintains homeostatic blood calcium levels
How do bone growth and bone remodeling differ?
Bone growth increases bone mass, as during childhood or when exceptional stress is placed on the bones; bone remodeling follows bone growth to maintain the proper proportions of the bone considering stresses placed upon it
Breaks in the bones
Mass of clotted blood that forms at the site of a bone fracture
Mass of repair tissue consisting of fibrous tissue and cartilage that forms to splint a broken bone
New bone trabeculae that appear in the fibrocartilaginous callus and convert it to spongy bone
How does an open fracture differ from a closed fracture?
In an open fracture, the bone ends are exposed to the external environment. in a closed fracture, the bone ends o not penetrate the external boundary of the skin.
number of disorders in which the bones are poorly mineralized; generally caused by insufficient calcium in the diet or by a vitamin D deficiency; often called "adult rickets"
Form of osteomalacia in which bones bend to form a bowed appearance; caused by insufficient calcium in the diet or by a vitamin D deficiency
Refers to a group of diseases in which bone resorption outpaces one deposit so that the bones become fragile to the point where a good sneeze or stepping off a curb can cause them to break; composition of the matrix remains normal but the bone bone mass declines and bones become porous and light
Bone disorder characterized by excessive and haphazard bone deposit and resorption; newly formed bone (pagetic bone) has an abnormally high ratio of spongy bone to compact bone and reduced mineralization, and can cause a spotty weakening of bones
Which bone disorder is characterized by excessive deposit of weak, poorly mineralized bone?
What are three measures to help maintain healthy bone density?
Sufficient vitamin D, calcium, and weight-bearing exercise
What name is given to "adult rickets"?