Chapter 6: The Skeletal System
The hormone calcitonin functions to
depress calcium levels in body fluids
A joint that permits no movement and is described as an interposition of cartilage plates is called a
synchondrosis.
The following are major steps in the process of endochondral ossification: 1. Bone forms at the diaphysis surface. 2. Secondary ossification centers form in the epiphyses. 3. Chondrocytes enlarge and calcify. 4. Osteoclasts create a marrow cavity. 5. Blood vessels invade the inner cartilage and new osteoblasts form spongy bone at a primary ossification center.
3,1,5,4,2
One role of the fontanels is to
Allow for change in shape during childbirth
What covers the ends of the epiphyses?
Articular cartilage
The special movement of the thumb that allows it to grasp an object and hold onto it is called
Oppostion
What is the process where cartilage is replaced by bone?
Ossification
Immature, active bone cells that produce new bone matrix are termed
Osteoblasts
What cells break down the spongy bone?
Osteoclasts
________ are giant bone cells with 50 or more nuclei, that secrete acid and enzymes.
Osteoclasts
What type of cells are located in the endosteum
Osteoclasts and osteoblasts
Two hormones that work together to elevate calcium levels in the body are ________ and ________.
Parathyroid hormone & calcitroil
In anatomical position, when the palm is moved to face posteriorly, the movement of the wrist and hand is called ________.
Pronation
When one crosses his/her arms, which movement is performed by the clavicles?
Protraction
What is a primary function of the skeletal system in the role of red bone marrow?
Blood cell production
What is the process called where deposits of Ca are laid down?
Calcification
Channels within bone, involved with cell-to-cell communication, are called
Canaliculi
What are skeleton made up initially?
Cartilage
The pectoral girdle consists of the
Clavicle and scapula
The organic component of the matrix, which makes up around one-third of the mass of bone, is dominated by
Collagen fibers
The shaft of a long bone is called the
Diaphysis
What is the lining of the marrow cavity called?
Endosteum
The presence of ________ strongly indicates that the long bone is still growing.
Epiphyseal plate
Which cell populations are particularly sensitive to changes in calcium ion concentration?
Neurons & muscle cells
What type of cartilage is articular cartilage?
Hyaline cartilage
What begins when osteoblasts differentiate within embryonic connective tissue?
Intamembranous ossification
Narrow sheets of calcified matrix are referred to as
Lamellae
What do osteoblasts form at the primary ossification center?
Spongy bone
What type of bone is located at the ends of long bones?
Spongy bone
What is the function of yellow marrow?
Storage of energy reserves- primarily lipids
What are the ends of long bones called?
The epiphyses
Spongy bone is made up of a network of bony rods or plates called
Trabecula
Rickets is a condition marked by a softening and bending of bones that occurs in growing children, as a result of ________ deficiency.
Vitamin D3 definicency
Bone diameter increases through
appositional growth
The presence of a epiphyseal line indicates
epiphyseal growth has ended
What is the open area surrounded by diaphysis called?
Marrow cavity
Fibrous cartilage discs that act as shock absorbers in joints are called
Menisci
