Chapter 5: Skeletal System Flashcards
What are joints?
where two or more bones join together
What do CARTILAGES do? (2)
connect some bones; provide smooth surfaces for bone movement
What do LIGAMENTS do?
connect bones together
What are the functions of the skeleton? (5)
supports the body, protects soft organs, provides leverage for movement, stores minerals and fats, and forms blood cells
How many bones does the adult skeleton have?
206
What are the two basic types of bone tissue?
Compact bone and Spongy bone
What are the four basic shape groups that bones are classified into?
long, flat, short, and irregular
What part of the bone makes up for MOST OF THE BONE’S LENGTH?
Diaphysis
What are the ENDS of the bone?
Epiphysis
What is the outer connective tissue that covers the bone?
Periosteum
What covers the end of the bone?
Articular Cartilage
What is the function of the ARTICULAR CARTILAGE?
decreases friction at moving joint surfaces
What causes lengthwise growth of a long bone?
Epiphyseal plate
What is the remnant of the epiphyseal plate founf in adult bones?
Epiphyseal line
What is the CELLULAR LINING of the inner surface of the diaphysis?
Endosteum
What is the cavity INSIDE the DIAPHYSIS?
Medullary cavity
What is the COMPOSITION of a SPONGY bone?
the spongy bone is composed of trabeculae (small, needlelike pieces of bone) and open spaces (which are filled by marrow, blood vessels, and nerves)
What is the COMPOSITION of a COMPACT bone?
the compact bones is composed of osteons (columns of dense tissue)
What are OSTEOCYTES?
mature bone cells that maintain the bone matrix
What are LACUNAE?
small spaces that osteocytes are found in
What makes the bone have flexibility and great tensile strength (1/3 of bone mass)
collagen fibers
What makes the bone hard (to resist compression); 2/3 of bone mass
calcium salts
What is OSSIFICATION?
the process of bone formation
What are the two major phases of ossification in long bones?
the process starts within a hyaline cartilage framework, them osteoblasts cover the hyaline cartilage with bone matrix
What are OSTEOBLASTS?
bone-forming cells
What are the two regions of cartilage that isn’t converted into bone?
articular cartilages and epiphyseal plates
What ADDS bone matrix to the OUTSIDE of the diaphysis?
osteoblasts in the periosteum
What REMOVES bone matrix to the INNER SURFACE of the diaphysis?
osteoclasts in the endosteum
What hormones (2) control bone growth?
growth hormones and sex hormones
What are the two factors that account for BONE REMODELING?
Calcium ion level and the pull of gravity and muscles
What determines WHEN bone matrix is broken down or formed?
Calcium ion levels
What determines WHERE bone matrix is broken down or formed?
pull of gravity and muscles
What leads to bone matrix FORMATION?
hypercalcemia (excess blood calcium levels)
What leads to bone matrix BREAKDOWN?
hypocalcemia (low blood calcium levels)
What happens in HYPERCALCEMIA?
parathyroid hormone (PTH) is released and osteoclasts are activated to break down bone matrix and release calcium ion into the blood
What happens in HYPOCALCEMIA?
calcitonin is released and osteoblasts prompt calcium storage in bones
What is a FRACTURE?
a break in a bone
What is a CLOSED fracture?
a break that does not penetrate the skin
What is a OPEN fracture?
a broken bone that penetrates through the skin
