Chapter 5 - The Skeletal System Flashcards
A framework of bones and cartilage that performs several functions
Skeleton
How many bones are in the human body?
206
Dense outer layer with few internal spaces; forms most of the shaft of long bones; covered by the periosteum that nourishes the bones
Compact bone
Latticework of bone; found in small, flat (skull) and in the head and near the ends of shafts of long bones
Spongy bone
The spaces of some spongy bones are filled with ___ _______ where blood cells form
Red marrow
The cavity in the shaft of long bones is filled with _____ _______, a fatty tissue for energy storage
Yellow marrow
The structural unit of compact bones
Osteon
Living bone cells
Osteocytes
Non-living component of bones; hard to to calcium and phosphorus salts
The solid matrix
When most of the skeleton is made of cartilage during embryonic development
Cartilage model
Bone-forming cells
Osteoblasts
Stimulates bone growth during childhood
Growth hormone
Ensure that the skeleton grows with the proper proportions
Thyroid hormone
Prompt and stop the growth spurt and puberty
Sex hormone
Released from the thyroid gland; decreases blood calcium levels
Calcitonin
Released from parathyroid glands increases blood calcium levels
Parathyroid hormone (PTH)
Results when bone is broken down faster than it is deposited
Osteoporosis
Protects and supports our internal organs; components include skull, vertebral column, sternum and rib cage
Axial skeleton
The most complex body structure in the body
Skull
Formed from 8 flat bones; protect the brain, house the structures for hearing; provide attachment sites for the muscles of the head and neck
Cranium
Support several sensory structures, serve as attachment sites for most facial muscles
Facial bones
The bones of the cranium are connected by these membranous areas before and shortly after birth to allow the skull of be compressed during birth
Fontanels
Allows movement and interaction with the environment; components include pectoral girdle, pelvic girdle, and limbs
Appendicular skeleton
Composed of scapulae and clavicles; functions to support arms
Pectoral girdle
More rigid than the pectoral girdle, composed of two pelvic bones joined in front at the pubic symphysis; functions to support the legs
Pelvic girdle
Places where bones meet
Joints
Three types of joints
Fibrous, cartilaginous, synovial
Held together by connective tissue, no joint cavity, most do not permit movement, ex skull
Fibrous
Allow very little movement, ex between vertebrae and ribs
Cartilaginous joints
Freely moveable and most joints in the body are of this type
Synovial joints
