Chapter 19 Flashcards
What does the skeleton do?
Provides attachment sites for the muscles.
What does the musculoskeletal system include?
The bones and muscles.
How are bones classified?
By their shape.
Describe long bones.
Enclosed by periosteum. Made of tough, fibrous connective tissue. Contains blood vessels that service bone.
What is epiphyses?
Expanded end of long bone.
What is diaphysis?
Shaft between the epiphyses.
Describe compact bone.
Highly organized, composed of osteons and tubular units.
What are osteocytes?
Bone cells that lie in lacunae which are spaces around osteocytes that contain cartilage. Central canals contain blood vessels, lymphatic vessels, and nerves.
What are lamellae?
Hard plates in osteons with collagen fibres and mineral salts like calcium.
What are canaliculi?
Tiny channels that connect lacunae to each other and move food/wastes.
Describe spongy bone.
Unorganized, osteocytes are found in trabeculae. Numerous thin plates surrounded by unequal spaces.
Describe cartilage.
Not as strong as bone but more flexible. Gel-like matrix with many collagen and elastic fibres. Cells lie within lacunae which are irregularly grouped. No blood vessels feed cartilage.
What are the 3 types of cartilage?
Hyaline, fibrocartilage, and elastic.
Describe hyaline cartilage.
Firm and somewhat flexible. In the ends of long bones, nose, ends of ribs, larynx, and trachea.
Describe fibrocartilage.
Stronger, thick collagen fibres, can withstand both pressure and tension. Found in intervertebral disks, and knees.
Describe elastic cartilage.
Most flexible, elastin fibres, found in ear flaps and epiglottis.
Describe ligaments.
Connect bone to bone.
Describe tendons.
Connect muscle to bone.
What does endochondral ossification do?
Replaces cartilage with bone. (Gradually).
Describe endochondral ossification.
Osteoblasts invade and produce spongy bone in what is called the primary ossification centre. Other osteoblasts then produce compact bone beneath the periosteum.
What are osteoblasts?
Cells that build up bone tissue. They also pick up calcium from blood and deposit it in the new bone matrix.
What are osteoclasts?
Cells that break down bone and release calcium into the blood.
What do both osteoclasts and osteoblasts do?
Bone remodelling, which can change bone thickness.
What are the functions of the skeleton that pertain to specific bones?
Support the body, protect soft body parts, produces blood cells, stores minerals and fats, assists with muscle movement.
How many bones do humans have in their skeleton?
206.
What are the 2 divisions of the skeleton?
Axial Skeleton: midline of the body.
Appendicular Skeleton: Bones of limbs and the limb girdles.
Describe the skull.
Formed by cranium and facial bones.
Describe the cranium.
Protects the brain, not completely ossified in infants. Also has sinuses, which are air spaces lined by mucous membranes and reduce the weight of the skull.