Name: Date: Period: Chapter 6: Checkpoint Questions The Skeletal System 1. Name the five primary functions of the skeletal system. a. Support b. Storage reserves (of minerals and bone marrow) c. Blood cell production (in red bone marrow) d. Protection (of vital organs) e. Leverage (help to move body) 2. Identify the three categories of how bones are classified. a. Shape b. Internal tissue organization c. Bone markings 3. Identify the four general shapes of bones AND provide a brief description of each bone type. a. Long Bones; bones that are longer than they are wide b. Short bones; bone dimensions are roughly equal c. Flat bones; bones that are relatively thin and wide d. Irregular bones; very complex shapes; do not fit other category descriptions 4. Explain the key similarities and differences between the diaphysis of a bone and the epiphysis. The diaphysis of a bone is the central shaft of the bone. It is made up of a heavy wall of compact bone. There is also a central space called the medullary cavity in which bone marrow is stored. The epiphysis of a bone is the wide part at each end of a bone, which provides articulation points with other bones. The bone tissue of the epiphysis is mostly spongy bone covered with compact bone. Anatomy and Physiology Chapter 6 Checkpoint Questions 2012-13.docx
5. What are the key similarities and differences between compact bone and spongy bone? Compact bone covers most bones (diaphysis) and are found where stresses are very severe and come from limited rage of directions. Compact bone can withstand great amounts of force from the ends of the bone, but are considered much weaker when the force is applied to the side of the bone shaft. Spongy bone is found where bones are not heavily stressed OR where stresses come from multiple directions (epiphyses). Spongy bone is much lighter than compact bone and it supports and protects the red bone marrow (location of red blood cell production). 6. Provide a brief description of the following bone tissue features: a. Osteocyte: Bone cells b. Lacunae: Small pockets c. Lamellae: Narrow sheets of calcified matrix d. Canaliculi: small channels that radiate through the bone matrix 7. What is the name of the basic functional unit of bone? Osteon 8. Mature bone cells are known as, bone-building cells are called, and are bone-resorbing cells. Osteocytes; Osteoblasts; Osteoclasts 9. Identify and explain the key functions of the three types of bone cells. a. Osteocytes; these cells are mature bones cells. The key function of osteocytes is to maintain protein and mineral content of the bone and to help repair damaged bone. b. Osteoclasts; these cells are responsible for maintaining mature bone. The key function of osteoclasts is to regulate calcium and phosphate concentrations in both bone and body fluids. c. Osteoblasts; these cells make new bone. Once an osteoblast becomes surrounded by bone tissue, it becomes an osteocyte. The key function of this cell is to produce new bone and to promote the deposition of calcium into bone.
10. If the activity of osteoclasts exceeds that of osteoblasts in a bone, how do you think the mass of the bone be affected (if at all)? Explain your answer. When osteoclast activity exceeds osteoblast activity, bone mass decreases because osteoclasts break down or demineralize bone. 11. Compare and contrast the periosteum and the endosteum of bone. The periosteum is the layer of tissue that surrounds the external surface of a bone. Creates an attachment point for tendons and ligaments; provides a route for blood and nerves; and involved in bone growth and repair. The endosteum is the lining of the medullary (marrow) cavity within bone. This layer is very active during bone growth, repair, and remodeling. 12. Compare and contrast the two skeletal divisions. The axial skeleton consists of the bones that lie around the longitudinal exist of the body; made up of 80 bones. The appendicular skeleton consists of bones in the upper and lower limbs, plus the bones forming the girdles that connect the limbs to the axial skeleton; made up of 126 bones 13. What are the key functions of the cranial bones? The key functions are to protect the brain and support the delicate sense organs (eyes; ears; balance; smell; taste) 14. Which bones make up the cranial cavity? Frontal bone; (2) parietal bones; (2) temporal bones; occipital bone; sphenoid bone; ethmoid bone 15. What are the key functions of the facial bones? The facial bones protect and support the entrances to the digestive and respiratory tracts AND provide sites for attachment of muscles that control facial expressions (talking and eating). 16. Identify the four major paranasal sinuses. a. Frontal b. Ethmoidal c. Sphenoidal d. Maxillary 17. What are the functions of the paranasal sinuses? The paranasal sinuses lighten some of the heavier skull bones. They contain a mucous epithelium that releases a mucous secretion into the nasal cavities that warms, moistens, and filters particles out of the incoming air.
18. Identify the 5 major regions of the vertebral column AND identify how many bones are in each region. a. Cervical (7 bones) b. Thoracic (12 bones) c. Lumbar (5 bones) d. Sacral (1 bone); formed from 5 fused bones e. Coccygeal (1 bone) 19. Identify the two primary spinal curves AND the two secondary spinal curves. In addition, briefly describe the function of the spinal curves. Primary Curves Thoracic and Sacral Help to support the majority of your body weight Secondary Curves Lumbar and Cervical Help to hold up your head and to transfer weight to pelvis 20. Identify and briefly explain the three features that are shared by ALL vertebrae a. Vertebral Body: this is the more massive, weight-bearing portion of the vertebrae; transfers weight along the spine; biggest portion of the vertebrae b. Vertebral Arch: This forms the posterior margin of the vertebral foramen (location of spinal cord); made up of walls called pedicles and a roof called the lamina. Also have two types of processes for muscle attachment: transverse processes and spinous processes c. Articular Processes: For m the lateral projections between the laminae and pedicles; point of movement between vertebrae occur at the articular facets 21. Compare and contrast the cervical vertebra, thoracic vertebrae and lumbar vertebrae. In your explanation, be sure to include general structure similarities/differences AND any key distinctive characteristics. Cervical vertebrae have a small body, body has more of an oval shape, large vertebral foramen, have stumpy spinous processes and have round transverse foramina to protect blood vessels Thoracic vertebrae have heart-shaped bodies, long/slender spinous processes (which point inferiorly) and have surfaces called costal facets which articulate with the ribs Lumbar vertebrae have the largest body size of the three categories, more massive spinous processes than the other types (muscle attachement), have blade-like transverse processes, no costal facets, and have a triangular vertebral foramen
22. Explain why the bodies of lumbar vertebrae so large compared to the other categories of vertebrae. Also, explain why the thicknesses of the vertebral bodies thicken as you travel from the L 1 vertebrae to the L 5 vertebrae. The lumbar vertebrae must support a great deal more weight than do vertebrae that are more superior in the spinal column. The large vertebral bodies allow the weight to be distributed over a larger area. As you travel down the lumbar vertebrae, there are more stresses and weight that need to be balanced along the pelvis, and the thicker vertebrae allow this to happen. 23. What are the differences between true ribs and false ribs? True ribs are each attached directly to the sternum by their own costal cartilage. False ribs either do not attach to the sternum (the floating ribs) or attach by means of a shared, common costal cartilage. 24. Improper administration of CPR could result in a fracture of which bone(s)? Why would breaking these bones be harmful? Improper compression of the chest during CPR could (and frequently does) result in a fracture of the sternum or ribs (and the xiphoid process). Breaking these bones (or cartilage) could cause damage to the heart or other organs in the abdominal cavity. 25. Identify the three key functions of the pectoral girdle. a. Connects the arms to the body b. Positions the shoulders c. Provides a base for arm movement 26. In what way would a broken clavicle affect the mobility of the scapula? By attaching the scapula to the sternum, the clavicle restricts the scapula s range of movement. A broken clavicle thus allows the scapula a greater range of movement (and reduces its stability). 27. The rounded projections on either side of the elbow are parts of which bone? The two rounded prominences on either side of the elbow are the lateral and medial epicondyles of the humerus. 28. Which bone of the forearm is lateral in the anatomical position? The radius is lateral when the forearm is in the anatomical position.
29. Which three bones make up the hip? The three bones that make up the hip are the ilium, the ishium, and the pubis. 30. The fibula neither participates in the knee joint nor bears weight. When it is fractured, however, walking becomes difficult. Why? The fibula is an important site of attachment for many leg muscles, so its fracture prevents proper muscle function, and moving the leg and walking become difficult and painful. The fibula also helps stabilize the ankle joint. 31. Provide a brief explanation of why the adult male and adult female pelvises are different in structure. The female pelvis will begin to change to provide modifications for childbearing that include a smoother and lighter weight, less prominent muscle and ligament attachments, an enlarged pelvis outlet, less curvature in the sacrum and coccyx, and the ilia project laterally, not upwards. The male pelvis is heavier and is much narrower in the pubic outlet. 32. Explain the five steps involved in endochondral ossification. a. Step 1: chondrocytes (cartilage cells) begin to enlarge and the surrounding matrix begins to calcify. The chondrocytes will begin to die due to the lack of nutrients. b. Step 2: Bone formation begins at the shaft surface; blood vessels invade the periochondrium and cells begin to differentiate into osteoblasts c. Step 3: Blood vessels begin to invade the inner region of cartilage; osteoblasts form new spongy bone at the center of bone called the primary ossification center. d. Step 4: As the bone enlarges, osteoclasts will break down spongy bone to create the marrow cavity; epiphyseal cartilages (at the ends of the bones) continue to enlarge, increasing the bone length. e. Step 5: Centers of epiphyses begin to calcify; blood vessels and osteoblasts invade the epiphyses; osteoblasts and cartilage will allow bone to grow longer.
33. How do bones grow during childhood and adolescence? Bones will grow throughout early childhood and adolescence, but begin to grow rapidly during puberty. The osteoblasts will produce bone faster than the epipyhseal cartilage expands. Bones will enlarge in diameter because new bone is deposited on the outer surface of the shaft. The inner surface is eroded by osteoclasts, causing the marrow cavity to enlarge. 34. What general effects do the following hormones have on calcium levels in the blood and bone? a. Calcitrol: Made in the kidneys; helps to absorb calcium and phosphorus from the small intestine. b. Vitamin C: Required for collagen synthesis and stimulation of osteoblast differentiation. c. Vitamin A: Stimulates osteoblast activity d. Androgens: Stimulate osteoblast activity e. Calcitonin: Regulates calcium and phosphate levels 35. Name and describe the three types of joints as classified by the amount of movement possible. The three types of joints as classified by their degree of movement are: 1) an immovable joint or synarthrosis; 2) a slightly movable joint or amphiarthrosis; and 3) a freely movable joint or diarthrosis. A synarthrosis can be fibrous or cartilaginous, depending on the nature of the connection, or it can be a bony fusion, which develops over time. An amphiarthrosis is either fibrous or cartilaginous, depending on the nature of the connection, while a diarthrosis joint is a synovial joint that permits the greatest amount of movement. 36. Give the proper term for each of the following types of motion: (a) moving the humerus away from the longitudinal axis of the body, (b) turning the palms so that they face forward, and (c) bending the elbow. a. Moving the humerus away from the body s longitudinal axis is abduction. b. Turning the palms forward is supination c. Bending the elbow is flexion.