Skeletal and Muscular Systems

Question 1

Compact bone

Answer 1

Very dense bone with few internal spaces; forms most of the shaft of long bones

Question 2

Periosteum

Answer 2

Glove-like membrane that covers compact bone and nourishes it (contains blood vessels and nerves)

Question 3

Spongy bone

Answer 3

Lattice work of tiny beans and thin plates of bone with open areas between; braces bone from within

Question 4

Osteocytes

Answer 4

Bone cells

Question 5

Osteoblasts

Answer 5

Bone-forming cells; produce the matrix of bone around the shaft by secreting collagen and depositing calcium salts on it

Question 6

What do bones start out as?

Answer 6

Cartilage

Question 7

Osteoclasts

Answer 7

Break down bone, releasing calcium and other minerals

Question 8

Calcitonin

Answer 8

Removes calcium from blood and causes it to be stored in bone

Question 9

Parathyroid hormone

Answer 9

Causes calcium to be released from bone and reabsorbed into blood

Question 10

Osteoporosis

Answer 10

Condition in which there is a progressive loss in bone density

Question 11

Axial skeleton

Answer 11

Includes skull, vertebral column, and bones of chest region

Question 12

Appendicular skeleton

Answer 12

Includes pectoral girdle, pelvic girdle, and limbs

Question 13

Process of repairing bone

Answer 13

1) blood clot is formed in periosteum
2) fibroblasts invade clot and form a callus which links broken surfaces of bone
3) osteoblasts invade callus and begin to convert the cartilage to bone
4) extra material is broken down over time and bone returns to normal size

Question 14

Joints

Answer 14

Places where bones meet

Question 15

Fibrous joints

Answer 15

Cannot move

Question 16

Cartilaginous joints

Answer 16

Areas of cartilage that hold bone together; immovable to slightly moveable

Question 17

Synovial joints

Answer 17

Most of joints in the body; freely movable

Question 18

What is found in synovial joints between bones which reduces friction?

Answer 18

Cartilage

Question 19

Functions/characteristics of muscles

Answer 19

• excitable (respond to stimuli)
• contractile (ability to shorten)
• extensible (ability to stretch)
• elastic (return to their original shape)

Question 20

Muscle fibers

Answer 20

Muscles cells

Question 21

Sarcomere

Answer 21

Contractile unit of muscle

Question 22

Motor unit

Answer 22

Motor neuron and the muscle cells it stimulates

Question 23

Skeletal muscle contraction

Answer 23

• signal from nerve
• calcium released from sarcoplasmic reticulum
• calcium binds to troponin releasing tropomyosin
• tropomyosin changes shape allowing myosin to bind to actin
• ATP is released causing myosin heads to forcefully swing back to original position
• myosin detaches
• myosin is reactivated for next contraction

Question 24

Sliding filament model

Answer 24

Muscle contracts when actin filaments slide along the myosin filaments increasing the degree of overlap between actin and myosin, this shortening the sarcomere.

Question 25

Process of a signal for muscle contraction

Answer 25

1) nerve impulse rescue neuromuscular junction
2) acetylcholine is released
3) acetylcholine binds to receptors on plasma membrane of sarcomere; electrochemical messages generated
4) calcium ions released from sarcoplasmic reticulum (contraction initiated)

Question 26

Energy for muscle contraction

Answer 26

1) ATP stored in muscle cells
2) creatine phosphate stored in muscle cells
3) anaerobic metabolic pathways within cells
4) aerobic respiration within cells

Question 27

Function of Skeletal system

Answer 27

• support
• movement
• protection
• production of red blood cells