Chapter 21

A hydrostatic skeleton consists of _______ a. fluid in an enclosed space b. hardened plates at the surface of a body c. bone cells in a mineral-rich matrix d. chitin

The human ______ consists of vertebrae and intervertebral disks. a. appendicular skeleton b. femur c. backbone d. pectoral girdle

Bones move when _____ contract. a. cardiac muscles b. skeletal muscles c. smooth muscles d. tendons

The insect exoskeleton ______ a. consists of living cells b. protects soft internal parts c. grows with the individual d. is a type of hydrostatic skeleton

Red marrow ____ a. is the outermost layer of a long bone b. fills the shaft of most long bones c. consists mainly of fat d. produces blood cells

Match each bone with its description. femur a. part of skull radius b. thighbone vertebra c. segment of backbone sternum d. breastbone cranial bones e. forearm bone

The knee is a _____ a. hinge-type synovial joint b. fibrous joint c. cartilaginous joint d. ball-and-socket type of synovial joint

Which of the following is not true? A vertebrate skeletal muscle ______ a. contracts in response to signals from a motor neuron b. pushes against and moves a bone c. is a voluntary muscle d. consists of many multinucleated muscle fibers

A sarcomere shortens when _____ a. actin filaments shorten b. myosin filaments shorten c. both actin and myosin filaments shorten d. actin filaments slide past myosin filaments

Release of calcium ions from a muscle fiber's ____ allows actin and myosin filaments to interact. a. nuclei b. sarcoplasmic reticulum c. mitochondria d. myofibrils

Binding of ATP to ____ activates this motor protein and prepares it to take part in muscle contraction. a. actin b. myosin c. collagen d. myoglobin

A red muscle fiber _______ a. contains oxygen-storing myoglobin b. produces ATP mainly by lactate fermentation c. has relatively few mitochondria d. is colored red by myosin

Prolonged muscle inactivity as in sitting causes a(n) ______ a. increase in blood lipids b. increase in calories burned c. decrease in blood glucose d. increase in muscle mass