Question

9 of 13
the most common and serious form is duchennes muscular dystrophy, which is expressed almost exclusively in boys. this tragic disease is usually (1. ) between the ages of 2 and 7 years. active, normal - appearing children become clumsy and fall frequently as their muscles weaken. the disease progresses from the extremities upward, finally affecting the head and chest muscles. children with this disease rarely live beyond their early twenties and generally die of (2. ) failure. although researchers have identified the cause of muscular dystrophy—the diseased muscle fibers lack a protein (called dystrophin) that helps maintain the sarcolemma—a cure is still elusive.
after birth, a babys movements are all gross reflex types of movements. because the nervous system must mature before the baby can control muscles, we can trace the increasing (3. ) of the nervous system by observing a babys development of muscle control. this development proceeds in a superior/inferior direction, and gross muscular movements precede fine ones. babies can raise their heads before they can sit up and can sit up before they can walk. muscular control also proceeds in a proximal/distal direction; that is, babies can perform the (4. ) movements like waving \bye - bye\ and pulling objects to themselves before they can use the pincer grasp to pick up a pin. all through childhood, the nervous systems control of the skeletal muscles becomes more and more precise. by midadolescence, we have reached the peak level of development of this natural control and can simply accept it or bring it to a fine edge by (5. ) training.

1. gross 2. athletic 3. diagnosed 4. respiratory 5. efficiency

1. respiratory 2. efficiency 3. gross 4. athletic 5. diagnosed

1. diagnosed 2. respiratory 3. efficiency 4. gross 5. athletic

1. athletic 2. diagnosed 3. respiratory 4. efficiency 5. gross

1. efficiency 2. gross 3. athletic 4. diagnosed 5. respiratory

Explanation:

1. Duchenne's muscular dystrophy is usually identified (diagnosed) between ages 2 - 7.
2. Patients generally die of respiratory failure as the disease progresses to chest muscles.
3. We can trace the increasing efficiency of the nervous system by muscle - control development.
4. Babies can perform gross movements before fine ones.
5. Athletic training can refine the natural control of skeletal muscles by mid - adolescence.

Answer:

1. diagnosed 2. respiratory 3. efficiency 4. gross 5. athletic