1 Structure And Function of Body Sys

Question 1

musculoskeletal system of the human body consists of b____, j_____, m_______, and t______ configured to allow the great variety of movements characteristic of human activity.

Answer 1

bones, joints, muscles, and tendons

Question 2

Muscles of the body do not act directly to exert force on the ground or other objects. Instead, they function by

Answer 2

pulling against bones that rotate about joints and transmit force to the environment.

Question 3

approximately ## bones in the body,

Answer 3

206

Question 4

axial skeleton consists of the

Answer 4

skull (cranium), vertebral column (vertebra C1 through the coccyx), ribs, and sternum.

Question 5

The appendicular skeleton includes

Answer 5

the shoulder girdle; bones of the arms, wrists, and hands; the pelvic girdle; and the bones of the legs, ankles, and feet

Question 6

Fibrous joints

Answer 6

(e.g., sutures of the skull) allow virtually no movement;

Question 7

cartilaginous joints

Answer 7

(e.g., intervertebral disks) allow limited movement;

Question 8

synovial joints

Answer 8

(e.g., elbow and knee) allow considerable movement. Sport and exercise movements occur mainly about the synovial joints, whose most important features are low friction and large range of motion.

Question 9

Articulating bone ends are covered with

Answer 9

smooth hyaline cartilage and the entire joint is enclosed in a capsule filled with synovial fluid

Question 10

Uniaxial joints,

Answer 10

such as the elbow, operate as hinges, essentially rotating about only one axis. The knee is often referred to as a hinge joint, but its axis of rotation actually changes throughout the joint range of motion.

Question 11

Biaxial joints,

Answer 11

such as the ankle and wrist, allow movement about two perpendicular axes.

Question 12

Multiaxial joints,

Answer 12

including the shoulder and hip ball-and-socket joints, allow movement about all three perpendicular axes that define space.

Question 13

vertebral column is made up of

Answer 13

vertebral bones separated by flexible disks that allow movement to occur.

Question 14

Each skeletal muscle is an organ that contains

Answer 14

muscle tissue, connective tissue, nerves, and blood vessels.

Question 15

Fibrous connective tissue, or e______, covers the body’s more than 430 skeletal muscles.

Answer 15

epimysium, is contiguous with the tendons at the ends of the muscle

Question 16

The tendon is attached to bone periosteum,.

Answer 16

a specialized connective tissue covering all bones;

Question 17

any contraction of the muscle pulls on the tendon and, in turn, the bone

Answer 17

TRUE

Question 18

Limb muscles have two attachments to bone:

Answer 18

Proximal (closer to trunk)

Distal (farther from the trunk)

Question 19

The two attachments of trunk muscles are termed _______ (closer to the head) and _________ (closer to the feet).

Answer 19

superior, inferior

Question 20

Muscle cells, often called muscle fibers, are

Answer 20

long (sometimes running the entire length of a muscle), cylin- drical cells 50 to 100 μm in diameter (about the diameter of a human hair).

Question 21

Under the epimysium the muscle fibers are grouped in bundles (f______) that may consist of up to 150 fibers, with the bundles surrounded by connective tissue called p_________

Answer 21

fasciculi, perimysium.

Question 22

Each muscle fiber is surrounded by connective tissue called e_________, which is encircled by and is contiguous with the fiber’s membrane, or s_________

Answer 22

endomysium, sarcolemma

Question 23

The junction between a motor neuron (nerve cell) and the muscle fibers it innervates is called the motor end plate, or, more often, the

Answer 23

neuromuscular junction

Question 24

A motor neuron and the muscle fibers it innervates are called a _____ ____. All the muscle fibers of a _____ ____ contract together when they are stimulated by the motor neuron.

Answer 24

motor unit

Question 25

sarcoplasm, which is the cytoplasm of a muscle fiber, contains contractile components consisting of

Answer 25

protein filaments, other proteins, stored glycogen, fat particles, enzymes, and specialized organelles such as mitochondria and the sarcoplasmic reticulum.

Question 26

myofibrils (1/100 the diameter of a hair) dominate the sarcoplasm. Myofibrils contain the apparatus that contracts the muscle cell, which consists primarily of two types of myofilament:

Answer 26

myosin and actin.

Question 27

myosin filament consists of a (3)

Answer 27

globular head, a hinge point, and a fibrous tail.

Question 28

The globular heads protrude away from the myosin filament at regular intervals, and a pair of myosin filaments forms a

Answer 28

cross- bridge, which interacts with actin.

Question 29

The actin filaments (thin filaments about 6 nm in diameter) consist of two strands arranged in a double helix.

Answer 29

TRUE

Question 30

A-band corresponds with the alignment of the

Answer 30

myosin filaments

Question 31

I-band corresponds with the

areas in two adjacent sarcomeres that contain only

Answer 31

actin filaments

Question 32

Z-line is in the middle of the I-band and appears as a thin, dark line running longitudinally through the I-band.

Answer 32

True

Question 33

H-zone is the area in the center of the sarcomere where only ______ filaments are present.

Answer 33

myosin

Question 34

Sarcoplasmic Reticulum

Answer 34

Parallel to and surrounding each myofibril is an intricate system of tubules which terminates as vesicles in the vicinity of the Z-lines. Calcium ions are stored in the vesicles.

Question 35

T-tubules, or transverse tubules,

Answer 35

Run perpendicular to the sarcoplasmic reticulum and termi- nate in the vicinity of the Z-line between two vesicles.

Question 36

_______ controls muscular contraction

Answer 36

Calcium (stored in vesicles)