Muscles And Movement

Question 1

What structures make up joints?

Answer 1

Bones, ligaments, muscles, tendons, and nerves

Question 2

Synovial joint

Answer 2

Most common in the body, freely movable, enclosed in a capsule containing a joint cavity (contains synovial fluid)

Question 3

Bones (exoskeletons)

Answer 3

Anchorage for muscles 
Protect soft tissue and organs 
Act as levers for movement 
Form blood cells (bone marrow)
Store minerals (calcium, phosphorus)

Question 4

Skeletal (striated) muscles

Answer 4

provide force for movement by shortening (contracting) the length of their fibers, responsible for skeletal movement
*note: since muscle fibers can only actively shorten, muscles always exist in opposing pairs

Question 5

Cartilage

Answer 5

lines bone surfaces for smoother movement, shock absorption, and distribution of load

Question 6

Synovial Fluid

Answer 6

provides nutrients (oxygen) to cells of the cartilage and lubricates joints to reduce friction

Question 7

Joint capsule

Answer 7

seals joint space, provides stability, restricts range of motion

Question 8

Tendons

Answer 8

cords of connective tissues that attach muscles to bone

Elbow: attach triceps and biceps to bone

Question 9

ligaments

Answer 9

stabilize joints (attach bone to bone)

Question 10

Biceps

Answer 10

Muscles that contract to provide flexion (bending) of the arm

Question 11

Triceps

Answer 11

Muscles that contract to provide extension (straightening) of the arm
**Note: biceps and triceps are opposing

Question 12

Humerus

Answer 12

Upper arm bone that provides leverage and attachment for upper portions of muscles of the elbow

Question 13

Radius (forearm)

Answer 13

Lower arm bone (smaller) that acts as a lever for the biceps (biceps attach to it)

Question 14

Ulna (forearm)

Answer 14

lower arm bone (larger) that acts as a lever for the triceps (triceps attach to it)

Question 15

nerves

Answer 15

stimulate and coordinate muscles contraction

Question 16

Flexion

Answer 16

decreases the angle between connecting bones (bending the joint)

Question 17

Extension

Answer 17

increases the angle between connecting bones (straightening a joint)

Question 18

Muscle contraction in the elbow

Answer 18

Biceps and triceps muscles in the elbow joint act antagonistically 
Biceps contract (shorten) to flex the arm and the triceps contract (shorten) to extend the arm 
** when one is contracting the other is relaxed

Question 19

Structure of a skeletal muscle order (order based on size)

Answer 19

Muscle, muscular bundle (fascicle), muscle fiber, sarcolemma, myofibril, sarcomere

Question 20

Structure of a muscle

Answer 20

bundles (fascicles) of muscle fibers

Question 21

Muscle fiber structure

Answer 21

cells that have fused together during development (as a result contains many nuclei)

Question 22

Sarcolemma

Answer 22

cell membrane that covers muscle fibers (cells)

has many tube-like invaginations into the muscle cell called transverse tubules

Question 23

Myofibrils

Answer 23

parallel filament within muscle cells that are made up of contractile proteins actin and myosin (responsible for the banded look on striated muscles)
made up of sarcomeres

Question 24

Sarcomeres

Answer 24

the functional unit of muscle cells
made up of actin and myosin
z lines mark the end of each sarcomere

Question 25

A bands of sarcomere

Answer 25

darker in appearance

contain both actin and myosin

Question 26

H band

Answer 26

contains only myosin and is supported by the M line (narrow band of proteins that hold myosin together)

Question 27

I bands

Answer 27

light in color
only contain actin
Z lines run through the middle of these

Question 28

Contraction (sarcomere)

Answer 28

as muscle fibers contract…
Z lines get closer together
I and H bands get smaller (actin filaments slide toward the center of the sarcomere)
A bands remain the same length