Chapter 1: Musculoskeletal system

Question 1

Muscles can only ____ not ___ through the system of bony levers

Answer 1

Pull, not push

Question 2

Axial skeletons consists of (4)

Answer 2

skull, cerebral column, ribs, and sternum

Question 3

Appendicular skeleton consists of (4)

Answer 3

shoulder, UE bones, pelvic girdle, LE bones

Question 4

Fibrous joints: consist of, allows…

Answer 4

sutures of skull, no movement

Question 5

Cartilaginous joints: consist of, allows…

Answer 5

intervertebral disks, limited movement

Question 6

synovial joints: consist of, allows…

Answer 6

elbow and knee, considerable movement

Question 7

What is special about synovial joints

Answer 7

used in most sport and exercise movements due to low friction and large ROM.

Question 8

Articulating bone ends are covered with ___ and the entire joint is enclosed in a capsule filled with ____. They support ___ and ___.

Answer 8

hyaline cartilage
synovial fluid
ligament and cartilage

Question 9

Uniaxial joints: body part, operate as, how many axis

Answer 9

elbow
hinges
one axis

Question 10

Biaxial joints: body part, how many axis

Answer 10

ankle and wrist, 2 axis

Question 11

Multiaxial joints: body part, operate as, how many axis

Answer 11

shoulder, hip, ball and socket, 3 axes

Question 12

Fibrous connective tissue

Answer 12

epimysium

Question 13

Where is the tendon attached to and what does it do?

Answer 13

Bone periosteum, during contraction, themuscle pulls on the tendon and in turn, the bone.

Question 14

Muscle fibers layers from superficial to deep

Answer 14

Epimysium, fasciculus (150 muscle fibers) surrounded by perimysium, muscle fiber each surrounded by endomysium, under endomysium is sarcolemma aka fibers membrane.

Question 15

All connective tissue (epi,peri, endomysium) is contiguous with

Answer 15

Tendon

Question 16

Motor neuron and muscle fibers it innervates are called

Answer 16

motor unit

Question 17

Sarcoplasm is

Answer 17

cytoplasm of a muscle fiber

Question 18

What dominates the sarcoplasm and what does it contain?

Answer 18

Myofibrils, contain the myofilaments that contracts the muscle cells: myosin and actin

Question 19

How myosin interacts with actin

Answer 19

Myosin filaments form a cross bridge

Question 20

How myosin and actin organized

Answer 20

Longitudinally win the smallest contractile unit of skeletal muscle, the sarcomere

Question 21

Adjacent myosin filaments anchor to each other at the

Answer 21

M bridge in the center of the sarcomere/ center of H zone.

Question 22

Actin filaments are anchored at the

Answer 22

Z line

Question 23

A band is what color and corresponds with

Answer 23

Dark, the alignment of myosin

Question 24

I band is what color and corresponds with

Answer 24

light, the areas in two adjacent sarcomeres that contain only actin filaments

Question 25

Z line is located at

Answer 25

middle of I band

Question 26

H zone located at and have only what filaments

Answer 26

center of the sarcomere, myosin filament

Question 27

During muscle contraction, what happens to the H zone

Answer 27

H zone decreases as actin slides over myosin toward the center of the sarcomere

Question 28

During muscle contraction, what happen to the I bands

Answer 28

Decreases as the Z lines are pulled towards the center of the sarcomere

Question 29

Sarcoplasmic reticulum and what does it vesicles contain and its role

Answer 29

Tubules surrounding each myofibril, vesicles contain calcium ions which controls muscle contraction

Question 30

T tubules: location and its role in muscle contraction

Answer 30

perpendicular to sarcoplasmic reticulum. Being contigous to sarcolemma at the surface of the cell allows action portential from motor nerve signals, releasing calcium into the sarcoplasmic reticulum into the myofibril, causing tension development in muscle.

Question 31

Sliding filament theory

Answer 31

actin filaments at each end of the sarcomere slide inward on myosin filaments, pulling Z lines towards center of sarcomere, thus shortening the muscle fiber.

Question 32

What is responsible for movement of actin filament and how many is needed

Answer 32

Myosin crossbridges pulling the actin filaments. Multiple rapid flexions from many crossbridges to allow measurable actin movment to occur.

Question 33

Resting phase

Answer 33

Little calcium is president in myofibril and most are stored in sarcoplasmic reticulum.

Question 34

Excitation contraction coupling phase

Answer 34

Sarcoplasmic reticulum release calcium ions, which binds to troponin protein along the actin filament. This causes a shift to the tropmyosin protein. Now the myosin crossbridge attaches to the actin filament to be pulled toward the center to the sarcomere.

Question 35

The amount of force produced by a muscle at any instant is related to

Answer 35

The number of myosin crossbridges bound to actin filaments at that instant in time

Question 36

Contraction phase: where does the energy of the pulling action/power stroke comes from

Answer 36

Breakdown/hydrolysis of ATP to ADP and phosphate, catalyzed by the ATPase enzyme. Another ATP molecule replace the ADP on the myosin crossbridge globular head, allowing the head to detact from active actin site and return to its original position, allowing contractions to continue.

Question 37

Recharge phase: occurs as long as (3)

Answer 37

calcium is available in the myofibril, ATP is available to assist uncoupling the myosin from actin, and sufficient myosin ATPase to catalyzing ATP breakdown.

Question 38

Relaxation phase

Answer 38

Calcium is pumped back to sarcoplasmic reticulum, preventing the link between actin and myosin thereby returning their filaments to their unbound state.