Muscles and Movement

Question 1

where is the ligament found in the elbow?

Answer 1

joint capsule

Question 2

what are the four roles for skeletal muscles?

Answer 2

helps you move, supports the skeleton, protects organs, maintains body temp

Question 3

name two fibrous connective tissues and their roles.

Answer 3

ligaments: connects bone to bone
tendons: connects bone to muscle

Question 4

What signals muscle contractions?

Answer 4

the nerve via acetylcholine

Question 5

what are the bones a site for?

Answer 5

muscle attachment

Question 6

what do the bones act as?

Answer 6

levers

Question 7

what is the role of the joint capsule (2)

Answer 7

seals the joint space and provides passive stability by limiting the range of movement

Question 8

what is the role of the synovial fluid (2)

Answer 8

it contains oxygen, food and nutrients. it also provides lubrication to the cartilage

Question 9

what does the radius act as? for what muscle?

Answer 9

acts as forearm levers for the biceps

Question 10

what does the ulna act as? for what muscle?

Answer 10

acts as forearm levers for the triceps

Question 11

what is bigger in a human body, the ulna or the radius?

Answer 11

the radius

Question 12

what is the role of the cartilage? (3)

Answer 12

the cartilage absorbs shock and distributes the load. also allows for easy movement since it is a smooth surface.

Question 13

what type of surface does the cartilage have?

Answer 13

a smooth surface

Question 14

what muscle is the flexor? what muscle is the extensor?

Answer 14

flexor - biceps
Extensor-triceps

Question 15

what is the role of the humerus?

Answer 15

the humerus anchors muscle

Question 16

what bone acts as the muscle origin? what muscle attaches to this bone? what does muscle origin mean?

Answer 16

the humerus acts as a muscle origin. it is the site where triceps are attached and do not move during contraction

Question 17

what bone acts as the muscle insertion? what does that mean?

Answer 17

the radius and the ulna act as muscle insertions. this is the attachment site that moves during contraction.

Question 18

what are antagonistic muscle pairs? name an example

Answer 18

antagonistic muscle pairs perform the opposite function. ex. the flexor biceps muscle vs the extensor triceps muscles

Question 19

why do muscles only pull and not push?

Answer 19

because of the way the sarcomeres work. the myosin will attempt to grasp the actin in a way that contracts the muscle.

Question 20

describe the shape of the skeletal muscle? (2)

Answer 20

striated and tubular

Question 21

how many nuclei does a skeletal muscle cell have?

Answer 21

many, more than one

Question 22

what are skeletal muscles attached to?

Answer 22

to bone except in eye muscles

Question 23

is the skeletal muscle voluntary or involuntary control?

Answer 23

voluntary

Question 24

how do muscles move bones?

Answer 24

by contracting and relaxing. they can not push them back into position so they have to use the extensor/flexor pair

Question 25

what are skeletal muscle cells called?

Answer 25

muscle fibre

Question 26

what is the hierarchy of muscle structure?

Answer 26

muscle---> muscle fibre bundle----> muscle fibre--->myofibrils---->myofilaments

Question 27

what is the sarcolemma

Answer 27

the muscle fibre membrane

Question 28

what are two types of myofilaments? describe them

Answer 28

actin- thin myosin- thick

Question 29

in a muscle, what contains large numbers of mitochondria?

Answer 29

the muscle fibre

Question 30

what is the sarcoplasmic reticulum? what does it contain?

Answer 30

it is like the endoplasmic reticulum but specialized for the muscle. it contains calcium ions

Question 31

what are fibres a bundle of?

Answer 31

myofibrils

Question 32

what are the segments myofibrils are separated in called?

Answer 32

segments called sarcomeres

Question 33

what is the z disc? what does it consist of? is it a dark or light area?

Answer 33

the z disc is the border of the Sarcomere and it consists of actin only. it is a light area

Question 34

what is the I Band? what does it consist of? is it a dark or light area?

Answer 34

a section of the sarcomere that only consists of actin. this is a light section.

Question 35

what is the A Band? what does it consist of? is it a dark or light area?

Answer 35

a section of the sarcomere that consists of both myosin and actin. This is the darkest area.

Question 36

what is the h-zone? what does it consist of? is it a dark or light area?

Answer 36

in the middle of the sarcomere and it consists of only myosin. this is a dark area

Question 37

what gets smaller on an electron micrograph when a muscle contracts?

Answer 37

the H-zone and the sarcomere width

Question 38

what is the m-line? what binds to this line?

Answer 38

a line in the middle of the sarcomere that makes up the H-zone. the myosin binds here

Question 39

what does an action potential from a motor neuron signal?

Answer 39

calcium release from the sarcoplasmic reticulum

Question 40

what does calcium ion bind to when released

Answer 40

troponin

Question 41

what is myoglobin?

Answer 41

carriers oxygen in the muscle

Question 42

what is the protein covering the binding sites for myosin?

Answer 42

tropomyosin

Question 43

what forms cross bridges with actin binding sites?

Answer 43

myosin

Question 44

what is needed to break the cross bridge?

Answer 44

ATP

Question 45

what is needed to change the myosin head's shape to make it suitable for binding with the actin?

Answer 45

ATP

Question 46

what two things pull together to shorten the sarcomere?

Answer 46

actin and myosin

Question 47

how is calcium returned to the sarcoplasmic reticulum?

Answer 47

active transport

Question 48

when is calcium returned to the sarcoplasmic reticulum?

Answer 48

when contraction ends