muscular system

Question 1

muscle tissue consists of

Answer 1

highly specialised elongated cells with elastic properties

Question 2

muscle cells get shorter when

Answer 2

stimulated. when stimulus is removed cells return to original shape (relaxed)

Question 3

muscles are a source of

Answer 3

power for movement, posture and alter the shape and size of internal organs

Question 4

locomotion and balance is facilitated by

Answer 4

structure and actions of skeletal muscles

Question 5

skeletal muscles work in groups around ?

Answer 5

joints to give a desired action while maintaining stability and providing strength

Question 6

the structure allows?

Answer 6

small amounts of movement at cellular level to produce large, strong movements for walking and balance

Question 7

functions of muscles

Answer 7

• contract or shorten
• extensibility
• elasticity

Question 8

contraction

Answer 8

to reduce the distance between parts they are connected to or decrease the space they surround

Question 9

extensibility

Answer 9

ability to be stretched

Question 10

elasticity

Answer 10

ability to return to original length after being stretched

Question 11

types of muscle tissues

Answer 11

skeletal, cardiac and smooth

Question 12

skeletal muscle

Answer 12

muscle cells are elongated, striated (stripy) in appearance and have many nuclei.
Most are attached to and move bones of the skeleton
these are normal voluntary (conscious) control

Question 13

cardiac muscles

Answer 13

occurs in only the heart and the cells have a striated appearance
from a network of interconnected cells, joining at the intercalated discs
they are involuntary and able to relax and contract rhythmically without becoming tired or stopping

Question 14

smooth muscles

Answer 14

cells are spindle shaped, have a single nucleus and are not striated
they will either occur in small clusters or form sheets
are capable of both slow and sustained and rhythmical, wave like contraction
occur the walls of external organs eg. blood vessels, bladder, uterus and intestines

Question 15

antagonist muscles

Answer 15

tri-ceps and hamstrings

Question 16

antagonists muscles are

Answer 16

spindle shaped with a broader belly and narrow tendon at the other eg. pectoralis

Question 17

others muscles may be

Answer 17

feather like (pennate) or circular (sphincter)

Question 18

most muscles work

Answer 18

antagonistically in pairs or groups, so when one contracts the antagonistic muscle relaxes and vice versa

Question 19

smaller muscles ?

Answer 19

assist the primary antagonist known as synergists

Question 20

agonist

Answer 20

bi-cep and quadriceps

Question 21

flexion

Answer 21

a movement that decreases the angle between 2 body parts

eg. elbow flexion is decreasing the angle between the ulna and humerus

Question 22

extension

Answer 22

a movement that increase the angle between 2 body parts

eg.the elbow extension is the increasing angle between the ulna and the humerus

Question 23

adduction

Answer 23

movement towards the midline of the body

eg. moving your arms against your side

Question 24

abduction

Answer 24

movement away from the body’s midline

eg. raising your arms from your sides

Question 25

rotation

Answer 25

medial (internal rotation) rotational movement towards the midline
eg. rotation of shoulder
lateral rotation rotating movement away from the midline
eg. pointing toes outwards

Question 26

Circumduction

Answer 26

conical movement of a limb extending from the joint where the movement is controlled
eg. forming circles using the arms extended from the shoulder

Question 27

structure of muscle fibre

Answer 27

• skeletal muscle
• bundles
• myofibrils
• myofilaments
• actin and myosin

Question 28

skeletal

Answer 28

stringy appearance, sliding of muscle fibres during contraction, connective tissue (tendons) taper at each end

Question 29

muscle fibre

Answer 29

cells are parallel, elongated with many nuclei and vary in length

Question 30

fasicle

Answer 30

made of many myofibrils and run parallel

Question 31

myofirbril

Answer 31

contain microfilaments made of proteins, thick filaments are myosin, thin filaments are actin, allows contractions, gives banded effect and are striated.

Question 32

sarcomere

Answer 32

functional unit of myosin and actin, dark are myosin, light are actin, they are shortened during contraction, they run from z line to z line

Question 33

sliding filaments theory

Answer 33

1. a nerve impulse at the muscle triggers that release of a neurotransmitter
2. this causes a reaction at he motor end plate (end of neuron)
3. myosin filaments (thick) attach to actin (thin) forming cross bridges
4. energy used to pull actin filaments along which shortens the muscle
5. myosin detaches from one actin so the cross bridge is broken, then it attaches to the next actin
   ratchet mechanisim ( repeated over and over)
6. once impules stop the actin returns to resting position

Question 34

muscle during relaxation

Answer 34

• actin and myosin filaments move back to orignal state.
• not all fibres contract at the same time
• energy (ATP) is required

Question 35

muscle during contraction

Answer 35

• sarcomeres shorten when actin and myosin slide over each other.
• z lines are drawn closer together
• myofilaments stay the same size but have increased overlapping