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Chapter 17
Movement in humans
Multiple-choice questions
Directions: Questions 1 to 3 refer to the diagram below, which shows the bones and
muscles in a human leg.
P
joint X
Q
muscle Y
femur
R
S
1.
2.
3.
The degree of movement allowed by which of the following joints is similar to t
hat by joint X?
A
shoulder joint
B
elbow joint
C
knee joint
D
the joint between bones of the index finger
Which of the following structures is involved in attaching muscles to bones?
A
P
B
Q
C
R
D
S
When muscle Y contracts,
A
B
C
D
the leg bends at the ankle.
the leg bends at the knee.
the leg straightens at the knee.
the femur is pulled backwards.
Directions: Questions 4 and 5 refer to the diagram below, which shows the structure
of a movable joint.
X
Y
bones
4.
Which of the following is the correct label of structure X?
A
B
C
D
5.
6.
bone
cartilage
ligament
synovial membrane
Which of the following is a correct description of structure Y?
A
It protects bones from wearing away.
B
It is elastic so that bones can move freely.
C
It is strong enough to provide support to our body.
D
It is present only in the axial skeleton.
Which of the following statements about cartilage is correct?
A
Cartilage is elastic.
B
Cartilage can be slightly compressed for shock absorption.
C
Cartilage secretes a fluid to reduce friction between the bones.
D
Cartilage is linked with bones by ligaments.
Directions: Questions 7 and 8 refer to the diagram below, which shows a
neuromuscular junction.
cell X
Y
muscle fibre
7.
8.
Which of the following is substance Y?
A
ATP
B
blood platelet
C
neurotransmitter
D
calcium ion
Cell X actively secretes Y when a nerve impulse arrives at the end of cell X.
Which of the following structures is most likely present in cell X for carrying out
this function but is missing in the above diagram?
A
B
C
D
9.
cell wall
mitochondrion
chloroplast
vacuole
The rib cage is part of the axial skeleton. Which of the following are the
functions of the rib cage?
(1) movement
(2) protection of internal organs
(3) storage of minerals
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
10. Calcium absorbed from a diet is mainly stored in the
A
B
C
D
cartilage.
bones.
skeletal muscles.
liver.
11. The appendicular skeleton includes the
A
B
C
D
skull.
vertebral column.
sternum.
girdles.
12. Which of the following about the biceps and triceps is correct?
Biceps
Triceps
A
flexor
extensor
B
extensor
flexor
C
flexor
flexor
D
extensor
extensor
13. The ball-and-socket joint is found in the
A
shoulder.
B
knee.
C
elbow.
D
ankle.
14. Which of the following about the degree of movement of a joint is correct?
Hip joint
Knee joint
A
in one plane
in one plane
B
in one plane
in many planes
C
in many planes
in one plane
D
in many planes
in many planes
15. Which of the following structures helps prevent dislocation of a joint?
A
cartilage
B
ligament
C
tendon
D
synovial membrane
16. The end surface of a bone inside a movable joint is covered with
A
ligaments.
B
tendons.
C
bone marrow.
D
cartilage.
17. The forearm is raised by
A
contracting the biceps and the triceps.
B
relaxing the biceps and the triceps.
C
contracting the biceps and relaxing the triceps.
D
contracting the triceps and relaxing the biceps.
18. Which of the following are parts of the axial skeleton?
(1) skull
(2) pelvic girdle
(3) vertebrae
A
(1) and (2) only
B
(1) and (3) only
C
(2) and (3) only
D
(1), (2) and (3)
19. Which of the following is a correct description of the functions of ligaments and
tendons?
A
Ligaments protect the brain and tendons attach the muscles to the bones.
B
Ligaments attach the muscles to the bones and tendons protect the joints.
C
Ligaments link bones together and tendons protect the muscles.
D
Ligaments protect the joints and tendons attach the muscles to the bones.
20. Refer to the following diagram, which shows the movement of the forearm.
joint P
forearm raised
joint Q
Which of the following is correct?
Joint P
Joint Q
A
allows movement in many planes.
allows movement in one plane only.
B
is a ball-and-socket joint.
is a ball-and-socket joint.
C
is the elbow joint.
is the shoulder joint.
D
is a movable joint.
is an immovable joint.
21. The diagram below shows the movement of the forearm.
muscle P
forearm raised
muscle Q
Muscles P and Q work in a pair and are called
A
B
C
D
cardiac muscles.
smooth muscles.
opposite muscles.
opposing muscles.
22. Which of the following structures attaches muscles to a bone?
A
B
C
D
ligament
tendon
movable joint
cartilage
23. Which of the following correctly explain(s) why bones are living tissues?
(1) Bones can respire.
(2) Bones can produce red blood cells.
(3) Bones are strong and rigid.
A
B
C
D
(1) only
(1) and (2) only
(1) and (3) only
(1), (2) and (3)
24. Which of the following structures can be found in bone tissues?
(1) muscle fibres
(2) nerves
(3) blood vessels
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
25. Cartilage can be found in
(1) the nose.
(2) the oesophagus.
(3) the trachea.
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
26. Which of the following parts belong to the axial skeleton?
(1)
A
B
C
D
(2)
(3)
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
27. The diagram below shows a human arm.
X
Which of the following statements about structure X is/are correct?
(1) Structure X contracts when the forearm is raised.
(2) Structure X can generate a force to raise the forearm.
(3) Structure X is a living tissue.
A
B
C
D
(3) only
(1) and (2) only
(1) and (3) only
(2) and (3) only
28. Which of the following statements about the functions of skeleton is/are not
correct?
(1) The rib cage protects the heart.
(2) The thigh bone produces blood cells.
(3) The cartilage acts as storage of minerals.
A
B
C
D
(2) only
(1) and (2) only
(1) and (3) only
(2) and (3) only
Directions: Questions 29 and 30 refer to the diagrams below. Diagram I shows an
athlete at the starting blocks. Diagram II shows the muscles and the
bones in his left leg.
X
P
R
S
Q
I
II
29. In diagram I, which muscles in the left leg of the athlete are contracting?
A
B
C
D
P and Q
P and S
Q and R
R and S
30. Which of the following are produced in structure X?
(1) calcium salts
(2) red blood cells
(3) white blood cells
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
Directions: Questions 31 to 33 refer to the diagram below, which shows a
ball-and-socket joint.
P
Q
R
S
31. Which of the following structures can reduce friction during movement?
(1) P
(2) Q
(3) R
A
B
C
D
(1) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
32. Which of the following is the function of S?
A
B
C
D
S prevents dislocation of the joint.
S secrets synovial fluid.
S generates a force for movement at the joint.
S contracts and relaxes to control the movement at the joint.
33. Which of the following is an example of this type of joint?
A
B
C
D
the joint between the toe bones
the elbow joint
the knee joint
the hip joint
34. The following diagram shows two types of bones, X and Y, at the elbow joint.
Which of the following comparisons between X and Y is/are correct?
(1) X contains more minerals than Y.
(2) X is made up of living cells while Y is made up of dead cells.
(3) X is softer then Y.
A
(3) only
B
(1) and (2) only
C
(2) and (3) only
D
(1), (2) and (3)
35. The appendicular skeleton includes
A
the girdles and the limb bones.
B
the girdles and the rib cage.
C
the limb bones and the rib cage.
D
the girdles, the limb bones and the rib cage.
36. Which of the following statements about human muscles is correct?
A
Muscles are usually arranged separately and work alone.
B
Muscles are attached on the bones by elastic tendons.
C
Tendons reduce the pulling force produced by the contraction of muscles.
D
Movement of bones is brought by the contraction and relaxation of muscles.
Directions: Questions 37 and 38 refer to the diagram below, which shows an arm
model.
T
S
U
37. When a person is holding a weight and raises his forearm, what will happen?
A
B
C
D
S
relaxes
contracts
relaxes
contracts
T
contracts
relaxes
contracts
relaxes
U
bends
bends
extends
extends
38. Which of the following statements about U is correct?
A
The action at U is in one plane only.
B
C
D
U is enclosed by a synovial membrane.
The action at U involves the upper arm bone and the pelvic girdle.
The degree of movement at U is the same as that at the shoulder joint.
39. Which of the following is/are the way(s) to keep our skeleton and muscles
healthy?
(1) To have a diet rich in vitamin D.
(2) To avoid wearing unfit clothes and shoes.
(3) To develop a correct posture when working.
A
C
(2) only
(1) and (3) only
B
D
(3) only
(1), (2) and (3)
Conventional questions
1.
The diagram below illustrates a muscle cell and motor neurone as seen with an
electron microscope.
A
D
E
B
C
X
Identify structures A to E, giving one function in each case.
Structure
A
B
C
D
E
Function
(5 marks)
2.
The diagram below shows the major bones of the upper limb of a mammal.
X
Y
Z
3.
a
Joints X and Y are movable joints. Describe how ligaments and cartilage in
the joints are involved during movement of the limb.
(4 marks)
b
The muscles that move part Z of the upper limb at joint Y are opposing.
Describe the action of the opposing muscles when the mammal lifts up Z.
(2 marks)
The diagram below shows a cross-section of a striated muscle and a muscle
fibre.
muscle
tendon
muscle fibre
Striated muscle
contractile
units
A muscle fibre
a
Muscles contract fully to bend a joint at the maximum degree. They can
also contract slightly to bring about bending of smaller degrees.
Explain how the above structures cause two different types of bending to
occur.
(3 marks)
b
Tendon is present at the end of muscles. Explain why a joint cannot bend if
the tendon of a muscle is damaged.
(2 marks)
4.
Read the passage below and answer the questions that follow.
A muscle relaxant is a drug which affects the function of skeletal
muscles. There are two groups of muscle relaxants: the peripherally-acting
relaxants and the centrally-acting relaxants, which are defined according to
their sites of actions.
The peripherally-acting relaxants act by interfering with the transmission
at neuromuscular junctions. As they do not affect the central nervous system,
they are often used in surgeries and emergency conditions to cause paralysis
temporarily. On the contrary, the centrally-acting relaxants are mainly used to
relieve muscle pain and cramps (non-coordinated contractions of a group of
muscles).
5.
a
Suggest one possible way by which the peripherally-acting relaxants cause
paralysis.
(2 marks)
b
State one possible site that the centrally-acting relaxants will act on when
they are used to relieve muscle pain and cramps respectively.
(2 marks)
c
Some fruits contain substances whose chemical structure is similar to that of
muscle relaxants. These fruits are toxic and often kill people who
accidentally eat them. Explain how these fruits can kill.
(2 marks)
a
The human skeleton provides protection for many parts of the body.
Give two other functions and one structure responsible for each of the
functions.
(4 marks)
b
Use lines to link the parts of the skeleton to the organs which they protect.
(3 marks)
Part of skeleton
Organs
Vertebrae
Spinal cord
Heart
Skull
Lungs
Kidneys
Rib cage
Brain
6.
The diagram below shows a movable joint.
bone
P
Q
S
R
a
Identify P, Q and R. What are their functions?
(3 marks)
b
Fluid S is found inside the cavity. Name it and give its function. (2 marks)
c
Give one specific example of this kind of joints and state its degree of
movement allowed.
(2 marks)
7.
The diagram below shows the muscles and the bones of a human leg.
X
P
Q
S
Y
R
a
b
T
Name structure P and state two of its functions.
(3 marks)
Using the letters in the diagram, state the muscle(s) that will contract in the
girl’s left leg as she moves from posture I to posture II.
(1 mark)
Posture I
c
i
ii
Name the types of joints at X and Y.
Compare the degrees of movement at X and Y.
Posture II
(1 mark)
(2 marks)
8.
The diagram below shows the structures in a neuromuscular junction.
motor neurone
X
Y
Z
cytoplasm of a
muscle cell
membrane P
a
i
Name structures X and Y.
(2 marks)
ii
State one function of X and one function of Y.
(2 marks)
b
Explain why structure Z is abundant in both the ending of the motor
neurone and the cytoplasm of the muscle fibre.
(2 marks)
c
The bacterium Clostridum botulinum releases a toxin which binds to
membrane P. Death may occur due to paralysis of the breathing system.
Explain how the toxin released by Clostridum botulunum results in paralysis
of the breathing system.
(3 marks)
9.
a
The diagram below shows a movable joint. The joints can be affected by
many conditions like dislocation.
cartilage
ligament
synovial fluid
synovial
membrane
bones
Describe the difference in the above diagram when the following conditions
arise.
i
ii
iii
b
Dislocation
Ligament injury during intense exercise
Pain and stiff joint after excessive use of joints
(1 mark)
(2 marks)
(1 mark)
The diagram below shows the skeleton of a foot when it is not on the floor.
The muscle is contracting at this moment.
bone of lower leg
muscle
joint
foot
Draw a labelled diagram to show a lever system representing the above
movement. Indicate, on your diagram, the corresponding structures in the
above diagram.
(5 marks)
10. a
The diagram below shows some of the bones and muscles of the leg.
Q
P
knee joint
X
i
Muscles P and Q work in a pair. Name this type of muscles and
describe how the actions of the muscles bring about the movement of
the leg.
(3 marks)
ii
Part X may develop osteoporosis with an increasing age. Osteoporosis
is caused by a continuous loss of calcium ions from bones.
Explain how osteoporosis leads to difficulty in moving around.
(2 marks)
b
State and explain one feature of ligaments which helps them adapt to their
functions.
(2 marks)
11. The diagram below shows the arrangement of plastic boards and strips joined by
bolts to represent the bones and joints in a human arm.
shoulder
bone
upper arm bone
bone of forearm
a
Given some rubber bands, draw the bands on the diagram, showing the
positions of attachment and state which rubber band should shorten when
the forearm is lifted and lowered.
(4 marks)
b
There are two movable joints in the model. Name the joints they represent
in the human body. Compare their degrees of movement between the model
and the body.
(4 marks)
c
What do the rubber bands represent? State the adjective that describes their
opposing actions.
(2 marks)
12. The diagram below shows a bent arm.
a
b
Name muscles X and Y.
(1 mark)
Describe how muscles X and Y act to bring about the bending of the arm.
(2 marks)
c
Name the types of joints of S and T. Apart from those shown in the diagram,
give one other example of each type of joints.
(2 marks)
d
What are the differences between the degrees of movement of joints S
and T?
(2 marks)
13. The diagram below shows the structure of a movable joint.
P
R
Q
S
a
Name structures P, Q, R and S.
(2 marks)
b
Which parts in the diagram are involved in reducing friction between the
bones? How do they work?
(3 marks)
c
Arthritis is an inflammation and painful swelling of joints commonly found
in old people. Suggest one cause of the disease.
(1 mark)
d
Unlike the one in the diagram, joints can be immovable. Give one example
and the function of an immovable joint.
(2 marks)
14. a
What does the skeleton consist of?
(2 marks)
b
Give five functions of the skeleton.
(5 marks)
c
What is the major inorganic mineral inside a bone?
(1 mark)
d
Is bone a living tissue? Explain.
(2 marks)
15. The diagram below shows a model which represents a tiptoeing leg.
rubber tubing P
rubber tubing Q
string
string
wooden block
joint R
fulcrum
a
Draw a diagram of the lever system represented in the above diagram. (Hint:
you may use the following words: fulcrum, effort and load.)
(3 marks)
b
c
What does the string represent? What is its role in tiptoeing?
(2 marks)
What does the rubber tubing represent? What is its role in tiptoeing?
(3 marks)
d
Give the term which describes the action of rubber tubing P and Q.
(1 mark)
e
A fluid in a human joint R enables the bones to move smoothly. Name this
fluid.
(1 mark)
16. The graph below shows the change in the length of the biceps and muscle X of
length of muscles (arbitrary unit)
the arm during movement.
7
6
5
biceps
muscle X
4
3
2
1
0
0
1
2
3
4
5
6
7
8
time (second)
a
Briefly describe the change in the length of the biceps and muscle X during
0–8 seconds.
(4 marks)
b
Based on your answer in a, write down the name given to the muscle pair,
the biceps and muscle X, and name muscle X.
(2 marks)
c
Is the biceps contracting or relaxing during
i
0–3 seconds?
ii 4–8 seconds?
(1 mark)
(1 mark)
Describe the movement of the forearm during
i
0–3 seconds.
ii 4–8 seconds.
(1 mark)
(1 mark)
d
17. The diagram below shows a human joint.
X
Y
a
Identify the type of joint shown in the diagram. Give one example of this
type of joint.
(2 marks)
b
Name structures X and Y. Give one function of each of the structures.
(4 marks)
c
i
Which part of the joint is most easily worn away due to the overuse of
the joint?
(1 mark)
ii
How will the movement at the joint be affected if the part in c i is worn
away?
(1 mark)
iii
Suggest one treatment for this case.
(1 mark)
18. Diagram I below shows a human arm. Diagram II shows the cross-section along
the line PQ.
P
Q
Diagram I
Diagram II
a
Name muscles X and Z.
(2 marks)
b
Redraw diagram II to show new shapes of muscles X and Z when the
forearm is lowered to straighten the arm.
(2 marks)
c
Explain why muscles X and Z are called opposing muscles.
(2 marks)
d
State two functions of structure Y in the arm.
(2 marks)
e
Structure Y is easily broken in people suffering from osteoporosis. Suggest,
with a reason, one mineral that is lost from structure Y.
(2 marks)
19. Describe the events happen in a neuromuscular junction when a nerve impulse
arrives at the ending of an axon.
(8 marks)
20. Explain how the difference in the elasticity of ligaments and tendons is adapted
to their functions.
(9 marks)
Answers
1.
A
21.
D
2.
C
22.
B
3.
C
23.
B
4.
D
24.
C
5.
B
25.
B
6.
B
26.
C
7.
C
27.
A
8.
B
18.
B
9.
D
19.
C
10.
B
30.
C
11.
D
31.
B
12.
A
32.
A
13.
A
33.
D
14.
C
34.
A
15.
B
35.
A
16.
D
36.
D
17.
C
37.
B
18.
B
38.
A
19.
D
39.
D
20.
A
40.
1.
Structure
A
Myelin sheath / Schwann cell
Function
To insulate the axon. / To increase
the impulse velocity.
B
Synaptic vesicle
To contain / store neurotransmitters. /
To cause depolarization to occur.
C
Myofibril
As a contractile unit of muscle. / To
cause the muscle to shorten.
D
Mitochondrion
E
Postsynaptic membrane
To provide ATP for active transport.
To carry receptors sensitive to
neurotransmitters.
0.5m x 10
2.
a
Ligaments are elastic to allow movement.
1m
Ligaments hold bones together / prevent dislocation of bones.
1m
Cartilage covers the ends of the bones. /
Cartilage absorbs shock. /
Cartilage reduces friction between the bones / prevents the bones from wearing
b
away. (any 2)
1m x 2
The flexor contracts.
1m
The extensor relaxes.
1m
When contractile units in a muscle fibre contract, the fibre shortens.
1m
3.
a
If all the fibres in a muscle shorten, the muscle fully contracts and bends a joint at
the maximum degree.
1m
If some of the fibres in a muscle shorten, the muscle contracts only slightly and
brings about bending of smaller degrees.
1m
b
Tendon attaches a muscle to its associated bones.
1m
If the tendon is damaged, the contraction force of a muscle cannot be transmitted
to bones, and therefore no bending of a joint occurs.
1m
It destroys the neurotransmitters released by the ending of axons.
1m
4.
a
The muscle fibres therefore cannot be stimulated to generate electrical impulses that
trigger muscle contraction.
1m
OR
It inactivates the muscle fibres.
1m
Even when nerve impulses stimulate the release of neurotransmitters from the
ending of axons, no electrical impulses are generated by the muscle fibres. (any 1)
1m
b
c
To relieve muscle pain: sensory neurones in the spinal cord
1m
To relieve cramps: motor neurones in the spinal cord
1m
The substances in these fruits can block the transmission at neuromuscular
junctions in intercostal muscles.
1m
This can stop the breathing process and cause death.
1m
5.
a
Support: vertebral column / hind limb, etc. /
Movement: limb bones / girdles. /
Production of blood cells: bone marrow. /
b
Storage of minerals: any named bone. (any 2)
2m x 2
Vertebrae: Spinal cord
1m
Skull: Brain
1m
Rib cage: Heart and lungs
1m
6.
a
P: ligament
0.5m
It binds pieces of bones together.
0.5m
Q: synovial membrane
0.5m
It secretes synovial fluid.
0.5m
R: cartilage
0.5m
It prevents wearing of bones.
0.5m
Synovial fluid
1m
To lubricate / reduce friction when the joint moves.
1m
Elbow joint / knee joint, etc.
1m
It allows movement in one plane.
1m
Tendon
1m
It connects the muscle to the bone.
1m
It transmits the pulling force produced by muscle contraction to the bone.
1m
b
S, T
0.5m x 2
c
i
b
c
7.
a
ii
X: ball-and-socket joint
0.5m
Y: hinge joint
0.5m
X allows movement of bones in many planes / in all directions.
1m
Y allows movement of bones in one plane only.
1m
8.
a
i
ii
X: myelin sheath
1m
Y: synaptic vesicles
1m
X protects / insulates the nerve fibres. / helps speed up the transmission of
nerve impulses.
1m
Y contains neurotransmitters that are released when a nerve impulse arrives.
1m
b
Z is abundant in the ending of the motor neurone because the ending secretes a
large amount of neurotransmitters when a nerve impulse arrives.
1m
Z is abundant in the cytoplasm of the muscle fibre because the muscle fibre
generates electrical impulses when neurotransmitters stimulate the muscle fibres.
1m
c
The toxin binds to membrane P and blocks the release of neurotransmitters.
1m
When a nerve impulse arrive at the ending of the motor neurone, there is no
stimulation of the muscle fibres by the neurotransmitters.
1m
The intercostal muscle cannot contract to carry out the breathing process.
1m
i
The bones separate.
1m
ii
Ligaments break / tear off.
1m
The bones are not held in original positions.
1m
Cartilage wears away / becomes thinner.
1m
9.
a
iii
b
effort
load
fulcrum
Correct diagram
2m
Load: foot
1m
Fulcrum: joint
1m
Effort: muscle
1m
10.
a
i
ii
Opposing muscles / Antagonistic muscles
1m
When P contracts and Q relaxes, the leg bends.
1m
When Q contracts and P relaxes, the leg straightens.
1m
Bones become brittle. /
Bones can break easily. /
Bones become less flexible. /
Pain arises when moving. (any 2)
b
1m x 2
They are elastic.
1m
This allows the bones to move.
1m
11.
a
rubber band shortens
--> forearm lifted
rubber band shortens
--> forearm lowered
b
Correct positions of two rubber bands
1m x 2
Correct descriptions of rubber bands
1m x 2
The joint at the shoulder: shoulder joint
1m
The joint between upper arm and forearm: elbow joint
1m
The shoulder joint in the body can move in many planes but that in the model only
c
moves in one plane.
1m
Both the elbow joints in the body and in the model move in one plane.
1m
Skeletal muscles
1m
Opposing / Antagonistic
1m
12.
a
X: triceps
0.5m
Y: biceps
0.5m
Muscle X relaxes
1m
and muscle Y contracts.
1m
S: hinge joint
0.5m
Example: Knee joint / finger joint / toe joint
0.5m
T: ball-and-socket joint
0.5m
Example: hip joint
0.5m
S allows movement of bones in one direction and one plane only.
1m
T allows movement of bones in many directions.
1m
P: cartilage
0.5m
Q: synovial fluid
0.5m
R: ligament
0.5m
S: synovial membrane
0.5m
P and Q
0.5m x 2
P is very smooth and it reduces friction between the ends of bones.
1m
Q acts as a lubricant, so movement at the joint is almost frictionless.
1m
c
Wearing away of cartilage and bones in the joint.
1m
d
Skull / Pectoral girdle / Pelvic girdle
1m
To protect the internal organs.
1m
b
c
d
13.
a
b
14.
a
Bone and cartilage
b
Support /
1m x 2
Attachment of muscles /
Producing blood cells /
Storing minerals /
Protecting the organs /
Help in breathing (any five)
1m x 5
c
Calcium phosphate / calcium compound
1m
d
Yes.
1m
It can respire / grow / produce blood cells.
1m
15.
a
effort
fulcrum
load
3m
b
Tendon
1m
It transmits the force to the bone.
1m
Muscle
1m
It contracts or relaxes to pull the bone.
2m
d
Opposing / Antagonistic
1m
e
Synovial fluid
1m
c
16.
a
The length of the biceps increases from 0–3 seconds, reaches its maximum at 3–4
seconds and decreases from 4–8 seconds.
2m
The length of muscle X decreases from 0–3 seconds, reaches its minimum at 3–4
b
c
d
seconds and increases from 4–8 seconds.
2m
Opposing muscles / Antagonistic muscles
1m
Triceps
1m
i
Relaxing
1m
ii
Contracting
1m
i
The forearm is lowered.
1m
ii
The forearm is raised.
1m
17.
a
b
Ball-and-socket joint
1m
Shoulder joint, hip joint (any 1)
1m
X: ligament
1m
It holds the bones in position to avoid dislocation of the joint during movement.
1m
c
Y: synovial membrane
1m
It secretes synovial fluid to reduce friction between the ends of the bones.
1m
i
Cartilage
1m
ii
The friction will increase when the two bones move against each other.
1m
iii
Replacement with an artificial joint.
1m
18.
a
X: biceps
1m
Z: triceps
1m
Muscle X is smaller.
1m
Muscle Z is larger.
1m
Muscles X and Z carry out opposite actions in a movement.
1m
When one contracts, the other relaxes.
1m
b
c
d
It provides a hard surface for the attachment of muscles. /
It acts as a lever during movement. /
It produces blood cells. /
e
It acts as storage of minerals. (any 2)
1m x 2
Calcium
1m
It provides strength to structure Y.
1m
19.
When a nerve impulse arrives at the ending of an axon, it stimulates the ending to
release neurotransmitters.
1m
The neurotransmitters diffuse across the junction to the muscle fibre
1m
and stimulate it to generate an electrical impulse.
1m
The electrical impulse spreads along the muscle fibre
1m
and the muscle contracts.
1m
Effective communication
3m
Ligaments are present at joint.
1m
They hold bones in position and prevent dislocation during movement.
1m
The elasticity of ligaments allows the bones to move.
1m
Tendons are present at the end of muscles.
1m
They attach muscles to bones.
1m
20.
The inelasticity of tendons effectively transmits the pulling force generated by muscle
contraction to the bones.
1m
Effective communication
3m