17: Movement in Humans

Question 1

State the name of the system which brings about movement.

Answer 1

Musculo-skeletal system, which consists of the skeleton and muscles.

Question 2

State the types of tissue the skeleton consists of.

Answer 2

Bone and cartilage.

Question 3

State three substances which the bone contains.

Answer 3

Minerals (eg. calcium phosphate), proteins (eg. collagen), water

Question 4

State the two types of bone.

Answer 4

Compact bone and spongy bone.

Question 5

State the properties and functions of compact bone.

Answer 5

It forms the outer shell of all bones and also the shafts of limb bones. It is dense and hard, providing great strength for supporting the body’s weight. The shafts of limb bones are filled with yellow bone marrow, which stories lipids.

Question 6

State the properties and functions of spongy bone.

Answer 6

It makes up much of the heads of limb bones. It is porous, providing strength with a minimum of additional weight. The cavities of spongy bone are filled with red bone marrow, which produced blood cells.

Question 7

State whether bone contains blood vessels and nerves.

Answer 7

Yes, bone contains blood vessels and nerves. The blood in the blood vessels supplies oxygen and nutrients to bone cells and removes waste from them.

Question 8

State the properties and functions of cartilage.

Answer 8

Cartilage is formed by living cells. It is softer and more elastic than bones as it contains fewer minerals.
It is present at the end surfaces of bones. It reduces friction between two bones the they move against each other.
It gives shape and support to some structure such as pinna, nose, and trachea.
Unlike bones, it does not have blood vessels and nerves.

Question 9

State the two parts the human skeleton can be divided into.

Answer 9

Axial skeleton and appendicular skeleton.

Question 10

State the properties and functions of the axial skeleton.

Answer 10

It lies on the central axis of the body. It consists of the skull, the vertebral column and the rib cage. It is mainly for support and protection of internal organs.

Question 11

State the properties and functions of the appendicular skeleton.

Answer 11

It lies on both sides of the body. It consists of the limb bones and girdles. It is mainly for movement.

Question 12

State the two types of bones making up the skull.

Answer 12

Cranium and facial bones (eg. jaw).

Question 13

State the properties and functions of the cranium.

Answer 13

The cranium is mode up of eight bones, which are fused together at immovable joints called sutures. The cranium protects the brain and some sense organs such as the eyes and ears. It is fused with the upper jaw. The lower jaw forms movable joints with the cranium, and the jaw forms the framework of the mouth and holds the teeth.

Question 14

State the properties and functions of the jaw.

Answer 14

The upper jaw is immovable and fused with the cranium. The lower jaw forms movable joints with the cranium, and the jaw forms the framework of the mouth and holds the teeth.

Question 15

State the properties and functions of the vertebral column.

Answer 15

It is made up of 33 vertebrae. It supports the weight of the upper body. Its S-shape acts as a spring to absorb shock during movement. It provides surfaces for muscles attachments to maintain out body upright. It also protects the spinal cord.

Question 16

State the properties and functions of the intervertebral discs.

Answer 16

They are compressible discs of cartilage between vertebrae. This allows bending of the vertebral column. They also act as a shock absorber.

Question 17

State the properties and functions of the rib cage.

Answer 17

The rib cage has 12 pairs of ribs, which are held by the sternum in the front and the vertebral column at the back.
It protects the lungs and the heart. It also helps bring about breathing actions.

Question 18

State the properties and functions of the limb bones.

Answer 18

They are the bones of the arms and legs. They allow movement of the body.

Question 19

State two examples of girdles.

Answer 19

1. Pectoral girdles, forming the shoulders. They attach the arms to the axial skeleton.
2. Pelvic girdle, forming the hip. It attaches the legs to the axial skeleton.

Question 20

State 5 functions of the skeleton.

Answer 20

1. Support our body weight
2. Allow movement
3. Protect organs
4. Produce blood cells
5. Store minerals and lipids

Question 21

Give 3 examples on how the skeleton protects organs.

Answer 21

1. The skull protects the brain, eyes and ears.
2. The vertebral column protects the spinal cord.
3. The rib cage protects the lungs and the heart.

Question 22

Give 2 examples on how the skeleton stores minerals and lipids.

Answer 22

1. Bones store minerals such as calcium and phosphorus.
2. The yellow bone marrow stores lipids.

Question 23

State the meaning of a joint.

Answer 23

A joint is the place where two or more bones meet.

Question 24

State whether all joints are movable.

Answer 24

No, there are immovable and movable joints.

Question 25

State the properties and functions of the ligament in a movable joint.

Answer 25

It is a fibrous tissue that holds bones together at a joint. It is holds the bones in position and **prevents dislocation** of the joint during movement. It is **tough and elastic**, which allows the bones to move.

Question 26

State the properties and functions of the cartilage in a movable joint.

Answer 26

It covers the end surface of bones. It **absorbs shock, reduces friction** between the bones during movement and prevents them from wearing away.

Question 27

State the properties and functions of the synovial membrane in a movable joint.

Answer 27

It is a membrane under the fibrous capsule. It secretes **synovial fluid**, which serves as a **lubricant** to **reduce friction** between bones during movement and **nourishes cartilage cells**.

Question 28

Name two main types of movable joints and provide two examples for each type of joint.

Answer 28

Hinge joint (eg. elbow joint, knee joint) and ball-and-socket joint (eg. shoulder joint and hip joint).

Question 29

State the plane of movement of the hinge joint.

Answer 29

It allows movement of bones in one plane only.

Question 30

State the plane of movement of the ball-and-socket joint.

Answer 30

It allows movement of bones in **many planes and almost all directions**.

Question 31

State the meaning of skeletal muscles.

Answer 31

Skeletal muscles are muscles which are **attached to bones** to bring about movement. A skeletal muscle is a *tissue** consisting of densely packed groups of elongated cells called **muscle fibres** which are grouped into bundles and surrounded by **connective tissues**.

Question 32

Explain why skeletal muscles are also called striated muscles.

Answer 32

When observed under the microscope, a muscle fibre is seen to contain **striation of light bands and dark bands**.

Question 33

State the meaning of tendons.

Answer 33

Tendons are sheets of **fibrous tissue** which attach muscles to bones. They are **tough and inelastic**.

Question 34

State how tendons allow muscles to move bones at joints.

Answer 34

When the muscle contacts, the **inelastic tendons** effectively **transmit the pulling force produced by muscle contraction to the bones**.

Question 35

State the meaning of flexors and extensors in a pari of opposing muscles.

Answer 35

A flexor is a muscle that bends a limb when it contracts, while an extensor is a muscle that straightens the same limb when it contracts.

Question 36

Describe the transmission of nerve impulses across a neuromuscular junction.

Answer 36

1. A nerve impulse arrives. 2. The nerve impulse triggers the release of **neurotransmitter** from the vesicles. 3. The neurotransmitter **diffuses** across the cleft. 4. The neurotransmitter **binds to the special receptors** on the membrane of the muscle fibre. 5. The muscle fibre generates an **electrical impulse**, which spreads along the muscle fibre and **triggers muscle contraction**.

Question 37

State the name of the synapse formed between the axon of a motor neurone and muscle fibres of a skeletal muscle.

Answer 37

Neuromuscular junctions / motor end plates.