B5.1/2 - Skeletons, Muscles & Joints

Question 1

Earthworms do not have a skeleton. How does the pressure of the fluid inside their body support their muscular body wall?

Answer 1

The fluid press outwards against their muscular body wall which supports it

Question 2

Name three things that have an external skeleton. What is their external skeleton made of?

Answer 2

• Insects
• Spiders
• Crustaceans

Their external skeletons are made of chitin.

Question 3

How does an external skeleton made of chitin work?

Answer 3

The chitin gives a protective outer covering which support the animal. It also gives a framework for muscle attachment. These animals all have joined legs and their skeleton , muscles and joints allow them to move. However, this hard covering of chitin prevents growth which is why they have to shed their old skeleton and grow before the new one hardens.

Question 4

Name three animals that have an internal skeleton

Answer 4

• Fish
• Reptiles
• Humans

Question 5

The human skeleton is made of bone but there are still places where there is still cartilage. Name three

Answer 5

• The top of your nose
• Your ear lobes
• At the ends of your long bones, such as limb bones and ribs

Question 6

Bone and cartilage are both (I) ________ tissues. They have blood vessels and nerves and can (II)_____ within the body.

Answer 6

(I) Living

(II) Grow

Question 7

The internal skeleton forms a framework. What allows this framework to move?

Answer 7

Joints and muscles allow it to move. (The many small bonds of the spine give great flexibility)

Question 8

What is ossification?

Answer 8

When you were growing in the womb your skeleton was first made of cartilage, which is mainly protein. After 6 weeks, calcium phosphate is deposited on the cartilage. The cartilage then becomes ossified and turns into bone. Children have more cartilage at the ends of their bones because they are still growing.

Question 9

How can scientists tell someone’s age by looking at their skeleton?

Answer 9

They can tell the age of a person according to how much cartilage is still present on their skeleton.

Question 10

Why shouldn’t you move someone with a broken backbone?

Answer 10

You could injure their spinal cord if you move them.

Question 11

What is the head of a long bone covered with?

Answer 11

Smooth cartilage

Question 12

The outer part of a long bone is made of hardened bone. It can withstand compression. This makes the bone light than solid bones. What is in the centre of a long bone?

Answer 12

In the centre of a long bone there is bone marrow and blood vessels. Some fat is stored here, and new blood cells are made.

Question 13

What is a green stick fracture?

Answer 13

When the bone is bent but not broken. Children with rickets are prone to this.

Question 14

What is a simple fracture?

Answer 14

When the bone is broken but the skin is intact.

Question 15

What is a compound fracture?

Answer 15

This is also called an open fracture. This is when the broken ends of the bones stick out through the skin.

Question 16

What do doctors use to look at the damage to s bone before treating it?

Answer 16

They use X-Ray’s

Question 17

What is osteoporosis?

Answer 17

A condition that causes people to have soft bones so are more susceptible to fractures.

Question 18

Define fracture

Answer 18

The cracking or breaking/displacement of a bone

Question 19

What happens as you bend your arm in term of muscles and joints?

Answer 19

• Your biceps muscle contracts and your triceps muscle relaxes.
• As your biceps contracts, the tendon that joins it to the radius(the bone in the lower arm) does not stretch.
• It pulls your radius(the bone in the lower arm) upwards and your arm bends.

Question 20

What happens in terms of muscles and joints when you straighten your arm?

Answer 20

• Your triceps muscle contracts and your biceps relaxes.
• The tendon from the triceps pulls on the ulna (the bone in your lower arm).
• Your arm straightens

Question 21

What is the fulcrum?

Answer 21

The fulcrum is the bone at the elbow.

Question 22

When the arm bens and straightens it acts as a lever. Describe how

Answer 22

The elbow(fulcrum) is the pivot point when your arm bends or straightens. The muscles exert are larger force than the load that the hand lifts. On a lever joint, movement can only be up and down (bend/straighten).

Question 23

What provides the force to move your bones?

Answer 23

The contraction of your muscles.

Question 24

What do joints do?

Answer 24

If you did not have joints in your skeleton you would not be able to move. Joints allow movement and are located where the end of your bone meets another bone, for example when the radius and ulna in the lower arm meet the fulcrum (elbow).

Question 25

What is a fixed joint?

Answer 25

A fixed joint is a joint that cannot move as they are fused. An example of this is the skull.

Question 26

What is a synovial joint?

Answer 26

Synovial joints are joints that are freely moveable. Synovial joints are well adapted to allow smooth, almost friction-free movement.

Question 27

How do synovial joints allow movement that is smooth and almost friction-free?

Answer 27

The ends of the two articulating (moving) bones are covered in smooth, slippery cartilage. The whole joint is enclosed in a capsule. Lining the inside of the capsule is a synovial membrane. This membrane secretes (makes) synovial fluid. Synovial fluid lubricates the joint. Ligaments join the two bones of a synovial joint together. They stretch and allow movement.

Question 28

Name three functions of the skeleton

Answer 28

Skeletons provide:

• Support
• Protection
• A framework for muscle attachment to allow movement.

Question 29

What is a hinge joint?

Answer 29

You have a hinge joint at your elbow. It allows movement in one plane. This allows you to bend and straighten your arm and to also lift heavy weights.

Question 30

Name another hinge joint apart from your elbow

Answer 30

Your knee ( It allows you to bend and straighten your leg to walk, but can also lock in place to bear your weight.

Question 31

What is a ball and socket joint and name an example

Answer 31

Your shoulder and hip joints are ball and socket joints. At these joint you can rotate the limb bones.