Musculo-Skeletal System

Question 1

What are the functions of the skeleton?

Answer 1

Support:
Provides a rigid framework to hold the body upright.

Protection:
Cranium- Protects the brain.
Vertebrae- Protect the spinal cord.
Rib cage- Protects the heart and lungs.

Assists in movement:
Skeletal muscles provide the pulling forces to move bone, which acts as rigid layers,

Production of red blood cells:
Occurs in the red bone marrow of long bones like the femur.

Storage:
The yellow marrow stores fat.
Minerals such as calcium are stored in the bone.

Question 2

How many bones do adults have?

Answer 2

206 bones.

Question 3

Why do children have more bones than adults?

Answer 3

Some bones fuse in adulthood.

Question 4

Distinguish between the axial and appendicular skeleton.

Answer 4

Axial Skeleton:
Consists of the skull, vertebral column and rib cage.

Appendicular Skeleton:
Consists of pectoral and pelvic girdles and their attached limbs-fore-limbs and hind-limbs.

Question 5

Describe the skull.

Answer 5

Has 22 fused bones- not the mandible or lower jaw.

Consists of the cranium and facial bones.

Question 6

Describe the vertebral column.

Answer 6

Consists of 33 bones called vertebrae arranged into 5 different regions:
Cervical-7 vertebrae.
Thoracic-12 vertebrae.
Lumbar-5 vertebrae.
Sacrum- 5 vertebrae.
Coccyx-4 vertebrae.
The spinal cord runs through the hollow central canal of each vertebra.

Question 7

Where are discs found?

Answer 7

Between the vertebra.

Question 8

What is the role of discs?

Answer 8

They are shock- absorbers and allow friction-free movement.

Question 9

What is a slipped disc?

Answer 9

When the disc has ruptured and the soft centre is squeezed out, it compresses the spinal nerves causing pain and numbness.

Question 10

Describe the rib cage.

Answer 10

Consists of the sternum and 12 pairs of ribs.

All ribs are attached to the vertebrae of the spine.

Question 11

How are ribs classified?

Answer 11

True ribs-First 7 pairs, attach directly to the sternum.
False ribs- Pairs 8-10, attach to the 7th rib pair at the front of the chest, but not to the sternum.
Floating ribs-Pairs 11-12, only attach to the vertebral column.

Question 12

Describe the pectoral girdle.

Answer 12

Consists of the clavicle and the scapula- collarbone and shoulder blade- and attached fore-limbs.
The clavicle prevents the shoulder from collapsing towards the chest.
The scapula contains the socket for the ball of the humerus to fit into forming the ball and socket joint.

Question 13

What bones are found in the fore-limb?

Answer 13

Humerus.
Radius.
Ulna.
Carpals- wrist bones.
Metacarpals- hand bones.
5 digits containing phalanges.

Question 14

Describe the pelvic girdle.

Answer 14

Consists of the hip bones fused to the sacrum and surrounding a cavity, attached to the hind- limbs.
The hip bones are called innominate bones as each is formed by the fusion of 3 bones.
Each hip bone provides a socket for the ball and socket joint with the femur.

Question 15

What bones are found in the hind- limb.

Answer 15

Femur.
Patella.
Tibia.
Fibula.
Tarsals- ankle bones.
Metatarsals- foot bones.
5 digits containing phalanges.

Question 16

What suggests common ancestry in terms of evolution?

Answer 16

As each limb ends in 5 digits, they are called pentadactyl limbs.

Question 17

Where is spongy bone located?

Answer 17

Mainly in the epiphysis of long bones.

Question 18

What is the structure of spongy bone?

Answer 18

Contains bony bares and plates separated by spaces filled with red marrow.

Question 19

What is the function of spongy bone?

Answer 19

Provides strength but lowers the density.

Question 20

What is the function of the medullary cavity?

Answer 20

It makes inactive yellow marrow.

It reduces the weight of long bone, making movement possible.

Question 21

What is the structure of the compact bone?

Answer 21

It is thickest along the diaphysis, thinner at the epiphysis.
Dense bone which is living as it has a nerve and rich blood supply.

Question 22

What is the function of the compact bone?

Answer 22

Gives strength and rigidity to long bone.

Question 23

What is the structure of cartilage?

Answer 23

Covers the ends of the long bones.

Contains the fibrous protein collagen.

Question 24

What is the function of cartilage?

Answer 24

Reduces friction.

Acts as a shock absorber.

Question 25

Where is red marrow located?

Answer 25

In the spaces between spongy bone.

Question 26

What is the function of the red marrow?

Answer 26

To produce red blood cells.

Question 27

Where is yellow marrow located?

Answer 27

Inside the medullary cavity.

Question 28

What is the function of the yellow marrow?

Answer 28

Stores fat.

Converts to red marrow when red blood cells are needed.

Question 29

What is the structure of the periosteum?

Answer 29

It is a tough membrane which encloses long bone.

Contains blood vessels and nerves.

Question 30

What is the function of the periosteum?

Answer 30

Forms an attachment with tendons.

Question 31

What is marrow?

Answer 31

A fatty substance that can be either red or yellow.