Lecture 17 - Skeletal System

Question 0

What are the four most common types of bone into which most bones can be classified

Answer 0

Long
Short
Flat
Irregular

Question 1

What is the major division of the skeleton?

Answer 1

Axial

Appendicular

Question 2

What are accessory bones?

Answer 2

These are evolutionary relics that appear as anomalies

Question 3

What are sesamoid bones?

Answer 3

These are bones that are embedded in tendon

Eg. Patella

Question 4

What are pneumatic bones?

Answer 4

These are bones that have been hollowed out during development to reduce the weight.

Eg. The skull and the sinuses of the face

Question 5

What are the articular surfaces of the bone?

Answer 5

These are the regions that interact with other bones

Question 6

What are the general features of long bones?

Answer 6

• Proximal and Distal end
• Shaft
• Articular surfaces

Question 7

What is the function of the periosteum?

Answer 7

Rich blood and nerve supply

Question 8

What are the two layers of the periosteum?

Answer 8

Inner: osteogenic
Outer: fibrous

Question 9

What is the function of the endosteum?

Answer 9

Osteogenic

Question 10

What are the different densities of bone?

Answer 10

Cancellous: spongy, holes
Compact: very dense

Question 11

What and where is the medullary cavity?

Answer 11

It is the cavity in the shaft of the bone

Red and yellow bone marrow are found here

Question 12

What is the different between red and yellow marrow?

Answer 12

Red: hematopoetic
Yellow: present in older people

Question 13

There are no nerves inside the bone, yet when a bone is fractured, it is painful. Account for this

Answer 13

The pain comes from the tearing of the periosteum, which has a rich nerve supply

Question 14

Differentiate between increasing width and length of bone

Answer 14

Increasing the width: inner periosteum and the endosteum

Increasing length: epiphysial line

Question 15

What is another name for compact bone?

Answer 15

Cortical

Question 16

What is important about trabecular bone?

What is meant by this term?

Answer 16

Capable of resisting static forces, due to:

• Special orientation of the spongy bone

Question 17

What are static forces?

Answer 17

Weight bearing forces

Question 18

What is intramembranous ossification?

Answer 18

This is when the bone forms in membrane

Eg. The skull

Question 19

What are the structural layers of the skull bone?

Answer 19

Outer compact
Spongy bone
Inner compact

Question 20

What is the name of the triangular hole in the skull present at birth?

Answer 20

Fontanelle

Question 21

What is endochondral ossification?

Answer 21

This is when the bone forms in cartilage

Question 22

What are the three types of cartilage?

Answer 22

Hyaline
Fibro
Elastic

Question 23

How do most bones of the body form?

Answer 23

After about 2 months, the foetus has bones that have grown out of hyaline cartilage

Endochondral ossification

Question 24

Where does ossification first occur in bone?

Answer 24

At the primary centres in the shaft of the cartilage precursor

Question 25

Describe replacement of cartilage with bone

Answer 25

At the primary centre in the centre of the cartilage, replacement of cartilage with bone occurs, extending towards the ends

Question 26

What is the name for the shaft of the developing bone?

Answer 26

Diaphysis

Question 27

What is the name of the ends of the developing bones?

Answer 27

Epiphysis

Question 28

What is the name of the site of high metabolic activity and remodelling? Where is it?

Answer 28

Metaphysis Forms the boundary of the diaphysis at each end

Question 29

Is the cartilage of the developing bone completely replaced with bone?

Answer 29

Yes, apart from at the Articular cartilage The cartilage at the epiphysial plate is replaced after growth

Question 30

What are where is the nutrient foramen

Answer 30

Located in the middle of the shaft of the bone Artery delivers bone forming cells

Question 31

Which cells are important for bone formation?

Answer 31

Osteoblasts: forming bone Osteoclasts: remodelling bone

Question 32

What is the name of the cartilage that remains on the bone forever?

Answer 32

Articular cartilage

Question 33

What disorders can occur to the development of bone?

Answer 33

Achondroplasic dwarfism Spontaneous mutation causes the long bones to stop growing. Other bones are unaffected Chondrocytes fail to mature and enlarge

Question 34

Why are epiphyses clinically important?

Answer 34

- indicate that growth is still occuring - if damaged, there may be problems with growth - indicate the age of an individual in a forensic setting - may be confused with a fracture

Question 35

What are the four types of arteries that deliver blood to bone?

Answer 35

Nutrient Periosteal Metaphysical Epiphyseal

Question 36

What is clinically significant about the blood supply to bones?

Answer 36

End arteries: the only supply to the bone If blocked, e bone receives no blood

Question 37

What are the two different types of fracture?

Answer 37

Simple fracture: no breaking through skin | Compound fracture: bone breaks through skin