Bone Structure and Function

Question 1

What is the skeletal system made up of?

Answer 1

Bones along with their cartilages.

Question 2

How many bones are you born with? Then later what happens?

Answer 2

You are born with 300 bones, which later fuse together into the 206 bones of an adult.

Question 3

What is a function of the skeletal system in red bone marrow?

Answer 3

Blood cell production.

Question 4

What is the function of the skeletal system in yellow bone marrow?

Answer 4

Triglyceride storage.

Question 5

What does the skeletal system protect?

Answer 5

Internal organs.

Question 6

The skeletal system has muscle attachments, what does this aid with?

Answer 6

Movement.

Question 7

The skeletal system stores minerals in a process called what?

Answer 7

Mineral homeostasis.

Question 8

What does the skeletal system do structurally?

Answer 8

Support the framework of the body.

Question 9

What are the 5 types of bones?

Answer 9

Long, short, flat, sesamoid, irregular.

Question 10

Where are long bones found?

Answer 10

In the arms and legs.

And collarbones (clavicle).

Question 11

Give some examples of long bones in the arms and hands. (5)

Answer 11

Humerus (upper arm).
Radius (lower arm).
Ulna (lower arm).
Metacarpals (hand).
Phalanges (fingers).

Question 12

Give some examples of long bones in the legs and feet. (5)

Answer 12

Femur (upper leg).
Tibia (lower leg)
Fibula (lower leg).
Metatarsals (feet).
Phalanges (toes).

Question 13

Where are short bones found?

(hint: where you sprain)

Answer 13

In the wrist and ankle.

(carpals and tarsals)

Question 14

Where are flat bones found?

Answer 14

Rib cage, skull, shoulder blade, breastbone

Question 15

What are two examples of sesamoid bones?

Answer 15

Pisiform (carpal)
Patella (kneecap_

Question 16

Give some examples of irregular bones. (4)

Think of capital i shape.

Answer 16

Skull, ears, spine, hips.

Question 17

With the macroscopic anatomy of a long bone, draw and label the different parts.

Name them starting from the top.

Answer 17

Articular Cartilage
Proximal Epiphysis
Metaphysis
Diaphysis
Metaphysis
Distal Epiphysis
Articular Cartilage

Question 18

What is the diaphysis?

Answer 18

Shaft of the bone.

Question 19

Where is the epiphysis?

Answer 19

Located at the distal and proximal ends of the bone.

Question 20

Where is the metaphysis?

Answer 20

Located between the diaphysis and epiphysis.

Question 21

What is articular cartilage?

Answer 21

Hyaline cartilage (connective tissue) covering the epiphysis where bone articulates with another bone.

Question 22

Where is the periosteum and what are its 2 layers?

Answer 22

It surrounds the external bone surface.
Outer surface = fibrous layer
Inner surface = cellular layer

Question 23

What is the endosteum?

Answer 23

A thin membrane that lines the surface of the medullary cavity.

Question 24

How does a paediatric (child) long bone differ from an adult long bone?

Answer 24

A child’s long bone has a growth plate (physis) which is a thin layer of hyaline cartilage responsible for the growth and development of long bones in children and adolescents.

Question 25

What are the two types of bone tissue?

Answer 25

Compact and cancellous.

Question 26

What is the function of compact bone tissue?

Answer 26

- To protect and support the bone. - To resist stresses of weight and movement.

Question 27

What are the structural units in compact bones that are shaped as microscopic cylinders?

Answer 27

Osteons.

Question 28

What is on the inner and outer surface of compact bone? What does it act as a boundary to?

Answer 28

Outer surface = periosteum. Inner surface = endosteum which acts as a boundary between compact and cancellous bone tissue.

Question 29

In an osteon, what is the central canal called and what does it contain?

Answer 29

- Haversian canal - Contains the arterial blood supply (blood vessels), venous drainages, lymphatic vessels and nerves.

Question 30

What run parallel to the long bone axis? What do they do?

Answer 30

Volkmann's canals are at right angles to the central canal. They join the various haversian canals. They allow blood vessels to enter the bone and haversian canal from the periosteum. (connect periosteum + haversian canal)

Question 31

What are the rings in an osteon called? What do they contain?

Answer 31

Lamellae. Contains extracellular matrix.

Question 32

What do the collagen fibres and mineral salts do?

Answer 32

They are in the bone matrix and run in opposite directions to give great torsion strength. (resists twisting force.)

Question 33

What do the canaliculi do?

Answer 33

Connect lacunae for nutrient delivery and waste removal.

Question 34

What are lacunae and what do they contain?

Answer 34

They are 'small lakes' that house osteocytes.

Question 35

Where is the extracellular matrix and what do they consist of?

Answer 35

- They are located in the lamellae between the osteocytes. - They consist of organic and inorganic components and water.

Question 36

What is the organic component of the extracellular matrix and what does it give?

Answer 36

- Osteoid - protein and collagen. - Gives bone its tensile strength.

Question 37

What is the inorganic component of the extracellular matrix and what does it give?

Answer 37

- Hydroxyapatite (calcium phosphate + calcium hydroxide) - Mineral portion of bone - Gives bone strength and density

Question 38

What is the function of cancellous bone tissue?

Answer 38

- To reduce the overall weight of the bone. - To support and protect red bone marrow.

Question 39

What is cancellous bone also referred to? Why? What does cancellous bone not contain as opposed to compact bone?

Answer 39

- Spongy bone (due to appearance, not its texture) - Does not contain osteons or a haversian canal.

Question 40

What does cancellous bone consist of? What do the spaces between them help with?

Answer 40

- They consist of an irregular lattice of thin columns called trabeculae. - Spaces between trabeculae help make bones lighter and sometimes contain red bone marrow.

Question 41

What are the openings on the surface of cancellous bones, what do they do?

Answer 41

- Canaliculi - Connect to adjacent cavities instead of a haversian canal for a blood supply.

Question 42

Where is bone marrow found and what is it?

Answer 42

- Found in cancellous bone. - Nutrient-dense, spongy tissue. - Produces white and red blood cells and platelets. - Contains stem cells.

Question 43

In contrast to compact bone, is cancellous bone: 1) Stronger or weaker? 2) More or less dense? 3) More or less flexible?

Answer 43

1) Weaker. 2) Less dense. 3) More flexible.

Question 44

What are the four types of cells found in bone? (cells of bone formation)

Answer 44

Osteoprogenitor cells, osteoblasts, osteocytes, osteoclasts.

Question 45

What are osteoprogenitor cells? Where are they located?

Answer 45

- Unspecialised stem cells, precursors to osteoblasts. - Located in inner layer of periosteum, the endosteum and epiphyseal plates of growing bone.

Question 46

What are osteoblasts? Where are they located? What can happen to osteoblasts? [CONSTRUCTION WORKERS]

Answer 46

- Osteoblasts make new bone, and synthesise osteoid and the enzyme required to form hydroxyapatite. Also regulate calcification. - They thicken the bone by depositing osteoid. - Located on all bone surfaces - As they deposit new bone and become trapped in bone matrix, they can become/differentiate into osteocytes and supply nutrition to the bone.

Question 47

What are osteocytes? What do they do? Where are they located? [MAINTENANCE GUYS]

Answer 47

- Mature osteoblasts. - They maintain daily metabolism and nutrient exchange. (regulate existing bone). - They have long cytoplasmic extensions which help supply nutrients to existing bone. - Located in the lacunae of cancellous and compact bone within the bone matrix.

Question 48

What are osteoclasts? What do they do? Where are they located? [PHAGOCYTIC CELLS]

Answer 48

- They are formed from white blood cells. - They release enzymes and acids to digest components of the matrix. (bone degradation, erodes and recycles existing bone by breaking down tissue). - Work with osteoblasts to maintain calcium homeostasis and respond to mechanical stress. - Located on all bone surfaces and particularly concentrated in the endosteum.

Question 49

What are the identifying features of osteoblasts, osteocytes and osteoclasts?

Answer 49

- Osteoblasts - single nucleus, sits on surface of bone. - Osteocytes - have cytoplasmic projections and a single nucleus. - Osteoclasts - large and multinuclear.