Skeletal- Histology

Question 1

Describe the process of the formation of the skeleton?

Answer 1

1. Bone collar forms around the hyaline cartridge model
2. Cartilage in the centre of the diaphysis calcifies and develops into cavities.
3. The periosteal bud invades the internal cavities and spongy bone begins to form.
4. The diaphysis elongates and a medullary cavity forms as ossification continues. Secondary ossification centre appears in the epiphyses in prep for stage 5.
5. The epiphyses ossify when completed, hyaline cartilage remains only in the epiphyseal plate and articular cartilage.

Question 2

What are the 6 functions of the skeleton?

Answer 2

Protects internal organs 
Stores and releases fats
Produces blood cells
Stores and releases minerals 
Facilitates movement 
Supports the body

Question 3

Define Axial?

Answer 3

Involves skeletal structures within the CNS such as the brain and the spinal cord

Question 4

Define Appendicular?

Answer 4

Involves skeletal structures such as the lower limbs and upper limbs.

Question 5

What are the 3 main types of cartilage?

Answer 5

Hyaline
Fibrocartlidge
Elastic

Question 6

Define Hyaline cartilage?

Answer 6

Translucent matrix which is the most common type.
Covered by dense perichondrium matrix contains closely packed collagen fibres.
Provides rough but flexible support.

Question 7

Define Elastic cartilage?

Answer 7

Contains elastic fibres allowing it to be flexible
Tolerates distortion
Found in the outer ear and epiglottis.

Question 8

Define fibrocartlidge?

Answer 8

Matrix dominated by large collagen fibres
Tough durable
Results in compression and absorption
Prevents bone damage

Question 9

What are the two types of bone?

Answer 9

Compact

Spongy

Question 10

What type of marrow is in bone?

Answer 10

Yellow bone marrow

Red bone marrow

Question 11

What is the function of yellow and red bone marrow

Answer 11

Yellow bone marrow - stores fat

Red bone marrow- Produced red blood cells

Question 12

Define and give an example of compact bone?

Answer 12

Osteons are an example of compact bone
Osteocytes are arranged in concentric circled layers around the central canal with blood vessels.
Lamellae of osteons form cylinders around central canal
Blood vessels supply blood to osteons

Question 13

What is a osteon surrounded by?

Answer 13

Periosieum

Question 14

Define and give an example of spongy bone?

Answer 14

Lamellae forms rods called TRABERCULAE.
Frequent branching causes thin trabecular creates an open network.
Nutrients via canaliculi
Red marrow is found between trabercuale.

Question 15

Define the structures of the bone?

Answer 15

Diaphysis- Bone shaft

Epiphysis- Proximal and distal ends of the bone

Metaphysis- Region between the diaphysis and epiphyses

Periosteum- Tough connective tissue sheath and its associated blood supply that supplies the bone surface

Medullary cavity- Cavity within the diaphysis that contains the bone marrow and vessels.

Question 16

Define what a long bone is?

Answer 16

Tubular structure e.g FEMUR

Question 17

Define what a short bone is?

Answer 17

Cuboidal structure e.g TARSALS

Question 18

Define what a flat bone is?

Answer 18

Protective function e.g CRANIUM

Question 19

Define what an irregular bone is?

Answer 19

Various shapes such as a zygomater

Question 20

Define a sesamoid bone?

Answer 20

Tendons e.g PATELLA

Question 21

What are the 4 types of cells present in bone tissue and define them

Answer 21

1. Osteoprogentior cells
   Tissue from which almost all connective tissue are formed
2. Osteoblast
   Secrete collagen fibres to build extracellular matrix of bone tissue.
3. Osteocytes
   Maintain daily metabolism of bone tissue, such as exchange of nutrients with blood.
4. Osteoclasts
   Releases powerful enzymes that digest the protein and mineral components of the extra cellular matrix.

OSTEOBLASTS BUILD BONE OSTEOCLASTS CONSUME BONE

Question 22

Explain the vasculature of bone?

Answer 22

Nutrient arteries pass through the foramen
Blood reaches the osteoclasts in the compact bone by Haversian systems.
Ends of the bones supplied by metapheseal and epiphyseal arteries

Question 23

How much calcium does the bone store

Answer 23

99%

Question 24

What cells depend on a stable level of calcium ions in extracelluar fluid

Answer 24

Nerve and Muscle cells

Question 25

How does bone regulate calcium homeostasis?

Answer 25

Regulates via blood plasma using osteoclasts when the levels decrease and absorbed calcium using osteoclasts when level rises.

Question 26

Whats the general treatment for fractures

Answer 26

To realign and immobilise the bone fragments to restore functions.

Question 27

Define what reduction is for a fracture?

Answer 27

Where the fracture ends must be brought into alignment.

Question 28

What are the 2 types of alignment?

Answer 28

Closed reduction | Open reduction

Question 29

Define the 2 types of reduction?

Answer 29

Closed reduction- Fractured ends of bones are brought into line alignment. My manual manipulation and skin remains intact. Open reduction- Fractured ends of a bone are brought into alignment by a surgical procedure using fixative devices such as screws.

Question 30

What are the 4 stages of healing?

Answer 30

1. Hematoma formation 2. Fibrocartildginous callus formation 3. Bony callus formation 4. Bone remodelling

Question 31

What cells remove the dead and damaged tissue around the fracture hematoma.

Answer 31

Phagocytes and osteoclasts.

Question 32

Define the entire process of heeling?

Answer 32

Blood vessels crossing the fracture line are broken Mass of blood forms around the site of the fracture Formation of a fibrocartilaginous callus, and a bony callus to bridge the gap between the broken ends of the bones. Blood vessels grow into the fracture hematoma and phagocytes begin to clear up dead blood cells. Fibroblasts from the periosteum invade the fracture site and produce collagen fibres. osteoprogenitor cells develop into osteoblasts, which begin to produce spongy bone trabeculae. the fibrocartilage is converted to spongy bone, and the callus is then referred to as a bony callus. Dead portions of the original fragments of broken bone are gradually resorbed by osteoclasts. Compact bone replaces spongy bone around the periphery of the fracture

Question 33

What are the 3 types of joints?

Answer 33

Fibrous Cartilaginous Sinovial

Question 34

What is a joint

Answer 34

Unison between two or more bones.

Question 35

Define fibrous joint?

Answer 35

Sutures on the cranium are examples of this are examples of fibrous joints. These bones are held close together, either interlocking along a wavy line or overlapping.

Question 36

Define Cartilaginous joint?

Answer 36

* United by hyaline cartilage or fibrocartilage. * Primary cartilaginous joints are temporary unions, such as those present during the development of a long bone. * Secondary cartilaginous joints are strong, slightly moveable joints united by fibrocartilage.

Question 37

Define Synovial joint?

Answer 37

The most common type of joint. •Provide free movement between the bones they join. •Joints of locomotion.

Question 38

Define plane joint?

Answer 38

Permit gliding or sliding movements in the plane of the articular surfaces. The opposed surfaces of the bones are flat or almost flat, with movement limited by their tight joint capsules. •Example includes acromioclavicular joint

Question 39

Define grade 1 fracture?

Answer 39

Grade I – AC sprain. A slight displacement of the joint. The acromioclavicular ligament may be stretched or partially torn. This is the most common type of injury to the AC joint.

Question 40

Define grade 2 fracture?

Answer 40

Grade II - A partial separation of the joint in which there may be some superior displacement of the clavicle that may not be obvious during a physical examination. The acromioclavicular ligament is completely torn, while the coracoclavicular ligaments remain intact.

Question 41

Define grade 3 fracture?

Answer 41

Grade III - A complete separation of the joint. The acromioclavicular ligament, the coracoclavicular ligaments, and the capsule surrounding the joint are torn. Usually, the displacement is obvious on clinical exam. Without any ligament support, the shoulder falls under the weight of the arm and the clavicle is pulled up by the trapezius and SCM, causing a bump on the shoulder.

Question 42

Define a hinge joint?

Answer 42

* Permit flexion and extension only. * The joint capsule is thin and lax anteriorly and posteriorly where movement occurs * Bones are joined by strong lateral collateral ligaments * (elbow joint)

Question 43

Define a condyloid joint?

Answer 43

* Permit flexion and extension as well as adduction and abduction. * Metacarpophalangeal joints

Question 44

Define a pivot joint?

Answer 44

* Permit rotation around a central axis. | * Atlantoaxial joint is a pivot joint in which the atlas rotates around the dens of the axis during rotation of head.

Question 45

What movement does ball and socket joint permit?

Answer 45

Allow movement in multiple axes and planes (flexion, extension, abduction, adduction, medial rotation, lateral rotation and circumduction. •Spheroidal surface of one bone moves within the socket of another.