Lecture: Anatomy 2: Principles of the skeletal system

Question 1

What are the 2 divisions of the skeletal system?

Answer 1

1. Axial

2. Appendicular

Question 2

What parts of the skeletal system are found in the axial division?

Answer 2

Cranium, thoracic cage, spine and sacrum

Question 3

What parts of the skeletal system are found in the appendicular division?

Answer 3

Shoulders, hips and limbs

Question 4

What are the functions of the skeletal system?

Answer 4

• Protection of organs
• Supports the body
• Movement
• Metabolic reservoir
• Production of new red blood cells

Question 5

Where are the skeletal system and connective tissue derived from?

Answer 5

Derived from the mesoderm which is formed by epiblasts during embryological development.

Question 6

What is cartilage?

Answer 6

A form of connective tissue which forms the skeleton in parts where flexibility is required.
Avascular.

Question 7

What is bone?

Answer 7

A hard form of connective tissue that provides a rigid framework.
Either compact or spongy.
Vascular

Question 8

What is ossification?

Answer 8

Bone development

Question 9

What are the 2 types of ossification?

Answer 9

1. Intramembranous

2. Endochondral

Question 10

What occurs during intramembranous ossification?

Answer 10

ells divide and condense around capillary network, starting at the primary ossification centre.

Question 11

What happens to undifferentiated mesenchyme in intramembranous ossification?

Answer 11

Undifferentiated mesenchyme gives rise to bone marrow.

Question 12

Where does intramembranous ossification take place?

Answer 12

The skull, mandible and clavicle.

Question 13

What occurs during endochondral ossification?

Answer 13

Cartilaginous template made from the mesenchyme is replaced by bone in a process known as osteogenesis.

Question 14

Where does endochondral ossification take place?

Answer 14

The skull base, vertebrae, long bones and pelvis.

Question 15

What are the 4 types of bone cells?

Answer 15

• Osteoprogenitor cells
• Osteoblasts
• Osteocytes
• Osteoclasts

Question 16

What dietary minerals and vitamins are required for bone maintence?

Answer 16

• Calcium
• Phosphorous
• Vitamin A
• Vitamin C
• Vitamin D

Question 17

How is bone development controlled by hormones?

Answer 17

Bone development is controlled by endocrine activity of parathyroid hormone and growth hormone.

Question 18

What is acromegaly?

Answer 18

Acromegaly is a condition caused by the overproduction of growth hormone resulting in large hands and feet.

Question 19

What is the periosteum?

Answer 19

The connective tissue that covers the skeletal system except where articulation occurs.

Question 20

What is the perichondrium?

Answer 20

The connective tissue surrounding cartilage.

Question 21

Describe the structure of compact (cortical) bone

Answer 21

Composed of lamellae (concentric layers) of bone formed by osteoblasts which become osteocytes.
Radiating from each lacunae are canaliculi.
Haversian canal in the centre of compact bone contains the neurovascular supply.

Question 22

Describe the structure of spongy (cancellous or trabecular) bone

Answer 22

Irregular bony plates called trabeculae which are surrounded by red marrow and are highly vascularised.

Question 23

What are the 3 classes of joints?

Answer 23

Synovial, fibrous, cartilaginous

Question 24

What are synovial joints?

Answer 24

Synovial joints have a joint capsule and a synovial cavity, and they permit movement.

Question 25

What are fibrous joints?

Answer 25

Fibrous joints are connected by collagen and do not permit movement, eg. sutures of skull

Question 26

What are cartilaginous joints?

Answer 26

Cartilaginous joints are connected by cartilage to allow some movement, eg. pubic symphysis and growth plate.