Skeletal System Self Test

Question 1

What are the 6 main functions of the skeletal system?

Answer 1

• Support: Keeps your body upright
• Protection: Shields vital organs from injury
• Movement: Works with muscles to move your body
• Mineral Storage: Acts as a mineral bank, especially for calcium
• Blood Cell Production: Produces cells vital for oxygen transport, immunity, and clotting
• Energy Storage: Stores fat that can be used as fuel

Each function plays a crucial role in maintaining overall health and mobility.

Question 2

What is an example of short bones?

Answer 2

The bones of the wrist are examples of short bones.

Short bones provide stability and support with little movement.

Question 3

What is an example of long bones?

Answer 3

The bone of the thigh is an example of long bones.

Long bones are primarily responsible for movement and support.

Question 4

What are irregular bones? Give an example.

Answer 4

Vertebrae are examples of irregular bones.

Irregular bones have complex shapes that do not fit into other categories.

Question 5

What is a sesamoid bone? Give an example.

Answer 5

The patella is an example of a sesamoid bone.

Sesamoid bones are embedded within tendons and help protect them.

Question 6

What are flat bones? Provide an example.

Answer 6

The skull bones that form a protective covering of the brain are flat bones.

Flat bones serve as protective plates and are typically thin.

Question 7

What are sutural bones?

Answer 7

Extra bones that sometimes develop between the flat bones of the skull are called sutural bones.

Sutural bones can vary among individuals and are not present in everyone.

Question 8

Why is bone tissue classified as connective tissue?

Answer 8

Bone tissue is classified as connective tissue due to its origin from mesenchymal stem cells and its significant extracellular matrix (ECM).

This classification is based on its structural characteristics and functions.

Question 9

What contributes to the hardness and tensile strength of bone?

Answer 9

• Mineralized matrix (hydroxyapatite): Provides hardness
• Collagen fibers (protein): Provides tensile strength

These components work together to ensure bones can withstand various forces.

Question 10

List the structural features of compact bone.

Answer 10

Compact bone is also called cortical bone and is characterized by:
* Osteons
* Dense structure
* Located in bone shafts and outer surfaces

Compact bone provides strength and support.

Question 11

List the structural features of spongy bone.

Answer 11

Spongy bone is also called cancellous or trabecular bone and is characterized by:
* Trabeculae
* Porous structure
* Located in bone ends and inside flat/irregular bones

Spongy bone is lightweight and houses red marrow.

Question 12

What are osteoblasts?

Answer 12

Bone-building cells that form bone matrix and lower blood calcium.

Osteoblasts are crucial for bone formation and growth.

Question 13

What are osteoclasts?

Answer 13

Bone-dissolving cells that resorb bone matrix and raise blood calcium.

Osteoclasts play a key role in bone remodeling.

Question 14

What happens when osteoblast activity is greater than osteoclast activity?

Answer 14

The amount of bone tissue increases.

This condition is important for bone growth and healing.

Question 15

What effect does greater osteoblast activity have on blood calcium levels?

Answer 15

Blood calcium levels decrease.

Osteoblasts deposit calcium into bone, reducing its availability in the blood.

Question 16

What is articular cartilage?

Answer 16

A smooth, white tissue that covers the ends of long bones where they meet to form joints.

It enables smooth and pain-free joint movement.

Question 17

What are the clinical consequences of degeneration of articular cartilage?

Answer 17

• Joint pain
• Stiffness
• Swelling and inflammation
• Reduced mobility
• Joint deformity
• Crepitus (grating sensation)

These symptoms can greatly impact quality of life and joint function.

Question 18

What is osteoarthritis?

Answer 18

The most common condition associated with articular cartilage degeneration.

Osteoarthritis results in joint pain and stiffness, often due to aging or injury.

Question 19

Differentiate between epiphyseal plate and epiphyseal line.

Answer 19

• Epiphyseal Plate: Growth plate, allows longitudinal growth, present in children and adolescents
• Epiphyseal Line: Remnant of growth plate, indicates growth is complete, present in adults

Injury to the epiphyseal plate can impair growth and lead to deformities.

Question 20

What are the steps of intramembranous ossification?

Answer 20

• Development of the Ossification Center
• Secretion of Bone Matrix (Osteoid) and Calcification
• Formation of Trabeculae
• Development of Periosteum and Compact Bone

This process forms flat bones directly from mesenchymal tissue.

Question 21

What are the steps of endochondral ossification?

Answer 21

• Development of the Cartilage Model
• Growth of the Cartilage Model
• Development of the Primary Ossification Center
• Development of the Medullary (Marrow) Cavity
• Development of Secondary Ossification Centers
• Formation of Articular Cartilage and Epiphyseal Plate

This process replaces hyaline cartilage with bone, forming most bones of the body.

Question 22

What gland releases calcitonin?

Answer 22

Thyroid gland (C cells).

Calcitonin plays a role in lowering blood calcium levels.

Question 23

What gland releases parathyroid hormone (PTH)?

Answer 23

Parathyroid glands.

PTH is crucial for increasing blood calcium levels.

Question 24

Which hormone promotes bone mass reduction?

Answer 24

Chronic PTH.

Excess PTH can lead to bone loss and osteoporosis.

Question 25

Which hormones promote bone growth?

Answer 25

* Growth Hormone (GH) * Estrogen/Testosterone * Thyroid Hormone (normal levels) * Insulin * Calcitonin (minor role) * Vitamin D (indirectly) ## Footnote These hormones contribute to bone density and strength.

Question 26

What suggestions would you prescribe for a young female patient to remain bone healthy?

Answer 26

Maximize bone density now through calcium- and vitamin D-rich foods, exercise, and healthy habits. ## Footnote Early intervention is key to preventing osteoporosis.

Question 27

What is the impact of very low vitamin D levels on bone health?

Answer 27

Impaired calcium absorption leads to poor bone mineralization and increased risk of fractures. ## Footnote Maintaining vitamin D levels is essential for bone health.

Question 28

Why is it important to engage in weight-bearing exercises before the epiphyseal plates close?

Answer 28

Enhances bone length, mass, and density, setting a strong skeletal foundation. ## Footnote This is critical for maximizing bone health.

Question 29

Why would you expect the arm bones of a weight lifter to be thicker and heavier than those of a jogger?

Answer 29

Bone responds to localized mechanical load by increasing in mass and strength—this is Wolff’s Law in action. ## Footnote Weight-bearing activities stimulate bone growth.

Question 30

What can happen if a bone is injured at the epiphyseal plate?

Answer 30

It can impair bone growth, leading to shortening, deformity, or asymmetry. ## Footnote Timely management is critical in pediatric orthopedics.

Question 31

What is the diagnosis for Kate, who has bowed legs and cranial and pelvic deformities?

Answer 31

Rickets, caused by a vitamin D deficiency. ## Footnote Rickets leads to poorly mineralized, soft bones during critical growth periods.

Question 32

How does vitamin D deficiency affect bone development?

Answer 32

It results in poorly mineralized bones, leading to deformities and increased fracture risk. ## Footnote Adequate vitamin D is necessary for proper calcium absorption and bone health.