Bone Tissue Concepts

Question 1

Describe the six main functions of the skeletal system – for the 3 more “cellular” or “molecular” processes, describe any relevant tissues, cells, or molecules

Answer 1

• Provide support acting as a structural framework and a point of attachment for tendons and ligaments
• Protect internal organs
• Assist body movement
• Store and release salts of calcium and phosphate
• Participate in blood cell production (hematopoiesis)
• Store triglycerides in adipose cells of yellow marrow

Question 2

Contrast the location and role of red and yellow marrow

Answer 2

Red Marrow
-found inside the trabeculae of spongy bone
-produces blood cells

Yellow Marrow
-is found inside the medullary cavity
-used for fat storage

Question 3

Specific to the periosteum, describe its location, the composition of its layers, and the roles of each layer.

Answer 3

The periosteum is the membrane that covers all of the external surfaces of the body. The outer fibrous layer is made of dense irregular connective tissue. The inner layer is made of osteogenic cells.

Question 4

Contrast the periosteum to the endosteum

Answer 4

Periosteum
- Tough, fibrous membrane that covers all of the external surfaces of bone that’s not covered in articular cartilage

Endosteum
- Membrane that lines the medullary cavity

Question 5

Compare the structural and functional differences between compact and spongy bone tissue.

Answer 5

Compact bone
- Provides protection and support
- Forms the diaphysis of long bones and the external layer of all bones

Spongy bone
- Lightweight and provides tissue support
- Forms much of epiphysis and the internal cavity of long bones

Question 6

Explain why bone tissue (and cartilage) are classified as connective tissue.

Answer 6

The bone tissue and cartilage are classified as connective tissue because they have components of connective tissue: cells, fibers, and ground substance.

Question 7

Relate bone tissue back to the 3 major components of C.T.

Answer 7

Three major components connective tissues must have are cells, fibers, and ground substance. In bone tissue, the cells are osteoprogenitor cells, osteoblasts, osteoclasts, and osteocytes. The fibers found are collagen fibers and the ground substance is made of calcium phosphate.

Question 8

Describe and locate the anatomical and physiological roles of typical cells, fibers, and ground substances of both the cartilaginous and bone aspects of bone tissue

Answer 8

Osteiorogenitor cells= origin of all other bone cells
Osteocytes= maintain bone homeostasis
Oseteoblasts= create bone
Osteoclasts= absorb bone
Collagebn fibers=give slight flexibility to bones
Calcium phosphate= forms crystals of hydroxyapatite to harden tissue

Question 9

Take a tissue-level look at the skeletal system and identify some examples of where the 4 tissue types are found associated with bone tissue

Answer 9

Nervous tissue in the nerves accompanying blood vessels in the bones
Connective tissue (dense irregular) in periosteum of bone

Question 10

Locate the 2 areas of cartilage found in bones and the type of cartilage for both. Locate some areas where other types of cartilage are presently associated with bones

Answer 10

Hyaline cartilage at the epiphyseal plate within bones and at the articular cartilage at the ends of long bones
Fibrocartilage is found between vertebrae and is tougher and within bones during fracture repair

Question 11

Describe the blood and nerve supply of bone.

Answer 11

Nerves accompany blood vessels. Periosteal arteries and veins supply the periosteum and compact bone. Epipseal and metaphyseal arteries and veins supply the spongy bone with blood. The central canal holds blood vessels, running parallel to the long axis of the bone, and through perforating Volkmann’s canals connect perpendicularly to the outer cortex of the bone.

Question 12

Describe the organic component of bone tissue, and how you might get rid of it in vivo, and in a lab setting. Do the same with the inorganic component.

Answer 12

The organic components of bone tissue are collagen fibers. In a lab setting, baking the bones in the oven for a long time at hot temperatures will get rid of the organic components (brittle bone disease)

The inorganic component of bone tissue is mineralized calcium salts. In a lab setting, soaking bone in acid will design the inorganic components. (rickets/osteomalacia)

Question 13

Describe the differentiation from osteoprogenitor cells to osteoblasts/osteoblasts to osteocytes

Answer 13

Osteoprogenitor cells undergo cell division and those cells become osteoblasts. Osteoblasts are responsible for bone deposition and initiate calcification. In that process, the osteoblasts trap themselves in their own secretion of extracellular matrix and turn into osteocytes.

Question 14

Describe osteons and their structural components of them, focusing on lamellae, lacunae, osteocytes & canaliculi.

Answer 14

Osteons are made of a series of concentric lamellae surrounding a central canal. Within the osteons, there are small spaces between the lamellae called lacunae, which houses osteocytes. Canaliculi are small channels filled with extracellular fluid that connects these lacunae.

Question 15

Contrast the 4 different types of lamellae found in bone.

Answer 15

Concentric lamellae= rings of calcified matrix surrounding a central canal, make osteons
Interstitial lamellae= between osteons
inner circumferential lamellae= encircle the medullary cavity
outer circumferential lamellae= encircles the bone beneath the periosteum

Question 16

Describe how Haversian and Volkmann’s canals relate to one another

Answer 16

Haverian canals carry blood and lymphatic vessels that run parallel to the axis of the long bone and Volkmann’s canals allow transit of the vessels to the outer cortex of the bone, running perpendicular to the long axis of the bone. This means that the Gaversian and Valkmann’s canals are perpendicular to each other.

Question 17

Be able to discuss ontogenetic times where osteoblastic activity is higher than osteoclastic activity, and when the opposite is true. Be able to link both osteoblastic & osteoclastic activity to calcium concentrations in the blood.

Answer 17

Osteoblastic activity is higher than osteoclastic activity during childhood as the bones are still developing. Osteoclastic activity is higher than osteoblastic activity during old age as the level of sex hormones goes down.