The Skeletal System: Bone Tissue

A comprehensive set of flashcards based on key concepts about the skeletal system and bone tissue from an anatomy and physiology lecture.

What are the six functions of the skeletal system?

Provides support, protects internal organs, assists body movements, stores and releases calcium and phosphorus, participates in blood cell production, and stores triglycerides.

What is the diaphysis of a long bone?

The diaphysis is the bone shaft.

What are epiphyses?

Epiphyses are the ends of the bone at the joints.

What is the function of metaphyses in long bones?

Metaphyses are the regions between the diaphysis and epiphyses.

What is the periosteum?

The periosteum is the connective tissue surrounding the diaphysis of a long bone.

What is the medullary cavity?

The medullary cavity is the hollow space within the diaphysis.

What lines the medullary cavity?

The endosteum is the thin membrane lining the medullary cavity.

What types of cells are found in bone?

Osteoprogenitor cells, osteoblasts, osteocytes, and osteoclasts.

What do osteoprogenitor cells do?

Osteoprogenitor cells are bone stem cells that can differentiate into other types of bone cells.

What is the function of osteoblasts?

Osteoblasts are bone-building cells that secrete the bone matrix.

What is the role of osteoclasts?

Osteoclasts remodel bones and cause them to release calcium.

What is compact bone known for?

Compact bone provides protection and support.

What is spongy bone and its advantage?

Spongy bone is lightweight and provides tissue support.

How do periosteal arteries enter the diaphysis?

Periosteal arteries enter through Volkmann’s canals.

What is ossification?

Ossification (osteogenesis) is the process of bone formation.

When does ossification occur?

It occurs during embryological development, prior to adulthood, when bones remodel, and when fractures heal.

What are the two forms of ossification?

Intramembranous and endochondral ossification.

What occurs during intramembranous ossification?

A connective tissue membrane is replaced by bone during the formation of flat bones.

How does endochondral ossification work?

Endochondral ossification replaces cartilage with bone in developing embryos and fetuses.

What happens to bones during remodeling?

Bones thicken due to the cooperative action of osteoblasts and osteoclasts.

What is a fracture?

A fracture is a break in a bone.

What are the phases of fracture healing?

The reactive phase, reparative phase (fibrocartilaginous callus and bony callus formation), and bone remodeling phase.

What is a fracture hematoma?

A fracture hematoma is formed in the reactive phase after a fracture.

What types of common fractures exist?

Open (compound), comminuted, greenstick, impacted, Pott, and Colles fractures.

What is the role of bones in calcium homeostasis?

Bones store 99% of the body's calcium and assist in regulating calcium levels.

What signals the release of parathyroid hormone (PTH)?

The parathyroid gland secretes PTH when calcium levels drop.

What effect does PTH have on osteoclasts?

PTH stimulates osteoclasts to increase bone resorption, releasing calcium.

How does PTH affect the kidneys?

PTH promotes calcium retention in the blood, excretion of phosphate in urine, and production of calcitriol.

What is the controlled condition when calcium levels drop?

Blood calcium (Ca2+) level.

What happens to bone mass from birth through adolescence?

More bone is produced than lost during remodeling.

How does bone mass change in older individuals?

Older individuals typically experience a decrease in bone mass when resorption outpaces deposition.

What happens during reactive phase of fracture healing?

Formation of a fracture hematoma.

What is formed in the reparative phase of fracture healing?

Formation of a fibrocartilaginous callus and then a bony callus.

What is the role of osteocytes?

Osteocytes maintain bone tissue.

What is the significance of trabeculae in spongy bone?

Trabeculae support and strengthen spongy bone.

What types of tissue are found in the periosteum?

The periosteum contains dense connective tissue.

What is calcification in bone formation?

Calcification is the deposition of calcium and other mineral salts in the extracellular matrix.

When do long bones grow in length?

Long bones grow in length during endochondral ossification at the epiphyseal plates.

What does the term epiphyseal line refer to?

The epiphyseal line is where the epiphyseal plate once was after growth stops.

What type of cartilage is replaced during endochondral ossification?

Hyaline cartilage is replaced by bone.

How do fractures heal?

Fractures heal through a series of controlled inflammatory and repair processes.

What is the role of blood vessels during ossification?

Blood vessels provide nutrients necessary for the differentiation and function of bone cells.

What mineral is primarily stored in bones?

Calcium.

Why is the endosteum important?

The endosteum is important for bone remodeling and growth.

What affects calcium absorption in the intestines?

Calcitriol, produced by the kidneys under the influence of PTH.

What happens to the rate of bone production and loss in adults?

The rates of bone production and loss become equal.

What is the effect of aging on women’s bone mass?

Post-menopausal women may experience a significant decrease in bone mass.

What does trabecular network in spongy bone do?

Provides structural support and houses red bone marrow.

What is the function of periosteal veins?

Periosteal veins accompany arteries and help drain blood from the bone.

What do osteoclasts utilize to break down bone?

Osteoclasts utilize acids and enzymes to resorb bone.

How is blood calcium level regulated?

By the balance between osteoclast activity and bone deposition.

What triggers the production of cyclic AMP in parathyroid gland cells?

A decrease in blood calcium concentration.