Bones and Skeletal Tissues Flashcards

Flashcards covering Marieb Human Anatomy & Physiology Twelfth Edition Chapter 06: Bones and Skeletal Tissues, focusing on cartilage, bone functions, classification, structure, cell types, microscopic anatomy, chemical composition, development, growth, remodeling, repair, and common disorders.

What is skeletal cartilage primarily made of?

Highly resilient, molded cartilage tissue that consists primarily of water, containing no blood vessels or nerves.

What is the function of the perichondrium?

It is a layer of dense connective tissue surrounding cartilage that helps it resist outward expansion and contains blood vessels for nutrient delivery.

What are the three types of cartilage found in the human skeleton?

Hyaline cartilage, Elastic cartilage, and Fibrocartilage.

Which type of cartilage is the most abundant and found in articular surfaces, ribs, larynx, and external nose?

Hyaline cartilage.

Which type of cartilage is similar to hyaline but contains elastic fibers, found in the external ear and epiglottis?

Elastic cartilage.

Which type of cartilage has thick collagen fibers for great tensile strength and is found in the menisci of the knee, public symphysis, and intervertebral discs?

Fibrocartilage.

What are the two ways cartilage grows?

Appositional growth and Interstitial growth.

What are the seven important functions of bones?

Support, Protection, Anchorage, Mineral storage, Blood cell formation (hematopoiesis), Triglyceride (fat) storage, and Hormone production of osteocalcin.

What are the two main groups of the human skeleton based on location?

Axial skeleton and Appendicular skeleton.

What are the four classifications of bones by shape?

Long bones, Short bones, Flat bones, and Irregular bones.

What is the main difference between compact bone and spongy bone?

Compact bone is the dense outer layer that appears smooth and solid, while spongy bone is made up of a honeycomb of small, needle-like or flat pieces of bone called trabeculae with open spaces filled with marrow.

What are the main components of a long bone's structure?

A shaft (diaphysis), bone ends (epiphyses), and membranes (periosteum and endosteum).

What is the periosteum?

A white, double-layered membrane covering external bone surfaces except joints, consisting of a fibrous layer and an osteogenic layer, and serving as anchoring points for tendons and ligaments.

Where is red bone marrow found in adults, and what is its function?

It is found within trabecular cavities of spongy bone and diploë of flat bones (like the sternum), and in the heads of the femur and humerus; its function is hematopoiesis (blood cell formation).

What are the five major cell types of bone tissue?

Osteoprogenitor (osteogenic) cells, Osteoblasts, Osteocytes, Bone-lining cells, and Osteoclasts.

What are osteoblasts and what do they secrete?

Bone-forming cells that secrete unmineralized bone matrix called osteoid, which is made up of collagen and calcium-binding proteins.

What are osteocytes and what is their role?

Mature bone cells in lacunae that no longer divide, which maintain bone matrix and act as stress or strain sensors, communicating information for bone remodeling.

Which bone cells are responsible for bone resorption (breakdown of bone)?

Osteoclasts.

What is an osteon (Haversian system)?

The structural unit of compact bone, consisting of an elongated cylinder that runs parallel to the long axis of the bone and acts as a tiny weight-bearing pillar.

What runs through the central (Haversian) canal of an osteon?

Blood vessels and nerve fibers.

What are canaliculi and what is their function?

Hairlike canals that connect lacunae to each other and to the central canal, enabling communication between osteocytes and relaying nutrients and wastes.

What are the organic and inorganic components of bone?

Organic components include bone cells and osteoid (collagen, ground substance); inorganic components are hydroxyapatites (mineral salts) mainly calcium phosphate crystals.

What is ossification (osteogenesis)?

The process of bone tissue formation.

What are the two main types of ossification that form the bony skeleton?

Endochondral ossification and Intramembranous ossification.

Which type of ossification forms most bones inferior to the base of the skull by replacing hyaline cartilage?

Endochondral ossification.

Which type of ossification forms flat bones like the frontal, parietal, occipital, temporal, and clavicle bones, developing from fibrous membranes?

Intramembranous ossification.

What allows long bones to grow lengthwise during postnatal bone growth?

Interstitial (longitudinal) growth of the epiphyseal plate.

What allows bones to increase in thickness (width)?

Appositional growth.

What hormones are most important in regulating bone growth?

Growth hormone, thyroid hormone, and sex hormones (testosterone and estrogens).

What is bone remodeling, and what cells are primarily involved?

A continuous process of bone deposit and bone resorption, coordinated by packets of adjacent osteoblasts and osteoclasts.

What two control loops regulate bone remodeling?

Maintaining Ca2+ homeostasis (hormonal control) and keeping bone strong (mechanical and gravitational forces).

What hormone is produced by the parathyroid glands in response to low blood calcium levels, stimulating osteoclasts?

Parathyroid hormone (PTH).

What is Wolff's law?

It states that bones grow or remodel in response to demands placed on them, explaining why bones thicken where bending stresses are greatest or where muscles attach.

What are the four major stages of fracture repair?

Hematoma forms, Fibrocartilaginous callus forms, Bony callus forms, and Bone remodeling occurs.

What are osteomalacia and rickets?

Osteomalacia is a disease where bones are poorly mineralized, resulting in soft, weak bones. Rickets is osteomalacia in children, leading to bowed legs and other bone deformities, often due to vitamin D deficiency or insufficient calcium.

What is osteoporosis and why are postmenopausal females more susceptible?

Osteoporosis is a group of diseases where bone resorption exceeds bone deposit, leading to declining bone mass. Postmenopausal females are more susceptible due to a drop in estrogen levels, which plays a role in maintaining bone density.

What is Paget's disease?

A bone disorder characterized by excessive and haphazard bone deposit and resorption, causing bone to grow fast and develop poorly, with a very high ratio of spongy to compact bone and reduced mineralization.