patho2final: Bone Basics

Questions and Answers

What is the primary function of the bones in the legs and pelvis?

Support of the body against gravity

What percentage of the body's calcium is found in the bones?

99%

What type of bone is the scapula?

Flat bone

What is the function of osteoblasts in bone tissue?

To synthesize and secrete collagen and bone matrix Signup and view all the answers

What type of tissue is found in bones?

Osseous tissue, fibrous connective tissue, cartilage, vascular tissue, lymphatic tissue, adipose tissue, and nervous tissue Signup and view all the answers

What is the function of the vertebrae in the skeletal system?

To protect the spinal cord Signup and view all the answers

What percentage of bone cells are osteocytes?

90-95% Signup and view all the answers

What is the function of the bones in hematopoiesis?

To produce all blood cells Signup and view all the answers

What is the primary function of osteoclasts in bone maintenance?

To secrete digestive enzymes to break down bone matrix Signup and view all the answers

What is the main protein component of bone matrix?

Collagen Signup and view all the answers

What is the term for the soft tissue occupying the medullary cavity of a long bone?

Bone marrow Signup and view all the answers

What is the purpose of the ruffled border in osteoclasts?

To increase the surface area for enzyme secretion Signup and view all the answers

What is the term for the honeycomb-like structure found in spongy bone?

Trabeculae Signup and view all the answers

What is the primary function of the haversian canal in compact bone?

To facilitate the passage of blood vessels and nerves Signup and view all the answers

What is the term for the delicate connective tissue membrane that covers internal bone surfaces?

Endosteum Signup and view all the answers

What is the characteristic of compact bone that helps it resist twisting forces?

The alternating direction of collagen fibers in neighboring lamellae Signup and view all the answers

What is the term for the process by which osteoclasts break down bone matrix?

Bone resorption Signup and view all the answers

What is the primary difference between red and yellow bone marrow?

Their function in blood cell production Signup and view all the answers

What is the primary function of Volkman's canals?

To bring in blood and nerve supply from the periosteum to the haversian canals Signup and view all the answers

Which type of ossification forms the bony skeleton in the embryo?

Both A and B Signup and view all the answers

What is the term for the incomplete lamellae that fill the gaps between osteons or are remnants of bone remodeling?

Interstitial lamellae Signup and view all the answers

What is the primary function of canaliculi in spongy bone?

To allow for the exchange of nutrients and waste between osteocytes Signup and view all the answers

What is the term for the process of bone tissue formation in embryos, children, and young adults?

Ossification Signup and view all the answers

In which type of ossification is a cartilagenous 'model' of the bone formed?

Endochondral ossification Signup and view all the answers

What is the term for the growth of bone in length?

Epiphyseal growth Signup and view all the answers

What is the term for the process of bone replacement with cartilage in the epiphyseal growth plate?

Endochondral ossification Signup and view all the answers

What is the term for the process of bone growth in thickness?

Appositional growth Signup and view all the answers

Which type of bone development occurs in the formation of the bony skeleton in the embryo?

Both endochondral and intramembranous ossification Signup and view all the answers

What occurs to the shaft diameter of a bone during puberty?

It increases even though the actual amount of bone is relatively unchanged Signup and view all the answers

What is the purpose of Wolff's law?

To state that bone grows or remodel in response to the forces or demands placed upon it Signup and view all the answers

What is necessary for the absorption of calcium and phosphate salts in the intestine?

Calcitriol Signup and view all the answers

What is the result of inadequate mineralization of osteoid?

Osteomalacia Signup and view all the answers

What hormone stimulates bone formation?

Insulin Signup and view all the answers

What is the goal of parathyroid hormone?

To keep ionized calcium levels adequate for metabolic needs Signup and view all the answers

What is the stimulus for the release of calcitonin?

Substantially elevated calcium levels Signup and view all the answers

What is the result of parathyroid hormone binding to osteoblasts?

Decreased osteoblast activity and release of osteoclast-stimulating factor Signup and view all the answers

What is the percentage of calcium in the blood that is ionized?

50% Signup and view all the answers

What is the purpose of bone remodeling?

To repair and prevent microdamage, respond to mechanical loading, and release growth factors and minerals Signup and view all the answers

What is the primary manifestation of hypercalcemia in patients with primary hyperparathyroidism?

Moans (bone pain, fatigue) Signup and view all the answers

What is the primary effect of growth hormone on bone growth?

Stimulation of protein synthesis and cell growth throughout the body Signup and view all the answers

What is the characteristic effect of estrogen on bone growth during puberty?

Closure of the epiphyseal plate Signup and view all the answers

What is the primary cause of osteoporosis in postmenopausal women?

Decreased levels of estrogen Signup and view all the answers

What is the effect of estrogen on osteoclasts and osteoblasts?

Estrogen increases osteoclast apoptosis and decreases osteoblast apoptosis Signup and view all the answers

What is the primary characteristic of a comminuted fracture?

Bone fragments into 3 or more pieces Signup and view all the answers

What is the primary function of the fibrocartilaginous callus during fracture repair?

To splint the broken bone Signup and view all the answers

What is the primary cause of avascular necrosis in bone?

Disruption of the vascular supply to the bone Signup and view all the answers

What is the primary effect of thyroid hormone on bone growth?

Increased rate of osteoblast activity Signup and view all the answers

What is the primary characteristic of a greenstick fracture?

Bone breaks incompletely Signup and view all the answers

Study Notes

The Human Skeletal System

The skeletal system is composed of bones, ligaments, tendons, and cartilages.
Functions of the skeletal system:
Supports the body's weight against gravity (legs, pelvis)
Supports teeth against pressure (mandible)
Protects internal organs (skull bones protect the brain, ribs and sternum protect the lungs and heart, vertebrae protect the spinal cord)
Enables movement through skeletal muscles
Acts as a reservoir for minerals and adipose tissue (99% of body's calcium and 85% of body's phosphate)

Bone Classification

4 types of bones:
Long bones (limb bones except patella and bones of the wrist/ankle)
Short bones (roughly cube-shaped, e.g. bones of the wrist and ankle)
Flat bones (thin, flattened, and curved, e.g. scapulae, sternum, ribs, and most bones of the skull)
Irregular bones (weird shapes, e.g. vertebrae, hip bones, sphenoid and ethmoid bones)

Bone Components

Bones are organs composed of multiple tissue types:
Osseous (bone) tissue
Fibrous connective tissue
Cartilage
Vascular tissue
Lymphatic tissue
Adipose tissue
Nervous tissue

Bone Functional Cells

3 types of bone cells:
Osteoblasts (bone-building cells that synthesize and secrete collagen and other organic components of bone matrix)
Osteocytes (mature bone cells that maintain bone tissue)
Osteoclasts (huge cells that digest bone matrix, part of normal bone growth, development, maintenance, and repair)

Bone Structure

Bone matrix consists of 1/3 organic and 2/3 inorganic components:
Organic component: mostly proteins (collagen) secreted by osteoblasts
Inorganic component: mainly calcium phosphate and calcium hydroxide, which form hydroxyapatite

Bone Marrow

Two types of bone marrow:
Red bone marrow (hematopoietic tissue that produces blood cells)
Yellow bone marrow (hematopoietically inactive, but can transform back into red marrow in cases of severe anemia)

Layers of Bone

Endosteum: delicate connective tissue membrane that covers internal bone surfaces
Periosteum: double-layered membrane covering the external surface of the bone
Outer layer: fibrous, dense irregular connective tissue
Inner layer: cellular, contains osteoprogenitor cells and osteoblasts

Bone Development and Remodeling

Ossification: the process of bone tissue formation
Intramembranous ossification: bone development from a fibrous membrane (occurs in skull cap, facial bones, clavicles, pelvis, scapulae, and part of the mandible)
Endochondral ossification: bone development from hyaline cartilage (most bones in the body)
Bone remodeling: a dynamic process that allows the skeleton to respond to mechanical loading, repair microdamage, and release growth factors and minerals stored in bone matrix

Hormonal and Nutritional Effects on Bone

Hormonal effects on bone:
Parathyroid hormone (PTH) and calcitonin antagonistically maintain blood calcium levels
Insulin and glucocorticoids affect bone formation and resorption
Sex hormones (estrogens and androgens) influence bone growth and density
Nutritional effects on bone:
Calcium and phosphate salts are essential for bone growth and maintenance
Vitamins C, A, K, and B12 are necessary for bone growth

Clinical Conditions

Osteomalacia and rickets: disorders of inadequate mineralization of bone
Osteoporosis: a group of diseases characterized by increased bone resorption and decreased bone deposition
Fracture repair: a complex process involving bleeding, inflammation, and bone remodeling

Fracture Types

Open fracture: bone ends penetrate the skin
Closed fracture: bone ends don't penetrate the skin
Comminuted fracture: bone breaks into 3 or more pieces
Greenstick fracture: bone breaks incompletely, common in children
Spiral fracture: ragged break caused by excessive twisting force
Impacted fracture: one bone fragment is driven into the medullary space or spongy bone of another

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Description

This quiz covers the basics of the human skeletal system, including its composition, functions, and roles in supporting the body, protecting vital organs, and facilitating movement.