exam 3 review

What is one function of bones related to movement?

Facilitate movement

How do bones provide support and protection?

Support the body structure and protect vital organs

What does the talus articulate?

Lower leg

Where does the patella attach?

The patella attaches to the tibial tuberosity.

What is the role of bones in hematopoiesis

Involved in the production of blood cells

What do bones store in terms of minerals

Bones store essential minerals like calcium and phosphorus (phosphates)

What is the primary mineral component of bone tissue?

Hydroxyapatite

What protein is a key component of bone tissue?

Key protein component of bone tissue

What is a characteristic of compact bone

Compact bone is very dense.

Where is compact bone located in relation to other bone layers

Compact bone forms the outer layers of bone

What surrounds compact bone?

Compact bone is surrounded by the periosteum

What shape is compact bone?

Flat bone

What is another name for spongy bone?

trabecular or cancellous bone

What is the structural feature of spongy bone?

Spongy bone has a mesh of bone fibers called trabecula

Where is spongy bone located in relation to other bone layers?

Inner layers of the bone

What surrounds spongy bone?

Endosteum

What shape is spongy bone?

Spongy bone is a flat bone

What is the outer layer of compact bone called?

The outer layer of compact bone is called the periosteum

What are the structural units of compact bone known as?

The structural units of compact bone are known as osteons

What are the concentric rings of bone matrix in osteons called?

The concentric rings of bone matrix in osteons are called lamellae

What is the hollow center of an osteon that contains blood vessels called?"

The hollow center of an osteon is called the central canal

What canals connect adjacent central canals in compact bone?

Perforating canals connect adjacent central canals in compact bone

What small spaces in the bone matrix contain osteocytes?

Lacunae are small spaces in the bone matrix that contain osteocytes

What are the tiny channels that connect lacunae to each other and to the central canal?

Canaliculi are the tiny channels that connect lacunae to each other and to the central canal.

What is the inner layer that lines the medullary cavity of bones called?

The inner layer that lines the medullary cavity of bones is called the endosteum

What is the primary function of red marrow?

Hematopoiesis, which is the production of blood cells

What happens to marrow as a person ages?

All marrow starts off as red marrow and is gradually converted to yellow marrow with age

Where is red bone marrow found in adults?

In adults, red bone marrow is found within flat bones and in the epiphyses of long bones

What is the significance of red marrow in the body?

Red marrow is significant because it is the site of hematopoiesis, producing red blood cells, white blood cells, and platelets.

What type of tissue primarily composes yellow marrow?

Yellow marrow is primarily composed of adipose tissue, which is fat tissue

Where is yellow marrow located in adults?

Medullary cavity of the diaphysis of long bones

What is the main function of yellow marrow?

The main function of yellow marrow is to store fat, serving as an energy reserve

How does yellow marrow differ from red marrow?

Unlike red marrow, which is involved in hematopoiesis, yellow marrow mainly consists of fat and is not actively involved in blood cell production

What is the composition of the extracellular matrix in bone?

The extracellular matrix of bone is primarily composed of collagen and a mineralized ground substance.

What role does collagen play in bone?

Collagen provides tensile strength and flexibility to the bone, helping it withstand various stresses.

What is the mineralized ground substance in bone?

The mineralized ground substance mainly consists of hydroxyapatite, which is a crystalline structure that provides hardness and rigidity to the bone

What is one property of collagen in bone?

Good tensile strength: Can withstand pulling forces without breaking

How does collagen behave under stress in bone?

Allows bones to absorb impact and maintain flexibility

What mineral is primarily found in bones?

Hydroxyapatite (Ca10(PO4)6(OH)2): Hard, keeps its shape but is also brittle.

What are the characteristics of hydroxyapatite in bones?

Hardness: Provides strength and rigidity, but it is brittle and can fracture under excessive force.

What is Osteogenesis Imperfecta?

Osteogenesis Imperfecta, also known as brittle bone disease, is a condition caused by defective or insufficient collagen in bones, leading to increased fragility and a higher risk of fractures.

What causes the fragility in Osteogenesis Imperfecta?

The fragility is caused by defective or insufficient collagen, which weakens the bone structure and makes bones more prone to breaking

What are osteoblasts?

Osteoblasts are fibroblasts that secrete the bone matrix, playing a crucial role in bone deposition, ossification, and osteogenesis.

What functions do osteoblasts perform in bone formation?

Osteoblasts are responsible for bone deposition, ossification, and osteogenesis, contributing to the growth and maintenance of bone tissue

What are osteoblasts?

Osteoblasts are fibroblasts that secrete the bone matrix.

What role do osteoblasts play in bone formation?

Osteoblasts are involved in bone deposition, ossification, and osteogenesis.

What do osteoblasts do?

Osteoblasts make the bone matrix.

What processes are osteoblasts involved in?

Osteoblasts are involved in bone deposition or ossification.

What are the functions of osteoclasts?

Osteoclasts break down the bone matrix, perform bone resorption, and release calcium into the blood.

What do osteocytes do?

Osteocytes maintain bone and probably communicate with osteoclasts and osteoblasts.

What are osteocytes and how do they form?

osteoblasts that become trapped in the mineralized bone matrix. They are located in pockets between the lamellae called lacunae.

How do osteocytes communicate with each other?

Osteocytes have interconnected cellular processes that extend into canaliculi, and the processes in adjacent osteocytes are connected via gap junctions.

What is the lifespan of osteocytes and how does their number change with age?

Osteocytes live a long time, but their numbers decrease with age

What is the function of osteocytes in bone maintenance?

Osteocytes function in bone maintenance, probably by communicating with osteoblasts and osteoclasts.

What are osteoclasts and what is their structure?

Osteoclasts are large multinucleate cells.

What is the primary function of osteoclasts?

The primary function of osteoclasts is to demineralize bone and break down collagen.

What process do osteoclasts perform in the body?

Osteoclasts are involved in bone resorption.

What is the difference between the diaphysis and epiphysis of a long bone?

The diaphysis is the long shaft of the bone, while the epiphysis refers to the ends of the bone that articulate with other bones.

What is the medullary cavity?

The medullary cavity is the central cavity within the diaphysis of long bones that contains bone marrow.

What is the role of bone marrow in long bones?

Bone marrow is responsible for producing blood cells and storing fat; it can be red marrow (involved in blood cell production) or yellow marrow (primarily fat storage).

When does initial bone formation begin?

Initial bone formation begins during fetal development.

When is the skeleton completely ossified?

The skeleton is typically completely ossified by early adulthood.

What are the two types of bone formation?

Endochondral ossification and intramembranous ossification.

What does intramembranous ossification form?

It forms many flat bones.

Which specific bone is formed by intramembranous ossification?

It forms the clavicle.

What is the process of intramembranous ossification?

It is the conversion of unspecialized connective tissue (mesenchyme) into bone.

Which flat bones are specifically formed by intramembranous ossification?

The flat bones of the skull are formed by intramembranous ossification.

What does endochondral ossification start from?

It starts from a framework of hyaline cartilage.

What type of bones are formed by endochondral ossification?

Most bones, including almost all long bones, are formed by endochondral ossification.

What is the process of endochondral ossification?

It is the conversion of hyaline cartilage into bone.

What types of bones are primarily formed by endochondral ossification?

Most other bones, including almost all long bones, are formed by endochondral ossification.

Where does cartilage remain during endochondral ossification?

Cartilage remains at the exterior regions of bones at sites of articulation (articular cartilage) and at the epiphyseal plates (sites of long bone growth).

What happens to cartilage at the epiphyseal plates during growth?

Cartilage continues to grow towards the epiphysis, while older cartilage tissue is ossified

What eventually happens to the epiphyseal plate?

Eventually, ossification overtakes cartilage growth, and the epiphyseal plate is completely ossified, leaving a remnant known as the epiphyseal line.

What occurs when long bone growth ceases?

Long bone growth ceases when the epiphyseal plate is completely ossified.

What happens during the late stages of endochondral ossification?

Almost all the cartilage has been replaced by bone.

What are the exceptions where cartilage remains during the late stages of endochondral ossification?

The exceptions are articular cartilage and epiphyseal plates.

What is articular cartilage?

Articular cartilage is the hyaline cartilage remnants that cap bones at the site of articulation.

Where is articular cartilage located?

It is located at the ends of bones where they articulate with other bones, providing a smooth surface for joint movement.

What are epiphyseal plates?

Epiphyseal plates are hyaline cartilage remnants known as "growth plates“

What is the function of epiphyseal plates?

They are responsible for the lengthening of long bones during growth.

What is the process by which long bones lengthen?

The lengthening of long bones stems from growth at the epiphyseal plates.

How does cartilage contribute to the lengthening of long bones?

Cartilage grows at the epiphyseal plates and is gradually ossified.

What happens to bone lengthening in early adulthood?

Complete ossification occurs in early adulthood, causing bone to stop lengthening and resulting in the formation of the epiphyseal line.

What is bone remodeling?

Bone remodeling is the process where bone tissue is constantly being broken down and remade.

How much of the adult skeleton is remodeled each year?

Approximately 10% of the adult skeleton is remodeled each year.

What is the role of osteoclasts in bone remodeling?

Osteoclasts are responsible for bone resorption, which is the process of breaking down bone tissue.

What is the role of osteoblasts in bone remodeling?

Osteoblasts are responsible for bone deposition, which is the process of forming new bone tissue.

Osteoclast activity > osteoblast activity =

Loss of bone mass

Osteoclast activity < osteoblast activity =

Gain of bone mass

What is the importance of calcium in bone homeostasis?

Calcium is needed for bone mineralization, which is essential for maintaining bone strength and structure.

Why is vitamin D important for bones?

Vitamin D is necessary for calcium absorption and utilization in the body, which supports overall bone health

What is rickets?

Rickets is a condition that occurs in children, characterized by soft and weakened bones due to insufficient calcium and vitamin D, leading to deformities.

What is osteomalacia?

Osteomalacia is the adult equivalent of rickets, where bones become soft and weak due to demineralization from a lack of calcium and vitamin D, resulting in increased fracture risk.

What role do parathyroid glands play in blood calcium levels?

The parathyroid glands secrete parathyroid hormone (PTH).

What is the function of parathyroid hormone (PTH)?

PTH functions to raise blood calcium levels by promoting the release of calcium from bones, increasing calcium absorption in the intestines, and reducing calcium loss in urine.

What happens to PTH when blood calcium falls

PTH rises

What happens to osteoclast activity when blood calcium falls and PTH rises

Osteoclast activity rises

What happens to calcium absorption when blood calcium falls and PTH rises

Calcium absorption rises

What happens to calcium excretion when blood calcium falls and PTH rises

calcium excretion falls