chapter 6 bones and skeletal tissue

What is the primary composition of cartilage?

Cartilage is mostly water and has no nerves or blood vessels.

What surrounds cartilage to prevent it from bulging?

The perichondrium.

What type of cartilage is known as the 'All-Purpose' jelly?

Hyaline cartilage.

Where can hyaline cartilage be found in the body?

Ends of bones (articular), ribs (costal), nose (nasal), and voice box (laryngeal).

What does elastic cartilage resemble?

A heavy-duty rubber band that snaps back.

Where is elastic cartilage located?

In the external ear and the epiglottis.

What is fibrocartilage known for?

Being extremely tough and compressible.

Where can fibrocartilage be found?

In the discs between vertebrae and knee pads (menisci).

What are the five main functions of bones?

Support, protection, movement, mineral storage, and hematopoiesis.

What are the two major divisions of the skeletal system?

Axial and appendicular.

What characterizes long bones?

They are longer than they are wide.

What is the hollow middle of a long bone called?

The medullary cavity.

What is the role of osteoblasts?

They are the builders that create bone matrix.

What do osteocytes do?

They monitor the health of the bone.

What is the function of osteoclasts?

They dissolve bone to recycle it.

What is the structural unit of compact bone called?

Osteon (Haversian system).

What is the primary inorganic component of bone?

Calcium phosphate (hydroxyapatite).

What is ossification?

The process of bone formation.

What type of ossification forms flat bones?

Intramembranous ossification.

What is Wolff's Law?

Bones grow or remodel in response to the stress placed on them.

What happens during the hematoma stage of fracture repair?

A massive blood clot forms at the fracture site.

What is osteomalacia?

A condition of soft bones caused by a lack of vitamin D or calcium.

What is the role of the periosteum?

It serves as the outer skin of the bone, containing nerves and blood vessels.

What is the epiphyseal line?

A scar in adults where the growth plate used to be.

What are canaliculi?

Tiny cracks that connect lacunae for nutrient sharing among osteocytes.

What is the difference between compact bone and spongy bone?

Compact bone is solid and organized, while spongy bone is less dense and has a more irregular structure.

What is the function of the endosteum?

It is the inner lining of the hollow middle and spongy bone spaces.

What condition in children is characterized by bowed legs?

Rickets

What is osteoporosis often referred to as?

"Porous bones"

What are the cells that break down bone called?

Osteoclasts (the Crushers)

What are the cells that build bone called?

Osteoblasts (the Builders)

What is Paget's Disease commonly described as?

"Messy/Chaos bone"

What is a foramen?

A hole in a bone, such as the Foramen Magnum for the spinal cord

What is a fossa?

A shallow depression in a bone

What is a process in bone terminology?

Any bony projection

What is a condyle?

A large, rounded "knuckle" for a joint

What is the axial skeleton composed of?

80 bones, including the skull, vertebral column, and thoracic cage

How many cranial bones are in the skull?

8 cranial bones

What is the function of the Atlas (C1) vertebra?

It helps you nod "yes"

What is the function of the Axis (C2) vertebra?

It allows you to shake your head "no"

What are true ribs?

Ribs 1-7 that attach directly to the sternum

What are false ribs?

Ribs 8-12 that have indirect or no attachment to the sternum

What is the strongest bone in the body?

The femur

What are fontanelles?

Fibrous membranes in a fetal skull that allow for compression during birth

What is the fundamental functional unit of compact bone?

The Osteon (Haversian System)

What is the central canal in an osteon?

The longitudinal channel containing the neurovascular bundle

What are lacunae in bone tissue?

Small cavities within the lamellae where mature bone cells reside

What is the role of osteocytes?

They monitor and maintain the mineralized matrix of bone

What is cancellous bone also known as?

Spongy or trabecular bone

What is the diploë?

The layer of spongy bone sandwiched between compact bone in flat bones

What are osteoprogenitor cells?

Mitotically active stem cells that give rise to osteoblasts

What is the organic portion of bone composed of?

Cells and osteoid (collagen fibers)

What is the periosteum?

The double-layered outer membrane of a bone

What is the medullary cavity?

The hollow internal space of the diaphysis of a long bone

What are the two main portions of bone?

Organic Portion (35%) and Inorganic Portion (65%)

What does the organic portion of bone consist of?

Cells and Osteoid (collagen fibers) which provide tensile strength and flexibility.

What is primarily found in the inorganic portion of bone?

Hydroxyapatites (mineral/calcium salts) which provide hardness and compression resistance.

What happens to bone if the organic portion is removed?

The bone becomes brittle and shatters.

What happens to bone if the inorganic portion is removed?

The bone becomes rubbery and bends, as seen in Rickets.

What is Intramembranous Ossification?

Bone develops from a fibrous membrane, forming flat bones like the skull and clavicles.

What is Endochondral Ossification?

Bone replaces a hyaline cartilage model, forming most of the skeleton.

What does Wolff's Law state?

A bone grows or remodels in response to the mechanical stresses placed upon it.

What is the first step in the fracture repair sequence?

Hematoma (massive blood clot).

What is the second step in the fracture repair sequence?

Fibrocartilaginous (soft) callus (internal/external splint of cartilage).

What is the third step in the fracture repair sequence?

Bony callus (spongy bone replaces cartilage).

What is the fourth step in the fracture repair sequence?

Bone remodeling (final cleanup by clasts/blasts).

What are Tuberosity, Trochanter, and Tubercle?

Various sizes of rough projections for muscle/ligament attachment.

What is the Osteon?

The structural unit of compact bone.

How does Hyaline Cartilage appear?

As a smooth, 'glassy' matrix with chondrocytes in lacunae.

What distinguishes Elastic Cartilage?

The presence of dark, thready elastic fibers in the matrix.

What does Fibrocartilage look like?

Thick, wavy collagen fibers that resemble 'ramen noodles' between the lacunae.

What is Spongy Bone identified by?

The 'honeycomb' or 'bridge' structure known as trabeculae.

What is the diaphysis of a long bone?

The shaft of the bone.

What are the proximal and distal epiphyses?

The ends of a long bone.

What is the epiphyseal plate?

Hyaline cartilage in children that allows for bone growth.

How many bones are in the axial skeleton?

80 bones.

What are the three regions of the vertebral column?

Cervical (7), Thoracic (12), and Lumbar (5).

What is the Atlas (C1)?

The first cervical vertebra.

What is the Axis (C2)?

The second cervical vertebra, characterized by its dens.