Ch 6- Bone Tissue Overview

What is the human skeleton initially made of during early embryonic development?

Cartilage

Around what embryonic week does most cartilage get replaced by bone tissue?

Around embryonic week 8

Why does some cartilage remain in the adult skeleton?

For flexibility in certain areas

What are the main 3 characteristics of skeletal cartilage?

High water content, No nerves, No blood vessels

What is the most common and most important type of skeletal cartilage in the body?

Hyaline

What kind of skeletal cartilage is flexible and stretchy?

Elastic

What kind of skeletal cartilage is strong and tough?

Fibrocartilage

What are the 3 types of Skeletal Cartilage?

Hyaline, Elastic, Fibrocartilage

What type of hyaline cartilage covers the ends of most long bones and joints?

Articular

What type of hyaline cartilage connects the ribs to the sternum?

Costal

What type of hyaline cartilage reinforces/supports air passageways?

Respiratory

What type of hyaline cartilage shapes/supports the external nose?

Nasal

Where is elastic cartilage found?

The external ear and the epiglottis

Where can you find fibrocartilage?

Intervertebral discs, pubic symphysis, and meniscus

What are the 2 ways in which cartilage can grow?

Appositional and Interstitial

What is appositional cartilage growth?

New cartilage is added to the outside of existing cartilage

What is interstitial cartilage growth?

The cartilage cells that already live inside the tissue divide to make more material from within

Which type of growth increases cartilage width?

Appositional growth

Which type of growth increases cartilage length/volume?

Interstitial growth

What are the two positional categories of bones?

Axial and Appendicular skeleton

What bones make up the axial skeleton?

Skull, vertebral column, and rib cage

What is the main function of the axial skeleton?

Protection and support of vital organs

What bones are in the appendicular skeleton?

Upper and lower limbs (arms and legs), shoulder and hip girdles

What is the main function of the appendicular skeleton?

Movement and interaction with the environment

What are the four bone shape categories?

Long, short, flat, and irregular bones

Give an example of a short bone:

Wrist and ankle bones

Give an example of an irregular bone:

Vertebrae, Hip bones

Bones act as levers for muscles which means muscles do what for movement?

Muscles pull on bones to create motion

What minerals do bones store? Where do they get released?

Calcium and Phosphorus; Into the bloodstream

Where are blood cells formed?

In the red marrow of certain bones

What are bone markings?

Distinct features on bones where things attach or pass through

Areas that stick out on bones; (Heads, trochanters, spines); Usually where muscles or ligaments attach:

Projections

Where stuff attaches are called _______:

Projections

Where stuff passes through are called _______:

Depressions

Indentations or holes where nerves or blood vessels pass:

sinuses- air-filled space in bone

foramina- hole for blood vessels/nerves

grooves- narrow channel in bone

Depressions

Why do projections form?

Due to muscle pull or stress on the bone

What are the two types of bone based on density?

Compact and spongy (cancellous) bone

Where is compact bone located?

On the outside of all bones (outer-layer)

What is the structure of compact bone like?

Strong and hard

Where is spongy bone located?

On the inside of bones (Inner-layer)

Where is spongy bone usually found?

At the ends of long bones and inside flat bones

What is the structure of spongy bone like?

Airy and honeycomb-like

Spongy bone is a honeycomb-like network of thin pieces called ________:

What fills the spaces between it?

Trabeculae; Red or yellow marrow

Where is fat (energy) stored in bones?

In the yellow marrow

What are the two main parts of a long bone?

Diaphysis (shaft) and Epiphysis (ends)

What is the diaphysis?

The long, middle part of the bone

What type of bone surrounds the diaphysis?

Compact bone

Where is the medullary cavity located in the bone?

In the diaphysis

In adults, what can be found inside the medullary cavity?

Yellow marrow (fat)

What is the epiphysis?

The expanded end of a long bone

What type of bone is in the epiphysis?

Compact bone on outside, spongy bone inside

What covers the surface of the epiphysis at joints?

A layer of hyaline cartilage

What is the function of the hyaline cartilage on the epiphysis?

To cushion and reduce friction

A double-layered membrane covering the entire outer surface of a long bone, except at joints:

Periosteum

What are the two layers of the periosteum?

Outer layer and Inner layer

What kind of connective tissue is the outer layer of the periosteum made of?

Dense Irregular (to protect the bone)

The inner layer of the periosteum is also known as the ________ layer:

Osteogenic

What does the osteogenic layer of the periosteum produce? what do they do?

Bone cells (osteoblasts and osteoclasts), which help with bone growth and repair

How does the periosteum stay attached to bone?

By Sharpey’s fibers

What are sharpey’s fibers made of?

Collagen

A thin, delicate connective tissue membrane that lines internal bone surfaces:

Endosteum

Where is the endosteum found?

In the trabeculae of spongy bone and canals of compact bone

What do both the periosteum and endosteum contain?

Osteogenic cells

What makes short, flat, and irregular bones different from long bones?

They don’t have a shaft or extended ends; Instead the bone is more sandwich-like

What are the outer layers of short, flat, and irregular bones made of?

Compact bone covered by periosteum

What are the inner layers of short, flat, and irregular bones made of?

Spongy bone lined with endosteum

What is produced in hematopoietic tissue?

Blood-cells

Where is hematopoietic tissue located in bones?

In between Trabeculae of spongy bone

What is compact bone made up of?

Osteons (haversion systems)

What are Osteons made up of?

Lamellae

What are Lamellae?

Rings of bone matrix in each osteon

What is the Central (Haversian) canal? What do they contain?

Canals in the center of the osteon containing blood vessels and nerves

What are Volkmann’s (perforating) canals?

Canals that run perpendicular (side to side)

What connects the blood supply of the periosteum with the central canal and marrow cavity?

Volkmann’s canals

What lines the inside of the canals in the osteon?

The endosteum

Where do osteocytes live?

In lacunae (small spaces between lamellae)

Tiny hair-like channels that connect one osteocyte to another & to the central canal:

Canaliculi

Incomplete rings of bone between osteons are called:

Interstitial lamellae

Rings that circle the entire diaphysis (go around the entire bone) are called:

Circumferential lamellae

In adults, where is hematopoietic tissue mostly found?

In the axial skeleton & in head of humerus and femur

Trabeculae are arranged along lines of ______ ______ to help bones resist pressure and stay strong where pressure hits:

Mechanical Stress

What are the two main organic components of spongy bone?

Cells and osteoid

What is osteoid?

The soft, unmineralized part of bone matrix; “pre-bone” material before it hardens

What is the main inorganic component of spongy bone?

Hydroxyapatites

What are hydroxyapatites?

Mineral salts (mostly calcium and phosphates)

What do hydroxyapatites (minerals) do?

Make bone hard and strong

What gives bone flexibility?

Collagen

What is osteoid mostly made up of?

Collagen