Where is cartilage found throughout the body?
ear, nose, articular cartilage (joints), costal cartilage (boney part of ribs), larynx and epiglottis
Name 4 characterisitcs of cartilage.
1. Found throughout the adult body
2. Primarily water
4. Mostly chondrocytes
What are the three types of cartilage?
Hyaline, Elastic and Fibrocartilage
This cartilage is the most abundant, provides support and flexibility in the joints and bones
This cartilage contains many elastic fibers and is able to tolerate the repeated bending and returning to original shape, resists compression and tension
This cartilage resists strong compression and strong tension and is unique because it can resist these opposite forces
When we find hyaline cartilage at the end of bones, what do we refer to it as?
When you bend over the vetebral column experience what to forces in the anterior and posterior direction?
What tissue make up bones?
Mostly CT but also NT, blood tissue and ET lining the bood vessels
Name the 6 functions of bones
Movement by contraction
Mineral Storage (calcium and phosphate)
Blood-cell formation (red bone marrow)
What is unique about bone''s function: energy metabolism?
There is something is bones that influences the pancrease (endocrine and exocrine gland) to release insulin
What percetage of the bones are composed of the organic components such as cells, fibers, organic substances, and collagen used to resist tesion?
What percentage of the bones are composed of inorganic mineral salts such as calcium and phosphate used to resist compression
What happens to a bone when it is heated?
destroys the collagen and it becomes brittle
What happens to a bone when you remove the mineral salts form it
becomes soft and flexible
What are the four types of cells found in bones
Osteogenic cells, osteoblasts, osteocytes and osteoclasts
These cells are stem cells that differentiate into osteoblasts
These cell actively produce and secrete bone matrix and allow calcium to be deposited
These cells help to keep the bone matrix healthy and are a mature form of osteoblasts
These cells are responsible for resorption of bone, are derived from a line of white blood cells and secrete hydrochloric acid and lysosomal enxymes to break down the bone by taking the mineral salts out
This type of bone is longer than it is wide. Give example.
This type of bone is thin and flat. Give example.
This type of bone is various and it does not fit into other categories. Give example.
This type of bone is cube in shape. Give example.
This kind of bone is found at the proximal and distal end of the epiphyseal lines and shaft
What is the difference between spongy bone and compact bone?
spongy bone is more porous than compact
Plate of hyaline cartilage at the junction of the diaphysis (shaft) and epiphyses (end) of most bones in the growing skeleton; provides growth in the lenght of the bone
The proximal end of a long bone, attached to the shaft
Elongated shaft of a long bone
The distal end of a long bone, attached to the shaft
Cavity in the middle or internal region of the long bone
Layer of cells lining the internal surfaces of bone, specifically, lining the central canals of osteons and the medullary cavity and coverning the trabeculae of spongy bone
Membrane of fibrous CT that cover the external surface of bones of the skeleton
Large blood vessel that carries nutrients and oxygen to nourish the cells, find holes in the bones for these
Tube-shaped unit in mature, compact bone; consist of concentric layers of bone lamellae surrounding a central canal, run parallel to bone where nerves and blood vessels travel
Passageways through the lamellae for movement of oxygen and nutrients
Bony Matrix that makes up the central canal that surrounds the artery, vein and nerve fiber
Space where an osteocyte resides
What are two important reasons why collagen fibers run in opposite directions in the lamellae?
1. To resist twisting forces
2. Helps to stop cracking of a bone
Bone tissue formation
Formed directly form mesenchyme or Intramembranous ossification
Develop initially from hyaline cartilage or Endochondral ossification
All other bones
What are the two important things to know about Intramembranous ossification?
1. Produced from mesenchym not cartilage model
2. Only a few bones in the skull and clavicles form from this mesenchyme
What bones undergo endochondral ossification?
all bones except bones of the skull and clavicles
What is the time range of EO?
begins in the 2nd month of human development and continues forming until early adulthood
What are the 5 stages in EO?
1. Formtion of bone collar around hyaline cartilage model
2. Cavitation of hyaline cartilage w/in the cartiage model
3. Invasion of internal cavities by periosteal bud and spongy bone formation
4. Formation of medullary cavity as ossification continues; appearance of secondary ossification centers in the epiphyses in preparation for stage 5
5. Ossification of the epiphyses; when completed, hyaline cartilage remains only in the epiphyseal plates and articular cartilages
At what time period do cells disintigrate faster than they replicate, thinnin the epiphyseal plate?
At the end of adolescence
Which end does replication of cells take place?
Which end does disintigration of cells take place?
In what area of the bone does the cartilage organize for quick, efficient growth and cartialge cells form tall stacks?
What happens when the chondroblasts at the top of stacks divide quickyl?
It pushed the epiphysis away form the diaphysis essentially lengthening the entire long bone
In childhood and adolescence how do bones lengthen?
Entirely by the growth of the epiphyseal plate cartilage is replaced by bone tissue and the plate remains a constant thickness because of constant balance of replication/disintigration
What all happens at the end of adolescence?
Chondroblasts divide less, epiphyseal plate becomes thinner (because cartilage stops growing and is replaced by bone tissue) and long bones stop lengthening when diaphysis and epiphysis fuse
What are the five zones in the postnatal growth of EO and what is happening at each?
Poliferation (cartilage cells undergo mitosis)
Hypertrophic (older cartilage cells enlarge)
Calcification (matrix becomes calcified; cartilage cells die; matrix begins to deteriorate)
Ossification (New bone formation is occuring)
Growth of a bone bt addition of bone tissue to its surface
What are the actions of osteoblasts and osteoclasts as the growing bones widen?
Osteoblasts: add bone tissue to the external suface of the diaphysis
Osteoclasts: remove bone from the internal surfae of the diaphysis
Explain what is going on in a healthy bone
There is constant remodeling; there is an equal balance of osteoblasts (building up the bone to be stronger: deposition) and osteoclasts (breaking down the bone and taking the calium out to become more porour: reabsorption)
Describe how bones have the ability to become stronger
Bones can adapt to their forces that allow them to get stronger. They do this by adding mineral salts to resist compression forces and more collagen fibers to resist tension forces
Descirbe how bones have the ability to become weaker
Bones can adapt to their forces that allow them to become weaker. With the removal of mechanical stress the bones experiences demineralization and collagen reduction.
Give three example of how bones can become weaker.
1. Reduced activity when in a cast
2. Astronauts in weightless environments
3. Bedridden individuals
How can you help build and retain bone mass?
weight-bearing activites such as walking or moderate weight lifting
What are the stages of healing a fracture?
Fracture a bone (and bood vessel), healing process starts with hematoma formation (collection of blood), followed by production of callus (fibrocartilaginous) then replace with bones. As bone is remodeled, boney callus goes away
Bone reabsorption outpaces bone deposition characterized bt low bone mass
What kind of individuals usually undergo osteoporosis and why?
Women after menopause because the estrogen levels decrease which is used to keep the bones strong
What usually happens during osteoporosis?
Mineral salts come out of bone, bone becomes more porous and less dense, bones are more commonly fractured
Disorder that occurs in adults when bones are inadequately mineralized
Disorder that occurs in childer when bones are inadequately mineralized
Disorder characterized by excessive rate of bone deposition therefor the bone never fully matures before it is remodeled again
Disorder that is a form of bone cancer occuring in the ages of 10-25 in the bone of the knee from osteoclasts becoming cancerous
What is a characteristic caused by Osteomalacia and Rickets?
Bow-leggedness because legs cannot withstand forces so they bend
What point does formation exceed reabsorption?
In children and adolescents
What point does formation equal reabsorption?
What point does reabsorption exceed formation?