Bill Nye song:

http://www.youtube.com/watch?v=Y1abT50xXyk&feature=related

Pre-assessment

• 3-2-1- Cards– List 3 things you already know about the

skeletal system.– List 2 questions you have about the

skeletal system.– List 1 thing you want to learn about the

skeletal system.

Function of the skeletal system

•1. Support•2. Protection•3. Movement•4. Blood Cell Formation•5. Storage of Nutrients

Classification of Bones

I . Composition of bones: two types of boneA. Compact B. Spongy

II. Shape of bones:A. Long bonesB. Short bonesC. Flat bonesD. Irregular bonesE. Sesamoid

Every bone is made up of either spongy bone, compact bone, or both.

I. Composition of Bones:A. Compact bone:

dense, smooth and homogeneous throughout.

B. Spongy bone: composed of small needle-like or flat pieces of bone called trabeculae and has many open spaces filled with bone marrow.

• Aka cancellous bone

A. Compact Bone

The structural unit of compact bone is an osteon.

Each osteon consists of concentric bone layers called lamellae, making the bone extremely hard and dense.

The lamellae surround a long hollow passageway, the Haversian canal.

This canal contains small blood vessels responsible for the blood supply to osteocytes (individual bone cells) a nerves.

Canaliculi are little canals which connect bone cell and are used to exchange nutrients and waste.

MATRIX

B. Spongy Bone• Light, porous bone

enclosing numerous large spaces that give a honeycombed or spongy appearance.

• The bone matrix, or framework, is organized into a three-dimensional latticework of bony processes, called trabeculae, arranged along lines of stress.

• The matrix is organized to provide maximum strength similar to braces that are used to support a building.

• The spaces between are often filled with marrow.

Bone Marrow

• Is made in the spongy bone

• When someone is born, all marrow is red.

• Eventually, some of it gets converted into yellow marrow.

• WHAT’S THE DIFFERENCE?

THERE ARE TWO TYPES OF BONE MARROW FOUND IN MOST BONES:

• YELLOW BONE MARROW - CONSISTS MOSTLY OF FAT CELLS (ADIPOSE TISSUE).

• IT SERVES AS AN ENERGY RESERVE. 

• CAN ALSO BE CONVERTED TO RED BONE MARROW AND PRODUCE BLOOD CELLS WHEN SEVERE BLOOD LOSS OCCURS.

• RED BONE MARROW - FOUND IN SPONGY BONE, THE ENDS OF LONG BONES, RIBS, VERTEBRAE, THE STERNUM, AND THE PELVIS –

• PRODUCES RED BLOOD CELLS AND SPECIAL WHITE BLOOD CELLS CALLED LYMPHOCYTES, AND OTHER ELEMENTS OF BLOOD (platelets)

II. Shape of Bones: A. Long Bones

• Bones that are longer than they are wide are called long bones.

• They consist of a long shaft with two bulky ends or extremities.

• They are primarily compact bone but may have a large amount of spongy bone at the ends or extremities. Ex. Humerus

You need to know this one for lab• Even though these are small, finger bones

are still classified as long bones.

Growth Plate

• Growth plates are located on the long bones of children and young people. These plates are areas of growing tissue near the end of the bones.

• Each long bone has at least two growth plates-one at each end. This is where the long bones grow. When young people finish growing, the growth plates close and are replaced by solid bone.

• Most growth plate fractures get better and do not cause any lasting problems.

II. Shape of Bones: B. Flat Bones

• Flat bones are thin, flattened, and usually curved.

• Most of the bones of the cranium are flat bones.

II. Shape of Bones: C. Short Bones

• Short bones are roughly cube shaped with vertical and horizontal dimensions approximately equal.

• They consist primarily of spongy bone, which is covered by a thin layer of compact bone.

• Short bones include the bones of the wrist and ankle.

II. Shape of Bones: D. Irregular Bones

• Bones that are not in any of the above three categories are classified as irregular bones.

• They are primarily spongy bone that is covered with a thin layer of compact bone.

• The vertebrae and some of the bones in the skull are irregular bones.

II. Shape of Bones:E. Sesamoid

• Sesamoid bones can be found on joints throughout the body, they are the hardest form of cartilage.

• Ex. the patella (within the quadriceps tendon)

FYI: The only floating bone• Is the hyoid

bone.• It is not joined to any

other bone but is suspended in position by muscles that connect it to the mandible, each temporal bone, at the base of the skull, to the thyroid cartilage, to the sternum and to the scapula.

•

Cartilage

• Cartilage is a solid connective tissue that is to a certain extent pliable, making it resilient. These characteristics of cartilage are due to the nature of its matrix.

• There are three kinds of cartilage: 1. hyaline cartilage

2. elastic cartilage 3. fibrocartilage.

1. Hyaline cartilage

• is the most abundant type of cartilage.

• Most of the skeleton of the fetus is laid down in cartilage before being replaced by bone.

• Hyaline cartilage in the adult is found in the nose, parts of the respiratory tract, at the ends of ribs and at the articular surfaces of bones.

2. Elastic cartilage

• similar to that of hyaline cartilage, but in addition to the other components, its matrix has elastic fibers and interconnecting sheets of elastic material.

• This gives elastic cartilage an elasticity not present in hyaline cartilage.

• Elastic cartilage is found in the external ear, the walls of the external auditory canal, the Eustachian tube, the epiglottis and the larynx.

3. Fibrocartilage

• is the strongest and most rigid type of cartilage.

• Fibrocartilage makes up the intervertebral discs, connects tendons and ligaments to bones, and appears in other high-stress areas.

• Damaged hyaline cartilage is often replaced with fibrocartilage, which unfortunately does not bear weight as well due to its rigidity.

Ligaments and Tendons• Bones are connected together by fibrous tissue

called Ligaments. • Tendons are also fibrous tissue and attach

muscle to bone. Both have some elasticity and do not heal on their own if torn.

• Bone to bone = ligaments• Muscle to bone = tendon• An inflamed tendon is called tendonitis and is

caused by overstretching the tendon. Cartilage is also fibrous tissue but is not elastic. Cartilage is used to cushion the junction of two bones.

OUCH!

There's 2 problems with the ACL and healing: 1) It's not highly vascularized (it has a poor blood supply) and 2) It tends to fray like a wire, which makes the ends difficult to put back together. A lot of times, for a rupture, surgeons will just clean out the old ACL and replace it with either a cadaver's (a dead guy's), part of the patellar tendon, or part of the hamstring.

Most PCL ruptures occur in car accidents when the dashboard rams into the knee. OUCH!

Common injuries involving ligaments/tendons

Cartilage Disorders• There are a few disorders associated with cartilage. • Chondrodystrophies are a group of disorders in which

the cartilage is ossified, or transformed into bone. • Arthritis is characterized by the degradation of

cartilage in the joints, leading to limited movement and pain.

• Achondroplasia is a cartilage disorder resulting in dwarfism.

• Benign tumors called chondroma can also arise in the cartilage.

General Skeleton Info.• The adult human

skeleton usually consists of 206 named bones.

• These bones can be grouped in two divisions: – Axial skeleton (80

bones) and – Appendicular

skeleton (126 bones).

Axial Skeleton1. Skull (adult, child, infant)

– Cranium– Facial bones– Hyoid bone

2. Vertebral column3.Thoracic cage

Appendicular Skeleton

• Shoulder Girdle

• Upper limbs

• Pelvic Girdle

• Lower Limbs

Pelvic Girdle

• Males have greater height and narrower pelvic width.  The absence of testosterone in girls prevents these skeletal developments; the presence of high levels of estrogen in a pubertal girl helps stimulate the growth and shape of the pelvic bones, but otherwise actually act to limit bone growth and final adult height. 

Axial Skeleton:

Cranium

Ribs & Sternum

Vertebrae

Appendicular Skeleton:

Arm & hand bones

Leg & feet bones

Clavicles

Scapulas

Hips

Classwork

• Play the skeleton game at:

• http://www.aaronmartini.com/network/games/skeleton/index.html

• Print out your results

Bone Injuries

Bone fractures1. simple - bone breaks cleanly, does not penetrate the

skin2. compound - broken ends of bone protrude through

skin3. comminuted - bone fragments into many pieces4. compression - bone is crushed5. depressed - broken bone portion is pressed inward6. impacted - broken bone ends are forced into each

other7. spiral - ragged break occurring when excessive

twisting forces are applied to bone8. greenstick - bone breaks incompletely similar to a

green twig

Jack Pires

• Simple full break of the right radius

• May 2010

• In a cast:

14 weeks

X*rays

Gross and a bit violenthttp://www.youtube.com/watch?v=muURh4vsXHc&feature=PlayList&p=CFE046E46D75EF31&index=0&playnext=1

Name the type of break

Try again A B C D E F

Bone break and repair:

http://www.youtube.com/watch?v=qVougiCEgH8

Broken Bones

• There are three main types of joints based on structure:

Fibrous

Cartilaginous

Synovial

• Fibrous joints (immovable joints) connect bones without allowing any movement. The bones of your skull and pelvis are held together by fibrous joints.

Cartilaginous joints are joints in which the bones are attached by cartilage. These joints allow for only a little movement, such as in the spine or ribs.

In common usage, the word "joints" generally refers to the freely moving joints with joint cavities. These are called synovial joints. They allow for much more movement than cartilaginous joints. Cavities between bones in synovial joints are filled with synovial fluid. This fluid helps lubricate and protect the bones.

Bursa sacks contains the synovial fluid.

Bursa sacks contains the synovial fluid.

3 of the 6 types of synovial joints

1. 2. 3.

Ex. Ex. Ex.

The other 3 types of synovial joints

Ex. Ex. Ex.

4. 5. 6.

Infant/child Skeleton

• Many of the bones in the body start off, in the early embryo, as tiny hyaline cartilaginous structures, with essentially the same shape as the eventual adult bone.

• As early as 8 weeks after conception, in the case of some of the long bones of the limbs, bone starts to be laid down, in the centre of the cartilage of the shaft, and gradually extends towards the ends.

• The ends remain as cartilage until just before birth or, in many cases, until some time later.

• Then, secondary bone centers appear at the ends (epiphyses) but do not join with the bone in the shafts: an intervening area of cartilage remains. This is known as the growth (epiphyseal) cartilage and is the region where the bone grows most in length.

• Growth continues, and the epiphyseal cartilage persists, in many of the long bones, until well after puberty; in girls until 16-17 and in boys a year or two later.

Six Common Bone Disorders

-is a long-term disease that leads to inflammation of the joints and surrounding tissues. It can also affect other organs.Eventually, joint pain appears. When the lining of the joint becomes inflamed, it gives off more fluid and the joint becomes swollen. Joint pain is often felt on both sides of the body, and may affect the fingers, wrists, elbows, shoulders, hips, knees, ankles, toes, and neck.

http://www.youtube.com/watch?v=ae4ZdRfZR3I

1.

- is caused by the breakdown and eventual loss of the cartilage of one or more joints.

2. Osteoarthritis

3. Osteoporosis-the thinning of bone tissue and loss of bone density over time

4. Bone Spur• A bone spur forms as the body tries to repair

itself by building extra bone. It generally forms in response to pressure, rubbing, or stress that continues over a long period of time.

• Bone spurs do not require treatment unless they are causing pain or damaging other tissues.

• Examples of spurs that may need surgery might include repair of a bunion or heel spur in the foot or removal of small spurs underneath the point of the shoulder.

Pump Bump

5. Spinal Curvatures

• A. Scoliosis: “S” shaped curve of the spine

• B. Kyphosis: Hunchback

• C. Lordosis: Sway back

Not so Common Anymore:

• Primary cause of scurvy is insufficient intake of vitamin C (ascorbic acid).

• This may be due to ignorance, famine, anorexia, restrictive diets (due to allergies, food fads, etc.), or difficulty orally ingesting foods.

• Historically, scurvy was the result of long sea voyages where sailors did not bring along enough foods with vitamin C.

6.

7. Ricketts• Rickets is a disorder

caused by a lack of vitamin D, calcium, or phosphate. It leads to softening and weakening of the bones.

• Positioning or bracing may be used to reduce or prevent deformities. Some skeletal deformities may require corrective surgery.

Virtual Knee & Hip Replacement & Hip Resurfacing

• Go to www.edheads.com

• Click on: – Virtual Knee Replacement or – Virtual Hip Replacement or– Virtual Hip Resurfacing

• Don’t forget your ear plugs!

• Complete all three surgeries.