SKELETAL SYSTEM

Functions of the Skeletal System

A. Bones are made of OSSEOUS TISSUE

FUNCTIONS:

1.Support

2. Protection

3.Body movement

4. Blood cell formation (bone marrow) - hematopoiesis

5. Storage of inorganic materials 

                   (salt, calcium, potassium….)

B. ORGANIZATION

1. About 206

bones

2. 2 Main

Divisions –

Axial &

Appendicular

Classification of Bones:BASED ON SHAPE

1.There is 2 basic types of osseus, or bone, tissue:

a. COMPACT BONE – dense, looks smooth, homogeneous

b. SPONGY BONE – composed of small needlelike pieces of bone and open space

2. Long bones – longer than they are wide, have shaft with heads at both ends; have mostly compact bone a. all limbs - ex, humerus and femur

3. Short bones – cube-shaped and contain mostly spongy bone. a. Wrist and ankle

4. Flat bones – thin, flattened, usually curved. a. Skull, ribs, sternum are flat

5. Irregular bones– do not fit into another category a. Vertebrae

Types of Bone Tissue

1. Compact (wall of the diaphysis)

2. Spongy (cancellous, epiphysis) - red marrow

Inside the Long Bone

1. Medullary Cavity

– hollow chamber filled with bone

marrow

2. Red Marrow - (red

blood cell formation)

3. Yellow Marrow - (fat replaces much of the red marrow

in diaphysis throughout childhood )

4. Endosteum– lining of the medullary

BONE STRUCTURE – 5 PARTS of a Long Bone

1.Epiphysis – on each end

2.Diaphysis – main body/shaft

of bone

3.Articular Cartilage –

on ends for joint movement

4. Periosteum – outer covering

5. Medullary cavity – hollow

chamber within diaphysis that

connect to spaces in spongy

bone. Filled with bone

marrow.

* Assignment

– Coloring of a Long

Bone

 

Structure of a Long Bone

Figure 6.3a-c

Review the Structure of a Long Bone

Matching quiz at http://www.mhhe.com/biosci/ap/holehaap/student/olc2/chap07matching01.html

Axial Skeleton

1. Head, neck, trunk

a. Skull

b. Hyoid Bone

c. Vertebral Column

d. Thoracic Cage

(ribs, 12 pairs including true

and false and floating ribs)

e. Sternum

Hyoid Bone – closely related to mandible and temporal bone

1. Unique that it is the only bone of the body that does not articulate directly with any other bone.

2. Serves as a movable base for the tongue and attachment point for neck muscles that raise and lower the larynx when we speak and swallow.

3. Is more prominent in males than females.

Appendicular Skeleton

•Limbs & Bones that connect to theo Pectoral Girdle (shoulders)o Pelvic Girdle (hips)

Microscopic Structure – of Bone Growth and Development

1. MATRIX - where the bone cells live 2. OSTEOCYTES  - mature bone cells, enclosed in tiny chambers called LACUNAE 3. OSTEOCYTES form rings (LAMELLAE) around a HAVERSIAN CANAL which houses blood vessels 4. Osteocytes are linked by CANALICULI 5. Haversian Canals are linked by VOLKMAN's CANALS 

Compact Bone

BONE COLORING!

Test Yourself

Find the...

Haversian CanalVolkman's Canal

Lamellae

Spongy BoneCompact Bone

BONE DEVELOPMENT & GROWTH

1.Intramembranous bones –

are flat, ex. Skull

2. Endochondral bones –

all other bones3. ALL BONES start as

hyaline cartilage, areas

gradually turn to bone (through the

process of OSSIFICATION)      4. PRIMARY ossification center (shaft)

      

5. SECONDARY ossification

center(ends)

 

Bone Development & Growth

6. EPIPHYSEAL DISK  (growth plate) is a band of cartilage between the epiphysis and diaphysis 7. These areas increase bone length as the cells ossify 8. Cartilage becomes OSTEOBLASTS become OSTEOCYTES

RESORPTION

a. Bone tissue is constantly being replaced as special cells called OSTEOCLASTS dissolve bone tissue from within the medullary cavity and releases minerals- a process called RESORPTION.

b. At the same time new bone tissue is being added to the outside of the bone.

Assignment: Coloring of an Aging Hand

Bone Growth

Bone Growth

Function of Joints1. Hold bones together securely2. Give the rigid skeleton mobility.

Types of Joints (Also called Articulations!)

1.Synarthrotic (not

moveable, ex. sutures

of the skull)

2.Amphiarthrotic

(slightly moveable,

ex. vertebrae)

3. Diarthrotic (moveable

joint, ex. synovial joints

like knee or hips)

Synovial fluid - fluid within the joints that helps to lubricate

Types of Joints:1.  Ball and Socket (example – shoulder/hip)2.  Hinge (example – knee)3.  Pivot (example – elbow)4.  Saddle (example – fingers)

BONES OF THE SKULL (Lab Test)

1. Frontal -2. Parietal - 3. Occipital -4. Temporal - 5. Sphenoid - 6. Maxilla - 7. Mandible - 8. Zygomatic -

More Bones of the Skull to know!

9. Lacrimal10. Ethmoid11. Nasal12. External Auditory meatus13. Mastoid process14. Styloid Process15. Temporo-mandibular joint16. Sagittal suture17. Lambdoid suture18. Squamous suture19. Coronal suture20. Foramen magnum21. Mental foramen

TOPOGRAPHY OF THE SKULL

Foramen - refers to any tiny opening, nerves and blood vessels leave this opening to supply the face

Mental Foramen

Suture - refers to any connection between large bones (in fetal skulls, these are called fontanels)

Fissure - any wide gap between bones

Sutures

1. Coronal - between frontal and parietal bones2. Lambdoid - between occipital and parietal bones3. Squamous - between temporal and parietal bones4. Sagittal - between parietal bones

Bones of the Skull & Sutures

Foramen Magnum

* Assignment: Skull Labeling

Figure 6.10

Figure 6.10

Fetal Skull1. The adult skull

represents only 1/8 of the total body length.

2. The newborn infant skull is only 1/4 as long as its entire body.

3. Areas of newborn’s skulls are still hyaline cartilage, called fontanels. (until age 2)

4. The rhythm of the baby’s pulse can be felt in these “soft spots”

5. The largest fontanels are the anterior fontanel and posterior fontanel; which allows the skull to be compressed slightly during birth. 6. Allows the brain to grow and develop in the womb and infancy.

The Rest of the Bones

Vertebrae

Neck = cervical (C1 – C7)

 Middle Back = thoracic (T1 – T12)

  Lower Back = lumbar (L1 – L5)

Sacrum = 5 fused vertebraeCoccyx = tailbone

Thoracic Cage

Pectoral Girdle

Bones of the Arm

a. Humerus – upper arm

b. Ulna goes to pinky  (P-U or “UP”)

c. Radius goes to thumb (RT)

Wrist Bones

For test:

a. Carpals

b. Metacarpals

c. Phalanges

Name the carpals for extra credit on test.

Pelvic Girdle – Wider in females than malesSacrum – 5 fused vertebrae

Bones of the Leg

Bones of the Ankle

Assignment –

Skeleton Labeling

For Test:

Calcaneous

Tarsals

Metatarsals

Phalanges

What you should have on your “Mr. Bones” labeling sheet!

https://youtube.googleapis.com/v/btMq9BYziIQ

Broken Bones – heal faster than ligaments or tendons because

they have a greater or richer blood supply

*A compound fracture is most dangerous.1. Because it’s an open fracture that may result in a severe bone infection (osteomyelitis), requiring massive doses of antibiotics.2. While a simple fracture is incomplete, not breaking the skin. A simple fracture is sometimes called a “closed fracture”.

Fractures are treated by reduction.

Closed Reduction:The bone ends are coaxed back into their normal position by the physician’s hands.

Open Reduction: Surgery is performed and the bone ends are secured together with pins or wires, then immobilized by a cast or traction for healing.

Abnormal Bone Conditions1. BONE SPURS: abnormal growth. Can occur on any bone (e.g. heel).

2. OSTEOPOROSIS: Increased activity of osteoclasts cause a break down bone, and the subsequent fewer minerals in the extracellular matrix make it fragile. The spongy bone especially becomes more porous.

3. Men get it as well as women. What’s the best way to prevent osteoporosis? Exercise! What does exercise do? Makes bones bigger.

4. The most common bone used for a bone graft is the iliac bone of the hip.

Osteoporosis

Figure 6.15

Arthritis

Rheumatoid arthritis is an autoimmune disease which causes joint stiffness and bone deformity

Source: http://www.thetimes.co.uk/tto/public/article3233439.ece 

ABNORMALITIES OF THE SPINE

1. SCOLIOSIS is a lateral curve in the spine

2. KYPHOSIS is a hunchback curve

3. LORDOSIS is a swayback in the lower region.

4. ANKYLOSIS is severe arthritis in the spine and

the vertebrae fuse.

SCOLIOSIS

LORDOSIS

ANKYLOSIS

Rickets – disease of children which bones fail to calcify resulting in bone softening and bowing of the weight-bearing bones of legs.

Is due to a lack of Vitamin D and calcium in the blood.

Bursitis Inflammation of the Bursa (fluid filled sac surrounding the joint).A bursa can become inflamed from injury, infection (rare in the shoulder), or due to an underlying rheumatic condition.Bursitis is typically identified by localized pain or swelling, tenderness, and pain with motion of the tissues in the affected area.

Tendonitis

Sometimes the tendons become inflamed for a variety of reasons, and the action of pulling the muscle becomes irritating.

If the normal smooth gliding motion of your tendon is impaired, the tendon will become inflamed and movement will become painful.

This is called tendonitis, and literally means inflammation of the tendon.

The most common cause of tendonitis is overuse.

Carpal Tunnel Syndrome

Any condition that causes swelling or a change in position of the tissue within the carpal tunnel can squeeze and irritate the median nerve. Irritation of the median nerve in this manner causes tingling and numbness of the thumb, index, and the middle fingers, a condition known as "carpal tunnel syndrome."

Gout

Gout is a disease that results from an overload of uric acid in the body. This overload of uric acid leads to the formation of tiny crystals of urate that deposit in tissues of the body, especially the joints.

When crystals form in the joints it causes recurring attacks of joint inflammation (arthritis). Chronic gout can also lead to deposits of hard lumps of uric acid in and around the joints and may cause joint destruction, decreased kidney function, and kidney stones.

GOUT

Leukemia

Leukemia is cancer of the blood cells. It starts in the bone marrow, the soft tissue inside most bones. Bone marrow is where blood cells are made.When you are healthy, your bone marrow makes:･White blood cells, which help your body fight infection.･Red blood cells, which carry oxygen to all parts of your body. ･Platelets, which help your blood clot.

When you have leukemia, the bone marrow starts to make a lot of abnormal white blood cells, called leukemia cells. They don't do the work of normal white blood cells, they grow faster than normal cells, and they don't stop growing when they should.

Bone Marrow Biopsy

FUN FACTS ABOUT BONESBone is made of the same type of minerals as limestone.

•Babies are born with 300 bones, but by adulthood we have only 206 in our bodies.

•The giraffe has the same number of bones in its neck as a human: seven in total.

•The long horned ram can take a head butt at 25 mph. The human skull will fracture at 5mph.