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….)

2. 2 Main Divisions – Axial & Appendicular B. ORGANIZATION 1. About 206 bones 2. 2 Main Divisions – Axial & Appendicular

Classification of Bones: BASED ON SHAPE 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

1. Compact (wall of the diaphysis) Types of Bone Tissue 1. Compact (wall of the diaphysis) 2. Spongy (cancellous, epiphysis) - red marrow

1. Medullary Cavity – hollow chamber filled with bone 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 Epiphysis – on each end Diaphysis – main body/shaft of bone 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 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 the Pectoral Girdle (shoulders) 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 Canal Volkman's Canal Lamellae Spongy Bone Compact Bone

BONE DEVELOPMENT & GROWTH Intramembranous bones – are flat, ex. Skull 2. Endochondral bones – all other bones 3. 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 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. 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 Joints Hold bones together securely Give the rigid skeleton mobility.

Types of Joints (Also called Articulations!) Synarthrotic (not moveable, ex. sutures of the skull) 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. Lacrimal 10. Ethmoid 11. Nasal 12. External Auditory meatus 13. Mastoid process 14. Styloid Process 15. Temporo-mandibular joint 16. Sagittal suture 17. Lambdoid suture 18. Squamous suture 19. Coronal suture 20. Foramen magnum 21. 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 bones 2. Lambdoid - between occipital and parietal bones 3. Squamous - between temporal and parietal bones 4. Sagittal - between parietal bones

Bones of the Skull & Sutures

Foramen Magnum * Assignment: Skull Labeling

Figure 6.10

Figure 6.10

Fetal Skull 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 adult skull represents only 1/8 of the total body length. The newborn infant skull is only 1/4 as long as its entire body. 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”

The Rest of the Bones

Vertebrae Neck = cervical (C1 – C7) Middle Back = thoracic (T1 – T12)   Middle Back = thoracic (T1 – T12) Lower Back = lumbar (L1 – L5) Sacrum = 5 fused vertebrae Coccyx = 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 males Sacrum – 5 fused vertebrae

Bones of the Leg

Bones of the Ankle For Test: Calcaneous Tarsals Metatarsals Phalanges Assignment – Skeleton Labeling

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 Conditions 1. 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

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Arthritis 60

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Rheumatoid arthritis is an autoimmune disease which causes joint stiffness and bone deformity Source: http://www.thetimes.co.uk/tto/public/article3233439.ece 

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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. 70

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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. 72

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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." 74

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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. 76

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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. 78

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Bone Marrow Biopsy 80

FUN FACTS ABOUT BONES Bone 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.