Skeletal System Chapter 6 Pages 86 – 117

Page 87 Functions Support – it supports body structures & provides shape to the body Protect – it protects the soft & delicate internal organs Movement & anchorage of muscles. Mineral storage (calcium & phosphorus) – in case of inadequate nutrition, the body is able to draw upon these reserves. Hematopoiesis (formation of blood cells) – occurs in red bone marrow There are 206 individual bones in the adult. Some bones are hinged; others are fused to one another. **** 3. Muscles that are attached to the skeleton are called skeletal muscles. Upon contraction, these muscles exert a pull on a bone & so move it. In this manner, bones play a vital part in body movement, serving as passively operated levers. Ligaments are fibrous bands that connect bones to bones & cartilage & serve as support for muscles. Joints are also bound together by ligaments. Tendons are fibrous cords that connect muscles to bone. 5. Stem cells in the red marrow tissue of the bone differentiate into red blood cells, white blood cells, & platelets. In an adult, the ribs, sternum, & bones of the pelvis contain red marrow. Red bone marrow at the ends of the humerus & femur are plentiful at birth but gradually decrease as we age.

Structure & Formation of Bone Chapter 6 Structure & Formation of Bone Osteocytes – Mature bone cell Bone is made of: 35% Organic material (flexibility) Collagen – a fibrous material Jellylike material – resides between the collagen 65% Inorganic material (hardness & durability) calcium phosphate, calcium carbonate, calcium fluoride, magnesium phosphate, sodium oxide, & sodium chloride Water When pressure is applied to a bone, the flexible organic material prevents bone damage, while the mineral elements resist crushing or bending under pressure.

Page 87 Bone Formation Embryonic skeletons initially consists of collagenous protein fibers secreted by osteoblasts. Later, during embryonic development, cartilage is deposited between the fibers. During the eighth week of embryonic development, ossification begins. (mineral matter starts to replace previously formed cartilage, creating bone). Infant bones are very soft & pliable because of incomplete ossification at birth. Cartilage, a connective tissue, is also found at the ends of certain bones in adults, providing a smooth surface for adjacent bones to move against each other. **** A familiar example is the soft spot on a baby’s head, the fontanel. The bone has not yet been formed there, although it will become hardened later. Ossification due to mineral deposits continues through childhood. As bones ossify, they become hard & more capable of bearing weight.

Structure of Long Bone Page 88 Diaphysis (Shaft) – Hollow cylinder made of compact bone Epiphysis – Each end of the long bone (Covered by articular cartilage – which acts as a shock absorber) Medullary canal – The center of the shaft of a long bone (contains Yellow bone marrow) Endosteum – lining of the marrow canal Haversian canal: carries blood vessels that nourish bone cells (osteocytes)

Structure of Long Bone (Cont’d) Page 88 Structure of Long Bone (Cont’d) Spongy (cancellous) bone – at the ends of long bones contains Red marrow where red blood cells & some white blood cells are manufactured Periosteum – covers the outside of the bone; contains blood vessels, lymph vessels, & nerves. Necessary for bone growth, repair & nutrition

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Pages 88 – 89 Growth Bones grow in length; Ossify from the center outward Osteoblasts = Deposit new bone Osteoclasts = Large cells that secrete enzymes that break down bone Growth stops when all the epiphyseal cartilage (also known as the growth plate) is ossified Females grow until about 18 years of age Males grow until about 20–21 years of age Medullary canal gets larger as the diameter of the bone increases. It eventually fills with yellow marrow

Page 89 Bone Types Long bones Flat bones Irregular bones Short bones

Page 90 Skeletal System Axial skeleton – Skull, spinal column, ribs, sternum, & hyoid bone Appendicular skeleton – Upper & lower extremities

Axial Skeleton Pages 90 – 94 22 bones of the skull 14 facial bones Spinal column (vertebra) Cervical 7 vertebrae Thoracic 12 vertebrae Lumbar 5 vertebrae Sacrum 5 fused bones Coccyx 4 fused bones Ribs (12) & sternum

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Appendicular Skeleton – Upper Extremities Page 94 – 95 Appendicular Skeleton – Upper Extremities Shoulder girdle – 2 clavicles & 2 scapulae Arm – Humerus, radius, ulna Hand – Carpals, metacarpals & phalanges (fingers)

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Appendicular Skeleton – Lower Extremities Pages 96 – 99 Appendicular Skeleton – Lower Extremities Pelvic girdle – Ilium, ischium & pubis Upper leg – Femur Lower leg – Tibia, fibula & patella Ankle – 7 tarsal bones Foot – Metatarsal & phalanges (toes)

Chapter 6

Chapter 6

Chapter 6

Chapter 6

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Joints (Articulations) Chapter 6 Joints (Articulations) Diarthroses – movable joint – most common Articular cartilage – smooth, slippery cap of cartilage Articular capsule – tough, fibrous connective tissue; encloses the articular surfaces of bone Synovial membrane – lines articular capsules; secretes Synovial fluid (lubricating substance) into the Synovial cavity (area between 2 articular cartilages) reduces friction Bursae – found in spaces of connective tissue between muscles, tendons, ligaments, & bones. Amphiarthroses – partially movable joints Synarthroses – immovable joints Points of contact between two bones ***** Articular cartilage – helps absorb shocks & prevent friction Bursae (closed sacs with a synovial membrane lining)

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Diarthroses Joints (Moveable) Page 101 Diarthroses Joints (Moveable) Ball-and-socket joints – Shoulder, hip Allow the greatest freedom of movement. Hinge joints – Knees, elbows, fingers Move in one direction or plane Pivot joints – Radius & ulna; atlas & head Allows the joint to rotate Gliding joints – vertebrae Allow bend forward, backward, & sideways as well as rotate Ball & socket joints = one bone has a ball-shaped head that nestles into a concaved socket of the second bone.

Amphiarthroses Joints Page 101 Amphiarthroses Joints Partially movable joints Cartilage between their articular surfaces Examples: Ribs to the spine Symphysis pubis

Synarthroses Joints Page 101 Immovable joints Connected by tough, fibrous connective tissue Example: Adult cranium (Cranial joints are called sutures)

Page 101 Types of Motion Flexion – Decreasing the angle between 2 bones Extension – Increasing the angle between 2 bones Abduction – Away from the midline Adduction – Towards the midline Circumduction – full range of motion Rotation – Movement around a central axis Pronation – Palm down & back Supination – Palm up & forward

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Disorders of the Bones & Joints Page 102 Disorders of the Bones & Joints Fracture (same as a “break”) Hairline – a tiny crack that usually heals itself Greenstick – simplest type of fracture. The bone is partially bend but never completely separates. Closed/simple – the broken ends do not piece through the skin to form external wounds Open/compound – broken ends piece & protrude through the skin. Comminuted – bone is splintered or broken into many pieces that can become embedded in the surrounding tissue

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Repairing Fractures Page 103 The process of restoring bone occurs through three main methods: Closed reduction – the bony fragments are brought into alignment by manipulation, & a cast or splint is applied Open reduction – through surgical intervention, devices such as wires, metal plates, or screws are used to hold the bone in alignment & a cast or splint may be applied Traction – a pulling force is used to hold the bones in place (used for fractures of the long bone)

Aging of the Bones & Joints Page 104 SB Aging of the Bones & Joints Bone mass & density decline External surfaces of the bones thicken Intervertebral cartilage disks shrink Center of balance is altered Joints less mobile Increased rigidity & decreased flexibility Fear of falling

Other Bone & Joint Injuries Page 104 – 105 Other Bone & Joint Injuries Dislocation – Displacement of a bone from its proper position Sprain – Ligament injury with pain & swelling Hammer toe – Curled toe due to a bend in the middle phalanx from abnormal pressure on the toe Whiplash – Neck (cervical) injury from car accident or fall RICE Treatment – Rest, ice compression, elevation

Diseases of the Bone Page 104 – 106 Arthritis – 20 different kinds most common: Rheumatoid arthritis = autoimmune disease affects the connective tissue Osteoarthritis = degenerative joint disease Gout Due to high levels of uric acid in the blood Usually affects the great toe Painful swollen red joint Rickets Lack of vitamin D in children Lifestyle & Home remedies = Weight loss, physical activity, rest, & heat & cold packs – use a cane Complementary & Alternative Therapies = Yoga & tai chi; Acupuncture; Supplement but do your research Surgical procedure = Joint replacement

Abnormal Curvatures of the Spine Page 107 Abnormal Curvatures of the Spine Kyphosis = hunchback Lordosis = swayback Scoliosis = side-to-side or lateral curvature of the spine

Page 108 – 109 Other Disorders Osteoporosis = Low bone mass with structural deterioration of the bone Osteomyelitis = Infection in the bone Osteosarcoma = Cancer of the bone