Bio exam 2

Compact Bone

o   Out portion of bone.

o   Surrounds spongy bone

o   Also called osseous bone

o   Covered by periosteum

o   80% of bone

Spongy Bone

o   Inner portion of bone

o   Helps absorbs shock

o   Location of bone marrow

o   Also called cancellous bone

o   Called diploe in flat bones

o   20 % of bone

Hydroxyapatite Bone

70% to 80% of bone composition

Types of Bones

• Long Bone

• Short Bone

• Irregular Bone

• Flat Bone

• Sesamoid Bone

Long Bone

o   Longer in length than width

o   Femur, humerus

Short Bone

o   Length and width about the same.

o   Carpal bones are examples

Irregular bones

o   No definite shape

o   Vertebral bone is an example

Flat Bone

o   Flat like the name indicates

o   Examples are bones of the cranium, sternum

Sesamoid bones

o   Bones found within a tendon

o   Example is the patella

Bone cells

• Osteoprogenitor

• Osteocytes

• Osteoblast

• Osteoclast

Osteoprogenitor

Stem cells that give rise to more specialized cells.

E.g osteoblasts.

Osteocytes

o   Major osteoblasts

o   Reside in the lacunae of bone

Osteoblast

o   Specialized cell that helps with bone build up

o   Give rise to osteoclasts due to low blood calcium

Osteoclast

o   Help to break down bones

o   Derived from osteoblasts

Parts of a bone

• Diaphysis

• Epiphysis

• periosteum

• Endosteum

• Osteons

Diaphysis

Shaft

Epiphysis

Ends of long bone

Periosteum

Fibrous sheet that surrounds out part of bone

Endosteum

Lines in the inner portion of bone

Osteons

• Basic structural and function al unit of mature compact bone

• Central canal

  • Parallel to center of osteon

• Concentric lamellae

  • Surround central canal

  • Rings of bone Connective tissue

• Osteocytes

  • Mature osteoblasts

  • Resides in lacunae

• Canaliculi

  • Extends from each lacuna and connects to central canal.

  • Allow exchange of nutrients, minerals etc. between blood vessels and osteocytes.

• Perforating canals

  • Perpendicular to central canals

• Circumferential lamellae

  • External- rings of bone rune immediately internal to periosteum

  • Internal- rings of bone run internal to the endosteum

• Interstitial lamellae

  • Components of compact bone between osteons or partially resorbed osteons

Hyaline Cartilage

·        Resilient and flexible

·        High percentage of water

·        Highly compressible and good shock absorber

·        Avascular and contains no nerves

Cartilage cells

• Chondroblasts

  • Produce cartilage matrix

• Chondrocytes

  • Mature chondroblasts

• Perichondrium

  • Covers cartilage and helps maintain its shape

Fractures

• Pathological fracture

  •   Caused by disease

• Simple fracture

  • Broken bone but does not penetrate skin

• Green stick

  •   Fracture in children

  • Buckles with a peaked crack on one side

Fracture healing

• Hematoma formation

• Soft callus formation

• Hard callus formation

• Bone remodeling

Function of skeleton

• Support

• Protection

• Calcium homeostasis

• Hematopoiesis

• Movement

Axial Bones

• 80 bones

• Skull

  • 22 Bones

    • Cranial Bones

      • Parietal

      • frontal

      • occipital

        • magnum foramen (pathway for spinal cord)

      • Temporal

      • sphenoid

        • Keystone bone (articulates with all other cranial bones)

      • Ethmoid

        • Sutures

          • Lambdoid - Divided occiput and parietal

          • Sagittal - divides parietal

          • Squamous - Divides parietal and temporal

          • coronal - divides frontal and parietal

• Facial Bones

  • Paranasal Sinuses

    • frontal

    • maxillary

    • Ethmoidal

    • Sphenoid

— Mandible biggest facial bone

• Ribcage

  • 12 ribs

    • 1-7 - True ribs

    • 8-12 - False ribs

    • 11-12 - floating ribs

• Spinal column

Cervical

·        7 Segments

·        Lordotic curve

Thoracic

·        12 segments

·        Kyphotic curve

Lumbar

·        5 segments

·        Lordotic curve

Sacrum

·        1 segment

·        Kyphotic curve

Coccyx

4 segments

Appendicular

Upper extremity

• Scapular

• clavicle

• humerus

• radius

• ulna

• carpal bones

  • scaphoid

  • lunate

  • triquetrum

  • pisiform

  • trapezium

  • trapezoid

  • capitate

  • hamate

• Metacarpals

  • 5

• Phalanges

  • 14

Lower Extremity

• pelvis

  • illium

  • ischium

  • pubis

• Femur

  • longest and heaviest bone of the body

• tibia

• fibular

• tarsal Bones

  • 3 cuneiform - medial cuneiform, Middle cuneiform, Lateral cuneiform

  • cuboidal

  • navicular

  • calcaneus

  • talus

• metatarsals

  • 5

• phalanges

  • 14

Joint

·        Also called articulations

·        Usually named after bones/structure forming the joint

·        A joint is were two bones meet

·        Acts as a lever system

·        Arthrology is the study of joints

Structural classes of joints

• fibrous

• cartilaginous

• synovial

Fibrous

• Gomphosis

  • Joint between tooth and mandible

  • synarthrosis

• Sutures

  • Synostosis

  • found in cranium

• Syndesmosis

  • Interosseous membrane

  • Found between ulna and radius and between tibia and fibular

  • Provides pivot for two long bones

Cartilaginous

• Synchondrosis

  • Hyaline cartilage can be found in rib attachment to sternum

  • Can be found at the growth plate of long bones

• Symphyses

  • Fibrocartilage

  • Shock absorber

  • Can be found at the intervertebral disc and pubic symphysis

Synovial

o   Diarthrosis

o   Majority of joints

o   Synovial joints   

§  Articular  capsule

·        Fibrous layer

o   Outer

·        Synovial membrane

o   Inner layer

§  Synovial fluid

§  Joint cavity

·        Lubricates articular cartilage on articulating surfaces

·        Nourishes chondrocytes

·        Acts as shock absorber

§  Articular cartilage

§  Ligaments

·        Connect bone to bone

§  Tendon

·        Connects muscle to bone

§  Bursae

·        Saclike structure filled with synovial fluid

Helps to reduce friction

Functional classes of joints

Synarthrosis

o   Immobile

o   Can be fibrous or cartilaginous

Amphiarthrosis

o   Slightly movable

o   Can be fibrous or cartilaginous

Diarthrosis

o   Freely moveable
o   Synovial

Classification of synovial joints

Uniaxial

o   Moves in one plane or axis

Example- flexion/extension of elbow

Biaxial

o   Moves in two planes or axis

Example- Flexion/extension and adduction/abduction of wrist

Multiaxial

o   Moves in multiple planes or axis

Example- Circumduction of the shoulder and hip

Types of Synovial joints

Plane

o   Carpal/tarsal

Hinge

o   Elbow/knee

Pivot

o   Radioulnar joint

Ball and socket

o   Hip and shoulder

Saddle

Condylar

Lever systems

Effort

o   Efforts applied at one point

Resistance

o   Resists efforts

Fulcrum

o   Lever rotates around this point

 First class

o   Fulcrum is between effort and resistance

o   EFR

Scissors is an example

Second class

o   Resistance is between effort and fulcrum

o   ERF

Example would be a wheel barrow

Third class

o   Effort is between fulcrum and resistance

o   FER

Example would be the elbow joint

Gliding movement

Angular Movement

Rotation Movement

Special Movement