Chapter 5 Bones and Skeletal Tissue The Skeletal

  • Slides: 35
Download presentation
Chapter 5 Bones and Skeletal Tissue

Chapter 5 Bones and Skeletal Tissue

The Skeletal System · Parts of the skeletal system · Bones (skeleton) · Joints

The Skeletal System · Parts of the skeletal system · Bones (skeleton) · Joints · Cartilages · Ligaments · Divided into two divisions · Axial skeleton (80) · Appendicular skeleton (126)

Functions of Bones · Support of the body · Protection of soft organs ·

Functions of Bones · Support of the body · Protection of soft organs · Movement due to attached skeletal muscles · Storage of minerals and fats · Blood cell formation

Bones of the Human Body · The skeleton has 206 bones · Two basic

Bones of the Human Body · The skeleton has 206 bones · Two basic types of bone tissue · Compact bone · Homogeneous · Spongy bone · Small needle-like pieces of bone · Many open spaces

Classification of Bones · Long bones · Typically longer than wide · Have a

Classification of Bones · Long bones · Typically longer than wide · Have a shaft with heads at both ends · Contain mostly compact bone • Examples: Femur, humerus

Classification of Bones · Short bones · Generally cube-shape · Contain mostly spongy bone

Classification of Bones · Short bones · Generally cube-shape · Contain mostly spongy bone · Examples: Carpals, tarsals

Classification of Bones on the Basis of Shape

Classification of Bones on the Basis of Shape

Classification of Bones · Flat bones · Thin and flattened · Usually curved ·

Classification of Bones · Flat bones · Thin and flattened · Usually curved · Thin layers of compact bone around a layer of spongy bone · Examples: Skull, ribs, sternum

Classification of Bones · Irregular bones · Irregular shape · Do not fit into

Classification of Bones · Irregular bones · Irregular shape · Do not fit into other bone classification categories · Example: Vertebrae and hip

Classification of Bones on the Basis of Shape

Classification of Bones on the Basis of Shape

Gross Anatomy of a Long Bone · Diaphysis · Shaft · Composed of compact

Gross Anatomy of a Long Bone · Diaphysis · Shaft · Composed of compact bone Figure 5. 2 a

Structures of a Long Bone · Medullary cavity · Cavity of the shaft ·

Structures of a Long Bone · Medullary cavity · Cavity of the shaft · Contains yellow marrow (mostly fat) in adults · Contains red marrow (for blood cell formation) in infants Figure 5. 2 a

Structures of a Long Bone Ø Epiphysis l l l Ends of the bone

Structures of a Long Bone Ø Epiphysis l l l Ends of the bone Composed mostly of spongy bone Epiphyseal line- line left over from cartilage growth

Structures of a Long Bone · Periosteum · Outside covering of the diaphysis ·

Structures of a Long Bone · Periosteum · Outside covering of the diaphysis · Fibrous connective tissue membrane · Sharpey’s fibers · Secure periosteum to underlying bone · Arteries · Supply bone cells with nutrients Figure 5. 2 c

Structures of a Long Bone · Articular cartilage · Covers the external surface of

Structures of a Long Bone · Articular cartilage · Covers the external surface of the epiphyses · Made of hyaline cartilage · Decreases friction at joint surfaces Figure 5. 2 a

Flat bones Ø Two thin plates of compact bone covered by periosteum Ø Spongy

Flat bones Ø Two thin plates of compact bone covered by periosteum Ø Spongy bone in the middle= diploe (the only place of hematopoiesis in the adult)

Microscopic Anatomy of Bone · Osteon (Haversian System) · A unit of bone ·

Microscopic Anatomy of Bone · Osteon (Haversian System) · A unit of bone · Central (Haversian) canal · Opening in the center of an osteon · Carries blood vessels and nerves · Perforating (Volkman’s) canal · Canal perpendicular to the central canal · Carries blood vessels and nerves

Microscopic Anatomy of Bone Figure 5. 3

Microscopic Anatomy of Bone Figure 5. 3

Microscopic Anatomy of Bone · Lacunae · Cavities containing bone cells (osteocytes) · Arranged

Microscopic Anatomy of Bone · Lacunae · Cavities containing bone cells (osteocytes) · Arranged in concentric rings · Lamellae · Rings around the central canal · Sites of lacunae Figure 5. 3

Microscopic Anatomy of Bone · Canaliculi · Tiny canals · Radiate from the central

Microscopic Anatomy of Bone · Canaliculi · Tiny canals · Radiate from the central canal to lacunae · Form a transport system Figure 5. 3

Bone Markings · Surface features of bones · Sites of attachments for muscles, tendons,

Bone Markings · Surface features of bones · Sites of attachments for muscles, tendons, and ligaments · Passages for nerves and blood vessels · Categories of bone markings · Projections and processes – grow out from the bone surface · Depressions or cavities – indentations · Study Chart on page 119 (little book), pg 172 (big book)

Changes in the Human Skeleton · In embryos, the skeleton is primarily hyaline cartilage

Changes in the Human Skeleton · In embryos, the skeleton is primarily hyaline cartilage · During development, much of this cartilage is replaced by bone · Cartilage remains in isolated areas · Bridge of the nose · Parts of ribs · Joints

Bone Growth · Epiphyseal plates allow for growth of long bone during childhood (longitudinal

Bone Growth · Epiphyseal plates allow for growth of long bone during childhood (longitudinal growth) · New cartilage is continuously formed · Older cartilage becomes ossified · Cartilage is broken down · Bone replaces cartilage

Bone Growth · Bones are remodeled and lengthened until growth stops · Bones change

Bone Growth · Bones are remodeled and lengthened until growth stops · Bones change shape somewhat · Bones grow in width (appositional growth; controlled by hormones)

Long Bone Formation and Growth

Long Bone Formation and Growth

Long Bone Formation and Growth

Long Bone Formation and Growth

Long Bone Formation and Growth Ø osteogenesis- the production of bone cells (may start

Long Bone Formation and Growth Ø osteogenesis- the production of bone cells (may start as cartilage) Ø ossification- the process of cartilage hardening into bone

Types of Bone Cells · Osteocytes · Mature bone cells · Osteoblasts · Bone-forming

Types of Bone Cells · Osteocytes · Mature bone cells · Osteoblasts · Bone-forming cells · Osteoclasts · Bone-destroying cells · Break down bone matrix for remodeling and release of calcium · Bone remodeling is a process by both osteoblasts and osteoclasts

Remodeling and Repair Ø 1. 2. 3. Dynamic changes constantly homeostasis- constantly adjusting to

Remodeling and Repair Ø 1. 2. 3. Dynamic changes constantly homeostasis- constantly adjusting to keep the same make-up by adding and subtracting bone cells etc. Remodeling bone mass remains constant by the result of remodeling bone deposit- at the site of an injury or where the bone needs more strength bone re-absorption- free bone surface is dissolved; minerals (Ca 2+) is released into blood (things reused)

Remodeling and Repair Control 1. hormonal- controls Ca 2+ levels in the body; if

Remodeling and Repair Control 1. hormonal- controls Ca 2+ levels in the body; if blood level drop too low then Ca 2+ leaves bones Ø (what type of feedback is this? ) 1. 2. leaves holes in the bone Calcitonin is secreted when blood Ca 2+ levels rise and encourages Ca 2+ salt deposits in the matrix Ca 2+ is needed for muscles and nerves to function 3. mechanical stress- based on needs of the bones and skeletal system 2. 1. where there is more stress bones are thicker

Repair of Bone Fractures · 1) Hematoma (blood-filled swelling) is formed · Break is

Repair of Bone Fractures · 1) Hematoma (blood-filled swelling) is formed · Break is splinted by fibrocartilage to form a callus 2) fibrocartilaginous callus) · Fibrocartilage callus is replaced by a 3) bony callus · Bony callus is 4) remodeled to form a permanent patch

Stages in the Healing of a Bone Fracture

Stages in the Healing of a Bone Fracture

Bone Fractures · A break in a bone · Types of bone fractures ·

Bone Fractures · A break in a bone · Types of bone fractures · Closed (simple) fracture – break that does not penetrate the skin · Open (compound) fracture – broken bone penetrates through the skin · Bone fractures are treated by reduction and immobilization · Realignment of the bone

Common Types of Fractures Table 5. 2 Copyright © 2003 Pearson Education, Inc. publishing

Common Types of Fractures Table 5. 2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5. 17

Imbalances osteoporosis- bone tissue is reabsorbed faster than it is replaced Ø l most

Imbalances osteoporosis- bone tissue is reabsorbed faster than it is replaced Ø l most often in middle age or older women; causes are: less estrogen, insufficient exercise, not enough Ca 2+ or vitamin D, abnormal metabolism Ø osteomalacia- “soft bones” bones inadequately mineralize. Not enough Ca 2+ or vitamin D in tissues, bones are brittle and weak Ø Paget’s disease- abnormal bone formation and high level of bone breakdown; Tissue can’t mineralize; bones become weak