1 / 27

What is this???????

What is this???????. Bone Connective Tissue. Skeletal System. The Skeletal System. Parts of the skeletal system Bones (skeleton) Joints Cartilage Ligaments Divided into two divisions Axial skeleton (skull, vertebrae, bony thorax) 1 st practical

tangia
Télécharger la présentation

What is this???????

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. What is this???????

  2. Bone Connective Tissue

  3. Skeletal System

  4. The Skeletal System • Parts of the skeletal system • Bones (skeleton) • Joints • Cartilage • Ligaments • Divided into two divisions • Axial skeleton (skull, vertebrae, bony thorax) 1st practical • Appendicular skeleton( pelvic girdle, pectoral girdle, limbs) 2nd practical

  5. Functions of Bones • Support of the body • Protection of soft organs • Movement due to attached skeletal muscles • Storage of minerals( calcium and phosphorus) and fats • Blood cell formation: Hematopoiesis • Red bone marrow

  6. Bones of the Human Body • The adult skeleton has 206 bones • Two basic types of bone tissue • Compact bone • Dense bone • Spongy bone • Small needle-like pieces of bone • Many open spaces Figure 5.2b

  7. Classification of Bones on the Basis of Shape Figure 5.1

  8. Classification of Bones based on shape • Long bones • Typically longer than wide • Have a shaft with heads at both ends • Contain mostly compact bone • All of the bones of the limbs except the ankle and wrist bones • Examples: Femur, humerus

  9. Classification of Bones • Short bones • Generally cube-shape • Contain mostly spongy bone • Examples: Carpals (wrist), tarsals (ankle)

  10. 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

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

  12. Gross Anatomy of a Long Bone • Diaphysis • Shaft • Composed of compact bone • Epiphysis (pl.epiphyses) • Ends of the bone • Composed mostly of spongy bone • Epiphyseal line remnant of epiphyseal growth plate Figure 5.2a

  13. Structures of a Long Bone • Periosteum • Outside covering of the diaphysis • Fibrous connective tissue membrane • Sharpey’s (perforating) fibers • Secure periosteum to underlying bone • Arteries • Supply bone cells with nutrients Figure 5.2c

  14. Structures of a Long Bone • Articular cartilage • Made of hyaline cartilage • Covers the external surface of the epiphyses • Protects ends of long bones • Decreases friction at joint surfaces Figure 5.2a

  15. Structures of a Long Bone • Medullary cavity • Cavity of the shaft • In adults: contains yellow marrow: stores primarily fat • In infants: contains all red marrow (site of blood cell formation) • As we get older, ½ is converted to yellow marrow (stores fat) • Primary location for red marrow in adults: • Cavities of spongy bone • Epiphyses of some long bones Figure 5.2a

  16. Bone Marrow • Primary location for red marrow in adults: • Cavities of spongy bone • Epiphyses of some long bones

  17. Microscopic Anatomy of Bone • Osteon • A unit of compact bone • Central (Haversian) canal • Opening in the center of an osteon • Carries blood vessels and nerves • Volkmann’s canal • Canal perpendicular to the central canal • Carries blood vessels and nerves

  18. Microscopic Anatomy of Bone Figure 5.3

  19. Microscopic Anatomy of Bone • Lamellae • Rings around the central canal • Sites of lacunae • Lacunae • Cavities containing bone cells (osteocytes) • Arranged in concentric rings Detail of Figure 5.3

  20. Microscopic Anatomy of Bone • Canaliculi • Tiny canals • Radiate from the central canal to lacunae • Form a transport system Detail of Figure 5.3

  21. Types of Bone Cells • Osteocytes • Mature bone cells • Osteoblasts (“b” build) • Bone-forming cells, later become osteocytes • Osteoclasts (“c”crash) • Bone-destroying cells • Break down bone matrix for remodeling and release of calcium • Bone remodeling is a process by both osteoblasts and osteoclasts

  22. Bone Growth • Epiphyseal plates allow long bones to grow in length during childhood • New cartilage is continuously formed • Older cartilage is broken down and becomes ossified (ossification: conversion to bone) • Bone replaces cartilage

  23. Bone Growth • Bones are remodeled and lengthened until growth stops • Bones change shape somewhat • Bones grow in width “appositional growth” (increase muscle mass, throughout life)

  24. Long Bone Formation and Growth Figure 5.4b

  25. Bone Remodeling • 2 Factors that contribute to Bone Remodeling (bone diameter) 1. Blood calcium levels • Low blood calcium levels: • Parathyroid glands release PTH(parathyroid hormone) into blood: • PTH stimulates osteoclasts to break down calcium in matrix and release calcium into blood

  26. High blood calcium levels: • Thyroid gland releases Calcitonin to decrease activity of osteoclasts, which lowers blood calcium

  27. 2. Mechanical Stress (pull of gravity and muscles on the skeleton) • Determines where bone matrix is to be broken down or formed. • Bones become thicker to increase their strength in regions where bulky muscles are attached. • Osteoblasts lay down the matrix and become trapped (osteocytes) Exercise helps to buildmuscle mass. • Bed-ridden, physically inactive lose muscle/bone mass (atrophy) because bones are not subjected to stress

More Related