Chapter 5 The Skeletal System

1
Chapter 5The Skeletal System Provides an
internal framework for the body, protects organs
by enclosure, and anchors skeletal muscles so
that muscle contractions can cause movement
2
The Skeletal System

• Divided into two divisions
• Axial skeleton
• Longitudinal axis
• Bones of the skull, vertebral column, bony thorax
  
• Appendicular skeleton
• Bones of the upper lower limbs, shoulder, hip

3
(No Transcript)
4
The Skeletal System

• Parts of the skeletal system
• Bones (skeleton)
• Joints
• Cartilages
• Ligaments
• Fibrous cords that bind bones together at joints

5
Functions of the Bones

• Support the body
• Protection of soft organs
• Movement
• Bones are attached to skeletal muscles by tendons
• Storage of minerals and fats
• Calcium phosphorus
• Blood cell formation
• Hematopoiesis

6
Classification of Bones

• Adult skeleton is composed of 206 bones
• Two basic types of osseous (bone) tissue
• Compact bone
• Dense, smooth, homogeneous
• Spongy bone
• Small needle-like pieces of bone
• Lots open spaces

7
Classification of Bones Based on Size Shape
8
Classification of Bones

• Long bones
• Typically longer than they are wide
• Shaft with heads at both ends
• Mostly compact bone
• Examples Femur, humerus

9
Classification of Bones

• Short bones
• Generally cube-shaped
• Contain mostly spongy bone
• Examples Carpals, Tarsals

10
Classification of Bones

• Flat bones
• Thin, flattened usually curved
• 2 thin layers of compact bone sandwiching 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
Structure of a Long Bone
13
Structure of a Long Bone

• Gross Anatomy
• Diaphysis
• Shaft
• Composed of compact bone
• Covered protected by the periosteum
• Epiphyses
• Ends of the bone
• Thin layer of compact bone enclose an area filled
  with spongy bone
• Covered by articular cartilage

14
Structure of a Long Bone

• Epiphyseal line
• Remnant of the epiphyseal plate
• Flat plate of hyaline cartilage
• Seen in a young, growing bone
• Epiphyseal plates
• Cause the lengthwise growth of a long bone

15
Structure of a Long Bone

• Periosteum
• Outside covering of the diaphysis
• Fibrous connective tissue membrane
• Sharpeys fibers
• Secures the periosteum to underlying bone
• Arteries
• Supply bone cells with nutrients

16
Structure of a Long Bone

• Articular cartilage
• Covers the external surface of the epiphyses
• Made of hyaline cartilage
• Decreases friction at joint surfaces

17
Structure of a Long Bone

• Medullary cavity
• Cavity of the shaft
• Contains yellow marrow (mostly adipose) in adults
• In adult bones, red marrow is confined to the
  cavities of spongy bone of flat bones epiphyses
  of some long bones
• Contains red marrow (for blood cell formation) in
  infants

18
Bone Marrow

• Soft, spongy tissue found inside bones
• Medium for development storage of the bodys
  blood cells
• Blood cells that produce other blood cells ? Stem
  cells
• Bone Marrow Transplants
• Special therapy for patients with cancer or other
  diseases which affect the bone marrow
• Leukemias, severe aplastic anemia, lymphomas,
  multiple myeloma
• Immune deficiency disorders
• Solid- tumor cancers
• Breast
• Ovarian

19
Bone Marrow Transplantation

• Involves taking cells that are normally found in
  the bone marrow (stem cells), filtering those
  cells, giving them back to either the patient
  or to another person
• Goal
• Transfuse healthy bone marrow cells into a person
  after their own unhealthy bone marrow has been
  eliminated

20
Bone Marrow Transplantation

• Leukemia
• Stem cells produce an excessive number of
  defective or immature blood cells
• To eliminate the cancer, high doses of
  chemotherapy (sometimes radiation) are
  administered
• Destroys the abnormal stem cells blood cells
• However, normal cells found in bone marrow are
  also damaged
• Healthy bone marrow is then transplanted to
  restore normal stem cell function

21
Bone Marrow Transplantation

• Autologous bone marrow transplants
• Your own bone marrow is harvested, preserved
  stored (frozen)
• Then, after high-dose chemotherapy and/or
  radiation therapy
• Your own bone marrow is infused back into your
  body
• This is possible if the disease affecting the
  bone marrow is in remission, or if the condition
  being treated doesn't involve the bone marrow (as
  in breast cancer)
• Allogeneic bone marrow transplants
• Bone marrow is harvested from a family member or
  an unrelated donor

22
Bone Marrow Transplantation

• Bone Marrow Harvesting
• Bone marrow is withdrawn through a needle
  inserted into a bone in the hip
• Performed in the operating room
• Patient is given general anesthesia
• If your own bone marrow can not be used for
  transplantation and if a donor is not found,
  peripheral stem cells may be harvested from your
  circulating blood
• What happens during the transplant?
• The day you receive your bone marrow transplant,
  the harvested bone marrow is infused into a vein
  (IV)
• Bone marrow looks like dark, thick blood
• It migrates to the large bone cavities (breast
  bone, skull, hips, ribs, and spine), engrafts,
  and begins producing normal blood cells after
  several weeks

23
Microscopic Anatomy of Compact Bone
24
Microscopic Anatomy of Compact Bone
Compact Bone Tissue Riddled with passageways
carrying nerves blood vessels ? provide the
living bone cells with nutrients a route for
waste disposal
25
Microscopic Anatomy of Compact Bone

• Lacunae
• Cavities containing bone cells
• Osteocytes mature bone cells
• Arranged in concentric rings called lamellae
• Lamellae
• Concentric rings around the central (Haversian)
  canals

26
Microscopic Anatomy of Compact Bone

• Osteon (Haversian System)
• Complex consisting of the central canal matrix
  rings
• Central (Haversian) canals
• Run lengthwise through the bony matrix
• Carrying blood vessels and nerves to all areas of
  the bone
• Perforating (Volkmanns) canals
• Canals perpendicular to the central canal
• Carry blood vessels nerves

27
Microscopic Anatomy of Compact Bone

• Canaliculi
• Tiny canals
• Radiate outward from the central canals to all
  lacunae
• Form a transportation system
• Connects all bone cells to the nutrient supply

28
(No Transcript)
29
Bone Markings

• Surface features of bones
• Reveal sites of attachment for muscles, tendons,
  ligaments
• Conduits for blood vessels nerves
• Two categories of bone markings
• Projections (processes)
• Grow out from the bone surface
• Depressions (cavities)
• Indentations in the bone

30
The Axial Skeleton