SKELETAL SYSTEM
Skeleton
Axial skeleton
- Forms the long axis of the body (vertical)
- Includes bones of the skull, vertebral column and rib cage
- Protect, support and carry other body parts
Appendicular skeleton
- Bones of upper and lower limbs and the girdles (shoulder, hip, leggs, arms and hands)
Structure of Bone
Compact/ cortical bone
- Surrouned by periosteum
- Contains pipe-like structures called osteons, they contain hollow centers for nerves
and blood cells
Spongy/ trabecular bone
- Looser structure: branching rods called trabeculae
- Contains bone marrow
- Consists of hematopoietic stem cells (“red marrow”) and adipocytes/ fat cells
(“yellow marrow”, usually in center)
o Red marrow ensures production of blood cells
o Yellow marrow ensures production of fat
, yellow can turn into red when a person gets anemia and needs more red
blood cells
Long bones
- Epiphysis
Outer ends of the bone, often wider as diaphysis. Outside contains compact bone
and inside spongy bone, the top is covered with cartilage.
- Ephipysial line
Remnant of ephysial plate, called also metaphysis.
- Diaphysis
Long axis of the bone, consist of compact bone containing marrow cavity
- Membranes (periosteum, endosteum)
o Periosteum= double- layer membrane which
surrounds the outer bone. It contains nerve
fibers and blood vessels, receive nutrients to
marrow. And provides anchoring points for
tendons.
Outer layer consist of irregular connetive
tissue.
Inner layer consist mainly of primitive
stem cells, from which all bone cells arise
o Endosteum = covers the internal surfaces of the
bone, contains cells that can differentiate in
other bone cells
Skeleton
Axial skeleton
- Forms the long axis of the body (vertical)
- Includes bones of the skull, vertebral column and rib cage
- Protect, support and carry other body parts
Appendicular skeleton
- Bones of upper and lower limbs and the girdles (shoulder, hip, leggs, arms and hands)
Structure of Bone
Compact/ cortical bone
- Surrouned by periosteum
- Contains pipe-like structures called osteons, they contain hollow centers for nerves
and blood cells
Spongy/ trabecular bone
- Looser structure: branching rods called trabeculae
- Contains bone marrow
- Consists of hematopoietic stem cells (“red marrow”) and adipocytes/ fat cells
(“yellow marrow”, usually in center)
o Red marrow ensures production of blood cells
o Yellow marrow ensures production of fat
, yellow can turn into red when a person gets anemia and needs more red
blood cells
Long bones
- Epiphysis
Outer ends of the bone, often wider as diaphysis. Outside contains compact bone
and inside spongy bone, the top is covered with cartilage.
- Ephipysial line
Remnant of ephysial plate, called also metaphysis.
- Diaphysis
Long axis of the bone, consist of compact bone containing marrow cavity
- Membranes (periosteum, endosteum)
o Periosteum= double- layer membrane which
surrounds the outer bone. It contains nerve
fibers and blood vessels, receive nutrients to
marrow. And provides anchoring points for
tendons.
Outer layer consist of irregular connetive
tissue.
Inner layer consist mainly of primitive
stem cells, from which all bone cells arise
o Endosteum = covers the internal surfaces of the
bone, contains cells that can differentiate in
other bone cells
