Skeletal system:
*each bone is characterized as its’ own organ*
- Bones
- Cartilage
- Tissue
- Tendons (bone to muscle)
- Ligaments (bone to bone)
Types of tissue:
- Connective
- Epithelial
- Muscle
- Nervous
Functions of the skeletal system:
- Support
- Protect
- Movement
- store/release minerals (calcium and phosphate) (contribute to bone
hardness)
- Haemopoiesis (erythrocytes, leukocytes, thrombocytes)
(bone marrow also creates macrophages and fibroblasts)
- Triglyceride storage (adipocytes in yellow marrow
Process of haemopoiesis:
● Stem cells(hematopoietic stem cells) beginning in bone marrow
● Undergo mitosis multiple times to form into erythrocytes, leukocytes, and
thrombocytes
Red bone marrow:
- Contains HSC’s
Yellow bone marrow:
- Mostly lipid that contains stem cells (adipocytes and mesenchymal stem
cells)
, - Preserve fat for energy production and develop bone, cartilage, muscles,
and fat cells
Types of bones:
● Long bones
- Longer than they are wide
- Outer layer of compact bone, inner cancellous bone
- Cancellous bone found at the epiphysis
- Contains a medullary cavity
Structure of long bone:
● Diaphysis
- Shaft of the bone
- Heavy wall of compact bone
- Central hollow space called the medullary cavity
● Epiphysis
- Distal and proximal wide ends of bone
- Articulation w/ other bones
- Mostly cancellous bone
- Contains epiphyseal line (cartilage)
● Metaphysis
- General area where epiphysis and diaphysis meet.
- Growth plate
- Hyaline cartilage
, ● Short bones
- Equal in length and width
- Inner cancellous bone layer and outer layer of compact bone
- No medullary cavity
● Flat bones
- Thin inner layer of spongy bone sandwiched between 2 outer layers
of compact bone
- No medullary cavity
- Similar to short bones except are sandwiched and not cube-shaped
● Irregular bones
- Various amounts of sponger inner bone and outer compact bone
- No medullary cavity
● Sesamoid bones
- Within tendons
- Not always fully ossified
- Typically small (mm)
- Prevent wear and tear on tendons
● Sutural bones
- Small bones between cranial structures
- “Wormian bones”
● Periosteum
- Covers bone surface like a sheet except for the ends that are
enclosed in a joint capsule
- Protects and nourishes bone
*each bone is characterized as its’ own organ*
- Bones
- Cartilage
- Tissue
- Tendons (bone to muscle)
- Ligaments (bone to bone)
Types of tissue:
- Connective
- Epithelial
- Muscle
- Nervous
Functions of the skeletal system:
- Support
- Protect
- Movement
- store/release minerals (calcium and phosphate) (contribute to bone
hardness)
- Haemopoiesis (erythrocytes, leukocytes, thrombocytes)
(bone marrow also creates macrophages and fibroblasts)
- Triglyceride storage (adipocytes in yellow marrow
Process of haemopoiesis:
● Stem cells(hematopoietic stem cells) beginning in bone marrow
● Undergo mitosis multiple times to form into erythrocytes, leukocytes, and
thrombocytes
Red bone marrow:
- Contains HSC’s
Yellow bone marrow:
- Mostly lipid that contains stem cells (adipocytes and mesenchymal stem
cells)
, - Preserve fat for energy production and develop bone, cartilage, muscles,
and fat cells
Types of bones:
● Long bones
- Longer than they are wide
- Outer layer of compact bone, inner cancellous bone
- Cancellous bone found at the epiphysis
- Contains a medullary cavity
Structure of long bone:
● Diaphysis
- Shaft of the bone
- Heavy wall of compact bone
- Central hollow space called the medullary cavity
● Epiphysis
- Distal and proximal wide ends of bone
- Articulation w/ other bones
- Mostly cancellous bone
- Contains epiphyseal line (cartilage)
● Metaphysis
- General area where epiphysis and diaphysis meet.
- Growth plate
- Hyaline cartilage
, ● Short bones
- Equal in length and width
- Inner cancellous bone layer and outer layer of compact bone
- No medullary cavity
● Flat bones
- Thin inner layer of spongy bone sandwiched between 2 outer layers
of compact bone
- No medullary cavity
- Similar to short bones except are sandwiched and not cube-shaped
● Irregular bones
- Various amounts of sponger inner bone and outer compact bone
- No medullary cavity
● Sesamoid bones
- Within tendons
- Not always fully ossified
- Typically small (mm)
- Prevent wear and tear on tendons
● Sutural bones
- Small bones between cranial structures
- “Wormian bones”
● Periosteum
- Covers bone surface like a sheet except for the ends that are
enclosed in a joint capsule
- Protects and nourishes bone
