Bones Flashcards
1
Q
What is bone?
A
- Specialized form of connective tissue
- mineralized collagen matrix, therefore very rigid and strong while still retaining some degree of flexibility
2
Q
Types of Connective Tissue
A
- Cartilage: semi-rigid form, glycoprotein rich
- Ligaments: flexible bands, rich in collagen fibers, contribute to stability of the joint
- Tendons: strong flexible bands, rich in collagen fibers, connect muscles with bone
3
Q
Function of Bone
A
- Support
- Protection (Skull)
- Mineral storage (e.g. calcium homeostasis) • Hematopoiesis (bone marrow - postnatal)
- Locomotion - muscular-skeletal system
- Hearing
4
Q
The Skeletal System
A
- Bones (skeleton)
- Joints
- Cartilages
- Ligaments (bone to bone) (tendon - bone to muscle)
5
Q
Skeletal System division
A
·Axial skeleton - cranium, spine, ribs
·Appendicular skeleton – limbs, pectoral and pelvic girdle
6
Q
Bones of the Human Body
A
- 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
7
Q
Classification
A
- Long bones
- Short bones
- Flat bones
- Irregular bones
8
Q
Long bones
A
- Typically longer than wide
- Have a shaft with heads at both ends · Contain mostly compact bone
- Examples: Femur, humerus
9
Q
Short bones
A
- Generally cube-shape
- Contain mostly spongy bone
- Examples: Carpals, tarsals
10
Q
Flat bones
A
- Thin and flattened
- Usually curved
- Thin layers of compact bone around a layerof spongy bone
- Examples: Skull, ribs, sternum
11
Q
Irregular bones
Irregular shape
·Do not fit into other bone classificationcategories
·Example: Vertebrae and hip
A
- Irregular shape
- Do not fit into other bone classificationcategories
- Example: Vertebrae and hip
12
Q
Gross anatomy of a long bone
A
Diaphysis:
- Shaft - Composed of compact bone
Epiphysis:
- Ends of the bone - Composed mostly of spongy bone
13
Q
Internal bone
A
14
Q
Structures of a long bone
A
Periosteum:
- Outside covering of the diaphysis
- Fibrous connective tissue membrane
Sharpey’s fibers:
- Secure periosteum to underlying bone
Arteries
- Supply bone cells with nutrients
15
Q
Structure of a long bone - articular cartilage
A
- Covers the external surface of the epiphyses
- Made of hyaline cartilage
- Decreases friction at joint surfaces
16
Q
Structures of a long bone - medullary cavity
A
- Cavity of the shaft
- Contains yellow marrow (mostly fat) in adults
- Contains red marrow
(for blood cell formation) in infants
17
Q
Components of Bone
A
- Cortical bone - Structural
- Trabecular bone - Structural
- Bone Marrow - Structural and RBC production
- Vessels - Nutritional
- Nerves – Trophical, Functional
18
Q
Cortical bone
A
- Compact Bone
- Shell around vertebral body (and all other bones)
- 1mm thick on sides
- 0.5mm thick on inferior/superior ends - Endplates
- 80% Bone Mass
- 20% Bone Surface
Osteon (harvesian canals):
- cylindrical tubes made of concentric lamellae
- central opening - blood vessels, neural tissure, lymphatic
Periosteum
- fibrous tissure covering
- enables attachment of muscles and tendons
19
Q
Cortical bone - Lamellae
A
- Concentric layers of mineralized bone
- Crisscross pattern at 90
- Torsion and bending strength
20
Q
Osteoclasts
origin: hematopoietic lineage; bone marrow
A
Bone-resorbing
21
Q
Osteoblasts
A
Bone-forming
origin: mesenchymal, bone marrow
the first OB differentiate within the periosteum and form the bone collar postnatal: bone marrow
22
Q
Trabecular bone
A
- Cancellous or Spongy
- Lattice structure
- Pores filled with marrow
- 20% Bone Mass
- 80% Bone Surface
23
Q
Trabecular structure
A
- Plate and rod structure
- Low loads - rod
- Higher loads - plate
- Light yet spongy
- Oriented in direction of loads - “Wolff’s Law”
24
Q
Bone Marrow
A
Consists of stroma, myeloid tissue, fat, lympatic tissues
25
Red marrow
- Involved with the production of RBC
- Consists of haemopoetic tissue
- Highly vascularized
26
Yellow marrow
- Not as vascularized as red marrow
- Large amount of fat cell
- Percentage increases wrt red marrow with age (up to20yrs)
27
Mechanisms of bone formation - membranous ossification
- direct differentiation of cells within mesenchymal condensations into bone forming cells (osteoblasts)
- flat bones of the skull, clavicle, periosteum
28
Mechanisms of bone formation - Endrochondral ossification
- endochondral bones - axial and appendicular skeleton, some bones in the skull
- replacement of a cartilagenous template by bone
29
Osteocytes
- terminal differentiated osteoblast
origin: mesenchymal, terminal differentiated OB
30
Postnatal bone cell differentiation
31
Outside factors affecting bone mass
Exercise: muscle contractions stimulate osteoblast, function - increased production of bone, peak mass age 30
Body weight: obesity can protect from osteoporotic bone loss
Diet affects bone: minerals and vitamins
Menopause in women: decrease in hormone level can lead to osteoporosis (treatment HRT)
32
Osteopenia (mild)
- osteoblasts are not active enough
- osteoclasts are too active
33
Osteoporosis (severe)
- osteroblasts are not active enough
34
Osteopetrosis
- osteoclast deficiency or no active osteoclast
35
Congenital bone disorders
- Achondroplasia
- Osteogenesis
- Marfan syndrome
- Osteochondromatosis
36
Osteopenia
decreased calcification or density of bone
37
osteoporosis
progressive reduction in quantity of bone
38
osteopetrosis
excessive formation of dense trabecular bone
39
osteosclerosis
abnormal hardening or eburnation of bone
40
osteohypertrophy
overgrowth of bone
41
osteosarcoma
tumor of the bone
42
osteochondrodysplasia
extreme bending of long bones
43
osteochondroma (exostosis)
benign cartilaginous neoplasma
44
osteoblastoma
benign tumor of osteoblasts
