Chapter 6 - Skeletal System I - Bone Tissue Flashcards
1
Q
Approximately how many bones are in the human body?
A
206
2
Q
Cartilage
A
embryonic forerunner of most bones and covers many joint surfaces
3
Q
Ligaments
A
hold bone to bone at joint
4
Q
Tendons
A
attach muscles to bone
5
Q
Functions of the Skeleton
A
- Support
- Movement
- Protection
- Blood Formation
- Electrolyte Balance (Ca+ and phosphate)
- Acid-Base Balance
- Detoxification
6
Q
Osteology
A
study of bone
7
Q
Bone is a ____________ tissue with a hard matrix.
A
connective
8
Q
Mineralization (calcification)
A
process of hardening
9
Q
Other Tissues Present in Bone
A
- Blood
- Bone Marrow
- Cartilage
- Adipose Tissue
- Nervous Tissue
- Fibrous Connective Tissue
10
Q
Shapes of Bone
A
Flat - thin, often curved (e.g. ribs)
Long - rigid levers for movement (e.g. humerus)
Short - glide within joints (e.g. carpals)
Irregular - complex shape (e.g. vertebrae)
11
Q
Features of Long Bones
A
- Compact and spongy (cancellous) bone tissue
- Two epiphyses (heads)
- Dyaphysis (shaft)
- Epiphyseal line - remnant of growth plate
- Periosteum covering bone
- Nutrient foramina
- Articular cartilage - smooths joints
12
Q
Features of Flat Bones
A
- Spongy bone sandwiched between plates of compact bone
13
Q
Types of Bone Cells
A
- Osteogenic (osteoprogenitor) cells
- Osteoblasts
- Osteocytes
- Osteoclasts
14
Q
Osteogenic (Osteoprogenitor) Cells
A
- Stem cells
- Found in: endosteum, inner periosteum, central canals
- Give rise to other bone cells
15
Q
Osteoblasts
A
bone-forming cells
16
Q
Osteocytes
A
- Mature, non-dividing bone cells
- Within a matrix
- Lacunae: cavities that house osteocytes
- Canaliculi: small canals that connect lacunae
17
Q
Osteoclasts
A
large, bone-dissolving marcrophages
18
Q
Bone Matrix
A
- 1/3 Organic (collagen & large protein-carbohydrate complexes)
- 2/3 Inorganic
- 85% hydroxyapatite (crystallized calcium phosphate salt)
- 10% calcium carbonate (CaCO3)
- 5% other inorganic minerals
19
Q
Compact Bone
A
- Osteon = basic unit
- Concentric lamellae
- Lacunae containing osteocytes
- Central (haversian) canal
- Perforating canals
- Circumferential lamellae
20
Q
Spongy Bone
A
- Spicules: rods and spines of bone
- Trabeculae: thin plates of bone
- Porous appearance (spaces filled w/ marrow)
- Light weight but strong
21
Q
Bone Marrow
A
- Soft tissue located in medullary cavities of long bones, spaces within spongy bone, and large canals within osteons
- Red Marrow (Myeloid Tissue): hemopoietic tissue, both RBCs and WBCs are made here
- Yellow Marrow: mainly fat
22
Q
Locations of Red Marrow
A
- Skull
- Vertebrae
- Sternum
- Ribs
- Parts of pelvic girdle
- Proximal heads of humerus and femur
23
Q
Location of Yellow Marrow
A
long bones of limbs
24
Q
Bone Growth: Elongation
A
- bones grow longer at epiphyseal plates
- plates made of hyaline cartilage, metaphyses
25
Bone Growth: Widening and Thickening
- appositional growth: growth in diameter and thickness
- intramembranous ossification at surface
* osteoblasts in periosteum deposit matrix
* once matrix hardens, cells become osteocytes
* circumferential lamellae are formed
- osteoclasts widen medullary cavity
26
Wolff's Law of Bone
- bone shape is determined by mechanical stress
- bone adapts to withstand stress
- form follows function
27
Calcium and Phosphate
raw materials for calcified ground substance
28
Vitamin A
promotes formation of glycosaminoglycans (protein-carbohydrate fibers)
29
Vitamin C (ascorbic acid)
promotes collagen cross-linking
30
Vitamin D (calcitriol)
necessary for calcium absorption by small intestine and reduces urinary calcium loss
31
Calcitonin
- secreted by thyroid gland
| - stimulates osteoblasts in children and pregnant women
32
Growth Hormone
- promotes intestinal absorption of calcium
| - stimulates growth plates and bone elongation
33
Estrogen & Testosterone
- sex steroids
| - stimulate long bone growth during adolescence
34
Parathyroid Hormone (PTH)
- secreted by parathyroid glands
| - stimulates bone reabsorption to boost level of calcium in blood
35
Ageing of Skeletal System
- osteopenia: loss of bone (severe = osteoporosis)
- reabsorption faster than deposition
* After 35 years: osteoblasts less active than osteoclasts
* After 40 years: females lose 8% of bone mass per decade, males lose 3%
- fracture more common, heal slowly
36
Stress Fracture
caused by abnormal trauma
37
Pathological Fracture
occurs in bone weakened by a disease such as osteoporosis
38
Fractures are Classified According to...
- breaking of skin
- direction of fracture
- separation of bone pieces
39
Treatment of Fractures
- closed reduction: nonsurgical manipulation
- open reduction: surgical setting involving plates, screws, or pins
- cast
- heal in 8-12 weeks
40
Osteoporosis
- bone lose mass and become subject to pathological fractures
- hip, wrist, vertebrae are especially vulnerable
- postmenopausal white, light-build women at greatest risk
- treatments: bis-phosphonates (destroys osteoclasts) and parathyroid hormone (stimulates osteoblasts)
- prevention: weight-bearing exercise, adequate calcium and protein
41
Orthopedics
prevention and correction of injuries and disorders of bones, joints, muscle
