The skeletal System Flashcards
1
Q
- What does the skeletal system include
A
- Bones of the sksleton
- Connective tissues of the skeleton:
- Tendons
- Ligaments
- cartilage
2
Q
Connective tissues of the skselton
- what are the connective tissues of the skeleton
A
- Tendons and ligaments = connective tissue proper (dense and regular) as well as fibroblast, colagen fibers and viscous gel matrix
- Cartilage (Supporting connective tissue) = matrix is a firm gel
- Bone (Supporting connective tissue = matrix is calcified
3
Q
Cartilage Histology
Cartilage (Chondro)
A
- Matrix - firm gel - chondrotin sulfate & collagen ,elastic, and reticular fibers
- Cells - chondrocytes, located in lacunae
- Perichondrium - seperated cartilage from surrounding tissues
- Three types of cartilage:
- Hyaline - collagen fibers and ground substrate
- Elastic - collagen and elastic fibers
- Fibrocartilage - dense collagen, little ground sub
4
Q
Cartilage
Cartilage Growth and Repair
A
- Interstitial - enlarges from within so internal chondrocytes devide
- Appositional - growth at surface so cells in inner layer of perichondrium divider
- Cartilage has very poor recovery from damage
5
Q
Bone Histology
Bone (Osteo)
A
- Cells - osteocytes, located in lacunae interconnected by canaliculi
- Matrix - Collagen fibers (1/3) and calcium salts (2/3)
- Highly vascularized
- Periosteom - covers bone surfaces
6
Q
Bones
Bone growth and Repair
A
- Appositional - growth at surface
- cells in inner layer of periosteium divide
- Good recovery from damage
7
Q
Tissues
Osseous Tissue
A
- Matrix = crystals of hydroxyapatite - composed of calcium phosphate, calcium carbonate, and potassium, sodium, and magnesium
- Collagen - protein fiber framework
- By weight = 1/3 collagen and 2/3 calcium salts
8
Q
Cells
Cells in Bones
A
- osteoprogenitor cells (stem cells) - differentiatie into osteoblasts
- osteoblasts - synthesize new matrix - osteogenesis
- Osteocytes = mature bone cells - in lacunae connected by canaliculi
- Osteoclasts - disolve bone matrix - osteolysis also multinucleated
- Osteoprogenitror cells -> Osteoblasts -> Osteocytes
9
Q
Tissue
Bone (osseus tissue)
A
- Bones contain two forms of osseus material:
- Compact Bone - (dense)
- Spongy Bone - (Cancellous)
- Marrow cavaties in bone contain connective tissue:
- Yellow Marrow - Adipose connective tissue
- Red marrow - Fluid connective tissue - red and white blood cells and blood stem cells
10
Q
Bone Types
Compact Bone and Spongy Bone
A
- Basic unit of a copmpact bone is an osteon - Haversian system
- Osteocytes arranged around a central canal
- Perforating canals extend between adjacent osteons
- Spongy bone contains a trabeculae
11
Q
Bones and Stress
Bones and Stress
A
- Compact Bone - located where stresses are applied in a focoused drection along the bine axis
- Spongy Bone - located where stresses are weaker, multi-directional, or spread out over a larger cross-sectional aera
12
Q
Long Bones
What does a long bone typically include?
A
- Diaphysis - shaft or central part of a long bone
- Epiphyses - the end of a long Bone
- Metaphysis - the wide part of a long bone and where growth occurs
- Articular cartilage
- Marrow cavity - filled with red or yellow marrow
13
Q
Bones
Bone Development and Growth
A
- Cells invloved in development and growth, as well as remodeling and repair come from:
- periosteum - covers outter surface of bone made of a fibrous outter layer and inner layer of stem cells
- Endosteum - lines inner surfaces of bone made of a layer of stem cells, plus osteoblasts and osteoclasts
14
Q
Bone Development
Bone Development
A
- Ossification:
- Converting other tissues to bone
- Intramembranous ossification (calcification)
- Endochondral ossification (calcification)
- Calcification = depositing calcium salts whithin tissues
14
Q
Bone Development
Bone Development
A
- Ossification:
- Converting other tissues to bone
- Intramembranous ossification (calcification)
- Endochondral ossification (calcification)
- Calcification = depositing calcium salts whithin tissues
16
Q
Ossification
Endochondrial Ossification
A
- During embryogenesis, hyaline cartalige forms first= cartilaginous model
- Cartilage model gradually replaced by bone
- Cartilage remains in articular cartilage at ends of bones
- Cartilage remain in epiphyseal plate (growth plate)until epiphyseal closure
- Endochondrial ossification contiues until closure
17
Q
Elongation of long bones
Growth at Epiphyseal Plates
A
- Cartilage growth - eppiphysis side
- Ossification - diaphysis side
- Diaphysis gets longer, as epiphyses are pushed further apart
- Equal rate of cartilage groth and ossification matains epiphyseal plate
- Higher rate of ossification leads to closure of epiphyseal plate
- Achondroplasia - slow cartilage growth leading to epiphyseal plate closure at very early age
18
Q
Remodeling
Dynamic nature of bone - Remodeling
A
- Organic and mineral components continually recycled and renewed
- Aproximatley 20% or 1/5 of adult bone replaced per year
- Osteocytes - monitor and mantain surrounding bone matrix
- Osteoblasts - form new bone matrix
- Osteoclasts - Remove bone matrix
20
Q
Bone growth and maintenance
Hormones Regulation of Bone Growth and Maintenance
A
20
Q
Bone growth and maintenance
Hormones Regulation of Bone Growth and Maintenance
A
21
Q
Development and Maintenance of Bone
Hormonal and Nutritional effects on development and maintenance of bone
A
- Dieatary intake of Ca and Phosphate salts
- Calcitriol (derived from cholecalciferol) - hormone synthesized in kidney needed for calcium and phosphate absorption from digestive tract
- Viatamin D (Cholecalciferol) - required for calcitriol synthesis and deficiency causes osteomalacia (rickets) due to insufficent minerelization of bone
- Vitamin Cneeded for collagen synthesis - defficency causes scurvy
23
Q
Blood Calcium levels
Blood Calcium level increase pathway
A
- low calcium ion level in blood (below 8.5mg/dL)
- Low calcium level causes the parathyroid gland to secrete PTH
-
Osteoclasts are triggerd to release stored calcium ions. Intestional absorption of calcium increases. Kidneys absorb more calcium and send more calcitriol to the intestines.
4.Calcetriol Aids in every step of the process
24
Q
Blood Calcium Levels
Decresing calcium ion concentration in blood
A
- High calcium ion level in blood (above 11mg/dL)
- C cells in the tyroid gland secretecalcitonin
- Osteoclast activity decreases. Intestinal absorption of calcium decreases. Kidneys excrete calcium ion and less calcitriol is sent to the intestiens.
27
Q
Aging
Effects of Aging on Skeletal System
A
- Osteopenia - osteoblast activity declines with declining levels of sex hormones resulting with a reduction in bone mass
- Vertebrae, maxillary and mandible, epiphyses of long bones
- more rapid in females than males
- Osteoporosis - Loss of bone mass sufficent to compromise normal functions
29
Q
Arthritis
Arthritis
A
- Osteoarthritis - normal wear and tear
- Rheumatoid arthritis - autoimmune disorder
- Gouty arthritis - uric acid crystals
