BONES

Question 1

Summary of Functions

Answer 1

• Support - posture
• Movement - as attachment points for muscle
• Protection - of soft tissue
• Storage - of both minerals and fat
• Hematopoiesis - production of RBCs, WBCs, and PLTs

Question 2

As a characteristic of CT, bone is composed of

Answer 2

• cells and abundant matrix
• Bone tissue on the whole is innervated, contains lymphatics, and is highly vascular

Question 3

Bone Matrix includes:

Answer 3

• protein scaffolding (mostly collagen) arranged in alternating layers (at 90 degrees to one another),
• deposited minerals (mostly Ca, P in the form of hydroxyapatite),
• cells referred to as osteocytes

Question 4

The composition matrix determines

Answer 4

• strength of bone

Question 5

Proteins provide _____ strength

Minerals provide _____ strength

Answer 5

• TENSILE (proteins)
• COMPRESSION (minerals)

Question 6

Osteoblasts

What are the 3 basic stages of existence?

What are these stages termed?

Answer 6

• bone-forming cells

1. produce protein fibers for the matrix
2. secrete enzymes that promote mineralization of the matrix
3. once engulfed in the calcified matrix, they stop the above and become known as osteocytes
   * * stages termed OSSIFICATION*

Question 7

Osteocytes

Answer 7

• thought to be mechanosensors within bone, sensing tensile and compressive stress
• no longer bone-forming cells
• remain connected and communicate with the osteoblasts

Question 8

Osteoclasts

Answer 8

• digest and remove excess (old) and damaged bone

• process is known as resorption and involves acid and enzyme secretion (think phagocytosis as this type of cell is a specialized macrophage)

Question 9

All individual bone has 2 distinct areas of varying matrix density:

Compact Bone

Cancellous Bone

Answer 9

• makes up the surface of all bone and the shaft of long bones
• this is where one will find bundles of collagen fibers stacked in alternating layers and tightly packed in concentric rings around a vessel-containing canal, collectively termed haversian systems. Intercellular communication/transport occurs in both the longitudinal and transverse directions. Columns.

Question 10

All individual bone has 2 distinct areas of varying matrix density:

Compact Bone

Cancellous Bone

Answer 10

• makes up the bulk of short, flat, and irregular bone, as well as the ends of the long bone
• it also lines the medullary cavity of long bone
• this is the more porous, marrow containing matrix
• aka - spongey bone, trabecular bone

Question 11

Marrow

Answer 11

• aka myeloid tissue, always co-exists with cancellous bone
• considered a type of CT, and occurs in 2 somewhat interchangeable forms based on preponderance of cell type

RED MARROW & YELLOW MARROW

Question 12

Red Marrow

Answer 12

• consists mainly of hematopoietic stem cells, and relative little fat
• site of RBC, WBC, and PLT production
• found at ends of long bone and center of other bone (but mainly flat bones)

Question 13

Yellow Marrow

Answer 13

• consists mostly of fat cells (yellow tissue)
• site for adipose storage
• found in central (medullary) cavity of long bone

Question 14

Endosteum

Answer 14

• thin CT lining the medullary cavity
• contains osteoblasts from the marrow

Question 15

Periosteum

Answer 15

• dense CT covering the outer bone surface
• contians stem cells that can differentiate into osteoblasts and chondroblasts (cartilage forming cells)
• contains nocireceptors (sensory neurons)

Question 16

Embryonic, Pediatric, and Adult Processes are depedent on:

Answer 16

hormones

Question 17

Endochondral Ossification

Answer 17

chondrocyte -> cartilage growth - mineralization - vascularization, then apoptosis - marrow formation and osteoblast activation

• basis for lengthening and growth of bone (growth plates)

Question 18

Intramembranous Ossification

Answer 18

osteoblast -> collagen matrix - mineralization

• basis for thickening and widening of bone (endosteum and periosteum)

* embryonic and child development involves both methods (embryonic skeleton begins primarily as cartilage, with activation of osteoblasts and subsequent ossification beginning in mid-to-late first trimester)

* adult skeleton undergoes constant intramembranous ossification balanced by osteoclast activity (a process termed remodeling), though both ossification methods are involved in fracture repair

Question 19

Fracture Repair Process

Answer 19

• begins with cartilage production and mineralization to spongy bone over the first weeks to months
• synthesis of compact bone will follow over the next 3-5 years

Question 20

Factors affecting osetoblask-osteoclast dynamic

Answer 20

• physical stress on bone stimulants
• nutritional factors such as Ca, P, Vitamin D promote strengthening
• hormonal influencers (look @ endocrine notes) include GH, estrogen, testosterone, parathyroid hormone, calcitonin, and steroid hormones
• direct toxicity and genetic factors may alter cellular activity
• other tissue needs for minerals or acid-neutralizing OH will stimulate resorption
  
  • hydoxyapatite - main mineral compound of bone
  • 99% of body Ca is in bone (when extracellular levels drop it gets pulled from bone
  • bone also reservior for Mg, Fe, Na

Question 21

Sinus (in reference to anatomy) may be defined as

“Undoubtedly, you will be treating conditions involving…”

Answer 21

• a hollow space, cavity within bone, narrow opening/canal, or a dilated channel as it relates to the cardiovascular system
• involving accessory nasal sinuses - cavities within skull bone

Question 22

Accessory Nasal Sinuses

Answer 22

• cavities within skull bone that connect to the nasal cavity
• should be empty (air-filled), but as they are lined with the same epithelial membrane found within the nose they may exhibit the same SSx that occur with rhinitis - over production of mucus and membrane inflammation

Question 23

Where are the 3 main sinuses found (for charting purposes)?

Answer 23

Frontal sinuses: above the eyes

Ethmoid sinuses: (anterior, middle, posterior): bridge of the nose, b/w the eyes

Maxillary sinuses: below the eyes and lateral to the nose

4th deep within the sphenoid bone and not accessible fo general observation

**observation techniques include: pen light, palpation, changes in voice tone

Question 24

Synarthrosis

Answer 24

• immovable (fixed) joint connected by fibrous tissue
• teeth, sutures (of the skull), 1st rib and sternum

Question 25

Amphiarthrosis

Answer 25

• slightly moveable cartilaginous joint (amphi = both sides)
• symphesis pubis, vertebral joints, interior tib-fib joint (interosseus membrane)

Question 26

Diarthrosis

Answer 26

• freely moveable synovial joint (di = away from)
• range of motion assessed through flexion, extension, abduction, adduction, etc.

Features: synovial (fluid, membrane), capsule, cavity, bursa, meniscus

Question 27

Types of Synovial Joints

Answer 27

• Gliding: sliding surfaces (could be 1+ planes) – acromioclavicular, carpals of wrist
• Hinge: unidirectional change in jt angle (1 plane) – elbow
• Pivot: longitudinal rotation –
• Condyloid: bidirectional changes in jt angle (2 planes) – radiocarpal joint, TM joint, C1, C2
• Saddle: bidirectional changes + rotation (2 planes + rotation) – sternoclavicular, carpometacarpal
• Ball & Socket: multi-directional (conical) angle changes = circumduction (ALL planes) – hip, shoulder (glenohumeral)