Week 2-Skeletal physiology Flashcards
Describe the functions of bone/skeletal system
-Support
-Storage of minerals
-Blood cell production
-Protection
-Leverage for movement
How the skeletal system interacts with other body systems
-Gives anchorage point for muscular system
-Cv-makes all roc,wbc and platelets
Endocrine-PTH and calcitonin- regulate blood levels of calcium
Describe bone tissue matrix organic
Collagen fibers (proteins) account for ~1/3 bone weight-flexibility and strength
Describe bone tissue matrix inorganic
Calcium phosphate accounts for ~2/3 bone weight-Provides rigidity and hardness which also
contributes to bone strength
What occurs overall in bone metabolism
-Responds to stress- remodel
-bone has to constantly rework itself after dealing with stressors
How do the bone cells assist in bone metabolism and maintaining bone structure?
osteoblasts-secrete matrix
osteocyte-(mature bone cell)
maintains bone
Osteocyte-breaks down bone to release calcium into blood
Describe the compact bone tissue –the specific arrangement
-organized in units calles osteons
Organized concentric lamellae(matrix) around a central canal-(contains small bv)
* Osteocytes (in lacunae) lie between
lamellae
circumferential lamellae surround all osteons ,bringing it together
Why does compact bone have this structure?
protective outer layer
takes on stresses
Describe the spongy bone structure—what makes it different from compact bone tissue
Lamellae form struts and plates (trabeculae) creating an open network to reduce weight
Has no BV
What tissue is found in the spaces in spongy bone?
Red bone marrow
Describe the importance/function of red bone marrow
Red bone marrow is hematopoietic (produces blood cells)
Describe the importance/function of yellow bone marrow
Yellow marrow consists of fat tissue
Briefly describe intramembranous ossification (bone formation)
-Fewer bones
1-template of fibrous connective tissue
2replaces tissue with bone-leaves room for growth(sutures) and (fontanelles-bump in baby head)
Briefly describe endochondrial ossification (bone formation)
-Most bones are formed this way
1-start with hyaline cartilage template/model
2-replace cartilage with bone through osteoblasts(secrete matrix and make osteocytes)
3-Replaces cartilage with bone in primary ossification center-diaphysis(shaft part)
4replaces at secondary ossification center-epiphysis(ends of bone)
5-not all cartilage is made into bone, leaves room for growth by epiphyseal plate(growth plates)
6-end of bone is articular cartlidge( made from hyaline) protective ends of bone
Describe process of bone growth in
width/appositional growth
-(Occurs all lifetime-Increases diameter of existing bone)
-occurs at periosteum(protective covers on bones)
-bone is laid down on inside of periosteum
-body will restore periosteum
-results in slighty thickened bone
* Trapped osteoblasts become osteocytes
Describe process of bone growth in length
Will eventually end
1-Growth of cartilage on epiphyseal plate
2-Replacment of cartridge with bone tissue in epiphyseal plate
3-grow more cartilage on top of existing cartilage, resulting in larger bone
mineral deposition (mineralization)
process by which the organic bone matrix becomes filled with calcium
mineral resorption (general processes).
pull calcium out of bone
How are blood calcium levels controlled in systems of body?
intestines-absorb calcium
bones-use calcium to remodel
kidneys-lose calcium in urine
Describe how calcitonin specifically affect blood calcium levels.
C- released fro, thryoid gland when blood calcium levels are too high
Bone-osteoblasts allow calcium to stay to bone
intestine-poop calcium out, won’t get reabsorbed
kidney-pee calcium out, won’t get reabsorbed
Describe how parathyroid hormone specifically affect blood calcium levels.
PTH-Released from parathyroid gland when calcium is low-stimulates relase of calcium into blood
B-stimulates osteoclasts to release calcium into blood
I-increases calcium absorption into blood
K- increase calcitorl- causes calcium reabsorption into blood
What would cause each of calcitonin or parathyroid hormones to be released?
Low levels of calcium-PTH
Too High levels of calcium-C
In addition to PTH and Calcitonin—what other hormones can influence bone health/homeostasis?
Calcitoral
growth hormone
t3 and t4
estrogen/testoterone
Differentiate between a pathological fracture and traumatic fracture
T-Caused by traumatic stress
P-Caused by a disease that weakens bones
List a few diseases that could lead to a pathological fracture
Osteoporosis
bone cancer
osteogenesis imperfecta
Briefly describe the steps involved in fracture healing
1-Large blood clot develops
2-Bony Calluses form-osteoblasts secrete matrix
3. Remodeling of healed bone—osteoclasts try to make bone look like it did before the fracture
Transverse traumatic fracture
Break shaft across long axis
Spiral traumatic fracture
aused by twisting stresses that spread along length of bone
Displaced traumatic fracture
Broken bones are not aligned
Non displaced traumatic fracture
broken ends of bones are aligned
Compression traumatic fracture
occurs in vertebral body due to extreme stresses
Greenstick traumatic fracture
one side is broken, one is bent, occurs in children
Communicated traumatic fracture
bone is shattered into many pieces
Epiphyseal traumatic fracture
occurs at epiphyseal plate, could affect growth
Open traumatic fracture
Bone protrudes outside of skin
Closed traumatic fracture
Bone does not protrude outside of skin
Osteocytes
Mature bone cells that cannot divide
Osteoblasts
Produce new bony matrix
Osteoprogenitor cells
Mesenchymal (stem) cells that produce cells that differentiate into osteoblasts
* Important in fracture repair
Osteoclasts
Remove and remodel bone matrix
Long bone organization
Periosteum (outermost layer)
* Compact bone (outer bone tissue)
* Circumferential lamellae
* Interstitial lamellae
* Osteons
* Spongy bone (innermost bone tissue layer)
Periosteum
- Isolate bone from surrounding tissues
- Route for blood and nervous supply
- Actively participate in bone growth and repair
Perforating fibers
Strongly connect tendons, ligaments, and joint capsules to bone through periosteum
