Chp 6 Skeletal System Flashcards
What composed the skeletal system (SS)?
- Bones of Skelton
- Cartilage
- Ligaments
- Connective Tissue
What are the 5 primary functions of the skeletal system?
- Support
- Storage minerals and lipids
- Blood cell production
- Protection
- Leverage
What does the SS support?
- Entire body
* A framework for the attachment of soft tissue
What minerals and lipids does SS store?
- Calcium (most abundant)
* Yellow bone marrow
Where are the cells produced in SS?
• Red bone marrow
How does the SS provide protection?
- skeletal structures surround many soft tissues and organs
* ex. Ribs protect the lungs and heart
What does leverage of the SS mean?
• force generated by the Skeletal muscles that can change the magnitude and direction
How are bones classified?
• Shape
• Internal tissue organization
-Compact, spongy
• Bone markings
What are the 6 bone shapes?
- Sutural bones
- Irregular bones
- Short bones
- Flat bones
- Long bones
- Sesamoid bones
How are suture bones?
- small
- irregular bones
- “Wormain bones”
Where can you find Suture Bones?
• Between the flat bones of the skull
How are Irregular bones??
- Complex shapes
* notches and processes
Where can you find Irregular bones?
- examples include
- Vertebrae
- Coxal bones
- Pelvic bones
How are short bones?
- similar in length and width
* roughly cubed shaped
What are some examples of short bone?
- Carpals
* Tarsals
How are flat bones?
- Thin like a plate
* Parallel surfaces
Why are flat bones important?
• Protect underlying structures/ soft tissue
• serve as large surface area for tendon and ligament attachment
(Skeletal muscles)
Where can you find flat bones
- Cranial Bones
- Sternum
- Ribs
- Scapula
How are Long bones?
- longer than wide
- most common type of bone
- range from very large femur to small phalangeal bones
What are some examples of long bones?
- arm and forearm
- leg and thigh (largest, heaviest)
- Palm
- soles
- fingers
- toes
How are sesame if bones?
- small
* flat
Where are sesame if bones found?
- Develop inside tendons
- near joints at hands, knee, feet
- ex: patellas
- other places may vary
- up to 26 locations
What is another name for bone markings?
- surface features
* landmarks
What are the 3 types of bone markings?
- Elevation or projections
- Depression or groove
- Tunnels
What happens at elevations and projections?
- Tendons and ligaments attach
* Articulations with other bones
What happens at Depressions or groove?
• Something else fits along side the bone surface
What happens at the Tunnels?
• Blood and nerves enter bone
Landmark names for elevations and projections
- Process
2. Ramus
What are processes?
• projection or bump
What is a ramus?
- extension of a bone
* forms angle with the rest of the structure
Landmark names for openings
- Sinus
- Foramen
- Fissure
- Meatus
- Canal
What is a sinus?
- chamber w-in a bone
* normally filled with air
What is a foramen?
• rounded passageway for blood/ vessels and/or nerves
What is a fissure?
- deep furrow
- cleft
- slit
What is a meatus?
- passage or channel
* opening of a canal
What is a canal?
- duct
* channel
In what processes do ligaments and tendons attach?
- Trochanter
- Crest
- Spine
- Line
- Tubercle
- Tuberosity
WhT is a trochanter?
• large rough projection
What is the crest of a bone?
• prominent ridge
What is a spine?
• pointed process
What is the line?
• low ridge
What is a tubercle?
• small, rounded projection
What is a tuberosity?
• rough projection
Landmark names for depressions
- Sulcus
2. Fossa
What is a sulcus m?
• narrow groove
What is a fossa?
• shallow depression
What processes form where joints (articulations) occur between adjacent bones?
- Head
- Neck
- Facet
- Condyle
- Trochlea
What is the head?
• articulate end of epiphysis
What is the neck?
• narrow connection between epiphysis and diaphysis
What is the facet?
- small, flat
* articular surface
What is Althea condyle?
• smooth, rounded articulate process
What is a trochlea?
- smooth, grooved articulates process
* shaped mine a pulley
What are the 3 parts of a long bone?
- Epiphysis
- Diaphysis
- Metaphysis
What is the epiphysis?
• the wife part at each end of a long bone
What happens at the epiphysis?
• articulation a with other bones
Describe the epiphysis
- mostly spongy (cancellous) bone
* covered with compact bone (cortex)
What is the diaphysis?
• shaft of long bone
Describe the diaphysis
- heavy wall of compact bone
* has a central space
What is the central space of the diaphysis called?
• medullary (marrow) cavity
What is the metaphysis?
• where the diaphysis and the epiphysis meet.
What does the structure of a flat bone resemble?
• a sandwich of spongy bone between 2 layers of compact bone
What is the compact part of a flat bone called?
• cortex
WhT is the spongy part of a flat bone called?
• diploë
What type of CT is bone (osseous) tissue?
• dense, supportive CT
What kind of cells does bone tissue contain?
• specialized cells
What does bone tissue produce?
• solid matrix
What is the solid matrix made out of?
• Calcium salt deposits that organized around collagen fibers
What are the characteristics of bone tissue?
- dense matrix
- osteocytes
- canaliculi
- periosteum
What does the dense matrix contain?
- Calcium salts
- fibrous protein
- osteocytes (bone cells) w/in lacunae
Where are osteocytes found?
• organized around blood vessels
What are canaliculi?
• pathways for access to blood vessels
What does canaliculi do?
• exchange nutrients and waste
What is periosteum?
• cover of outer surfaces
What does periosteum consists of?
- outer fibrous layer
* inner cellular layer
What are the 2 components of bone matrix?
- Minerals
2. Matrix Proteins
How much of bone matrix is composed of minerals?
• 2/3 calcium phosphate
What happens when calcium phosphate reacts wth other minerals?
• forms crystals of hydroxyapatite
How much of bone matrix is made of proteins?
• 1/3 collagen
How much of bone mass is made up of bone cells?
• 2%
How many types of cells does bone contain?
•4
- Osteocytes
- Osteoblasts
- Osteogenic cells
- Osteoclasts
What are osteocytes cells?
- mature bone cells
- maintain bone matrix
- do not divide
Where are osteocytes found??
• living in lacunae, between layers of lamellae
How are osteocytes connected through each other?
• through cytoplasmic extensions of canaliculi
Whats te the 2 major functions of osteocytes?
- Maintain protein and mineral content of matrix that continually dissolve and rebuild matrix
- Repair damage bone
What are osteoblasts?
- immature bone cells
* osteogenesis
What does osteoblasts do?
- secrete matrix compound
* builds
What is the matrix produced by osteoblasts called?
• osteoid
Why can osteoid form bone?
• not yet calcified
What happens when osteoblasts is surrounded by bone?
• it becomes osteocytes
Where is osteoblasts found??
• outer edge
What are osteogenic cells?
• Mesenchymal stem cells that divide to produce osteoblasts
What is another name for osteogenic cells?
• osteoprogenitor cells
Where are osteogenic cells located?
- endosteum that lines medullary cavity
* inner cellular layer of periosteum
What does osteogenic cells assists with?
• fracture repair
What are osteoclasts?
• giant, multinucleate cells
What does osteoclasts secrete?
- acids and protein-digesting enzymes
* to remove and recycle bone matrix
What is the process of dissolving bone matrix and release of stored minerals called?
• osteolysis (lysosomes)
—–degradation
What maintains homeostasis of the bone?
- osteoblasts (builds)
* osteoclasts (recycles)
What happens when more breakdown than building occurs?
• bones become weak
What type of exercise causes osteoblasts to build bone?
• weight bearing exercise
What is the beach unit of compact bone?
• osteon
Osteocytes are arranged in concentric lamellae around what type of canal?
• central canal containing blood vessels
What runs perpendicular to central canals?
• perpendicular canals
What do perpendicular canals do?
• carry blood vessels into bone and marrow
What is wrapped around the long bone?
• circumferential lamellae
What does circumferential lamellae do?
• binds osteons together
Instead of osteon, what does spongy bone have?
• open network or trabeculae
Does trabeculae contain blood vessels?
• false
With what is the space between trabeculae filled with?
• red bone marrow
What does ten bone marrow contain?
- blood vessels
- red blood cells
- nutrients for osteocytes
What other type of marrow can sometimes be found in spongy bone?
• yellow bone marrow
Why is yellow bone marrow it’s color?
• contains fat cells
What is compact bone covered with?
• periosteum
The periosteum covers all bones; except?
• parts enclosed in joint capsules
Collagen fibers of the periosteum that connect with collagen fibers of bone are called?
• perforating fibers
What do perforating fibers also connect wth?
- fibers of joint capsules
- tendons
- ligaments
What are the 3 functions of the periosteum?
- Isolate bone from surrounding tissue
- Provides route for circulatory and nervous supply
- Participates in bone growth and repair
What is compact bone covered by on the inside?
• endosteum
Around what age does human bone growth stops?
• 25
What is the formation of bone called?
• ossification
What is the process of depositing calcium salts into the bone during ossification called?
• calcification
What are the 2 mains forms of ossification?
- Endochondral ossification
2. Intramembranous ossification
What is it called when a bone replaces existing cartilage?
• Endochrondral ossification
What is it called when a bone develops directly from connective tissue?
• Intramembranous ossification
Which of the process of bone making involves cellular differentiation?
• both
What is cellular differentiation?
• cells change their gene expression in response to signal molecules
In endochondral ossification; where do ossified bones originate from?
• hyaline cartilage
Where do most bones originate from?
• hyaline cartilage
How many steps is there in endochondral ossification?
•7
Where does those 7 steps occur?
• during fetal development
What happens during step1?
- cartilages enlarges
- chondrocyte swear center increases in size
- matrix reduces and begins to calcified
- enlarged chondrocytes die and disintegrate leaving cavities in cartilage
What happens in step2?
- blood vessels grown around the edges of the cartilage
- cells in the periosteum convert to osteoblasts
- shaft of cartilage becomes ensheathed
What happens in step3?
- blood vessels penetrate the cartilage, invade central region
- fibroblast differentiate into osteoblasts, producing spongy bone
- bone formations spreads along shaft
What happens in step 4?
- remodeling occurs as growth continues
- medullary cavity is created
- osseous tissue thickens
- cartilage near epiphysis is replaced by shafts of bone
What happens at step5?
- capillaries and osteoblasts migrate into epiphysis
* creates secondary ossification center
What happens at step6?
- epiphysis becomes filled w/ spongy bone
- metaphysis (epiphyseal plate) is created
- on the shaft; osteoblasts invades cartilage and replaced it with bone
- new cartilage is produced at epiphyseal side
What happens at step6 at the epiphyseal region? ? Pt2
- In the epiphyseal cartilage chondrocyte organize into zones
- chondrocyte continue to divide/enlarge/degenerate
- osteoblasts migrates and replaces cartilage with bone
What happens at step7?
- at puberty; epiphyseal cartilage slows down
- rate of osteoblasts accelerates
- epiphyseal closure happens
- epiphyseal line is left behind
- thin cap of original cartilage remains for articulation
What is the epiphyseal closure?
• narrowing of the epiphyseal cartilage until it disappears
What is another name for intramembraneous ossification?
• dermal ossification
Why is it called dermal ossification?
•occurs at the dermis
What type of bone is created during intramembraneous ossification?
• dermal bones
What are some examples of dermal bones??
- mandible
* clavicle
When does intramembraneous ossification begin?
• around 7th week of embryonic development
How many steps of intermembranous ossification is there?
•5
What happens in step1 if dermal ossification?
- mesenchymal cells group together and becomes osteoblasts
* starts to secrete organic compounds of the matrix
What happens in step2 of dermal ossification?
- some osteoblasts get trapped inside bony pockets
- trapped osteoblasts become osteocytes
- developing bone fries outward in small struts called spicules
What happens in step3 of dermal ossification?
- blood vessels begin to branch out and grow between spicules
- rate of bone growth accelerates
- as spicules interconnect; they trap blood vessels w/in bone
What happens in step4 of dermal ossification?
• deposition of bone by osteoblasts located close to blood vessels result in PLATE of spongy bone
What happens in step5 of dermal ossification?
- Osteons are produced
* osteoblasts become periosteum
How is blood supplied to mature bone?
- Nutrient artery and vein
- Metaphyseal vessels
- Periosteal vessels
What happens at nutrient artery and vein?
- single pair of large blood vessels enter diaphysis through nutrient foramen
- femur has more than 1 pair
What does the metaphyseal vessels do?
• supply epiphyseal cartilage where bone growth occurs
What does the periosteal vessels do?
- supply blood to superficial patrons
* secondary ossification centers
What happens to 1/5 of the human skeletal each year?
• it is recycled and replaced
What does this process of remodeling involve?
- osteocytes
- osteoclasts
- osteoclasts
What happens if deposit is greater than removal?
• bones get stronger
What happens if removal is greater than replacement?
• bones get weaker
How does mineral recycling affect bones?
• allows bones to adapt to stress
What happens to heavily stressed bones?
• become thicker and stronger
How much bone can degenerate after a few weeks of inactivity?
• 1/3
What are some source of. Untrue ts we must consume?
- calcium
- phosphate salts
- magnesium
- fluoride
- iron
- manganese
What hormone facilitates calcium and phosphorus absorption?
• calcitriol
What is required for synthesis of calcium and phosphate?
• vitamin D3
What are some important vitamins we need to consume?
• A, C, K and B12
What hormones stimulate bone growth?
- growth hormone
* thyroxine
What is thyroxine?
• thyroid hormone
What stimulates osteoblasts?
- estrogen
* androgen
What regulates calcium and phosphate levels?
- calcitonin
* parathyroid hormone
Why is calcium important?
• for function of membranes, neurons and muscle cells
How much of the body is calcium and phosphate?
• 99%
How much of the body contains carbonate?
• 80%
How much of the body contains magnesium?
• 50%
How much of the body co rains sodium?
• 35%
How much of the. It’s contains potassium?
• 4%
What maintains homeostasis of hormones and calcium?
- calcitonin
* parathyroid hormone
Where is calcium stored?
• in bones
Where is calcium absorbed?
• in digestive Tract
Where is calcium excreted?
• kidneys
Where is parathyroid (PTH) hormone produced?
• parathyroid glands in neck
How does PTH increases calcium ion levels?
- Stimulates osteoclasts
- Increase interstitial absorption
- Decrease calcium excretion
What secretes calcitonin and where?
- C cells
* in thyroid
What is another name of C cells?
• parafollicular cells
How does calcitonin decrease calcium ion levels?
- Inhibiting osteoclasts activity
- Decrease interstitial absorption of calcium
- Increases calcium excretion at kidneys
How many steps are needed to repair fractures?
• 4
What is step1 of fracture repair?
- blessing produces clot
* establishes fibrous network
What is step2 of fracture repair?
- cells of endosteum and periosteum decide and move into fracture area
- form calluses of cartilage/bone to stabilize fracture
What is step3 of fracture repair?
- osteoblasts replace cartilage of callus with spongy bone
* straits of spongy bone connect broken ends
What is step4 of fracture repair?
- osteoclasts and osteoclasts remodel bone for up to a year
* when remodeling is complete, calluses dare gone and compact bone remains
What is inadequate ossification that occurs between ages 30 and 40?
• osteopenia
How much bone mass do women lose per decade?
• 8%
How much bone mass do men lose per decade?
• 3%
What are the bones most affected by age?
- epiphyses
- vertebrae
- jaws
What realists with bone mass reduction?
- fragile limbs
- height reduction.
- tooth loss
What is osteoporosis?
• severe bone loss
What is the percentage of woman and men that have osteoporosis?
- 29% of woman
- 18% of men
- over 45 yrs of age
When does bone loss in woman accelerate?
• after menopause
What helps maintain bone mass?
• estrogen and androgen
In cancer patients; what do cancerous tissue release?
• osteoclasts- activating factors
What does osteoclasts- activating factors stimulates?
• osteoclasts which produces severe osteoporosis
