CH6 Skeletal System Anatomy & Phyisology

describe osteoporosis

describe osteoporosis

- bone resorption exceeds deposit
- bone mass declines
- matrix remains normal
- common in POSTMENOPAUSAL WOMEN
- porous & thin

what are the risk factors of osteoporosis?

- petite body form
- insufficient exercise
- diet poor in CALCIUM and PROTEIN
- smoking
- immobility
- hormone-related conditions

what are the known preventions of osteoporosis?

- calcium
- vitamin d supplements
- weight bearing exercises

describe paget's disease

- excessive and haphazard bone deposit and resorption cause bone to be made fast and poorly
- high ratio of spongy to compact bone
- reduced mineralization

describe osteomalacia

- bones are POORLY MINERALIZED
- results in soft & weak bones
- pain upon bearing weight

place the four major stages of healing a fracture

- (1) Hematoma formation
- (2) Fibrocartilaginous callus formation
- (3) Bony callus formation
- (4) Bone remodeling

what is hematoma formation?

blood clotting

what is fibrocartilaginous callus formation?

- repair tissue
- fibroblasts cartilage, & osteogenic cells begin reconstruction of bone

what is bony callus formation?

new trabeculae

describe the classification of fractures

- position of bone ends after fracture: Nondisplaced & displaced
- Completeness of break: Complete & Incomplete
- Whether skin is penetrated: Compound & Closed

what are the position of bone ends after fracture?

- nondisplaced: ends that retain normal position
- displaced: ends are out of normal alignment

what are the completeness of break fractures?

- complete: broken all the way through
- incomplete: not broken all the way through

what is "whether skin is penetrated" fractures?

- compound (open): skin is penetrated
- simple (closed): skin is not penetrated

what is the epihyseal plate?

- growth plate in children
- growth occurs in diaphysis (long bone)
- not fused

thin layer of cartilage that lies between the epiphysis and metaphysis

what is the epiphyseal line?

- diaphysis & epiphysis fuse
- no growth
- ossified (stopped growing / OLD)

FUSION

examples of long bone? be able to identify it

- longer than they are wide
- limb bones
- have expanded ends

humerus, femur

examples of short bone? be able to identify

- cube-shaped bones
- vary in size and number

carpals, tarsals

examples of flat bone? be able to identify it

- thin
- flat
- slightly curved

sternum, scapula, ribs, skull bones

examples of irregular bone? be able to identify it

- complicated shapes

vertebrae, hip bones

examples of sesamoid bone? be able to identify it

- within tendons

patella

identify the parts of a long bone

- epiphysis: ends of long bone
- diaphysis: shaft of long bone
- articular cartilage (covers joint surfaces)
- compact & spongy bone
- epiphyseal line
- periosteum
- endosteum
- medullary cavity

what is hyaline cartilage?

- provides support
- flexibility
- resilience
- most abundant
- contains collagen fibers

what is elastic cartilage?

- similar to hyaline cartilage
- contains elastic fibers

where can you find elastic cartilage?

- external ear
- epiglottis

what is fibrocartilage?

- thick collagen fibers
- has great tensile strength

where can you find fibrocartilage?

- menisci of knee
- vertebral discs

what is red marrow?

- found within trabecular cavities (spongy bone) & diploe of flat bones

what is yellow marrow?

- MADE MOSTLY OF FAT

- can be converted to red if person is anemic

what is osteoblasts?

- BUILDING
- bone forming cells that secrete osteoids

what is osteoids?

- unmineralized bone matrix
- made up of collagen and calcium-binding proteins

what is osteogenic cells?

- AKA osteoprogenitor cells
- mitotically active (stem cells in periosteum & endosteum)
- DIFFERENTIATE INTO OSTEOBLAST

what is osteocytes?

- mature bone cells in lacunae that no longer divide
- maintain bone matrix
- acts as stress or strain sensors

what is bone lining cells?

- help maintain bone matrix
- flat cells on bone surfaces

place the steps involved with endochondral ossification

- (1) bone collar forms around the diaphysis of the hyaline cartilage
- (2) central cartilage of diaphysis calcifies and develops cavities
- (3) periosteal bud invades internal cavities, leads to formation of spongy bone
- (4) diaphysis elongates, medullary cavity forms
- (5) epiphyses ossify

what is primary ossification centers lead to?

- DIAPHYSIS
- first area of bone to start ossifying
- blood vessels infiltrate perichondrium, converting to periosteum
- mesenchymal cells specialize into osteoblasts

what is secondary ossification centers lead to?

- EPIPHYSIS
- develops in the epiphyseal region after birth

what is closed reduction?

physician manipulates bone to correct position

what is open reduction?

- surgical pins or wires secure ends

think of opening patient

where is hyaline cartilage found?

- articular (joints)
- costal (ribs)
- respiratory (larynx)
- nasal cartilage (nose tip)

what is osteoclasts?

- CRUSH (think clasts = crush)
- responsible for bone resorption
- break down

what does endochondral ossification form replaces what?

hyaline cartilage

what does intramembranous ossification replaces what?

fibrous membrane

what bone form from endochondral ossification?

all bones INFERIOR to the skull except clavicle bones
(below skull)

what bone form from intramembranous ossification?

- skull bones & clavicle
- frontal, parietal, occipital, temporal, clavicle

steps of the endochondral ossification?steps of the endochondral ossification?

(1) Bone collar forms around diaphysis of cartilage
(2) Central cartilage in diaphysis calcifies and develops cavities
(3) Periosteal bud invades cavities, leading to formation of spongy bone
(4) Diaphysis elongates, and medullary cavity forms
(5) Epiphyses ossify

steps of the intramembranous ossification?

(1) Ossification centers are formed when mesenchymal cells cluster and become osteoblasts
(2) Osteoid is secreted, then calcified
(3) Woven bone is formed when osteoid is laid down around blood vessels, resulting in trabeculae
(4) Lamellar bone replaces woven bone, and red marrow appears

what is growth hormone?

stimulates epiphyseal plate activity (infancy & childhood)

what is thyroid hormone?

modulates activity of growth hormone

(ensures proper proportions)

what is testosterone and estrogen hormone?

puberty - promotes growth spurts

what is diploe?

thin plates of SPONGY bone

in FLAT, SHORT, or IRREGULAR BONES

what are the functions of the bones?

- support
- protection
- movement
- mineral & growth factor storage
- triglycerides (fat) storage
- blood cells formation/production
- hormone production (insulin)

what is an osteon?

- structural unit of compact bone
- tiny weight bearing pillars

what are sherpey's fibers?

- dense irregular CT
- consists of bundles of strong collagenous fibers
- secures the bone matrix

what is sharpey's fibers connection to the periosteum?

CONNECT PERIOSTEUM TO BONE MATRIX

what is periosteum?

- white
- double-layered membrane
- covers external surfaces except joints

What are Volkmann's canals?

connect blood vessels and nerves of periosteum, medullary cavity, and central canal

- CANALS WITH VEINS AND ARTERIES

LEARN EVERYTHING ON THE DIAGRAM!!!!!!!!!!!!!!!!!!!!!!!!!!!

What is in the Haversian canal?

- runs through core of OSTEON
- contains BLOOD VESSELS and NERVE FIBERS
- LAMALLAE (contains collagen fibers)

what is responsible for its high tensile strength and flexibility of the bone?

collagen fibers

What is responsible for its resilience of the bone?

Sacrificial Bonds

What is responsible for the hardness and allows bone to resistance to compression?

Hydroxyapatites

What is appositional growth?

makes cartilage growth increase in width

What is interstitial growth?

makes cartilage growth increase in density and length

what is the effect on calcitonin in humans?

lower calcium levels in your blood

What makes up a spongy bone?- made up of trabeculae

- made up of trabeculae

- open spaces BETWEEN trabeculae are filled with red/yellow marrow

what is trabeculae?

a honeycomb of small, needle like or flat pieces of bone

what is osteogenesis?

- process of bone tissue formation
- AKA ossification

what is wolf's law?

- bones grow or remodel in response to demands placed on them

what is comminuted fracture?

- bone fragments into 3 or more pieces
- common in older age whose bones are more brittle

think COMMUNITY OF BONES FRAGMENT

what is spiral fracture?

- excessive TWISTING FORCES are applied to bone
- cracks in oblique way

what is greenstick fracture?

- bone breaks incompletely (not all the way)
- one side of shaft breaks while other bends
- common in children (bcuz of more organic matrix)

what is compound fracture?

- skin is penetrated
- bone breaks through skin

what is simple fracture?

- skin is NOT penetrated
- bone breaks but still within the insides of skin

what is nondisplaced fracture?

- bone remains aligned
- still in regular position
- ends retain normal position

what is displaced fracture?

- bones are not anatomically aligned
- not in position
- ends are out of normal alignment

what is depressed fracture?

broken bone portion is pressed inwards

think HAMMERED

what is compression fracture?

- bone is CRUSHED
- common in porous bones

COLLAPSING

where is the lacunae?

cells encased in small cavities (collagen fiber)

where is the osteocytes?

found in mature bones

where is the canaliculi?

hair light canals that connect lacunae to each other & central canal

where is the volkman's canal?

canal's lined with endosteum that occur at right angles to central canal

where is the periosteum?

covers outside of compact bone

where is the circumferential lamellae?

- outer layer of the bone matrix
- layers of lamellae extend around entire surface of diaphysis
- superficial to endosteum

where is the haversian canal?

runs through core of osteon

where is the osteon?

haversian system

where is the compact bone?

dense outer layer on every bone

where is the spongy bone?

made up of a honeycomb-like (trabeculae)

what is osteocalcin?

- secreted by bones
- helps to regulate insulin secretion, glucose levels, & metabolism