Anatomy & Physiology 319 (Lecture 4 continued...)February 12, 2015Infant skull- Has fontanels (refers to fountain)- Can feel infants pulse from back of head- Soft spot is robust fibrocartilage (delicate)- Advantage of being born with skull full of fibrocartilageo Coming down birth canal, tight space (gives)o Proportions of head are different from adult skull- Nose and mandibular region is part that catches up to rest of skullo Not a lot of variationo Mandible, maxilla, cheek bone- Doesn’t reach full facial features until reach teenage years- Cranium is already ahead of rest of skullGrowth- Body changes throughout life- Head for most part doesn’t change as muchGross Anatomy- Appendicular skeletonLong Boneso Longer than they are wideo Straight o Very close to being cylindricalo Have knobby endso Apart of appendicular skeleton- Why ribs aren’t long bones?o Fail because not straight o Flato And don’t have knobby ends- Long bones don’t have to be really long, can be short- Bones in fingers are long bones- Diaphysis- shaft of long boneo Most of length- Metaphysis- knobby end Region where line of epiphysis and diaphysis exists- Epiphysis- knobby end, where bone swells at either end- Periosteum- Outer coating of bone, only represented in living boneo Connective tissue (dense fibrous tissue)o Tough outer coatingo Attached to boneo Manufactures shell that allows bones to grow thicker- Sharpey’s fibers- one outside of bone- Compact bone- outer layer of the (cortical bone)o Outer bark- Trabeculea (pleural)- all beams going off in different directionso Spongy looking (spongy bone)- Living bone- very dynamic o Has living soft tissue living in ito In spongy bone is full of red bone marrowo Blood vessels running througho Bone marrow- Can be red (blood forming)- Yellow marrow- Hollow space - Medullary Cavityo Central cavityo Medulla- filled with tissue… adrenal medulla, adrenal cortexFlat Boneso Cranial bones, scapula, ribs, skullo Have a flat aspect, even though curvedo Collar bone and skull develop in same wayo Out growth of embryotic mesenchymeo Diploe- same as spongy bone in skullMarrowo Red marrowo Where all blood cells come fromo Hematopoietic tissue= red marrowo Limited in life spano Missing mitochondria so can’t repair geneso 3 month life span in average individualo Spleen kills old RBC, and recycles nutrients in RBCo Heme taking away and turned into bileo Red marrow in all long bones  In teenage years start converting red marrow into yellow Adults have red marrow in vertebrae,hip, ribs, skull flat bones Can increase in proportion on demand- Go from low elevation to higher concentration RBC levels trying to increase- Hematopoietic level- amount of RBC per mL- Through hormonal regulationproduce more blood cells per mL- Plasticity can rise to bar that is set- Can increase red marrowo Compact boneo Osteon- structural unit, group of lamellaeo Lamellae- individual ringso Haversian canal (central canal)- passageway for blood vessels, small arteries and veins; normally run down in pairs, and nerveso Perforating canal (Volkmann’s Canal)- have alot of there canals running at right angles to central canal, give advance grid like blood vessels in boneo Dense blood and nerve supplyo Palliative care- make people feel comfortable when sick or dyingo When cancer spreads to bone- can cause bone paino Bones have cells- located in Osteocytes in lacunaeo Can’t look at live cells through electron microscopeo Connective tissue has a minimal amount of cellsspaced outo Canaliculi- can radiate out and get free oxygeno As bone grows manufactures interstitial lamellaeo Has collagen fibersOsteons- heart and sole of long bone- Alternating lamellae have alternating collagen fibers (run 90 degrees to each other)- Alternating lamellae reinforces structure against twisting structures- Lets bone be hard and tough (good shield also hard to tear or shatter)- Collagen fibers reinforceSpongy bone- Filled with trabeculaeo Made of lamellaer boneo Irregular ringso Have osteocyteso Canaliculi- tiny tubes that go to one lamellae to nexto Osteocytes not starving, share environment, livingo Trabeculae- have a pattern  Certain regions where they are all aligned Capable of changing orientation Constantly breaking down, and building self back up Start progressively build self up along patterns Patterns dictated over pressures of bone Realign self to withstand forces they are being put under Better serves to support weight- Spongy bone in diaphysis of long bones- All things in electron microscope are dead- Cancelloes bone- spongy bone (diploe- spongy bone of head)All bones come from embryotic mesenchyme- Flat bones and collar bones develop directly from embryotic mesenchyme Bone cellsOsteoprogenitors- ancestors. Cell that comes before real bone cell (pre-bone cell)- Stem cell- any cell that is in starting to become specific cell, but hasn’t become it yet- Periosteum- bone cells are born here, against outer surface of bone- When becomes a bone cell can begin adding thickness- Endosteum- same material as periosteum, lines all internal surfaces - Undergo mitosisOsteoblasts- real working bone cells- Makes real new bone- Bigger and rounder, more oval- Full grow bone cells- -blasts- build- Actively adding new bone to surface- Secrete collagen and organic matrix that will make up bone- Remodel existing bone, rebuild broken down bone- Remodeling always necessary because bone is always breaking itself down and rebuilding itselfOsteocytes- In lacunae with bone- NO longer making new bone- Just maintaining own bone- Lives in lacunaOsteoclast- different from other types of bone cells- Bone destroyer- -clast- break down - On compact bone, will degrade bone- House-ships lacuna- erosion of bone from osteoclast to what it is sitting on top of- Anatomically different- bigger compared to other types of cells- Multiple nuclei- In periosteum and endosteum- Reabsorb calcium and phosphate- Collagen and break into amino acids, which go into blood stream- Necessity for bone to function normally- Origin different- born in bone marrow- When mature full member of bone cell communityTwo types of bone cells1. Osteoclasts2. OsteocprogenitorsOsteoblastsOsteocytes - Same cell going through different stages through life history- All same cell- Change a lot throughout lifeExtracellular Matrix- Can break into organic and inorganic matrix- Organic- composed of water- Living bone low on water compared to