anatomy unit 3: skeletal system

connective tissue

most tissues in the skeletal system are _______

osseous tissue

• bone tissue

• dense and mineralized matrix (what surrounds the cells)

• concentric rings make it able to hold a lot of weight

tendons

connect muscle to bones

ligaments

connect bone to bone

fibroblasts

cells in the tendons and ligaments 

elastic cartilage

• has the most elastic fibers

• found in the outer ear & epiglottis

hyaline cartilage

found in the ribs, nose, larynx, trachea, bronchi

fibrocartilage

• has the least amount of elastic fibers

• found in the vertebrae

• holds pelvis together 

chondrocytes

cells in cartilage

bone tissue

what type of tissue is this?

dense regular tissue

what type of tissue is this?

elastic tissue

what type of tissue is this?

hyaline tissue

what type of tissue is this?

fibrocartilage

what type of tissue is this?

axial skeleton

• includes the skull, vertebral column, and bony thorax (ribs)

• protects the brain, spinal cord, and thoracic organs

• divided into 3 regions: skull, vertebral column, bony thorax (ribs)

appendicular skeleton

includes the shoulders, upper limbs, hands, lower limbs, hips, legs, and feet

parietal & temporal

paired bones of the cranium

frontal, occipital, sphenoid, ethmoid

unpaired bones of the cranium

sutures

interlocking joints that unite bones of the skull

coronal suture

frontal bone and parietal bones

sagittal suture

two parietal bones

squamous suture

parietal bone and temporal bone

lambdoid suture

parietal bone and occipital bone

vomer & mandible

only unpaired bones of the face

palatine bone

bone that is affected by cleft lip disease

vomer bone

makes up the nasal septum

five skull bones with sinus cavities

frontal, sphenoid, ethmoid, maxillary 1, maxillary 2

functions of sinuses

• lightens skull

• voice resonance

• warms and humidifies air

• mucus accumulation

hyoid bone

• only bone that does not articulate (touch or conjoin) with any other bone

• miniature version of the mandible

• moveable bas of tongue

scoliosis

lateral curvature of the thoracic region

kyphosis

hunchback; dorsally exaggerated thoracic curvature

lordosis

sway back; lumbar curvature; can happen in overweight or pregnant people

true ribs

attach to the sternum at their own attachment

false ribs

all grouped together at one attachment point to the sternum

floating ribs

aren’t attached to the sternum at all, just the vertebrae

femur 

largest bone in the body

functions of bones, ligaments, tendons, and cartilage

support, protection, movement, mineral and adipose storage, and hematopoiesis (blood cell formation)

long bones

all bones of limbs except patella and bones of wrist and ankle

short bones

cube-shaped, wrist and ankle

flat bones

thin & flattened; shoulder blades, ribs, skull

irregular bones

vertebrae and hip bones

bone marrow

soft tissue occupying the medullary cavity of a long bone

red bone marow

forms blood cells in the spongy bone

yellow bone marrow

makes fat cells in the medullary cavity

phosphorus & calcium

two minerals stored in bones

osteoblasts

bone-building cells

osteocytes

mature bone cells

osteoclasts

bone-destroying cells

bone remodelling

occurs every day due to microfractures in the bone

bone matrix

• organic compounds (collagen) secreted by osteoblasts provide bone with resiliency

• inorganic compounds (calcium, phosphate, calcium hydroxide) help with hardness and resistance of compression

osteons

cylindrical structural units that make up bone; weight-bearing pillars

haversian canal

a passage of blood vessels down the length of the bone

lamellae

tiny, small, concentric circles that make up an osteon

volkman’s canal 

perpendicular to osteons and connects osteons together 

lacune

spider-shaped osteocytes that reside in tiny gaps in the lamellae

canaliculi

canals that connect lacunae together

compact bone

dense, solid outer layer of bone

spongy bone

inner honeycomb-like structure made of trabeculae 

diaphysis

aka the shaft; thick collar of compact bone with central marrow cavity

epiphysis

• at the ends of the bones

• thin layer above compact bone

• covered in articular cartilage (helps cushion the bone and reduce friction)

periosteum

• external double layer membrane of the bone

• outer fibrous layer is dense irregular CT

• inner cellular layer contains osteoblasts

• rich in nerves, lymphatics, and blood vessels

• Sharpey’s fibers - periostium connects to the bone vis these strong fibers

endosteum

inner bone surface covered with delicate connective tissue; covers the trabeculae of spongy bone

osetogenesis

• process of ossifiication and bone formation

• leads to the formation of bony skeleton in an embryo

• children & adults

fibrous membrane and hyaline cartilage

makes up an embryo before week 8

intramembranous ossification

• happens in face, cranial, and clavicles

• development of bone from fibrous membrane

• occurs in an embryo after week 8

endochondral ossification

• replaces hyaline cartilage completely

• happens in long bones

• occurs in embryos after week 8

factors affecting bone growth

• vitamins D, A, and C

• growth hormone

• thyroid hormone

• parathyroid hormone

• sex hormones 

• physical stress

osteomalacia

disease making bones soft due insufficient calcium and vitamin D & nutrient deficiency

rickets

children’s osteomalacia, more detrimental since bones aren’t done growing

osteomyelitis

inflammation of the bone marrow through an open wound

osteoporosis

when bone reabsorption happens too quickly

osteogenesis imperfecta

genetic brittle bone disease

bone cancers

• can happen in the bone or cells within the bone

• bone tumors = sarcomas

paget’s disease

• elderly disease

• excessive and haphazard bone deposits and resorption 

• spotty bone weakening

steps to a bone fracture

• hematoma forms

• granulation tissue forms

  • fibroblasts → collagen

  • osteoblasts → spongy bone

  • both = fibrocartilaginous callus

• bony callus forms

• continuous modification

open (compound) bone fracture

bone penetrates skin

closed (simple) bone fracture

bone does not penetrate skin

comminuted bone fracture

bone fragments in three or more pieces, usually due to brittle bones

greenstick bone fracture

bone breaks incompletely, common in children due to softer bones

spiral bone fracture

ragged break, usually in sports

impacted bone fracture

one bone fragment is driven into the medullary space of another

fibrous/syntharoses joints

• generally immoveable

• dense regular CT

• sutures (skull), syndesmoses (distal end of tibia & fibula), gomphoses (root of tooth and mandible)

cartilaginous/amphiathroses joints

• slightly moveable 

• connected by plate or pad of cartilage

• synchondrosis (hyaline cartilage, first rib & sternum), symphysis (fibrocartilage, intervertebral joints, pubic symphysis)

synovial/diarthroses joints

• freely moveable

• fluid-filled joint cavity

• plane, hinge, pivot, condyloid, saddle, ball & socket

• articular cartilage (covers the ends of bones), fibrous articular capsule (two layers of connective tissue), joint cavity

nonaxial

slipping motion, no axis

uniaxial

movement in one plane; hinge and pivot joints

biaxial

movement in two planes

multilateral

movement in all three planes

plane synovial joints

• short movements

• nonaxial

• ex. femorpatellar

hinge synovial joints

• like a door 

• uniaxial 

• ex. elbow

pivot synovial joints

• shaking head no 

• uniaxial

• ex. atlas and axis

condyloid synovial joints

• side to side, back and forth

• biaxial

• ex. occipital and atlas

saddle synovial joints

• side to side, back and forth

• biaxial

• ex. thumb joint

ball & socket synovial joints

• most freely moving

• multiaxial 

• ex. glenohumeral joint

sprains

• happen when a ligament it stretched or torn

• heal slow due to a lack of blood supply

dislocation

happens when a bone is out of its normal place

arthritis

• inflammatory or degenerative disease of the joints

• acute - bacterial infection

• chronic - no cure

osteoarthritis

most common; due to aging and degrading of articular cartilage

rheumatoid arthritis

autoimmune disease; joint is attacked by immune cells

gout

buildup of uric acid in the joint cavity