Skeletal System Flashcards
how many bones does the adult skeleton have?
206
functions of bones
- support
- protection
- movement
- storage
- blood cell formation
What is stored in the bones
mainly calcium and phosphorous
hematopoiesis
- AKA blood cell formation
- occurs w/ in marrow cavities of certain bones
parts of skeleton
- axial
- appendicular
makes up axial
- skull
- vertebral column
- bony thorax
makes up appendicular
- limbs
- pectoral girdle
- pelvic girdle
types of osseous tissue
- compact
- spongy
compact bone
- dense
- looks smooth and homogeneous
- contains nerves and blood vessels (supply nutrients)
- has osteocytes
- lacunae arranged in lamellae around haversian canal
- contains canaliculi
- contains volkmann’s canals
spongy bone
- small needlelike pieces of bone
- lots of open space
osteocytes
-mature bone cells located inside lacunae
lacunae
-tiny, matrix-filled cavities that hold osteocytes
lamellae
concrete circles that surround a haversian canal
haversian canal
-central canal in the middle of compact bone
osteon
- each central canal and matrix ring
- AKA Haversian system
canaliculi
- tiny canals, connecting all bone cells to nutrient supply through hard bone matrix
- in compact bone
volkmann’s perforating canals
-run into compact bone at right angles to the shaft
Types of bones
- long
- flat
- short
- irregular
long bones
- usually longer than wide
- composed of shaft w/ heads at both ends
- mostly compact
- example: all limbs except wrist and ankle
short bones
- cube-shaped
- mostly spongy bone
- example: wrist and ankle bones, sesamoid bones
sesamoid bones
form with tendons
- example: patella
flat bones
- thin, flattened, usually curved
- made up of 2 thin layers of compact bone w/ layer of spongy bone in between
- example: skull bones, ribs, sternum
irregular bones
- don’t fit other categories
- example: vertebrae, hip bones
long bone structure
- diaphysis makes up most of bone’s length
- covered & protected by periosteum
- epiphyses
- articular cartilage covers external surface of epiphyses
- epiphyseal line (adults)
- yellow marrow makes up cavity of diaphysis
- red marrow in diaphysis of infants
diaphysis
- shaft
- composed of compact bone
periosteum
- covers and protects long bone
- fibrous connective tissue membrane
epiphyses
- ends of long bone
- made of thick layers of compact bone w/ spongy inside
articular cartilage
-made of hyaline cartilage
epiphyseal line
-comes from epiphyseal plate
epiphyseal plate
- causes lengthwise growth of longbone
- replaced by bone by end of puberty
yellow marrow
- composed of adipose tissue
- in medullary cavity
red marrow
- in medullary cavity of infants
- in adults, in the cavities of spongy bone of flat bones and epiphyses of some long bones
bone markings
- show where muscles, tendons, and ligaments were attached
- shows where blood vessels and nerves passed
- projections/processes (start with t)
- depressions/cavities (start with d)
bone formation
- skeleton formed by cartilage & bone
- embryo is primarily hyaline cartilage
- cartilage remains only in isolated areas (bridge of nose, rib parts, joints)
ossification
-bone formation
steps of ossification
- hyaline cartilage model is completely covered with bone matrix by osteoblasts
- (cartilage bones are enclosed by bony bones)
- enclosed hyaline cartilage model is digested away, opening up medullary cavity within newly formed bone
osteoblasts
bone forming cells
bone development(length)
- by birth, most hyaline cartilage models have been converted to bone, except articular cartilages and epiphyseal plates
- new cartilage is formed continuously on external face of articular cartilage and epiphyseal plate farther away from medullary cavity
- old cartilage replaced by bony matrix
bone development (width)
- oppositional growth
- osteoblasts add bone tissue to external face of diaphysis as osteoclasts in endosteum remove bone
- length and width occur at same rate
how is bone development regulated
- growth hormones
- sex hormones
- calcium levels
endosteum
-thin membrane that lines medullary cavity
osteoclasts
-bone destroying cells
bone remodeling
- influenced by calcium levels in the blood and pull of gravity and muscles on skeleton
- when blood calcium levels are too low, parathyroid glands release PTH hormone into the blood, which activates osteoclasts to break down bone & release calcium ions into blood
- when blood calcium levels are too high, calcium is deposited into bone matrix as hard calcium salts
Rickets
- occurs in children whose bones fail to calcify
- bones soften and bowing of weight-bearing bones occurs
- due to lack of calcium in diet/ lack of vitamin D
closed fracture
- AKA simple fracture
- doesn’t penetrate skin
open fracture
- AKA compound fracture
- penetrates the skin
reduction
- treatment of fractures
- realignment of broken bone ends
closed reduction
-ends coaxed together by doctor’s hands
open reduction
- surgery performed
- bones secured together w/ pins, wires
repair of fractures
- hematoma formed & bone cells deprived of nutrients die
- break is splinted by fibrocartilage callus & new capillaries form
- fibrocartilage replaced by bony callus made of spongy bone
- bony callus is remodeled around mechanical stresses
hematoma
blood-filled swelling
fibrocartilage callus
-contains bony matrix, cartilage matrix, and collagen fibers
Transverse fracture
- occurs at exactly 90 degree horizontal angle
- caused by a bending force that causes bone to snap like a carrot
oblique fracture
- occurs sloped at an angle/curve
- caused by trapping of one bone while other twists over it
- foot caught in rock and leg twists
spiral fracture
- spirals around bone
- caused by twisting force
-comminuted fracture
- breaks into multiple pieces
- caused by crushing force
avulsion fracture
- ligament or tendon pulls away from attached bone, and bone fragment breaks off
- caused by muscle contraction or stretch that is stronger than force that holds the tendon/ligament to bone
impacted fracture
- occurs in the middle of a bone when it is driven into itself and buckles
- caused by compression of bone from end to end
fissure/hairline fracture
- incomplete bone fracture
- multiple small lines often visible, don’t pass thru entire bone
- caused by a less great force
greenstick fracture
- bone bends rather than breaks
- occurs most often in children whose bones haven’t completely ossified
skull
- made of cranium and facial bones
- bones joined together by sutures
- only the mandible is attached to the rest of the skull by a freely moveable joint
- cranium is composed of long, flat bones
paranasal sinuses
- hollow portions of bones surrounding nasal cavity
- lighten the skull
- give resonance and amplification to voice
hyoid bone
- only bone in body that doesn’t articulate directly with any other bone
- anchored by ligaments to styloid process
- moveable base for tongue
- attachment point for neck muscles that raise and lower larynx when swallowing/speaking
fetal skull
- very large
- considered unfinished at birth
- has fontanels that are replaced about 2 years after birth
- fontanels aka soft spots
vertebral column
- extends from skull to pelvis
- 26 irregular bones reinforced by ligaments
- before birth, 33 vertebrae but 9 fuse together forming sacrum & coccyx
- supports/protects spinal cord
- separated by intervertebral discs
cervical vertebrae
- 7 vertebrae of the neck
- atlas (C1) is for nodding
- axis(C2) pivot for rotation of skull
- C3-C7 are smallest lightest vertebrae
thoracic vertebrae
-12 vertebrae in the middle
-
lumbar vertebrae
-5 vertebrae of lower back
intervertebral discs
-made of flexible fibrocartilage
scoliosis
-sideways curvature of spine
-kyphosis
- hunchback
- over curvature of thoracic region
lordosis
-inward curvature of cervical and lumbar regions
Sacrum
- fusion of 5 vertebrae
- between L5 and coccyx
- forms posterior wall of pelvis
Coccyx
- tailbone
- fusion of 3-5 tiny vertebrae
bony thorax
- made of sternum, ribs, thoracic vertebrae
- aka thoracic cage
sternum
- breastbone
- attached to first 7 pairs of ribs
ribs
-12 pairs form thoracic cavity walls
false ribs
5 pairs attached indirectly to sternum
true ribs
7 pairs attached directly to sternum by costal cartilages
floating ribs
last 2 pairs that lack sternal attachment
pectoral girdle
- clavicle
- scapula
clavicle
- attaches to sternum and scapula
- acts as brace to hold arm away from thorax and prevent shoulder dislocation
scapula
- only attaches at one point
- easily dislocated
- poorly reinforced ligaments
pelvic girdle
- bears weight of upper body
- protects reproductive organs, urinary bladder, parts of intenstines
pelvic girdle male vs. female
- female inlet is larger & more circular
- female pelvis as a whole is shallower & bones are lighter and thinner
- female ilia flare more laterally
- female sacrum is shorter & less curved
- female ischial spines are shorter and farther apart; outlet is larger
- female pubic arch is greater and more rounded
foot arches
- 3
- 2 longitudinal and 1 transverse
joints
- aka articulations
- every bone forms one except hyoid
classification by function
- synarthroses
- amphyiarthroses
- diarthroses
classification by structure
- fibrous
- cartilaginous
- synovial
synarthroses
-immovable
amphyiarthroses
-slightly moveable
diarthroses
-freely moveable
fibrous joints
- immovable
- sutures of skull
- syndesmoses
syndesmoses
- connecting fibers are longer than sutures, providing more give to the joint
- distal ends of tibia and fibula
cartilaginous joints
- can be slightly moveable (pubic symphysis or intervertebral joints)
- can be immoveable (cartilage b/w first rib and sternum)
synovial joints
- bone ends separated by joint cavity containing synovial fluid
- articular cartilage covers ends of bones
- fibrous articular capsule encloses joint and is lined w/ a smooth synovial membrane
- joint cavity contains lubricating synovial fluid
- reinforcing ligaments
- bursae and tendon sheaths found close by
bursae
-flattened fibrous sacs lined w/ synovial membrane and contains thin film of synovial fluid
tendon sheath
-elongated bursae that wraps completely around tendon
types of synovial joints
- plane
- hinge
- pivot
- condyloid
- saddle
- ball and socket
plane joint
- short slipping or gliding movements
- nonaxial
- example: carpals
hinge joint
- angular movement in one plane
- uniaxial
- example: humerus and ulna
pivot joint
- rotating bone can turn only round its axis
- uniaxial
- example: head moving back and forth
condyloid joint
- oval areas fit together to move bone side to side/ back and forth
- can’t rotate around axis
- biaxial
- example: metacarpals
saddle joint
- convex and concave areas like a saddle
- biaxial
- example: thumb
ball and socket joint
- spherical head of one bone fits into round socket of another
- multiaxial
- example: shoulder
osteoarthritis
- material from cartilage is worn down causing friction in joints
- caused by being overweight, being active
- symptoms: achy pain, soreness in joints
- treatments: medications, occupational therapy, physical therapy
osteoporosis
- causes bones to become weak and brittle
- losing bone structure
- caused by drinking alcohol, smoking
- symptoms: back pain, height loss, greater chance of fractures, lose posture
- treatments: care and keep up with your body
Osteogenicsarcoma
- tumor forms in growth plate
- young or old people
- symptoms: pain, swelling, fractures
- treatments: surgery, chemotherapy
spina bifida
- unknown cause, but believed to be environmental and genetic factors
- incomplete development of spinal cord
- symptoms: bladder, bowel problems, fluid buildup in brain, seizures
- treatments: surgery, therapy
craniosynostosis
- premature fusion of sutures
- caused by genetics or other disorders
- symptoms: deformed skull, pressure in skull
- treatments: surgery (traditional or endoscopic)
gout
- uric acid builds up in joints
- caused by severe arthritis and high red meat diet
- symptoms: limited movement, itching, red/purple skin, fatigue, fever
- treatments: medicine (anti-inflammatory), blocking uric acid production, improve removal of uric acid
osteogenesis imperfecta
- caused by genetics
- severe lack of collagen fibers
- extremely fragile bones
- symptoms: fractures, short stature, tinted whites of eyes, flat feet, brittled teeth, scoliosis, kyphosis
- treatments: experimental drugs, low impact sports, rods in bones, surgery
acrania
- caused by amniotic syndrome
- failure of ectodermal mesenchyme
- flat bones in skull are absent
- symptoms: absence of top of skull, autism
- treatments: prenatal folic acid treatments
herniated disc
- caused by old age
- degenerated cartilage bulges out of vertebrae
- symptoms: leg pain, arm pain
- treatments: pain relievers, anti-inflammatory
ankylosing spondylitis
- caused possibly by genetics
- long term arthritis
- symptoms: pain in side of lower back, fever, lost appetite, pain anywhere in back, lack of mobility, bowel inflammation, pain in peripheral joints
- treatments: medication, physical therapy, exercises, alternative meds, NSAIDs, DMARDs
osteochondrosis
- cause is unknown, common in trauma victims
- poor blood supply to bone
- symptoms: locked and popping joints, pain
- treatments: physical therapy, surgery
carpal syndrome
- causes are hereditary, genetic, compression of nerve, moving hands in same position continuously
- symptoms: numbness, tingling, weak grip
- treatments: taking breaks from typing, icing, splinting
bone grafting
- purpose: to replace dead bone marrow w/ new marrow or actual bone
- side effects: pain in surgical area, nerve injuries, rejection, inflammation, infection, bleeding, trouble breathing
