Skeletal system Flashcards
what are the 2 types of bone? describe
cortical/compact bone - weight bearing; has osteons
spongy bone - has holes/porous; NOT weight bearing; deep to compact bone
List some functions of Bone
support and protection
movement
hemopoiesis
storage - calcium and phosphate and fat
How are bones classified? List the 4 classes of bone
classified by shape
- long bones - longer than width ex. limbs
- short bones - length almost = width ex. carpal bones of wrist/tarsal bones of foot
- flat bones - flat thin surfaces, may be slightly curved ex. ribs, sternum, scapulae, some of the cranial bones
- irregular bones ex. vertebrae
what are the two sesamoid bones that are counted as proper bones?
patella and pisiform
name and describe the regions/anatomy of long bones
epiphysis - proximal/distal ends; attached to articular cartilage
diaphysis - cylindrical shaft in middle
medullary cavity - hollow space in middle of diaphysis; bone marrow storage
what is the epiphyseal plate?
thin layer of hyaline cartilage for continued lengthwise bone growth
becomes the epiphyseal LINE in adults when growth ends
What is the periosteum? describe its anatomy
outer surface of bone
2 layers
- fibrous layer outer
-inner cellular layer - osteoprogenitor cells (stem cells), osteoblasts, and osteoclasts
attached to bone by perforating fibers (collagen)
what is the endosteum? describe anatomy and list the cells it houses
covers internal surfaces of LONG bones w/in medullary cavity
contains osteoprogenitor cells, osteoblasts, and osteoclasts
what is the nutrient foramen(foramina)? what is it’s significance?
small opening in bone for veins, arteries, and nerves
what is the spongy bone in the cranial flat bones called?
Diploë
List the 4 bone cells. describe them
osteoprogenitor cells - stem cells tht become osteoblasts
osteoblasts - make and secrete osteoid (organic part of matrix)
osteocytes - mature bone cells derived from osteoblasts ; maintain bone matrix
osteoclasts - break down bone to increase blood Ca++ levels
what are the 2 parts of bone matrix? how does each contribute to the characteristics of bone?
organic component = osteoid => collagen, proteoglycans, glycoproteins; made by osteoblasts; gives bone flexibility
inorganic = minerals => calcium phosphate makes hydroxyapatite crystals around collagen, which gives bones its rigidity
name the process in which new bone is formed
ossification
what are the 2 types of ossification? how do they differ
intramembranous - only in flat bones of cranium, some facial bones, mandible and clavicle
endochondral - starts with hyaline cartilage fetal model; makes most bones of skeleton; upper/lower limbs; pelvis and vertebrae
where does primary/secondary ossification centers form during endochondral ossification?
primary - diaphysis
secondary - epiphysis
during endochondral ossification, almost all cartilage is replaced by bone expect for…?
articular cartilage where joints articulate and epiphyseal plates
what is required for healthy bone formation>
vitamin C - collagen formation
vitamin D - calcium absorption
calcium and phosphate = calcification
at what part of the bone does continuous bone remodeling occur?
periosteal and endosteal surfaces
what can effect bone remodeling
mechanical stress or lack of mech. stress - weight bearing movement/exercise
hormones - GH, Thyroid hormones sex hormones calcium regulators
what 2 primary hormones regulate blood Ca++
parathyroid hormone, calcitriol
elevate blood Ca++ to normal range
regulated via negative feedback
what is blood Ca++ needed for>
muscle contraction, nervous system, stimulation of heart, blood clotting
How does calcitonin effect blood Ca++
lowers blood Ca++; stimulates kidneys to lose calcium in urine; inhibits osteoclast activity in bone
what causes Rickets? list some common symptoms
vitamin D deficiency in childhood
lack of calcification of osteoid
bowlegged
slow growth
what does hypocalcemia cause
Tetany
define osteopenia
osteoblast activity declining
occurs in all people with age early as 35-40
define osteoporosis
reduced bone mass = comprised normal function
occurs mostly in older women
list and define the types of bone fractures
pathologic - from weaken bone due to disease
simple - broken bone doesn’t penetrate skin
compound - one or both ends piercing overlying skin
comminuted - several small pieces btwn main fragments (fragments = no blood supply -> can become necrotic if bacteria is present)
what are the 4 steps of bone fracture repair
fracture hematoma forms from clotted blood
fibrocartilaginous callus forms
hard bony callus forms
bone = remodeled
what are the 3 structural classifications of joints
fibrous - immovable; no joint cavity; connected by dense regular CT proper ex. skull sutures
cartilaginous - no joint cavity, ex. intervertebral articulations
synovial - fluid filled cavity; free movement; bones attached by ligaments ex. elbow joint
list the functional classification of joints
synarthrosis - immobile can be fibrous or cartilaginous ex. tooth to jaw
amphiarthrosis - slightly mobile; can be fibrous or cartilaginous ex. articulation btwn tibia and fibula
diarthrosis - freely mobile; ALL synovial joints ex. knee joint
describe the relationship btwn mobility and stability of joints
inverse relationship - more mobility = less stability of joint
less mobility = more stability
what are the 3 most common fibrous joints
gomphoses (tooth attached to jaw)
sutures btwn skull
btwn radius and ulna
list the basic features of a synovial joint
articular capsule articular cartilage joint/ synovial cavity synovial fluid ligaments, nerves, blood vessels
where are synovial joints usually located
where any two long bones meet ex. humerus to ulna or proximal phalanx to metatarsal (remember a long bone is any bone longer than it is wide)
Name/describe the 2 layers of the joint/articular capsule
outer- fibrous layer formed by dense CT; strengthens joints to prevent bones being pulled apart
inner - synovial membrane made of areolar CT; covers all internal joint surfaces not covered by cartilage; makes synovial fluid (fills synovial cavity)
what are some functions of articular cartilage?
reduce friction during movement
act as cushion to absorb joint compression
prevent damage to articulating ends of bones
which cartilage makes up articular cartilage? what characteristic of this cartilage is significant when damage occurs?
hyaline cartilage
avascular = no blood vessels = slower healing time
what are the functions of synovial fluid
lubricates articulating surfaces
nourish chondrocytes
remove wastes
acts as shock absorber
what are some characteristics of a healthy joint in terms of synovial fluid appearance?
fluid should be clear and thick
cloudy = infection
describe a ligament
made of regular CT
connects one BONE to another BONE
stabilizes, strengthens, and reinforces most synovial joints
found in surrounding tissue not inside cavity
Describe the role of blood vessels and sensory nerves in synovial joints
innervate and supply articular capsule and ligaments
detect painful stimuli in joint
report movement and stretch w/in joint
what is a tendon? how does it differ from a ligament
made of dense regular CT
attach MUSCLE to BONE
help stabilize joints and sometimes limit range of movement allowed at a joint
define bursa
fibrous saclike structure tht has synovial fluid
found where bones, ligaments, muscles, skins, tendons rub together
define tendon sheath
elongated bursa
wraps around tendons where excessive friction may occur
common in wrist and ankle
list the classification of synovial joints from least to most mobile
plane hinge pivot condylar saddle ball-and-socket
define flexion
movement in an anterior-posterior plane
decreases angle btwn bones
ex. bending finger toward palm
define extension
increase angle btw articulating bones
describe the gleno-humoral joint
ball and socket joint
greatest range of motion of any joint in body
most unstable
gets joint strength from rotator cuff muscles
describe the hip joint
articulation btwn head of femur and acetabulum of os coxae
gets stability from deep bony socket, strong articular capsule, muscular padding
possible movements = flexion, extension, abduction, adduction, rotation, circumduction
what 2 articulations make up the knee joint
tibio-femoral joint
patella-femoral joint
what type of synovial joint is the knee joint
hinge joitn
name the 2 menisci of the knee joint
medial meniscus and lateral meniscus
made of fibrocartilage
c-shaped pads
partially stabilize joint medially and laterally
deep to articular capsule on condyles of tibia
name the 2 cruciate ligaments
limit anterior/posterior movement of femur on tibia
anterior cruciate ligament - prevents hyperextension
posterior cruciate ligament - prevents hyper flexion and prevents posterior displacement of tibia on femur
define rheumatic arthritis
a disease causing damage to articular cartilage (autoimmune)
