Skeletal system

Question 1

what are the 2 types of bone? describe

Answer 1

cortical/compact bone - weight bearing; has osteons

spongy bone - has holes/porous; NOT weight bearing; deep to compact bone

Question 2

List some functions of Bone

Answer 2

support and protection
movement
hemopoiesis
storage - calcium and phosphate and fat

Question 3

How are bones classified? List the 4 classes of bone

Answer 3

classified by shape

1. long bones - longer than width ex. limbs
2. short bones - length almost = width ex. carpal bones of wrist/tarsal bones of foot
3. flat bones - flat thin surfaces, may be slightly curved ex. ribs, sternum, scapulae, some of the cranial bones
4. irregular bones ex. vertebrae

Question 4

what are the two sesamoid bones that are counted as proper bones?

Answer 4

patella and pisiform

Question 5

name and describe the regions/anatomy of long bones

Answer 5

epiphysis - proximal/distal ends; attached to articular cartilage
diaphysis - cylindrical shaft in middle
medullary cavity - hollow space in middle of diaphysis; bone marrow storage

Question 6

what is the epiphyseal plate?

Answer 6

thin layer of hyaline cartilage for continued lengthwise bone growth
becomes the epiphyseal LINE in adults when growth ends

Question 7

What is the periosteum? describe its anatomy

Answer 7

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)

Question 8

what is the endosteum? describe anatomy and list the cells it houses

Answer 8

covers internal surfaces of LONG bones w/in medullary cavity
contains osteoprogenitor cells, osteoblasts, and osteoclasts

Question 9

what is the nutrient foramen(foramina)? what is it’s significance?

Answer 9

small opening in bone for veins, arteries, and nerves

Question 10

what is the spongy bone in the cranial flat bones called?

Answer 10

Diploë

Question 11

List the 4 bone cells. describe them

Answer 11

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

Question 12

what are the 2 parts of bone matrix? how does each contribute to the characteristics of bone?

Answer 12

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

Question 13

name the process in which new bone is formed

Answer 13

ossification

Question 14

what are the 2 types of ossification? how do they differ

Answer 14

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

Question 15

where does primary/secondary ossification centers form during endochondral ossification?

Answer 15

primary - diaphysis

secondary - epiphysis

Question 16

during endochondral ossification, almost all cartilage is replaced by bone expect for…?

Answer 16

articular cartilage where joints articulate and epiphyseal plates

Question 17

what is required for healthy bone formation>

Answer 17

vitamin C - collagen formation
vitamin D - calcium absorption
calcium and phosphate = calcification

Question 18

at what part of the bone does continuous bone remodeling occur?

Answer 18

periosteal and endosteal surfaces

Question 19

what can effect bone remodeling

Answer 19

mechanical stress or lack of mech. stress - weight bearing movement/exercise
hormones - GH, Thyroid hormones sex hormones calcium regulators

Question 20

what 2 primary hormones regulate blood Ca++

Answer 20

parathyroid hormone, calcitriol
elevate blood Ca++ to normal range
regulated via negative feedback

Question 21

what is blood Ca++ needed for>

Answer 21

muscle contraction, nervous system, stimulation of heart, blood clotting

Question 22

How does calcitonin effect blood Ca++

Answer 22

lowers blood Ca++; stimulates kidneys to lose calcium in urine; inhibits osteoclast activity in bone

Question 23

what causes Rickets? list some common symptoms

Answer 23

vitamin D deficiency in childhood
lack of calcification of osteoid
bowlegged
slow growth

Question 24

what does hypocalcemia cause

Answer 24

Tetany

Question 25

define osteopenia

Answer 25

osteoblast activity declining | occurs in all people with age early as 35-40

Question 26

define osteoporosis

Answer 26

reduced bone mass = comprised normal function | occurs mostly in older women

Question 27

list and define the types of bone fractures

Answer 27

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)

Question 28

what are the 4 steps of bone fracture repair

Answer 28

fracture hematoma forms from clotted blood fibrocartilaginous callus forms hard bony callus forms bone = remodeled

Question 29

what are the 3 structural classifications of joints

Answer 29

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

Question 30

list the functional classification of joints

Answer 30

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

Question 31

describe the relationship btwn mobility and stability of joints

Answer 31

inverse relationship - more mobility = less stability of joint less mobility = more stability

Question 32

what are the 3 most common fibrous joints

Answer 32

gomphoses (tooth attached to jaw) sutures btwn skull btwn radius and ulna

Question 33

list the basic features of a synovial joint

Answer 33

``` articular capsule articular cartilage joint/ synovial cavity synovial fluid ligaments, nerves, blood vessels ```

Question 34

where are synovial joints usually located

Answer 34

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)

Question 35

Name/describe the 2 layers of the joint/articular capsule

Answer 35

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)

Question 36

what are some functions of articular cartilage?

Answer 36

reduce friction during movement act as cushion to absorb joint compression prevent damage to articulating ends of bones

Question 37

which cartilage makes up articular cartilage? what characteristic of this cartilage is significant when damage occurs?

Answer 37

hyaline cartilage | avascular = no blood vessels = slower healing time

Question 38

what are the functions of synovial fluid

Answer 38

lubricates articulating surfaces nourish chondrocytes remove wastes acts as shock absorber

Question 39

what are some characteristics of a healthy joint in terms of synovial fluid appearance?

Answer 39

fluid should be clear and thick | cloudy = infection

Question 40

describe a ligament

Answer 40

made of regular CT connects one BONE to another BONE stabilizes, strengthens, and reinforces most synovial joints found in surrounding tissue not inside cavity

Question 41

Describe the role of blood vessels and sensory nerves in synovial joints

Answer 41

innervate and supply articular capsule and ligaments detect painful stimuli in joint report movement and stretch w/in joint

Question 42

what is a tendon? how does it differ from a ligament

Answer 42

made of dense regular CT attach MUSCLE to BONE help stabilize joints and sometimes limit range of movement allowed at a joint

Question 43

define bursa

Answer 43

fibrous saclike structure tht has synovial fluid | found where bones, ligaments, muscles, skins, tendons rub together

Question 44

define tendon sheath

Answer 44

elongated bursa wraps around tendons where excessive friction may occur common in wrist and ankle

Question 45

list the classification of synovial joints from least to most mobile

Answer 45

``` plane hinge pivot condylar saddle ball-and-socket ```

Question 46

define flexion

Answer 46

movement in an anterior-posterior plane decreases angle btwn bones ex. bending finger toward palm

Question 47

define extension

Answer 47

increase angle btw articulating bones

Question 48

describe the gleno-humoral joint

Answer 48

ball and socket joint greatest range of motion of any joint in body most unstable gets joint strength from rotator cuff muscles

Question 49

describe the hip joint

Answer 49

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

Question 50

what 2 articulations make up the knee joint

Answer 50

tibio-femoral joint | patella-femoral joint

Question 51

what type of synovial joint is the knee joint

Answer 51

hinge joitn

Question 52

name the 2 menisci of the knee joint

Answer 52

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

Question 53

name the 2 cruciate ligaments

Answer 53

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

Question 54

define rheumatic arthritis

Answer 54

a disease causing damage to articular cartilage (autoimmune)