BONES AND CARTILAGE TISSUE (EXAM1)

Question 1

Define the following regions of a bone: diaphysis

Answer 1

the elongated, usually cylindrical shaft

Question 2

Define the following regions of a bone: epiphysis

Answer 2

knobby region at each end, enlarged to strengthen joint and provide added surface for attachment of tendons and ligaments

Question 3

Define the following regions of a bone:metaphysis

Answer 3

region in bone between diaphysis and epiphysis containing epiphysial (growth) plate

Question 4

Define the following regions of a bone:medullary cavity

Answer 4

hollow, cylindrical space within the diaphysis containing yellow bone marrow

Question 5

Define the following regions of a bone:articular cartilage

Answer 5

thin layer of hyaline cartilage covering the epiphyseal surfaces, reduces friction between articulating bones

Question 6

Define the following regions of a bone:periosteum

Answer 6

tough, irregular dense connective tissue, covers most of the external surface of the bone (except articular cartilage) and anchors itself, blood vessels and nerves to the bone by sending perforating collagen fibers into the underlying diaphysis

Question 7

Define the following regions of a bone:endosteum

Answer 7

covers most of the internal surface of the bone

Question 8

Define the following regions of a bone:epiphyseal plate

Answer 8

A layer of hyaline cartilage at the boundary of the epiphysis and diaphysis

Question 9

Name four types of bone cells and give functions

Answer 9

Osteoprogenitor – stem cells from mesenchyme, found in endosteum and periosteum, produce either another stem cell or an osteoblast

Osteoblast – forms bone matrix, “builds bone”, differentiates into osteocytes

Osteocytes – maintain the bone matrix and communicate with osteoblasts which deposit further bone matrix

Osteoclasts – large, multinuclear cells that dissolve bone. Osteoclasts and osteoblasts have opposite effects on bone density and serum Ca++

Question 10

Characterize red and yellow marrow and give locations in the adult skeleton (red)

Answer 10

Red bone marrow Gets color from abundance of red blood cells Present in medullary cavity of children Produces all cells of the blood In adults: present in skull, vertebrae, sternum, ribs, hip, proximal heads of femur and humerus

Question 11

Describe endochondral and intramembranous ossification

Answer 11

• Intramembranous ossification develops from mesenchyme to produce flat bones of the skull, some facial bones, the mandible and central portion of clavicle
• Endochondral ossification begins with a hyaline cartilage model and produces the majority of bones in the body

Question 12

Describe zones of epiphyseal plate and explain signficance for bone growth (zone 1)

Answer 12

Zone of resting cartilage – farthest away from medullary cavity of diaphysis and nearest the epiphysis, consists of small chondrocytes and matrix of hyaline cartilage

Question 13

Describe interstitial and appositional bone growth A) Also know ages during which these processes are active

Answer 13

Interstitial growth – growth in bone length at the epiphyseal plate

Appositional growth – growth in bone diameter

Question 14

Describe the following common bone fractures: colles

Answer 14

Distal end of radius

Question 15

Describe the following common bone fractures:comminuted

Answer 15

Bone is broken into three or more pieces

Question 16

Describe the following common bone fractures: compound

Answer 16

broken end protrude through skin

Question 17

Describe the following common bone fractures: greenstick

Answer 17

Bone is bent on one side and has incomplete fracture on opposite side

Question 18

Describe the following common bone fractures: pott

Answer 18

fracture at distal end of tibia, fibula or both

Question 19

Describe the following common bone fractures: spiral

Answer 19

fracture spirals around long axis of bone due to twisting

Question 20

Describe the following common bone fractures: compression

Answer 20

Bone is crushed

Question 21

Describe the following common bone fractures: epiphyseal

Answer 21

fracture within epiphyseal plate

Question 22

Describe the following bone-related diseases:paget disease

Answer 22

Caused by excessive bone resorption by osteoclasts which are abnormally large and active Deposition by osteoblasts is insufficient to keep pace Affects pelvis, skull, vertebrae, femur and tibia Causes bone deformity and pain; may lead to bowing of lower limbs

Question 23

Describe the following bone-related diseases:osteogenesis imperfecta

Answer 23

Also called brittle bone disease Heredity defect of collagen deposition in the bones Symptoms include -Bone fractures at birth -Spontaneous fractures -Deformed teeth -hearing impairment due to deformity of ossicles

Question 24

Describe the following bone-related diseases: rickets

Answer 24

Due to vitamin D deficiency Hence calcium is not absorbed from GI tract and bone is insufficiently mineralized or hardened during bone formation Leads to bowed legs in children as weight increases Fractures are also common

Question 25

Describe the following bone-related diseases: achondroplastic dwarfism

Answer 25

Long bones of limbs stop growing while other bones grow normally Results in short stature but large head Due to failure of chondrocytes in second and third zones of epiphyseal plate to multiply and enlarge Causes inadequate interstitial growth Caused by spontaneous genetic mutation or inherited as autosomal dominant

Question 26

Describe the following bone-related diseases:osteoporosis.

Answer 26

Osteoporosis means porous bone Disease that leads to decreased bone mass and weakened bones Both bone matrix and calcium are lost especially in spongy bone Leads to increase bone fractures Prevention is best treatment Good nutrition and physical activity

Question 27

Describe zones of epiphyseal plate and explain signficance for bone growth (zone 3)

Answer 27

Zone of hypertrophic cartilage – chondrocytes cease dividing and become enlarged

Question 28

Describe zones of epiphyseal plate and explain signficance for bone growth (zone 2)

Answer 28

Zone of proliferating cartilage – chondrocytes are slightly larger and undergoing rapid mitotic cell division, aligned like a stack of coins

Question 29

Describe zones of epiphyseal plate and explain signficance for bone growth (zone 4 and significance)

Answer 29

Zone of calcified cartilage – minerals are deposited between stacks of lacunae. This kills the chondrocytes and makes the matrix appear opaque

Epiphyseal plate remains through adolescence and acts as a growth plate

Question 30

Characterize red and yellow marrow and give locations in the adult skeleton (yellow)

Answer 30

Yellow bone marrow Gradually replaces red bone marrow with age Contains fat cells No longer produces blood but may revert in chronic anemia