skeletal system

Question 1

compact bone tissue

Answer 1

composed of osteons= structural units of compact bone

Question 2

spongy bone tissue

Answer 2

like a honeycomb, composed of needle- like structures called trabeculae= structural unit of spongy bone

Question 3

epiphyses

Answer 3

expanded ends of the long bones
spongy bone surrounded by a thin layer of compact bone

Question 4

diaphysis

Answer 4

• shaft, long axis of a long bone
  composed of a thick collar of compact bone which surrounds a medullary cavity- contains red bone marrow in childhood and yellow bone marrow in adulthood
• membranes: endosteum and periosteum

Question 5

hematopoiesis

Answer 5

the process by which blood cells and platelets are formed, occurs only in the red bone marrow.

Question 6

endosteum: connective tissue membrane

Answer 6

convers the internal surfaces of bone such as the canals and trabeculae of spongy bone tissue
- it contains:
osteoblast (bone forming cells)
osteoclasts (bone-resorbing cells

Question 7

periosteum

Answer 7

double layered- composed of the outer fibrous layer and the inner osteogenic layer.

Question 7

The fibrous layer(periosteum) is composed of?

Answer 7

irregular connective tissue

Question 8

The osteogenic (or periosteal layer) layer contains?

Answer 8

osteoblasts and osteoclasts

Question 9

the periosteum is attached to compact bone by tough collagenous fibers called the?

Answer 9

Sharpey’s (perforating) fibers

Question 9

Osteoblast

Answer 9

bone-forming cells – secrete bone
tissue

Question 10

osteogenic cells (mesenchymal cells)

Answer 10

give rise
to osteoblasts

Question 11

Osteocytes

Answer 11

mature osteoblasts that reside in lacunae

Question 12

osteoclasts

Answer 12

bone- resorbing cells-destroy/breakdown bone tissue

Question 13

Haversian canal

Answer 13

centreal canal, runs in the core of each osteon, contains blood vessels and nerves

Question 13

perforating or volkmanns canals

Answer 13

connect blood vessels and nerves between the periosteum and the haversian canals

Question 14

lacunae

Answer 14

shallow cativites in the solid bone matrix that house the osteocytes

Question 15

canaliculi

Answer 15

tiny canals that connect lacunae to each other and to the haversian canal to allow for transfer of substances from the blood vessel in the haversian canal.

Question 16

composed of osteons=

Answer 16

structural units of compact bone

Question 17

lamellae

Answer 17

each osteon is an elongated cylinder consisting of concentric tubes called lamellae hence, compact bine is also known as the lamellar bone. The
collagen fibers in adjacent lamellae run in opposite directions to resist twisting

Question 18

ossification (osteogenesis)

Answer 18

begins before birth (prenatal ossification) and continues after birth postnatal ossification. development of the bony skeleton from the embryonic skeleton.
2 forms: prenatal and postnatal

Question 19

space physiology

Answer 19

in micro gravity your bones do not need to support your body. The size and mass of the bones decrease at a rate of 1-2% each month.

Question 20

causes of osteoporosis

Answer 20

-low calcium
lack of physical activity (wolffs law)
family history
gender: women are more likely.
ethnicity: white and Asian peeps more likely

Question 21

bone remodeling

Answer 21

adult bones constantly undergo bone formation on the periosteal surface and bone resorption on the endosteal surface
In healthy adults, the bone density remains constant because
Rate of Bone formation = rate of bone resorption

Question 22

if the rate of resorption outpaces the rate of formation=

Answer 22

osteoporosis

Question 23

rate of bone formation outpaces the rate of bone resorption.

Answer 23

pagets disease

Question 24

functions of bone remodeling

Answer 24

- to maintain calcium homeostasis - to allow for bone repair after fractures

Question 25

comminuted

Answer 25

bone breaks into many fragments. old people and those with brittle bones

Question 26

compression

Answer 26

bone is crushed. common in osteoporotic bones

Question 27

depression

Answer 27

broken bone portion is pressed inward typical of skull fracture.

Question 28

impacted

Answer 28

broken bone ends are forced into each other. common when one attempts to break their fall with outstretched arms.

Question 29

spiral

Answer 29

ragged break occurs when excessive twisting forces are applied to a bone. common sport fracture

Question 30

green stick

Answer 30

bone break incompletely, much in the way a green twig break. common in children, there bones are more flexible than adults.

Question 31

what two factors control bone remodeling?

Answer 31

hormonal control and mechanical stress

Question 32

intramembranous ossification

Answer 32

develops from fibrous CT membrane (derived directly from mesenchyme) and result in the formation of membrane bones = 8 cranial bones and 2 clavicles * all membrane bones are flat bones

Question 33

articular cartilage

Answer 33

capping the ends of the epiphyses of long bones

Question 34

epiphyseal plate

Answer 34

at the junctions of epiphyses and the diaphysis of a long bone (epiphyseal diaphyseal junctions= metaphyses

Question 35

longitudinal bone growth

Answer 35

linear bone growth increases the length of long bones= height

Question 36

appositional bone growth

Answer 36

increases the width/diameter of all bones= long bones, short bones, flat bones, irregular bones

Question 37

ossification that occurs after birth

Answer 37

2 types: Longitudinal bone growth and Appositional bone growth

Question 38

medullary cavity

Answer 38

contains red bone marrow in childhood and yellow bone marrow in adulthood - membranes: endosteum and periosteum

Question 39

prenatal ossification/bone development

Answer 39

occurs before birth; 2 types: intramembranous ossification and endochondral ossification.

Question 40

endochondral ossification

Answer 40

hyaline cartilage is ossified into bone and persists into two areas in the long bone as articular cartilage and the epiphyseal plates

Question 41

factors that control bone remodeling

Answer 41

hormonal control and mechanical stress

Question 42

forms of evidence in support of wolfs law.

Answer 42

Bone attachment sites for active skeletal muscles appear thicker – projections such as trochanters, spines, * Bones of the upper limb often used are thicker than the less used limb – bones in the right arm of a right-handed individual are thicker than bones in the left arm and vice versa * Long bones are thickest in the middle region of the diaphysis where bending stresses are greatest * Bedridden individual not subjected to the stresses of walking or exercises lose bone density * Astronauts who spend appreciably amount of time in space (where there’s no gravity and they cannot walk), lose bone density

Question 43

Mechanical stress

Answer 43

Bones remodel/grow in response to mechanical stresses placed on the bones =WOLFF’S LAW. Bones respond to stresses/forces by increasing the rate of bone formation that outpaces bone resorption. Absence of stresses/forces on bones results in rate of bone resorption outpacing rate of?

Question 44

longitudinal bone growth includes

Answer 44

Involves the epiphyseal plates New hyaline cartilage is added on at the epiphyseal faces of the epiphyseal plates * New bone tissue is added on at the diaphyseal faces of the epiphyseal plates * Results in lengthening of the diaphysis of the long bone = lengthening of the long bone

Question 45

appositional bone growth involves

Answer 45

All bones widen and increase in diameter/thickness via appositional bone growth * Sequence of events: Osteoblasts in the osteogenic layer of the periosteum secrete new bone tissue onto the external surface of the bone Osteoclasts in the endosteum slightly resorb bone tissue in the internal surface of the bone

Question 46

red bone marrow in bone

Answer 46

in medullary cavity in children and in the spongy bone of the epiphysis in both