Lecture 2 - Bone Remodeling Flashcards Preview

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Flashcards in Lecture 2 - Bone Remodeling Deck (28)
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1
Q

_____ canals are the central canals that form in the center of osteon units. ____ essentially wrap around these vascular pores, forming the cortical bone around it.

A

Haversion

Lamellae

2
Q

Trabeculae in heads of long bones, like the femur, take on an _____ formation that distributes the load the bone bears,

A

Arcade

3
Q

At 26 days development, upper _____ buds appear, which are important for patterning of the musculoskeletal system.

A

Upper Limb Buds

4
Q

At about 32 days development, first ______ contractions are observed, and are important for developing the proper function of joints.

A

Muscle

5
Q

The cranium and shoulder girdle are formed from embryonic ____, the post cranial skeleton (the rest of the bones) is formed from embryonic _____.

A

Ectoderm

Mesoderm

6
Q

Collagen synthesis begins with the generation of procollagen ____ chains with _____ ends, which are what allow the coiling of the collagen molecule into triple helicies. Once the collagen molecules are secreted out of the cell, the _____ ends are cleaved to allow for proper arrangement of the molecules into fibrillar structures which are reinforced by covalent cross-linking facilitated by the enzyme ____ oxidase.

A

Alpha chains

Propeptide

Propeptide

Lysyl oxidase

7
Q

_____ are the cells primarily responsible for creation of cartilage. They are derived from _____ stromal cells. As it matures, it moves into the _____ (newly formed boned), and then differentiates into ______ as it moves into the mineralized bone.

A

Osteoblasts

Mesenchymal stromal cells

Osteoid

Osteocytes

8
Q

Type ___ collagen is comprised of two alpha I strands and one alpha II strand. The 300nm periodicity of collagen “striping” is very important to the structure and function of the collagen fibers, allowing them to bend and kink. The overlapping region accounts for about ___% of the tropocollagen length. Together with the Lacunar region, this accounts for exactly ___nm.

A

Type I collagen

10%

67nm

9
Q

Cartilage is comprised of Type ___ collagen.

A

Type II

10
Q

The energy that it takes to cause bone to fail is termed _____.

A

Toughness

11
Q

______ refers to cells’ ability to sense and respond to mechanical events. It has three main components:

  1. ______ –> cells’ detection of mechanical stimulus outside of cells and relay message inside.
  2. ______ –> biochemical and cytoskeletal relaying of the message within the cells.
  3. ______ –> signal reaches its target, the target is activated, causing alterations in cell behavior.
A

Mechanotransduction

  1. Mechanoreception
  2. Signal Transmission
  3. Target Activation
12
Q

_____ are dynamic structures that grown and shrink. They are found in ____ and ____ and are often associated with molecular motors that transport intra-cellular vesicles.

A

Microtubules

Cilia and Flagella

13
Q

_____ (actin filaments), are comprised of ____ and ____. They are more mechanical in structure, and are found adjacent to the cell _____.

A

Microfilaments

F-actin

G-actin

cell Membrane

14
Q

_____ junctions connect cells in epithelial tissue, and are important in mechanical signal transduction between cells.

A

Adherens

15
Q

_____, the “all purpose glue,” connects the cytoskeleton/nucleus to the ECM, allowing for mechanical signal transduction.

A

Fibronectin

16
Q

_____ is a component of the ECM that helps retain _____, increasing cellular resistance to compression.

A

Proteoglycan

Water

17
Q

_____ are transmembrane proteins that bind the cell to the ECM.

A

Integrins

18
Q

Cellular response to mechanical signals begins with a _____ receiving the stimulus from the ECM –> the _____ relays the signal to the nucleus –> DNA is trancribed into RNA –> RNA is translated in the ____ –> proteins are assembled and modified in the _____ –> these proteins are secreted

A

Mechanoreceptor

Cytoskeleton

ER

Golgi

19
Q

Osteocytes connect with one another via _____ protrusions, while their cell bodies reside in the ____.

A

Canalicular

Lacunae

20
Q

_____ progenitor cells give rise to _____, while ______ progenitors give rise to all of the other orthopedic tissues (bone, muscle, cartilage, tendons/ligaments, and fat.)

A

Hematopoietic progenitors

Osteoclasts

Mesenchymal progenitors

21
Q

Interestingly, pre-_____ give rise to both _____ and adipocytes.

A

pre-Osteoblasts

Osteoblasts

22
Q

Deficiency of BRM-SWI/SNF favors _____ lineage of MSCs and confers resistance to _______.

A

Osteoblast

Osteoporosis

23
Q

Remember that osteoclasts are _____-nucleate.

A

Multi-nucleate

24
Q

In order to resorb the mineralized bone, osteoclasts secrete hydrogen and _____, which is prevented from leaking out laterally by an _____ ring.

A

Chloride

Actin

25
Q

HSCs congregate in niches within bone marrow and associate with _____ cells (particular osteoblasts.) They mobilize from _____ niches to _____ niches in response to fibroblast growth factor 4 (FGF4) and O2.

A

SNO cells

Endosteal niches

Stromal niches

26
Q

VitD3, PTH, and IL-___, factors that drive the differentiation of HSCs to _____, are secreted by _____ and stromal cells. Also, M-CSF is produced by stromal cells, which causes HSCs to differentiate into monocyte/macrophage cells –> these bind to ____, which is produced and expressed on the stromal cell membrane –> causes differentiation into ______ precursors –> acted on by M-CSF to commit to _____ differentiation, but they are not considered _____ until they fuse and exhibit at least 3 nuclei.

A

IL-11

Osteoclasts

Osteoblasts

RANKL

Osteoclast

Osteoclast

Osteoclasts

27
Q

____ is a factor secreted by osteoclasts that competitively inhibits monocyte/macrophage cells from binding ____, and thus from differentiating into osteoclasts.

A

OPG

RANKL

28
Q

A factor necessary for MSC differentiation into pre-osteoblasts is _____. It also facilitates differentiation of pre-osteoblasts into osteoblasts. Another factor that does the latter is _____.

A

Runx2

Osx