Exam 3: Lecture 10

Question 0

What 3 ways can connective tissue be classified?

Answer 0

Type of matrix
Fiber density
Fiber organization

Question 1

What are characteristics of connective tissue?

Answer 1

Few cells
Abundant matrix
Matrix contains varying protein fiber amounts

Question 2

What are the major connective tissue classes?

Answer 2

Loose
Dense
Reticular
Elastic

Question 3

What are the characteristics of Loose connective tissue?

Answer 3

High ratio of fibroblasts to fibrous components
Type I collagen
Found beneath epithelial tissues of most organs

Question 4

What are the characteristics of Dense connective tissue?

Answer 4

High ratio of fibrous components to fibroblasts
Thicker bundles of collagen than loose CT
Dense irregular CT has no specific orientation
Dense regular CT has highly ordered bundles

Question 5

What are the characteristics of Reticular connective tissue?

Answer 5

Forms stroma of spleen and lymph nodes, allows cells to be packed in between fibers

Question 6

What are the characteristics of Elastic connective tissue?

Answer 6

Highly specialized, not found in many places in body

Question 7

What are the special types of connective tissue?

Answer 7

Adipose
Cartilage
Bone
Hematopoietic

Question 8

What are the 3 cellular components of connective tissue?

Answer 8

Fibroblasts/Fibrocytes
Glycosaminoglycans
Adipocytes

Question 9

T/F: Fibroblasts/Fibrocytes are the least common cell in connective tissue?

Answer 9

False, they are the most common cell in connective tissue

Question 10

What are the functions of fibroblasts/fibrocytes?

Answer 10

Secretion & maintenance of CT matrix
Secrete precursor fibrous molecules
Secrete amorphous components of matrix, including glycosaminoglycans

Question 11

What are glycosaminoglycans?

Answer 11

Large, negatively charged polysaccharides consisting of repeating disaccharide units

Question 12

What are the 4 groups of glycosaminoglycans?

Answer 12

Hyaluronic acid
Heparin/Heparan sulfate
Chondroitin/Dermatan sulfate
Keratan sulfate

Question 13

Where is Hyaluronic acid found?

Answer 13

Cartilage, skin, synovial fluid, general CT

Question 14

Where are Heparin/Heparan sulfate found?

Answer 14

Basement membrane, skin, lung, liver, blood vessels, mast cell granules

Question 15

Where are Chondroitin/Dermatan sulfate found?

Answer 15

Cartilage, bone, skin, blood vessels, heart, cornea

Question 16

Where is Keratan sulfate found?

Answer 16

Cartilage, cornea, intervertebral disks

Question 17

Describe the structure of a proteoglycan

Answer 17

Hyauronan backbone
Linker proteins connect core proteins
Core protein has extensions of four groups of glycosaminoglycans
Core protein + glycosaminoglycans = proteoglycan

Question 18

What are adipocytes?

Answer 18

Undifferentiated mesenchymal cells

15 times larger than normal cell

Question 19

What are the 2 types of adipocytes?

Answer 19

White fat

Brown fat

Question 20

What are characteristics of White fat?

Answer 20

Unicolar (one lipid droplet)

Distributed throughout body

Question 21

What are characteristics of Brown fat?

Answer 21

Multicolar (numerous lipid droplets)

Abundant mitochondria give brown coloration

Question 22

Describe collagen fiber synthesis

Answer 22

Begin as prepropeptide
Pre- signal sequence cleaved off after translocation into ER lumen
Pro-collagen with terminal, non-helical ends secreted into ECM
Terminal, non-helical ends cleaved to form tropocollagen
Tropocollagen spontaneously assembles into staggered arrays

Question 23

T/F: Elastic fiber synthesis is the same as collagen fiber synthesis?

Answer 23

False, the last step is different
The pro-collagen is converted to tropoelastin instead of tropocollagen and assembles into amorphous fibers or sheets with aid of fibrillin

Question 24

What are the different types of cartilage?

Answer 24

Hyaline Elastic Fibrocartilage

Question 25

T/F: Hyaline cartilage is the most common.

Answer 25

True

Question 26

What are the characteristics of Hyaline cartilage?

Answer 26

Avascular, type II fibers, surrounded by perichondrium, solid but flexible, chondrocytes often found in cell groups

Question 27

Where is Hyaline cartilage found?

Answer 27

External auditory meatus, larynx, trachea, bronchi, fetal long bones, articular ends of bones

Question 28

What are the 2 growth patterns of Hyaline cartilage?

Answer 28

Appositional-Growth on top of existing surface (non-organic things) Interstitial-Growth by adding new material within existing material (unique to living things)

Question 29

What are the characteristics of Elastic cartilage?

Answer 29

Addition of elastic fibers, surrounded by perichondrium, yellow b/c of elastic fibers, more opaque, flexible, & elastic than hyaline, chondrocytes located singly, type II collagen + elastic fibers

Question 30

Where is Elastic cartilage found?

Answer 30

Auricle of ear, epiglottis

Question 31

What are the characteristics of Fibrocartilage?

Answer 31

Increased collagen in matrix, reduced cellularity compared to hyaline, NOT surrounded by perichondrium, opaque appearance from fibrous texture, type I collagen, single sparse chondrocytes

Question 32

Where is Fibrocartilage found?

Answer 32

Intervertebral discs, pubic symphysis, insertion of some tendons/ligaments, closely associated with dense CT or hyaline cartilage

Question 33

T/F: The skeletal systems of all vertebrates begin as cartilage.

Answer 33

True

Question 34

What are the 3 major components of cartilage formation?

Answer 34

Chondroblasts-Produce new matrix (top) Chondrocytes-Maintain matrix (middle) Lacunae-Cells within matrix (lakes) *All are avascular

Question 35

Perichondrium contains an outer _________layer and an inner _________ layer.

Answer 35

Fibrous | Chondrogenic

Question 36

T/F: More hydroxyapatite means weaker, frailer bones.

Answer 36

False, increased hydroxyapatite in the matrix means stronger, more solid bones

Question 37

What are the 3 types of bone?

Answer 37

Woven Compact Spongy

Question 38

Where/when does woven bone occur?

Answer 38

During development and repair

Question 39

What is another name for compact bone?

Answer 39

Lamellar bone

Question 40

What are other names for spongy bone?

Answer 40

Trabecular | Cancellous

Question 41

What are the characteristics of compact bone?

Answer 41

Dense plate on outside of long/flat bones Concentric lamellae (Haversian) encircle central blood vessel forming an osteon (Haversian system) Osteocytes found between lamellae connected to Haversian canal via canaliculi Volkmann's canals run perpendicular to Haversian canals connecting Haversian canals to each other and bone surface

Question 42

What are the characteristics of spongy bone?

Answer 42

3-D lattic of branching, bony spicules intertwined to form trabeculae surrounding bone marrow spaces in long/flat bones

Question 43

What is the macroscopic structure of bone?

Answer 43

Periosteum-Surrounds exterior of bone Marrow/Medullary cavity-Inside bone Endosteum-Lining of marrow/medullary cavity Sharpey's fibers-Connect periosteum to bone matrix

Question 44

What are osteoprogenitor cells?

Answer 44

Stem cells described as bone lining cells in adult Found in inner portion of periosteum, endosteum, & lining vascular canals of compact bone Derived from mesenchyme of embryonic somite and possess mitotic potential Give rise to osteoblasts

Question 45

What are osteocytes derived from?

Answer 45

Osteoblasts and are trapped by the matrix they secrete

Question 46

What are osteoclast cells derived from?

Answer 46

Monocyte linkage, which is derived from monocyte precursors in bone marrow

Question 47

What is ARF?

Answer 47

Activation-resorption-reversal-formation | A cycle that occurs in adult remodeling sites and during development

Question 48

What are the first 5 steps of Osteoblast/Osteoclast regulation?

Answer 48

1) PTH regulates bone turnover 2) Osteoblast formation stimulated by low PTH 3) Osteoclast differentiation factors stimulated from osteoblast at high PTH 4) PTH stimulates monocyte precursors to form osteoclasts 5) Elevated PTH results in erode bone & fibrosis of resulting spaces

Question 49

What are steps 6-9 of Osteoblast/Osteoclast regulation?

Answer 49

6) PTH binds to receptors on osteoblast 7) Osteoblast stimulated to synthesize M-CSF & RANKL 8) M-CSF binds to M-CSF receptor on monocyte near by 9) Monocyte is no macrophage and expresses RANK

Question 50

What are steps 10-13 of Osteoblast/Osteoclast regulation?

Answer 50

10) RANK binds to RANKL making macrophage multinucleated immature osteoclast 11) Osteoblast secretes osteoprotegerin 12) Non-functional osteoclast uncouples from osteoblast and becomes functional osteoclast 13) Calcitonin acts to reduce bone resorption