Connective Tissue

Question 1

what does the connective tissue mainly consist ?

Answer 1

ECM of protein fibers, ground substance, and cells

originate

Question 2

where do connective tissue originate?

Answer 2

from the Mesenchyme – mesoderm

Question 3

what does mesenchyme largely consist ?

Answer 3

viscous ground substance with few collagen fibers and mesenchymal cells

Question 4

Mesodermal cells give rise to ______________ and are the ________ stem cells to other tissues such as blood, vascular endothelium, and muscle

Answer 4

connective tissues, stem cells

Question 5

describe embryonic mesenchyme

Answer 5

• undifferentiated
• large nuclei
• scant collagen (white looking)
• look like floating sperms with tails
• high synthetic activity
• stem/progenitor cells
• spindled shaped like fibroblasts

Question 6

Why do embryonic mesenchyme have large nucleus?

Answer 6

because they are always actively dividing

Question 7

fibroblasts, adipocytes, macrophages, mast cells, adult stem cells, plasma cells, lymphocytes, eosinophils, monocytes, basophils, neutrophils are all cells derived from?

Answer 7

bone marrow

Question 8

fibroblasts, adipocytes, macrophages, mast cells, adult stem cells are all what kind of connective tissue cells?

Answer 8

resident cells

Question 9

plasma cells, lymphocytes, eosinophils, monocytes, basophils, neutrophils are what kind of connective tissue cells ?

Answer 9

transient cells

Question 10

What do transient cells do and give an example

Answer 10

go in and out
ex: from blood –> peripheral tissue

Question 11

what cells secret immunoglobins ?

Answer 11

plasma cells

Question 12

what proteins do fibroblasts secrete ?

Answer 12

• the different types of
  collagen
• elastin / elastic fibers
• proteoglycans
• glycosaminoglycans
• Multi adhesive glycoproteins of the ECM

Question 13

fibroblasts form ________ cells.

Answer 13

fiber

Question 14

What is a characteristic of fibroblasts?

Answer 14

• thin, attenuated cytoplasm
• sharp ends
• resident cells
• large nucleus
• ovoid
• euchromatic (less dense, transcriptionally active)
• prominent nucleolus
  -ER, Golgi Apparatus

Question 15

fibroblast vs. fibrocyte

Answer 15

fibroblast: active cell (euchromatic)
fibrocyte: quiescent (quiet, no function cell (heterochromatic)

Question 16

what are fibroblasts involved in wound healing called?

Answer 16

myofibroblasts

Question 17

where are adipocytes derived from?

Answer 17

mesenchyme/ mesoderm

Question 18

what are the two types of adipocytes, what colors are they, and what are their functions?

Answer 18

unilocular (white) & multilocular (brown)

• storage of neutral fats for insulation and heat generation
• key regulators of energy metabolism
• sensitive to hormones and nervous stimuli

Question 19

What are the chief phagocytic cells of the human body and are found in loose connective tissue or the interstitium?

Answer 19

macrophages

Question 20

where do macrophages derive from?

Answer 20

RBCs ka monocytes that enter the bloodstream from the bone marrow

Question 21

In connective tissue, monocytes differentiate into macrophages also known as…

Answer 21

histiocytes

Question 22

True or False: Macrophages are difficult to identify in routine hematoxylin and eosin (H&E) stained sections.

Answer 22

True

Question 23

Macrophages contain numerous ___________ and are actively
phagocytic for material in connective tissue or interstitium.

Answer 23

residual bodies of lysosomes (numerous folds, fingerlike projections)

Question 24

What feature assists in identifying macrophages ?

Answer 24

indented/kidney shaped nucleus

Question 25

What substances do macrophages ingest in the alveolar interstitium (lung)?

Answer 25

carbon deposits (look like holes/huge pores/pen stabs)

Question 26

What are alveolar macrophages clinically referred to ?

Answer 26

dust cells

Question 27

While the main function of macrophages is to engulf/ digest (phagocytic), they also act as ___________ in immune reactions

Answer 27

antigen presenting cells - ingesting antigens and secreting cytokines that influence immune response, anaphylaxis (swelling of throat, tongue), and inflammation

Question 28

what are the names of the multinucleated foreign body giant cells fuse to make?

Answer 28

Langhans cells

Question 29

True or False: Mast cells are bone marrow-derived

Answer 29

True

Question 30

Are the dense mast cell granules that exhibit metachromasia (certain tissues or cells stain a different color than the dye used) acidophilic or basophilic?

Answer 30

mast cell granules are basophilic

Question 31

what do mast cells release that cause increased vascular permeability and smooth muscle contraction?

Answer 31

histamine

Question 32

what do mast cells release that activate various mediators of inflammation?

Answer 32

serine protease

Question 33

what do mast cells release that attract leukocytes?

Answer 33

eosinophil and neutrophilic chemotactic factors

Question 34

what do mast cells release that direct activities of leukocytes?

Answer 34

cytokines

Question 35

what do mast cells release that are precursors converted to prostaglandins, leukotrienes, and other mediators of inflammation?

Answer 35

phospholipids

Question 36

where are mast cells found?

Answer 36

- near small blood vessels in skin and mesenteries - digestive and respiratory tract

Question 37

after activation, what do mast cells granules extrude?

Answer 37

mediators and generate lipid-derived substances that induce immediate allergic inflammation

Question 38

what do mast cells look like physically?

Answer 38

- nucleus very hard to see - big round purple flowers or black - vascular permeability

Question 39

how can plasma cells be identified?

Answer 39

position of their nuclei and pattern of heterochromatin

Question 40

Why is the plasma cell cytoplasm basophilic?

Answer 40

due to rough ER content

Question 41

Why does the plasma cell membrane have a great amount of rough ER ?

Answer 41

Because the cell is actively synthesizing and secreting protein

Question 42

How many nucleoluses are in the plasma cell ?

Answer 42

1 nucleolus

Question 43

plasma cells are derived from .... and why?

Answer 43

B-lymphocytes to produce immunoglobins for immune system

Question 44

Because plasma cells don't undergo mitosis, they are terminally...

Answer 44

differentiated cells

Question 45

where are plasma cells normally found and what is their life span?

Answer 45

approximately 2 weeks

Question 46

Leukocytes are known as the _______ cells in the connective tissue.

Answer 46

wandering

Question 47

How do Leukocytes leave blood?

Answer 47

by migrating between endothelial cells of venules to enter connective tissue

Question 48

when are leukocytes most numerously seen?

Answer 48

during inflammation response to injury and foreign substances

Question 49

What common leukocyte cell is seen in acute cases?

Answer 49

neutrophils

Question 50

What common leukocyte cells are seen in chronic situations?

Answer 50

lymphocytes & monocytes

Question 51

What common leukocyte cell is seen in parasitic cases?

Answer 51

eosinophils

Question 52

What is the most abundant protein secreted largely by fibroblasts and the key fiber on all connective tissues, epithelial basement membrane and external laminae of muscle and nerve cells?

Answer 52

Collagen

Question 53

How many collagens are there and what are there 3 subgroups?

Answer 53

28 - 4 fibrillar: Types, I, II, III, V - 2 network-forming collagens: Types IV, X - 1 linking/anchoring collagen: Type VII

Question 54

describe Type I Collagen

Answer 54

- most abundant form of eosinophilic bundles called collagen fibers - connective tissue (dermis in skin, tendon, ligament, bone, & organ capsules) - fibrillar

Question 55

describe Type II Collagen

Answer 55

- found in cartilage and vitreous body - fibrillar

Question 56

describe Type III Collagen

Answer 56

- argyrophilic reticular fibers - found in skin, muscle, blood vessels - fibrillar

Question 57

describe Type V Collagen

Answer 57

- fetal tissue, skin, bone, placenta, & interstitial tissue - fibrillar

Question 58

describe Type IV Collagen

Answer 58

- basal & external lamina - supports epithelial cells - serves as filtration -network-forming

Question 59

Describe Type X Collagen

Answer 59

- hypertrophic zone in endochondral bone formation, increasing bone density -network-forming

Question 60

Describe Type VII Collagen

Answer 60

- epithelial basement membrane -anchors the basal lamina to underlying reticular lamina

Question 61

What is collagen secreted by?

Answer 61

fibroblasts

Question 62

How does collagen appear in histology?

Answer 62

overlapping paint brush look - dark and light bands

Question 63

What does Masson Trichrome stain and what color does it appear?

Answer 63

Masson Trichrome stains collagen - collagen bundles appear blue

Question 64

What Type Collagen do reticular fibers consist of ?

Answer 64

Type III Collagen

Question 65

What do reticular fibers form?

Answer 65

an extensive network called reticulum

Question 66

What color are reticular fibers stained when impregnated with silver salts?

Answer 66

black

Question 67

why are reticular fibers termed argyrophilic ?

Answer 67

because they have a high affinity for silver salts and can be stained by them

Question 68

Why do reticular fibers stain also stain with PAS?

Answer 68

due to high sugar chains bound to Type III Collagen

Question 69

what are reticular cells

Answer 69

fibroblasts that produce reticular fibers

Question 70

where are reticular cells found?

Answer 70

- reticular lamina of basement membrane - surrounding adipocytes, smooth muscle, nerves, & blood vessels - supporting stroma for liver & endocrine glands - adrenal cortex - stroma of hemopoietic tissue (spleen, lymph nodes)

Question 71

what do reticular fibers sort of look like?

Answer 71

frog eggs, silver stain, black fibers

Question 72

what are elastic fibers?

Answer 72

thin fibers that form sparse networks interspersed among collagen bundles

Question 73

Why are elastic fibers seen in organs that are subjected to stretch and bending?

Answer 73

due to their rubberlike properties

Question 74

what are elastic fibers called in very large arteries?

Answer 74

elastic lamellae

Question 75

what does fibrillin form?

Answer 75

network of microfibrils - embedded in larger mass of cross-linked elastin - many lysine rich regions

Question 76

when fibrillin micro fibrils decompose, ________ converts the lysine amino groups to from a desmosine ring to maintain the rubberlike properties.

Answer 76

lysyl oxidase

Question 77

fibrillin makes ________ that are secreted by fibroblasts and smooth muscle cells

Answer 77

microfibrils

Question 78

_______ is deposited on microfibrils and forms an _______________ structure

Answer 78

elastin, amorphous

Question 79

in a hematoxylin & orcein stain, how can one identify elastic fiber?

Answer 79

dark stained, thin amongst pink acidophilic collagen fibers - look wavy in H&E stains between multiple nuclei of smooth muscle cells

Question 80

describe ground substance

Answer 80

viscous clear substance with slippery feel and high water content

Question 81

what are the 3 major divisions of connective tissue?

Answer 81

1.Connective tissue proper 2. Embryonic connective tissue 3. Specialized connective tissue.

Question 82

What are the 2 types of Connective tissue proper?

Answer 82

Loose and Dense (irregular & regular)

Question 83

describe loose connective tissue

Answer 83

aka areolar tissue - found below lining epithelial and fills spaces between tissues

Question 84

describe connective tissue

Answer 84

contains fibroblasts & increased bundles of Type 1 Collagen

Question 85

how can you distinguish dense irregular and dense regular connective tissue?

Answer 85

irregular: collagen fibers interwoven, dermis, capsules regular: collagen arranged parallel, tendons, aponeuroses, ligaments

Question 86

blood and lymphatic vessels found in Connective Tissue