Test 1 - Lecture 5 (connective)

Question 1

Where is connective tissue located?

Answer 1

underlies or surrounds muscle, nervous, and/or epithelial tissues

Question 2

What items are found in the connective tissue?

Answer 2

cells & extracellular matrix (ECM)

Question 3

What are 4 ways that connective tissue differs from epithelial tissue?

Answer 3

1. cells not attached to each other
2. cells are more randomly distributed
3. space between cells is ECM
4. embryonic origin is all 3 germ layers (epithelium is only mesoderm)

Question 4

How is connective tissue classified?

Answer 4

by composition and organization of cellular and extracellular components and special functions

1. types of cells present
2. types of fiber present
3. ground substance components

Question 5

What is connective tissue proper?

Answer 5

How packed the fibers are and amount of ground substance

Question 6

Describe the appearance of/what is found in loose connective tissue.

Answer 6

1. thin, sparse collagen fibers
2. lots of cells
3. lots of ground substance
4. viscous, gel-like

Question 7

Where is loose connective tissue found?

Answer 7

1. beneath epithelial mucosa and serosa
2. associated epithelial glands
3. around small blood vessels

Question 8

Describe the appearance of/what is found in dense irregular connective tissue.

Answer 8

1. mostly collagen fibers in bundles
2. bundles in varying directions
3. sparse cells
4. little ground substance

Question 9

Where is dense irregular connective tissue found?

Answer 9

1. submucosa of hollow organs
2. reticular layer of dermis

Question 10

Describe the appearance of/what is found in dense regular connective tissue.

Answer 10

1. sparse cells
2. many collagen fibers
3. fibers have organized parallel arrangement
4. little ground substance

Question 11

Where is dense regular connective tissue found?

Answer 11

1. tendons
2. ligaments
3. aponeurosis

Question 12

What features would help you distinguish between loose and dense irregular?

Answer 12

1. amount of cells (loose has more)
2. amount of fibers (dense irregular has more)
3. ground substance (loose has more

Question 13

Describe the appearance of collagen fibers with light microscopy vs. electron microscopy.

Answer 13

EM: highly striated tube-like structures

LM: eosinophilic w/ H&E (glycine and hydroxy p have positive charge)

Question 14

How is collagen produced (short version-6)?

Answer 14

1. mRNA formed in nucleus
2. synthesis of pro-a chains on rER
3. hydroxylation of proline & lysine
4. glycosylation of specific hydroxylysl residues
5. formation of procollagen triple helix
6. helixes wrap to make full fiber

Question 15

Type 1 collagen fiber

Answer 15

1. loose and dense C.T.
2. 90% collagen
3. heterotrimeric
4. gives resistance to force, tension, strength
5. fibrillar

Question 16

Type II collagen fiber

Answer 16

1. hyaline and elastic cartilage
2. resistance to pressure
3. fibrillar
4. homotrimeric

Question 17

Type III collagen fiber

Answer 17

1. loose C.T.
2. makes reticular fibers
3. fibrillar
4. support scaffold for specialized cells

Question 18

Type IV collagen fiber

Answer 18

1. basal lamina
2. support & filtration barrier
3. not fibrillar
4. sheet forming

Question 19

Type VII collagen fiber

Answer 19

1. anchoring fibrils of skin, eye, uterus, esophagus
2. not fibrillar
3. secure basal lamina to C.T.

Question 20

Describe reticular fibers and why they do not stain well with H&E.

Answer 20

1. type III
2. 20 nm
3. branching (tree)

it doesn’t stain well because all sugar groups in type III (no charge)

Question 21

Describe elastic fibers and why they do not stain will with H&E.

Answer 21

1. branching but thin like hair
2. make a network with elastin and fibrillin

cannot be easily differentiated with collagen fibers in H&E

Question 22

Consider the 3 fiber types (collagens, reticular, elastic). What are their functions and how does structure and function go together?

Answer 22

1. collagen: tension & strength (big & “braided)
2. reticular: support scaffolding & lymphatic system (branching network)
3. elastic: keep from overstretching (thin, wiry, network)

Question 23

How would you differentiate collagen and elastin fibers using electron microscopy?

Answer 23

collagen fibers are in individual fibers all clumped to make up one big one and elastin is all one big fiber with rough surface

Question 24

What is ground substance and what is it made of?

Answer 24

It is the space between cells and fibers

1. water
2. proteoglycans
3. multiadhesive glycoproteins
4. glycosaminoglycans (GAGs)

Question 25

Describe proteoglycans.

Answer 25

large molecules with protein core and many long chain polysaccharides (GAGs) covalently bonded to the core.

Question 26

What are the different types of glucosaminoglycans?

Answer 26

In cartilage: 1. hyaluronic acid 2. heparin sulfate 3. chondroitin 4- & 6- sulfate In other places: 4. heparin 5. dermatan sulfate 6. keratan sulfate

Question 27

What are multiadhesive glycoproteins and what are their functions?

Answer 27

protein + small sugar group 1. stabilized ECM & link to cell surface 2. regulate functions of ECM to cell movement & migration 3. stimulation of cell proliferation and differentiation

Question 28

What are the multiadhesive glycoproteins?

Answer 28

1. Fibronectin 2. Laminin 3. Tenascin 4. Osteopontin

Question 29

Fibronectin

Answer 29

cells attach to ECM (most abundant)

Question 30

Laminin

Answer 30

attaches tissues together (basal lamina of BM)

Question 31

Tenascin

Answer 31

embryonic (except injury/cancer)

Question 32

Osteopontin

Answer 32

specific to bone - attaches osteoclast to bone spicule (bone reabsorption & remodeling)

Question 33

What are the fixed cell populations in connective tissue?

Answer 33

1. fibroblasts & myofibroblast 2. mononuclear phagocytic system 3. mast cells 4. adult stem cells & pericytes 5. adipocytes

Question 34

What does a fibroblast do and are these a fixed cell population?

Answer 34

Yes. 1. make and secrete collagen, elastic, reticular fibers & complex carbs of ground substance 2. make majority of ECM & ground 3. activated in growth and wound repair

Question 35

What are the functions of the MPS cells and are these a fixed cell population?

Answer 35

Yes 1. phagocytosis 2. secretion 3. antigen processing and presentation

Question 36

What do mast cells do and are they a fixed population?

Answer 36

Yes 1. mediate hypersensitivity, reactions, allergies, and anaphylaxis 2. secrete histamines & leukotriene

Question 37

Is adipose tissue solely for storage of lipids?

Answer 37

No, white provides insulation, cushioning for vital organs, and hormone secretion

Question 38

Do brown adipocytes and white adipocytes arise in the same manner?

Answer 38

No, they have differing cell lineage, but both are from mesenchymal cells. white - perivascular stem cells brown - skeletal myogenic progenitor cell - transdifferentiation

Question 39

Where does one find white adipose tissue?

Answer 39

1. subcutaneous C.T. 2. greater omentum 3. mesentery 4. kidneys 5. palms, soles 6. orbit around eyeballs

Question 40

What are some possible harmful effects of too much white adipose?

Answer 40

1. increase eating (indirectly with leptin) 2. increase inflammation 3. increase blood pressure

Question 41

Are white adipocytes true "cells"?

Answer 41

They have all the features of a "true cell" except for a plasma membrane... instead membrane similar to external lamina

Question 42

What does it mean for brown adipose to be multi-ocular?

Answer 42

multi-ocular brown has multiple small sacs of lipids uni-ocular white has one large sac of lipid

Question 43

What is the function of brown adipose tissue?

Answer 43

heat production

Question 44

Would you expect and adult human to have much brown adipose?

Answer 44

No, high in children/newborns (baby fat) and hibernating animals