CONNECTIVE TISSUE

Question 1

What are the characteristics of connective tissue?

Answer 1

They have large amount of ECM
cells are widely separated
Connects the cells, tissues and organs together
Provides support to the organ and body

Question 2

What are the components of CT?

Answer 2

Fibres (collagen, reticular, elastic), ground substances which consist of glycosaminoglycans, proteoglycan, glycoprotein and cells which can be permanent or wandering.

Question 3

What are the permanent cells present in CT

Answer 3

Fibroblasts, adipocyte, macrophages, mast cells

Question 4

What are the wandering cells

Answer 4

Lymphocytes, plasma cells, neutrophils, eosinophils, basophils, monocytes

Question 5

Where do fibroblasts and adipocytes locate from?

Answer 5

Mesenchymal cells

Question 6

Where do macrophages and mast cell originate from?

Answer 6

Haemopoitic stem cells in bone marrow

Question 7

State characteristic features of fibroblasts

Answer 7

Is the principal cell of connective tissue. Has abundant cytoplasm and is irregularly branched. Nucleus is ovoid, large and pale stained with a prominent nucleolus

Question 8

What is the fxn of fibroblasts

Answer 8

Synthesize the fibres and ground substances and growth factors.

Question 9

What is the feature of macrophages

Answer 9

Irregular surface with an oval nucleus.

Question 10

What is the fxn of macrophage

Answer 10

Phagocytosis of bacteria, dead cell debris and foreign substance
Processes antigen and presents to lymphocytes

Question 11

What is the feature of plasma cells

Answer 11

Large ovoid cells derived from B-lymphocytes with a spherical eccentric appearance due to heterochromatin clumps

Question 12

What is the function of plasma cells

Answer 12

Synthesizes antibody in response to antigens presented by macrophages

Question 13

What is the feature of mast cells

Answer 13

Abundant basophilic secretory granules containing chemical mediators for allergic reactions. (Histamine, heparin, proteoglycans, ECF-A, SRS-A)

Question 14

What is the fxn of mast cells

Answer 14

Synthesis and secretion of chemical mediators in response to allergic reaction.

Question 15

What is the function of adipocytes cell

Answer 15

Storage of lipids, large storage of energy and heat

Question 16

What are the two types of adipocytes

Answer 16

Unilocular fat cell which is a white adipose tissue with a signet ring appearance

Multilocular fat cell which is a brown adipose tissue which is common in newborns and is a bundant in mitochondria

Question 17

How are fibres formed?

Answer 17

Alpha polypeptide chain arranges to form a collagen molecule as triple helix, the collagen molecules polymerise to form fibrils. The fibrils bundle up to form fibres

Question 18

What are the characteristics of collagen fibres

Answer 18

Most abundant proteins in the body
Collagen 1 fibres are the strongest and present in bones tendons, capsules of organs, dermis
Collagen 2 fibres are present in cartilage
The fibres have high tensile strength and low elasticity.

Question 19

Explain appearance of collagen fibres

Answer 19

White in appearance, acidophilic stain.

Question 20

What are the characteristics of reticular fibres

Answer 20

Made of collagen 3 fibres and are common in haemopoitic and lymphatic tissue
Fibrils are thin, branching and extensive network and do not bundle to form fibres

Question 21

What is the appearance of reticular fibres under microscope

Answer 21

They are agyrophilic, stains black with silver stain.
In H&E stain is not seen.

Question 22

What are the characteristics of elastic fibres and where are they found

Answer 22

Predominant in dermis, elastic cartilage, lung, large artery
Elastic fibres allow tissues to respond to stretch and distension
Stretch and recoil

Question 23

What is the appearance of elastic fibres under microscope

Answer 23

Macroscopically yellowish in colour
Arranged in branching patterns
Elastic fibres poorly stained with eosin in H&E stain
Special dye, orcein, resorcin-fuschin stain elastic fibres selectively
Elastin protein molecules are in extensive cross-linked network

Question 24

Explain main characteristics of ground substances

Answer 24

Colourless and transparent jelly like liquid that is highly hydrated and holds a lot of water that acts as both a lubricant and a barrier to the penetration of invaders like foreign bodies and bacteria

Question 25

Explain glycosaminoglycans in ground substances

Answer 25

Glycosaminoglycans are unbranched polysaccharides They are hydrophilic bc of abundant hydroxyl, carboxyl, sulfates in chain Linear chains are bound to protein core forming proteoglycans except hyaluronic acid

Question 26

Explain proteoglycans

Answer 26

GAGs are bound to a protein core forming proteoglycans

Question 27

Explain glycoproteins structure and function

Answer 27

Are polypeptide chains attached with branched chains of monosaccharides They have multiple adhesive sites that play the important role in the interaction between cells and adhesion of other cells to their substrates.

Question 28

What are the functions of CT

Answer 28

Connects and bind tissues, organs, etc Structural support of organ and body Defense and protection Medium for exchange of nutrients and metabolites Energy reservoir and heat production

Question 29

What are the components of loose connective tissue

Answer 29

Ground substance, cells are mostly fibroblasts and macrophages

Question 30

What is the fxn of LCT

Answer 30

supports the lining epithelium that are normally under pressure or friction Forms a layer that sheathes blood vessels

Question 31

What are the characteristics of dense connective tissue

Answer 31

Collagen fibres dominanr and very few cells Less flexible and more resistant to stress

Question 32

Explain dense regular connective tissue structure

Answer 32

Collagen bundles are arranged in regular pattern

Question 33

Explain function of dense regular connective tissue and give examples

Answer 33

Great resistance to stresses in longitudinal direction, example : tendon and ligament.

Question 34

Explain structure of dense irregular connective tissue

Answer 34

Bundles of fibres are irregularly arranged

Question 35

Explain function of dense irregular connective tissue and give an example

Answer 35

Offere great resistance to stresses in all direction, example : dermis.

Question 36

Explain embryonic connective tissue structure (mesenchyme)

Answer 36

Mesenchymes found in embryo are abdundant in thick ground substance with very fine and sparse reticular collagen fibres

Question 37

Explain the structure of mucous embryonic connective tissue

Answer 37

Gelatin like ground subtance with very fine reticular collagen fibres. They are spindle shaped.