Lecture 3; Connective tissue

Question 1

Function of connective tissue

Answer 1

• binds, supports and strengthens other body tissues
• a major transport system of the body (blood)
• a major site of stored energy reserves (adipose)

Question 2

features of connective t

Answer 2

unlike epithelium; not found on body surfaces, CT is highly vascular. Like epithelium, CT has nerves (except cartilage)

Question 3

what is CT compose off?

Answer 3

ECM and cells

Question 4

what ECM composed off?

Answer 4

Ground substance and protein fibres

Question 5

what is ground substance made out off?

Answer 5

water, protein and polysaccharides (including GAGs)

Question 6

Describe proteoglycans

Answer 6

Made up of proteins and GAGs

Question 7

describe glucosaminoglycans (gags)

Answer 7

• otherwise called mucus polysaccharides
• long, unbranched polysaccharides
• repeating disaccharide unit
  (ie. an amino sugar and a uronic sugar)

Question 8

what is the repeating unit of hyaluronic acid?

Answer 8

amino sugar - N acetyl glucosamine

uronic sugar- glucuronic acid

Question 9

Give examples of glucoaminoglycans

Answer 9

Sulfated GAGs- dermatan sulphate, keratan sulphate, heparin and chondroitin sulphate. these bind to proteins to form proteoglycans
Non-sulfated GAGs- hyaluronic acid (not covalently bound to a core protein)

Question 10

What is the function of GAGs?

Answer 10

collectively they trap water making the substance jelly like

Question 11

application of hyaluronic acid

Answer 11

viscous slippery substance that binds cells together, lubricates joints and maintains shape of eyeball

Question 12

Application of chondroitin sulphate

Answer 12

support and provide adhesive features of cartilage, bone, skin, blood vessels

Question 13

application of Keratan sulphate

Answer 13

found in bone, cartilage and cornea of the eye

Question 14

Application of dermatan sulphate

Answer 14

found in skin, tendons, blood vessels, heart valves

Question 15

What is hyaluronidase?

Answer 15

produced by WBC, sperm and some bacteria. Makes ground substance more liquid so that they can move more easily in it and makes access to the egg easier for the sperm

Question 16

Describe exopthalmos

Answer 16

periorbital ECM deposition and thyroid disease
-most common in younger women, associated with goitre, autoimmune over-activation of thyroid (goitre), autoimmune action of fibroblasts in ECM of the eye.The deposition of GAGs and the influx of water increase periorbital contents

Question 17

What are the 3 types of fibres in CT?

Answer 17

produced by the cells of the CT; collagen, reticular and elastic fibres

Question 18

describe collagen fibres

Answer 18

very strong and flexible to resist pulling forces; features vary in different tissues (ie. more water around collagen in cartilage than bone); most abundant protein of your body (25%); common in bone, cartilages, tendons and ligaments; occur in parallel bindles

Question 19

Reticular fibres description

Answer 19

composed of collagen with a coating of glycoproteins; collagen in fne bundles (with glycoprotein coating); made by fibroblasts; strength and support; are part of BM; thinner, branching and spread through the tissue; form networks in vessels through tissue, especially adipose tissue, nerve fibres, smooth muscle tissue

Question 20

Elastic fibres description

Answer 20

thinner than collagen fibres; fibrous network; consists of the protein elastin surrounded by glycoprotein fibrillin to give strength and stability; can be stretched up to 150%; found in skin, blood vessels and lungs

Question 21

Marfan syndrome

Answer 21

hereditary defect in elastic fibres usually the result of a dominant mutation that codes for fibrillin; TGFb is a growth factor produced by the body and doesn’t bind to fibrillin to keep it inactive
individuals usually tall and long limbed; have a chest deformity; normal lifespan but needs medical vigilance; may have weakened heart valves and arterial walls; 1 in 20,000 live births

Question 22

Fibroblasts location and function

Answer 22

one of 2 most common CT cells
location: widely distributed in CT; is migratory cells
Function: secrete components of the matrix (fibres and ground substance)

Question 23

Adipocytes location and function

Answer 23

second most common cell in CT
Location: under the skin and around organs
Function: stores fat

Question 24

macrophages (histiocytes) location and function

Answer 24

Location: phagocytic cells; fixed and wandering forms of CT.
Function: fixed cells in CT (dust cells-lungs; kupffer cells-liver; Langerhans cells-skin)
Wandering in CT (sites of infection/inflammation/injury)

Question 25

Mast cells function

Answer 25

Produced from B-lymphocytes and they produce antibodies.

Found in many CT sites but especially in gut and lungs, salivary glands, lymph nodes, spleen, red bone marrow

Question 26

Leucocytes

Answer 26

White blood cells (ie. neutrophils and eosinophils). Migrate out of blood.