Connective Tissue

Question 1

Where do you find the 3 different kinds of connective tissue proper?

Answer 1

Loose connective tissue- deep to epithelium
Dense regular- tendons
Dense irregular- deeper below epithelium than loose, in various organs

Question 2

Role of a fibroblast?

Answer 2

Fibroblasts produces and releases collagen, elastic fibers, and reticular (mesh-like) fibers

Question 3

1. When would loose connective tissue be called lamina propria?
2. Texture of loose connective tissue?
3. Is it vascularized?
4. Function?

Answer 3

1. When the epithelium it is deep to is mucous releasing
2. Gel like (viscous)
3. Yes, it exchanges contents between blood and epithelium (which is unvascularized)
4. Forms second line of defense (after epithelium) against invading pathogens/foreign substances and contains various types of blood/immune cells (outside blood vessels)

Question 4

When looking at a slide, how would you be able to differentiate between epithelium, LCT, and DCT?

Answer 4

Epithelium is most superficial and has the most cells
LCT is intermediate and has dark staining nuclei of cells and low density of ECM
DCT is similar but a higher density of blue staining fibers (and less cells and can sometimes look wavy)

Question 5

Glandular cells vs. secretory cells

Answer 5

Glandular is epithelium that has been rolled into a tube; secretory cells are basically one cell versions of a gland

Question 6

1. How to identify regular connective tissue from a picture?

Answer 6

1. It is all aligned on one axis

~check out this PowerPoint before lab practical to review pictures~

Question 7

Fibroblasts also produce molecules of ground substance. What does this mean and give some examples

Answer 7

Refers to more types of ECM material, dominated by glycoaminoglycans but also includes proteoglycans and multi-adhesive glycoproteins

Question 8

A single collagen protein is modified by attaching what three amino acids?

Answer 8

Glycine, proline, and hydroxyproline

Question 9

Broad organization for bundling of collagen

Answer 9

Single collagen protein -> collagen proteins wound together to form triple helix -> helices are cross linked to form a fibril -> fibrils bundle to form fibers

Question 10

1. Name one place in the body where collagen fibers are located?
2. Function of reticular fibers?
3. What kind of adhesions does collagen form?
4. Function of collagen?

Answer 10

1. Tendons
2. Similar to cartilage except thinner; they provide scaffolding for tissues and organs
3. Cell to cell junctions (focal adhesions and hemidesmosomes) for anchoring basal surface of epithelial cells to basal lamina (connective tissue)
4. Resists pressure or tension exerted on the cell

Question 11

VERY broad pathway of collagen synthesis?

Answer 11

Modify protein intracellularly (in rER), golgi modifies some more then secretes it to extracellular environment where collagen gets bundled together

Question 12

Disorders of collagen production:

1. Osteogenesis Imperfecta is caused by a gene mutation that causes?
2. ____ (Type IV, VI, VII)
3. Scurvy is caused by vitamin C deficiency that impairs?

Answer 12

1. Weak tendons (so affects connective tissue) and bones
2. Ehlers-Danlos - problem for collagen and/or connective tissue
3. Impairs proline hydroxylase

Question 13

Fibroblasts generally produce reticular fibers except where in the body? What produces them there?

Answer 13

In lymphatic system organs, reticular cells make reticular fibers

Question 14

Elastic fibers are NOT collagen

1. Elastic fibers are composed of many ?
2. This protein that composes elastic fibers is what kind of protein? How is it synthesized?

Answer 14

1. Elastin proteins cross linked (by help of fibrillin protein) to each other in a mesh like arrangement
2. Glycoprotein synthesized by fibroblasts and secreted into ECM

Question 15

1. Name some places in the body where elastic fibers are located?
2. What enzyme degrades elastic fibers? Why?
3. Clinical dysfunction that has to do with elastic fibers? Brief overview

Answer 15

1. Skin, interior wall of arteries and aorta, some ligaments (vertebral column, and larynx
2. Elastase because elastic fibers are highly resistant to breakdown by common mechanisms (like heat and acid)
3. Marfans syndrome: elastin is not organized effectively due to mutation in fibrillin gene

Question 16

1. Main function of glycoproteins
2. Two most common?
3. ~. Glycoproteins are part of __ produced by ___~

Answer 16

1. Cell to cell junctions (between basal surface of epithelium and connective tissue)
2. Fibronectin and laminin (bind with collagen to connect to junctions)
3. Ground substance; fibroblasts

Question 17

1. Glycosaminoglycans (GAGs) attach to a core protein to form ____ which does what?
2. Name a specific type of GAG
3. Main function of GAGs?

Answer 17

1. A proteoglycan which attach GAGs to collagen fibers via linker proteins
2. Hyaluronan
3. Shock absorbers (because of viscous ECM) and regulates movement of macromolecules and cells through ECM

~ look at slide to see common names to recognize of GAGs ~

Question 18

1. Myofibroblasts are a type of ___; function?
2. Myofibroblasts contain 2 key proteins __ and ___; similar to those found in ___
3. Clinical correlation?

Answer 18

1. Fibroblast; have contractile proteins that allow the entire cell to contract and recoil and can apply traction to the surrounding tissue
2. Alpha smooth muscle actin (alpha- SMA) and form of myosin (that acts as a motor protein); muscle
3. Dupuytrens Contracture- myofibroblasts create scar tissue which leads to abnormal contraction of connective tissue in parts of the palmar aponeurosis

Question 19

Function of the blood cells present in connective tissue:

1. Macrophages
2. Mast cell
3. Plasma cells
4. 3 other blood cells present?

~look at slides to be able to recognize these in a picture

Answer 19

1. Phagocytosis of pathogens and present antigens on their cell membrane to activate immune cells
2. Inflammation, immune responses, allergic reactions (release histamine, proteases, etc.)
3. Make and release antibodies against foreign substances
4. Basophils, eosinophils, neutrophils