Connective And Adipose Tissue

Question 1

What are the main cell types found in connective tissue?

Answer 1

Fibroblasts
Chocndrocytes
Osteocytes/osteoblasts
Stem cells/progenitor cells/bone marrow/ bloood/ adipocyte

Question 2

What er the main products of connective tissue?

Answer 2

Fibres
“Ground substance”
Wax and gel-like materials

Question 3

What are the components of connective tissue?

Answer 3

Cells

The extracellular matrix=fibres + ground substance

Question 4

What does ground substance contain?

Answer 4

Proteoglycans

Question 5

What fibres are present in/made by connective tissue?

Answer 5

Collagen
Elastin
Reticular fibres

Question 6

What are the functions of connective tissue? (Give examples)

Answer 6

Binding and supporting (hold skin,lung etc together)
Protecting (bone protect organ, fat as shock absorb)
Insulation (fat under skin, marrow holds warm blood)
Store reserve fuel + cells (marrow and fat)
Transport (blood and interstitial)
Separate tissues (fascia and tendons/cartilage)

Question 7

What is loose connective tissue sometimes known as?

Answer 7

Areolar tissue

Question 8

Give an example of loose connective tissue/

Answer 8

Lamina propria beneath mucosal membranes and abound the basal lamina

Question 9

What is dense connective tissue sometimes known as?

Answer 9

Fibrous or collagenous tissue

Question 10

What are the 2 type of dense connective tissue and what are the differences?

Answer 10

Irregular=fibres run in diff directions

Regular=fibres run parallel to each ther

Question 11

Describe the structure of loose coercive tissue.

Answer 11

Multiple cell types=fibroblast, macrophages, white blood cells, mast cells and adipocytes

Contains 2 main fibres=collagen and elastic

Gel like ground substance

All cells + fibres lie in ground substance and are free to move around as they have room

Question 12

What are the functions of loose connective tissues?

Answer 12

Holds fluid-supplying vessels 
Permits cell migration 
Involved in inflammation pathways 
Act as packaging around organs 
Hold everything in place 
Cushion + stabilise organs

Question 13

Where can loose connective tissue e found?

Answer 13

It’s widely distributed, under epithelial cell layers (such as lamina propria) and around glands. It surround capillaries, nerves and sinusoids.

Question 14

What is a fibroblast and why is it important?

Answer 14

They synthesise and secrete the fibres that lie in the ground substance to make up the ECM.

They are key in the wound healing process and are primarily responsible for scar tissue formation

Question 15

What is a myofibroblast and what is its purpose?

Answer 15

A modified form of fibroblast that contains ACtin and Myosin.

They are responsible for wound contraction once tissue loss has occurred.

Question 16

What is a macrophage and what is its purpose?

Answer 16

Derived from blood monocytes, they move into connective tissue, esp in local inflammation.

They are phagocytise and degrade foreign organisms/cell debris
They C.N. present material to T lymphocytes

Question 17

What are mast cells and what is their purpose?

Answer 17

Contain abundant granules
Histamine-increase blood vessel wall permeability
Heparin-anticoagulant (bleed out so macrophage reach injury site)
Cytokines-attract eosinophils and neutrophils

Found in loose connective near blood vessels but absent from CNS as inflammation can cause damage.

Coated with immunoglobulin, which bind allergens. When an allergen cross-links the surface bound immunoglobulin the contents of the granules are rapidly released.

Question 18

What form of adipocytes are present in loose connective tissue and what is their role?

Answer 18

Mainly white (single large droplet with nucleus, organelles and cytoplasm squeezed to one side)

Paddin, shock absorption, insulation and energy reserve

Question 19

Describe the structure and role of brown adipocytes ad where they can be found.

Answer 19

Multiple small lipid droplets, the nucleus, cytoplasm etc is in the middle

Provide insulation and energy reserve

Very few in an adult, mainly found around th organs of a newborn baby

Question 20

Compare the th number of mitochondria in white and brown adipose.

Answer 20

White-normal number

Brown-increased number

Question 21

Compare the breakdown of White and brown adipose tissues.

Answer 21

White-in adults lipid breakdown is slow, heat is only generated by the shivering reflex

Brown-in neonate and young children lipid breakdown is accelerated, oxidative phosphorylation is uncoupled to generate heat. (Calories generated can double)

Question 22

List and describe the types of collagen present in our bodies connective tissues.

Answer 22

Type I = widely distributed, aggregate (as a 3 helix) into fibres and fibre bundles.(tendons, capsules, skin dermis)

Type II = do not form fibres. (elastic cartilage and hyalin)

Type III = form fibres around muscle and nerve cells, within lymphatic tissues and lymphatic organs and in tendons (reticulin)

Type IV = unique from present tin basement membranes

Question 23

What fibres are present in all forms of connective tissue and what are there roles?

Answer 23

Collagen-flexible with high tensile strength

Elastin-allow tissues to recoil after stretch or distension

Question 24

What fibre is not present in loose connective tissue and what is its role in other tissues?

Answer 24

Reticular/reticulin- provides a supporting framework/sponge

Question 25

Why is connective tissue placed beneath the epithelium, neat epithelium of glands, and around small blood vessels?

Answer 25

As these are sites where pathogens can breach. They can then be challenged and destroyed by the immune system. During this reaction, loose connective tissue can undergo sig swelling as it has facility to return to original size,

Question 26

What is ground substance? What is it made from?

Answer 26

A viscous, clear substance-feels slippery (high H2O content) Composed of proteoglycans (macromolecules with core protien to which 2 glycosaminoglycans or GAGs are covaently bound) GAGs attract H2O to from hydrated gel-this allows rapid diffusion but resists compression.

Question 27

Give an example of a unique GAG and its location.

Answer 27

``` Hyaluronic acid (bound to proteoglycans by link protein to form giant hydrophilic molecule) Found in ground substance of cartilage. ```

Question 28

What is the structure of proteoglycans in ground substance? What is their relationship with water?

Answer 28

GAGs attached to core proteins. These then attached to hyluronate The sager moieties attract water making ground substance sticky and slippery.

Question 29

What does Irregular dense connective tissue’s structure mean for its function?

Answer 29

Because the fibres are densely [packed but irregularly oriented, Skin can resist forces in multiple directions to prevent tears Elastin fibres allows degree of stretch and restoration to original shape after skin is bent/folded.

Question 30

Give an example of regular dense connective tissue.

Answer 30

In tendons that connect muscle to bones. All collagen bundles are Parallel and densely packed in line with the tensile force from the muscle. (A row of elongated + flattened fibroblasts lie between collagen bundles)

Question 31

What is a myotendinous junction?

Answer 31

This is where skeletal muscle fibres connect with tendon collagen . They provide huge physiological strength The collagen passes from tendon to muscle fibre, where it interacts with the collagen coating the muscle fibres. They cross link to give strength.

Question 32

Why can forces be transmitted along collagen bundles in tendons?

Answer 32

Because they can glide over one another

Question 33

What are tendons made from (use %).

Answer 33

30% collagen (70% collagen 1, 30% collagen 2) 2% elastin 68% water

Question 34

Describe (basics) of ligaments/

Answer 34

Similar to tendon Connect bone to Bon Parallel collagen fibres but undulating Wrapped in loose connective tissue (fascicles)

Question 35

What is fascia?

Answer 35

A connective tissue with 3 types (superficial, deep and visceral or parietal) Made of fibrous connective tissue with closely packed collagen fibre bundles, in a wavy pattern parrelel to direction of pull. Is flexible and able to resist great unidirectional force until wavy pattern is stretched out.

Question 36

How are collagen fibrils produced?

Answer 36

Fibroblasts secrete procollagen, then converted to collagen OUTSIDE the cell. Then aggregate to form final fibrils. In some tissues these fibrils then clump together again for strength.

Question 37

What is Vitamin C used for in collagen production?

Answer 37

Is required for the INTRACELLULAR production of pro-collagen (it hydrolates proline and lysine). Without it collagen formation is distrusted, causing variety problems throughout body-scurvy

Question 38

What are some symptoms of Scurvy?

Answer 38

Gum disease Bruised skin Bleeding Poor wound healing

Question 39

Why does the disruption to collagen production in scurvy not lead to the body falling apart completely?

Answer 39

As the thin collagen fibres that are present aggregate in some ares to form thicker ones.

Question 40

What is Marfan’s syndrome and what are some symptoms?

Answer 40

An autosomal dominant disorder, effects expression of Fibrillin 1 gene- abnormal elastic tissue Sufferers are abnormally tall, show arachnodactyly (long fingers), have freq joint disclocation and an arm span greater than height. They’re at risk of aortic rupture=death

Question 41

Summarise key info about elastin.

Answer 41

Primary component of elastic fibres. Enfolds and is surrounded by fibrillin Occurs in most connective tissues but at varying degree Important in dermis, artery walls, lungs and elastic cartilage Made of protiens Demsosine and isodesmosine (if found in urine=disease of elastic fibres)

Question 42

What is Osteogenesis Imperfecta? (Cause + symptoms/effects)

Answer 42

“Brittle bone disease” Number of diff genetic aetiologies (most autosomal dominant) Mild to severs Due to mutated collagen fibres that don’t knit together or don’t produce enough or both ``` Result in- Weak bones Short stature (depends on type) Blue sclera Hearing loss Hyper mobility and flat or arched feet Poor teeth development ```