CONNECTIVE TISSUE

Question 1

Connective tissue forms _______ ________ for the body; provides __________ ________ and its the site of exchange of waste products ,______ and ______

Answer 1

connective tissue forms structural support of the body and provides mechanical stability and its the site of exchange of waste products, oxigen and nutrients

Question 2

___ is stored in connective tissue

Answer 2

Fat is stored in connective tissue

Question 3

Connective tissue is composed of:

Answer 3

support cells and their associated matrix

Question 4

Fibroblast can be ________ or _________

Answer 4

Fibroblast can be active or quiescent fibroblast (fibrocyte)

Question 5

Mesenchymal stem cells give rise to:

Answer 5

Bone/osteoblasts , cartilage/chondroblasts , connective tissue and adipose tissue

Question 6

The most common type of cells in connective tissue is:

Answer 6

fibroblast

Question 7

Hematopoietic stem cell give rise to:

Answer 7

blood cells, monocytes (macrophages and osteoclastos), lymphocytes (plasma cell and T cell).

Question 8

Conective tissue can be _____ and _____.

Answer 8

Conective tissue can be mature and embryonic

Question 9

The 2 groups of connective tissue are:

Answer 9

Connective tissue proper and Spcialized connective tissue

Question 10

Types of connective tissue proper : (name and describe them )

Answer 10

1. Loose connective tissue
2. dense connective tissue
   
   • dense irregular connective tissue
   • dense regular connective tissue

Question 11

Adipose tissue, cartilage tissue, blood and bone are types of ________ _______ ________

Answer 11

Adipose tissue, cartilage tissue, blood and bone are types of specialized connective tissue

Question 12

Name the support cells in the connective tissue:

Answer 12

• fibroblastos
• chondrocytes
• osteoblasts
• myofibroblasts
• adipocytes

Question 13

What are fibroblasts ?

Answer 13

fixed cell in connective tissue that secrete extracellular matrix components, collagen and elastin.

origin: mesenchymal cells

Question 14

What are chondrocytes?

Answer 14

secrete EMC of cartilage

Question 15

What are osteoblast?

Answer 15

Secrete EMC of bone

Question 16

what are myofibroblasts?

Answer 16

Secrete EMC and have contractile function and are enriched with a form of actin also found in smooth muscle cells.These are abundant in aras undergoing healing.

Elongated, spindly connective tissue cell.

It’s not easily stain with H&E dye by llight microscopy.

Question 17

What are adipocytes?

Answer 17

specially adapted lipid-storing support cells that act as energy store AND cushioning and padding.

Question 18

What is extracellular matrix?

Answer 18

consists of ground substance (gelly like), cells and fiber embbeded in it. Provides mechanical, structure support, extracellular communication, provides pathways for cell migration and modulate cell growth.

Question 19

What are the components of ground substance?

Answer 19

1. proteoglycans: aggrecan, syndecan
2. cell adhesion glycoproteins: fibreonectin, laminin
3. glycosaminoglycans: keratan sulfate, hyaluronic acid

Question 20

Explain ground substance components structure

Answer 20

As shown here schematically, connective tissue ground substance

contains a vast complex of proteoglycans linked to very

long hyaluronan molecules. Each proteoglycan monomer has

a core protein with a few or many side chains of the sulfated

glycosaminoglycans (GAGs)

Question 21

What are glycosaminoglycans- GAGs?

Answer 21

negatively charged long, rod- like chains of repeating disaccharides that have the capability of binding large quantities of water. Ex hyalyronic acid

Question 22

What are proteoglycans?

Answer 22

It constitute the family of macromolecules, each composed of a protein core to wich GAGs are covalently bonded

Question 23

hyaluronidase

Answer 23

Enzyme that cleaves hyaluronic acid into numerous small fragments. thus convesting the gel state of the ECM to a liquid state letting rapid spread of the bacteria through the connective tissue spaces

Question 24

What are cell adhesion glycoproteins?

Answer 24

Large molecules with several domains and they bind to: integrins, collagen fibrils and proteoglycans. These permit the cells to adhere to components of the ECM.

Types of glycoproteins: fibronectin, laminin, entactin, tenascin, chondronectin, and osteonectin

Question 25

Identify the image and describe

Answer 25

active state of fibroblast. The active fibroblast have a basophilic cytoplasm reflectinve collagen synthesis.

Question 26

What are the cellular components of Extracellular matrix?

Answer 26

**fixed cells**: which develop and remain in place withing the connective tissue. **Ex** fibroblasts, adipose cells, macrophages and pericytes **transcient cells**: originate in bone morrow and circulate the bloodstream. **Ex** lymphocytes, neutrophils, eosinophils, basophils, monocytes, macrophages and mast cells

Question 27

Identify the image and describe

Answer 27

Quiescent fibroblast or **fibrocytes** The fibroblast lose thei voluminous basophilic cytoplasm and the nuclei gets reduced.

Question 28

Active fibroblasts show **\_\_\_\_\_\_ _____ \_\_\_\_\_\_ _____ and \_\_\_\_\_\_**

Answer 28

Active fibroblasts show **abundant rough endoplasmic reticulum and nuclei**

Question 29

What are pericytes?

Answer 29

These cells surround endothelial cells of capillaries and small venules. Reside outside of the connective tissue because they have their own basal lamina. Have characteristics of: endothelial cells and smooth cells (actin, myosin, and tropomyosin) may function on contraction

Question 30

What are Adipose Cells?

Answer 30

* **Origin**: undifferentiated fibroblast-like mesenchymal cells * **Function**: synthesis or storage of **triglycerides** * Produce hormones like Adipokines * Types of fat cells: unilocular fat cells white adipose tissue and multilocular fat cells brown adipose tissue

Question 31

what are mast cells?

Answer 31

**Origin**: bone morrow stem cells **Structure** : They are ovoid and posses a centrally placed, spherical nucleus, have numerous granules in the cytoplasm. **Function**: inflammatory response, innate immunity, and tissue repair. Primary mediator: **histamine**; Secondary: leukotrienes, thromboxanes, and prostaglandins.

Question 32

What are macrophages?

Answer 32

Mononuclear **phagocytic** system and are divided in two groups: **phagocytes and antigen presenting cells.** These cells phagocytose foreign substances and damaged senescent cells as cellular debirs **All:** arise from stem cell in bone marrow ---\> monocytes----\> macrophages (monocytes circulate the blood and signaling lead them to connective tissue where they mature and become macrophages) have **lysosomes** capable of **phagocytosis** display **receptors** for complement

Question 33

What are the cells of mononuclear phagocyte system? (tipos de macrophagos)

Answer 33

* monocyte: * in liver * precursos of macrophages * macrophage: * connective tissue, lymphoid organs, lungs, bone marrow * prodcution of cytokines, chemotactic factors and other molecules in inflammation, antigen presentation * Kupffer cells : * liver * same as macrophages * microglial cell: * in CNS * same as macrophages * langherhans cell: * epidermis of skin * antigen processing and presentation * dendritic cell: * lymph nodes, spleen * * antigen processing and presentation * osteoclast (from fusion of several macrophages): * bone * localized digestion of bone matrix * mulinuclear giant cell: (from fussion of several macrophages) * in connective tissue under various pathological conditions

Question 34

Decribe loose connective tissue/ aereolar tissue

Answer 34

**What**? Its characterized by abundant ground substance and extracellular fluid housing the connective tissue cells: fibroblasts, adipose cells, macrophages and mas cells (equal parts). Its very flexible and not resistant to stress **Composition**? Predomina las fibras de colageno pero tiene fibras elasticas y reticulares. **Location**? below mesothelial lining od body cavities, sorrounds parenchyma of glands. *\*\* this is where the body first attack antigens, bacteria and foreign invaders, therefore, it has MANY cells for inflammation, allergic reactions and immune reponse\*\**

Question 35

what is lamina proria?

Answer 35

loose connective tissue of mucous membranes as alimentary canal

Question 36

Describe dense connective tissue

Answer 36

In comparison with loose connective tissue has **MORE fibers** and **FEWER cells.** Theres two types: dense **irregular** and dense **regular**

Question 37

Identify the type of tissue here and describe

Answer 37

Dense irregular connective tissue Contains mostly coarse collagen fibers interwoven into a meshwork that resist stress from all direction. collagen is very tightky packed so theres no space for ground substance. fibroblasts, most abundandt cell, are located between collagen bundle. It's located in the dermis of the skin, sheaths of nerves, capsules of spleen, testes, ovary, kidney, and lymph nodes

Answer 38

Question 39

Identify tissue and parts

Answer 39

Question 40

Identify tissue and parts

Answer 40

Question 41

Dense Regular **collagenous** connective tissue

Answer 41

It has a parallel organization of collagen and resist tensile forces with little ground substance. Thin sheet like fibroblast are located between bundles of collagen.

Question 42

Dense regular **elastic** connective tissue

Answer 42

It has coarse branching elastic fibers with only a **few** collagen fibers. It's present in blood cells, ligamentum flavum of the vertebral column, and the suspensory ligament of the penis

Question 43

Connective Tissue Fibers

Answer 43

proteins that determine tensile properties of support tissues. **Major 4:** collagen fibrillin elastin fibronectin

Question 44

Collagen Fibers

Answer 44

family of proteins and sre the most important fibrillar extracellular matrix components. They are **flexible, high tensile strength** **Masson's stain-** light green **Acidic dyes-** readily with eosin **Mallory -** anylin blue

Question 45

Families of collagen are:

Answer 45

**fibrillar collagen**: 1,2,3,5,11 **short-chain collagen**: 8,10 **basement membrane collagens**: 4 **other collagen**: 6,7,13 ***1,2,3 are arranged as rope like fibrils and are the main forms of fibrillar collagen***

Question 46

Reticulin fibers

Answer 46

proide supporting framework for the cellular constituents of various tissues and organs thin fibrils of type 3 collagen Stain: PAS, black

Question 47

Elastic Fibers

Answer 47

hydrophobic fiber produced by fibroblast. Formed by interaction of elastin and fibrillin. This give elasticity to the tossues and allow them to recoil after stretching. Microfibrils are important in this fibers Thinnr than collgen fibers Stain: take acidic dye better than collagen special dye: orcein or resorcin-fuchsin

Question 48

microfibirls are prominent in elastic containing EM like

Answer 48

lung, skin, blood vessel walls

Question 49

Marfan's syndrome

Answer 49

abnormal expression of the fibrillin gene, autosomal dominant connective tissue disorder. Abnormal elastic tissue because of absence of elastin-associated fibrillin microfibers