CONNECTIVE TISSUE Flashcards
Connective tissue forms _______ ________ for the body; provides __________ ________ and its the site of exchange of waste products ,______ and ______
connective tissue forms structural support of the body and provides mechanical stability and its the site of exchange of waste products, oxigen and nutrients
___ is stored in connective tissue
Fat is stored in connective tissue
Connective tissue is composed of:
support cells and their associated matrix
Fibroblast can be ________ or _________
Fibroblast can be active or quiescent fibroblast (fibrocyte)
Mesenchymal stem cells give rise to:
Bone/osteoblasts , cartilage/chondroblasts , connective tissue and adipose tissue
The most common type of cells in connective tissue is:
fibroblast
Hematopoietic stem cell give rise to:
blood cells, monocytes (macrophages and osteoclastos), lymphocytes (plasma cell and T cell).
Conective tissue can be _____ and _____.
Conective tissue can be mature and embryonic
The 2 groups of connective tissue are:
Connective tissue proper and Spcialized connective tissue
Types of connective tissue proper : (name and describe them )
- Loose connective tissue
- dense connective tissue
- dense irregular connective tissue
- dense regular connective tissue
Adipose tissue, cartilage tissue, blood and bone are types of ________ _______ ________
Adipose tissue, cartilage tissue, blood and bone are types of specialized connective tissue
Name the support cells in the connective tissue:
- fibroblastos
- chondrocytes
- osteoblasts
- myofibroblasts
- adipocytes
What are fibroblasts ?
fixed cell in connective tissue that secrete extracellular matrix components, collagen and elastin.
origin: mesenchymal cells
What are chondrocytes?
secrete EMC of cartilage
What are osteoblast?
Secrete EMC of bone
what are myofibroblasts?
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.
What are adipocytes?
specially adapted lipid-storing support cells that act as energy store AND cushioning and padding.
What is extracellular matrix?
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.
What are the components of ground substance?
- proteoglycans: aggrecan, syndecan
- cell adhesion glycoproteins: fibreonectin, laminin
- glycosaminoglycans: keratan sulfate, hyaluronic acid
Explain ground substance components structure
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)
What are glycosaminoglycans- GAGs?
negatively charged long, rod- like chains of repeating disaccharides that have the capability of binding large quantities of water. Ex hyalyronic acid
What are proteoglycans?
It constitute the family of macromolecules, each composed of a protein core to wich GAGs are covalently bonded
hyaluronidase
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
What are cell adhesion glycoproteins?
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
Identify the image and describe
active state of fibroblast.
The active fibroblast have a basophilic cytoplasm reflectinve collagen synthesis.
What are the cellular components of Extracellular matrix?
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
Identify the image and describe
Quiescent fibroblast or fibrocytes
The fibroblast lose thei voluminous basophilic cytoplasm and the nuclei gets reduced.
Active fibroblasts show ______ _____ ______ _____ and ______
Active fibroblasts show abundant rough endoplasmic reticulum and nuclei
What are pericytes?
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
What are Adipose Cells?
- 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
what are mast cells?
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.
What are macrophages?
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
What are the cells of mononuclear phagocyte system? (tipos de macrophagos)
- 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
Decribe loose connective tissue/ aereolar tissue
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**
what is lamina proria?
loose connective tissue of mucous membranes as alimentary canal
Describe dense connective tissue
In comparison with loose connective tissue has MORE fibers and FEWER cells.
Theres two types: dense irregular and dense regular
Identify the type of tissue here and describe
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
Identify tissue and parts
Identify tissue and parts
Dense Regular collagenous connective tissue
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.
Dense regular elastic connective tissue
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
Connective Tissue Fibers
proteins that determine tensile properties of support tissues.
Major 4:
collagen
fibrillin
elastin
fibronectin
Collagen Fibers
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
Families of collagen are:
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
Reticulin fibers
proide supporting framework for the cellular constituents of various tissues and organs
thin fibrils of type 3 collagen
Stain: PAS, black
Elastic Fibers
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
microfibirls are prominent in elastic containing EM like
lung, skin, blood vessel walls
Marfan’s syndrome
abnormal expression of the fibrillin gene, autosomal dominant connective tissue disorder. Abnormal elastic tissue because of absence of elastin-associated fibrillin microfibers
