Connective Tissue Flashcards
Es la matriz extracelular (inerte) que rodea alas celulas vivas
Sustancia fundamental
La esencia estructural del TC es la abundancia de
Matriz extracelular
La MEC es rica en
Fibras de colagena, reticulares y elásticas
Las células fundamentales del TC son los
Fibroblastos
Celulas residentes o en migración son
Adipocitos, celulas cebadas, macrofagos, y leucocitos
Principal celula del TC, responsable de la síntesis de los elementos de la matriz, de origen mesodermico
Fibroblasto
Los fibroblastos tienen forma de
Huso fusiforme en corte longitudinal con extremos alargados en punta y una parte central de pared lisa que aloja al núcleo eucromatico y de bordes redondeados
Encargados de la producción de colagena
Fibroblastos
Cuantos tipos de colageno existen
28
Se localiza en la MEC del hueso, tendón.piel,fascias, en las fases tardías de la reparación de las heridas y en la cornea
Tipo I
Se encuentra en cartílago (incluyendo el cartílago hialino) cuerpo vítreo, núcleo pulposo
Tipo II
Se localiza en (reticulina) en la piel , vasos sanguíneos, utero, tejido fetal,tejido de granulacion
Tipo III
Se encuentra en la lamina basal
Tipo IV
Fibroblastos en estado de reposo se denominan , que presentan un citoplasma de escaso desarrollo con núcleo pequeño
Fibrocitos
Marcadores funcionales de los fibroblastos que son
Actividades de fosfatasa alcalina, y esterasa inespecifica (ANAE)
Celulas con forma estrellada con un cuerpo celular que aloja un núcleo y ramificaciones que contactan con celulas vecinas o abrazan fibras de colagena conocidas como fibras de reticulina
Células reticulares
Forman el tejido reticular
Celulas reticulares y fibras de reticulina
Se dispone formando un entramado o red y forma el estrofa de órganos linfáticos y hematopoyeticos
Tejido reticular
De acuerdo a que se clasifica el TC
A la distribución de fibras de colagena y de la densidad y densidad
Soporta epitelios de los órganos internos formando la lamina propia de las mucosas que recubren órganos huecos como el tubo digestivo,vías respiratorias aéreas y vías urinarias y sexuales , túnica adventicia de dichos conductos y de otros órganos rellenando los espacios entre ellos , el endomisio del músculo estriado.
Tejido conjuntivo laxo o areolar
Contiene un bajo número de fibras conjuntivas fundamentalmente de colageno y reticulina en relación con la sustancia fundamental y al número de fibroblastos
Tejido conectivo laxo o areolar
TC está formado por celulas de diversos tipos en su mayoría de origen
Mesenquimatico
Se encuentra en órganos sometidos a fuerzas moderadas proporcionando un soporte estructural a epitelios externos , forma el estrato denso de la dermis y la túnica media de las venas
TC denso irregular
Posee abundantes fibras de colageno agrupadas en haces orientados irregularmente y fibras elásticas de recorrido sinuoso , forma mallas en la túnica media de las arterias elásticas, y entre las fibras alineados a los haces de colageno se encuentran los fibroblastos denominados fibrocitos
TC denso irregular
Tipo especial de TC denso irregular , que permite la ereccion de diversos órganos que carecen de tejido muscular
Eréctil
TC característico de los órganos que soportan fuerzas elevadas en una dirección como tendones o ligamentos
TC denso regular
Esta formado por grandes haces de colageno y elásticas, ordenados en paralelo orientados en sentido longitudinal a las fuerzas con fibroblastos en baja proporción
TC denso regular
TC especializado que se encuentra en la dermis de los embriones así como el el cordón umbilical
TC mucoso
En el cordón umbilical recibe el nombre el TC especializado mucoso de
Gelatina de wharton
Esta formado por una gran cantidad de sustancia fundamental con bajarlo porción de haces de colagena dispuestos irregularmente Y fibroblastos con largas ramificaciones
TC mucoso
Forma el estroma de tejidos hematopoyeticos y linfoides formado por celulas reticulares y fibras dé reticulina dejando huecos donde se localizan células sanguíneas
Tejido reticular
Celulas que se pueden encontrar en TC
Fibroblastos Adipocitos Macrofagos Linfocitos Células plasmaticas Celulas cebadas
Proceden de monocitos que circulan en la sangre y migran a través de los tejidos madurando con propiedades fagociticas
Macrofagos
Cuando se localizan en TC se denominan los macrofagos
Histiocitos
procede de órganos hematopoyeticos, se diferencian por sus granulos citoplasmaticos siendo meta cromáticas.
Células cebadas
Participa en respuestas inflamatorias por la secreción de sus granulos de histamina y síntesis de compuestos vaso activos que producen aumento en la permeabilidad vascular facilitando acumuló de agua en TC (inflamación) atraen otros leucocitos al área de inflamación y inducen contracción de músculo liso mediante respuestas alérgicas
Células cebadas
Muchas células pocas fibras , con un fondo lila o transparente y se puede encontrar macrofagos , plasmocitos, y mastocitos
TC laxo
Muchas fibras, pocas células desorden de fibras rosa fuerte en distintas direcciones , se puede identificar fibroblastos
Irregular denso
Fibras en orden ,muy confundible con músculo estriado esquelético pero tiene ausencia de estriaciones
Regular denso
Consist mainly of cells, the mayor constituent of TC is the
Extracellular matrix ECM,extra fibers, ground substance
Protein fibers
Collagen and elastic fibers
Complex of anionic, hydrophilic proteoglycans,GAGs, and multiadhesive glycoproteins
Ground substance
Multiadhesive of glycoproteins
Laminin,fibronectin,
Connective tissues originate from ebryonic
Mesenchyme
Originate from locally mesenchymal cells
Fibroblast
ECM Consist largely of a simple ground substance rich in
Hyaluronan acid
Most abundant protein in body
Collagen
Products of fibroblast
Collagen, elastin, GAGs,proteoglycans and multiadhesive
Quiescent cells
Fibrocitos
Active cells
Fibroblastos
Fibroblast are targets of many families of proteins called
Growth factors
The regenerative capacity of connective tissue is clearly observed in organs damaged by
Ischemia, inflammation or traumatic injury
Fibroblast involve in wound healing that have a contractile function reach with a form of actin also found in smooth muscle cells
Myofibroblast
Diameter of macrophages
10 and 30 micrometers
Has a kidney shaped nucleus
Macrophages
Macrophages increase in size and fuse to form
Multinuclear giant cells
Major product or activity of plasma cells
Antibodies
Major product or activity of lymphocytes
Immune/ defense function
Major product or activity of elsinophilic leukocytes
Modulate allergic/vasoactive reactions and defense against parasites
Major product or activity of neutrophilic leukocytes
Phagocytosis of bacteria
Mast cells and basophic leukocytes Major product or activity is
Pharmacologically active molecules
Diameter of a mast cell whose Cytoplasm is filled with Basophilic secretory granules
7 and 20 micrometers
The granules of the mast cell’s diameter
From 0.3 to 2.0 micrometers
Mast cells because of their high content of acidic radicals in their sulfated GAGs mast cells granules display ….. , which means that the can change the color of some basic dyes
Metachromasia
Example of dyes that change with metachromasia
Toluidine blue that change from blue to purple or red
Major locations of kupffer cells
Liver (perisinusoidal)
Major locations of microgrial cells
SNC
Major locations of langerhans cell
Epidermis of skin
Major locations of dendritic cells
Lymph nodes, spleen
Major locations of osteoclast
Bone
Major locations of multinuclear giant cells
In connective tissue under various pathological conditions
A sulfated GAGs that acts locally as an anticoagulant
Heparin
Molecules that promote increased vascular permeability and smooth muscle contraction
Histamine
Molecules that activate various mediators of inflammation
Serine protease
Molecules that attract those leukocytes
Eosinophil and neutrophil chemotactic factors
Polypeptide directing activities of leukocytes and other cells of the immune system
Cytokines
Precursors for conversion to prostaglandins, leukotrienes and other important lipids mediators of the inflammatory response
Phospholipids
Location of mast cells
Especially numerous near small blood vessels in skin and mesenteries , and in the tissue that lines digestive and respiratory cells
Certain chemical mediators stored in mast cells promotes the allergic reactions also known as
Immediate hypersensitivity reactions
Number of receptors a mast cell have
300,000
Are B lymphocytes derived with Basophilic Cytoplasm and appearance of a clock face
Plasma cells
The average lifespan of a plasma cell is only
10 to 20 days
Responsable for the synthesis of immunoglobulin antibodies
Plasma cells
Process that happens when leukocytes lease blood by migrating between the endothelial cells lining venules to enter connective tissue by a Process called
Diapedesis
Signs of inflamed tissues included
Redness, and swelling with heat and pain
Increased vascular permeability is caused by the actions of vasoactive substances such as histamine released from mast cells during
Inflammation
Is due to the action of the chemical mediators on nerve ending
Pain
The 3 main types of fibers
Collagen , reticular and elastic fibers
Elastic fibers are composed Mainly of the protein
Elastin
The most abundant protein in the body
Collagen
% of collagen in the body in dry weight
30%
Collagen categories according to the structures are
Fibrillar collagen, Sheet forming collagen , linking/anchoring collagen
Fibrillar collagen that have subunits that aggregate to form large fibrils clearly visible in microscope
Collagen I, II, III
Collagen most abundant and widely distributed collagen forms large eosinophilic bundles usually called collagen fibers
Type I
Major structural proteins of external laminae and the basal lámina in the epithelia
Type IV collagen
Binds type IV collagen and anchors the basal lámina to the underlying reticular lamina in the basement membranes
Type VII
Major locations is on skin, tendon, bone, dentin , main function is resistance to tension
Collagen I
Structure of collagen I
300 nm molecule, 67 nm banded fibrills, thick , highly picrosirius
Major locations is on cartilage, and vitreous body , main function is resistance to pressure
Collagen II
Main locations fetal tissues , skin , bone, placenta, most interstitial tissues
Collagen V
Structure of collagen V
390 nm molecule , N- terminal globular domain,
Major locations in all basal and external laminae and main function is support of epithelial cells and filtration
Collagen IV
Major locations in epithelial basement membranes, anchors basal laminae to reticular lamina
Collagen VII
Found in placenta , skin and tendons
collagen XII
Are made in the cells abundant RER
Procollagen alfa chain
ER three alfa chain are selected , aligned and stabilized by disulfide bonds at their carboxyl terminals
Triple helix
The triple helix undergoes exocitosis and is a cleaved to rodlike
Procollagen molecule
Each molecule of subunits of collagen I
Two alfa1 and one alfa2 peptide chains with a molecular mass of 100kDa held together by hydrogen bonds and hydrophilic interaction
Lenght of a molecule of collagen called tropo collagen is
300 nm and its width is 1.5 nm , each complete turn of the helix spans a distance of 8.6 nm
Is a local swelling caused by abnormally large amount of collagen that form in scars of the skin
Keloid
% of collagen Type I of all the body’s collagen
90%
Collagen typically have long central domains rich in
Proline and lysine
In collagen I every third amino acid is
Glycine
Enzymes in RER cisternae add hydroxyl groups to some prolines and lysines that require O2, Fe, and vitamina C
Hydroxylase
Remove the terminal globular peptides converting the procollagen in collagen molecules
Procollagen peptidase
Diameter of collagen Type I ranging from
20 to 90 nm adjacent rodlike collagen subunits of the fibrils are staggered by 67nm
Collagen fibers are Acidophilic they stain with eosin
Pink
Collagen fibrils with mallory stain
Blue
With sirius red collagen stain
Red
Degradation is initiated by specific enzymes called
Collagenases members of MMPs
Consist Mainly of collagen III
Reticular fibers
Diameter of reticular fibers
0.5 - 2 micrometers
Reticular fibers are stain black with
Impregnation with silver salt and are termed argyrophylic
% of carbohydrates in reticular fibers
10% and the other fibers only have 1%
Reticular fiber produced by fibroblast surround
Adiposytes
Smooth muscle
Nerve fibers
Small blood vessels
Reticular fibers serve as supportive stroma for parnchimal secretory cells and rich microvasculature of
The liver and endocrine glands, hematopoyetic tissue, and some lymphoid organs
Disorder cause by defect of faulty transcription or traslation of collagen Type III with sympthom of aortic and/or intestinal rupture
Ehlers-Danlos Type IV
Disorder cause by defect of faulty lysine hydroxylation increasing skin elasticity , rupture of eyeball
Ehlers- Danlos Type VI
Disorder cause by defect of decrease in procollagen peptidase activity increasing articular mobility, frequent luxation
Ehlers-Danlos Type VII
Disorder cause by defect of Lacks of vitamin C causing ulceration of gums, hemorrages
Scurvy
Disorder cause by defect of change of 1 nucleotide in genes for collagen type I
Osteogenesis imperfecta
In the wall of blood vessels specially arteries, Elastin also occurs as fenestrated sheets called
Elastic lamellae
Elastic fibers stain darkly with
Orcein and aldehyde fuchsin
Elastic fibers are composite of
Fibrillin microfibrils Embedded in a larger mass of cross linked Elastin
Microfibrils diameter form from fibrillin
10 nm
Elastin molecules are rich in
Glycine
Proline
Lysine giving random coiled conformation
Most of the cross links between Elastin subunits consist of the covalent cycling structure called
Desmosine
Elastin resist digestión by most proteases, but it is hydrolyzed by pancreatic
Elastase
Mutation in the fibrillin genes result in this syndrome that cause a Lacks of resistance in tissues rich in elastic fibers
Marfan syndrome
The wall of large arteries are rich in elastic components and because the blood pressure is high in the aorta, patients with this disease often experience aortic swellings called
Aneurysms
The ground substance of the ECM is hydrated, transparent and a complex mixture of
GAGs , proteoglycans and multiadhesive glycoproteins
Ground substance acts as
Lubricants and a barrier to the penetration of invaders
Also called mucopolysaccharid, consist of the repeating disaccharide units, usually a uronic acid and hexosamine
GAGs
The largest and most ubiquitous GAGs is
Hyaluronic acid
Molecular weight of hyaluronic acid from
100s to 1000s kDa
Hyaluronate synthase is located in
Cell membrane
GAGs are attached to proteins called… That are synthesized in golgi complexes
Proteoglycans
The four major GAGs found in proteoglycans are…, that bind a great numbers of cations
Dermatan sulfate, chondroitin sulfates, keratan sulfate and heparan sulfate
Core of proteins to which are covalently attached various numbers and combinations of the sulfated GAGs , are synthesized on RER
Proteoglycans
The major cartilage constituent
Aggrecan
Small proteoglycan that has few GAGs side chains and binds fibrils of type I collagen
Decorin
Proteoglycans that have transmembrane core proteins and serve as additional attachments of the cell to the ECM
Syndecan
Aggrecan, a very large core protein bearing many
Chondroitin sulfate, and keratan sulfate chains
GAGs found on umbilical cord , synovial fluid, vitreous humor, cartilage
Hyaluronic acid
GAGs found on cartilage, bone, cornea , skin notochord,aorta
Chondroitin 4 sulfate
GAGs found in skin, tendon, aorta ( adventicia)
Dermatan sulfate
GAGs found in aorta, lungs, liver,basal laminae
Heparan sulfate
GAGs found in cartilage, nucleous pulpous, annulus fibrosus
Keratan sulfate
All have multiple binding sites for cell surface receptors( integrins)
Multiadhesive glycoproteins
The Lack of specific hydrolases in lysosomes has Been found to be the cause of several disorders including
Hurler, Hunter, Sanfilippo and morquio syndromes
La mucopolisacaridosis tipo I , conocida también por las siglas MPS I, es una enfermedad congénita que esta causada por el déficit de una enzima, la alfa-L-iduronidasa, que ocasiona acumulación progresiva de mucopolisacaridos en las células del tejido conectivo, incluido cartílago y hueso. Es una enfermedad por depósito o tesaurismosis. Se presenta un caso por cada 100.000 nacimientos por lo que está incluida dentro del grupo de las enfermedades raras.
Sindrome de hurler
Es un trastorno hereditario del metabolismo, el cual hace que el cuerpo no sea capaz de descomponer apropiadamente cadenas largas de moléculas de azúcar llamadas glucosaminoglicanos (anteriormente denominados mucopolisacáridos).
Sanfilippo syndrome
Integral membrane proteins that act as matrix receptors for laminin , fibronectin collagens
Integrins
Form insoluble fibrilar network important for cell migration and adhesión
Fibronectin
Basal and external laminae are rich in
Laminin
Clustered integrins - microfilaments complexes in fibroblasts form structures called
Focal adhesions
Accumulation of water
Edema
Quantity of plasma proteins stored in the matrix of connective tissue
1/3