Cell Functions- Connective Tissue

kms013's version from 2015-09-25 20:24


Question Answer
Connective Tissue originates from ____________embryonic mesenchyme
Mesenchymal cellsundifferentiated with large nuclei
Embryonic mesenchymetissue developing mainly from the middle layer of the embryo, the mesoderm; viscous ground substance, few collagen fibers; mesodermic derivative that in addition to producing all types of CT proper, it includes stem cells for other tissues such as blood, the vascular endothelium, and muscle
Why is fasica hard to see in cadavers?hard to see in cadavers b/c different planes get all stuck together but in normal person they are all separate
Unlike other tissue types of epi, muscle, and nerve, which consist main of cells, the major cosnitiuents of CT is _______extracellular matrix ECM
What are the functions of CT?1. Enclosing and separating other tissues (capsula fascia) 2. Connecting (makes tendons/ligs) 3. supporting and moving (bones, hyaline cartilage) 4. storage (adipose) 5. Cushioning and insulating (adipose) 6. Transporting (blood) 7. Protecting (immune system)
composition of CTground substance which is the space; the stuff that is non-cellular that is out there like water, bone, and lipids...2. the fibers that hold it all togheter whicha re elastin, collagen, and reticular 3. cells- what is interspersed throughout
the typical CT ____, _____, and ________.supports, separates, and connects stuff...3 examples are cartilage, bone, and special: adipose, blood
Fibroblasts (fibrocytes)the major cells of CT proper, are elogated, irregularly shaped cells with oval nuclei that synthesize and secrete most components of ECM; involved in the creation of, growing of; sythesizes and secretes collagen (the most abundant protein of the body) and elastin which form large fibers and other stuff that comprise the ground substance; are targets of many families of proteins called growth factors that influence cell growth and differentiation.
myofibroblastfibroblasts involved in wound healing
osteoblastcells that produce bone
chondroblastsprecursor to cartilage
blastinvolved in the creation/growing of
cytesthe make up of whatever; the mature form in its functional level
fibrocytesquiescent cell; inactive mesenchymal cell
chondrocytecells within cartilage
osteoclastsdestroy bone
what two cells balance bone remodeling?Osteoblasts and osteoclast
fibroblastmost common cell in CT;they synthesize and secrete collagen and elastin which forms long fibers, GAGs, proteoglycans, multiadhesive proteins;Nucelus is evident; spiral like shape; myofibroblasts- fibroblasts that are active in wound care; target growth factors
adipocytes"fat cells" found in CT of many organs; specialized for storage of lipids as neutralized fats or production of heat; serve to insulate and cushion organs and such; rare in tissue of tendon and cartilage; brown (soles): mostly in infants; adults around kidneys and neck have increase mitro yellow and increased vasculature used for hetat production--most abundant in adults; so much fat pushes organelles to the side of cell
macrophagescharacterized by phagocytic ability; specilized in turnover of protein fibers; removal of dead cells, tissue, debris; fixes us, mobile, looks for areas of infection, leave blood and enter tissues; 10-30 um; oval or kidney shaped; referred to as histoiocytes; has antigen processing and presentation feature that signal immune cells; secrete growth factors, cytokines, and other agents; monocyte- circulate through blood; once outside turns into a macP; other names are Kupffer cells (liver), microglia (NS) LangerHans cells (skin) osteoclast (bone)-- modified macrophage that become sbad when osteoporotic; alveolar- type II cells waiting for dust;
ground substancegel like substance that surrounds cells and includes all components of ECM except fibers (collagen and elastin); acts both as lubricant and barrier; rich in GAGs; watery unstained ECM that is more abundant than biers in some types of CT
Yellow vs. brown adipocyteyellow- stores energy; brown- abundant in newborn but can still be seen in upper shoulder and around nuchal ligament; what makes differerence is mitochondria that stays within cell and has lipid within it where yeyllow and white it takes over whole cll and pushes stuff to periphery; function of brown is to generate body heat,incread mitochondria, more capillaries
What are the cells of CT?Embryonic mesenchyma cells (blasts, cytes, clasts), fibroblasts, adipocytes, macrophages, mast cells, leukocytes
Mast celloval, irregular, 7-20 um; filled with basophilic secretory granuoles (blue or black); due to their acidic radicals in GAGs; display metachromasia (change in color with different dyes) Releases heparin and histamine, important molecules releaed from mast cells secretory granules
heparina sulfated GAG that acts locally as an anticoagulant; after big surgeries, Worferan does not want collting; want increase blood flow for healing
histaminepermits increased vascular permeability and smooth muscle contraction like from an allergic reaction; found in loose CT; respond to quick line of immune defense and start non by IGE receptors; As soon as these receptors are introduced, cause an allergic reaction
clastmodified macrophage whose job is to break down bone (osteoclast)
LeukocyteWBC; leave blood via diapedesis which increase during inflammation; most of cell is overtaken by nucleus; 1. neutrophils (60%) bacteria, fungi 2. lymphocytes (30%) B and T cells 3. Monocytes (5%) macrophage 4. eosinophil (2%) parasitic, allergy 5. basophil (1%) inflammation; most leukocytes cuntion for a few hours or days in CT and then die but some lymphocytes and pagocytic antigen presenting cells normally leave the interstitial fluid of CT, enter the lymph, and movet o selected lymphoid organs
ECMDifferent fluid compartments- 1. intracellular fluid, intersitital space (2nd), intravascular space (plasma), thrid space-- not typically fluid the interperitoneal space
fibrous components of CTelongated structures formed from protines that polymerize after secretion from fibroblasts; collagen, reticular, and elastic
Collagenkey element of all CT; epithelial basement membrane; external lamina of nerve and muscle cells; most abundant in human body; will stretch but not bounce back; looks like straiated muscle but difference is banded; T1-T4; a major product of fibroblasts
Types of collagen fiberT1- tendon, ligaments, bone, skin T2-cartilage T3 reticular T4 basil lamina T5- basement membrane
Reticular fibersdound in delicate CT of many organs; consist mainly of collagen type III which forms an extenisve network and thin in diameter; webbed looking around the spleen and lymph nodes; argyrophic because they are seldomly visible; they can be impregnated with silver salts; fibroblasts produce RF that occur in reticular lamina of basement membrane; surround adipocytes, small muscle, and nerve fibers of small blood vessels; delicate reticular networks serve as the supportive stroma for the parenchymal secretory cells and rich microvasculature of the liver and endocrine glands; abundant reticular fibers also characterize the stroma of hemopoietic tissue (bone marro) and some lymphoid organs (spleen and lymph nodes) where they supprot rapidly changin populations of proliferating cells and phagocytic cells
Elastic fibersthinner than T1 collagen fibers; interspersed in many organs subject to much bending/stretching; In the walls of large blood vessels, it occurs in fenestrated sheets and is called elastic lamella;; secreted from fibroblasts; composed of proteins elastin and fibrillin, which provides the elastic ability
GAGs"glycosaminoglycans"; dense network of polymers that bind to water which causes the polyanions to swell and occupy a large space in the tissue; HA (hyaluronic acid) are the major types of GAGs which is a very long polymer of the disaccharide gulcosamine-glucuronate, and various shorter chains of sulfated GAGs composed of other disaccharide polymers
ProteoglycansCore proteins; attach to polymers of HA via linker proteins to form huge complexes in ground substance that bind to water and other substances; sythesized on RER, amture in Golgi, where the GAG side chains are added ; one of the best known is "aggrecan" which is very large with a core protien bearing many chondroitin sulfate and keratan sulfate chains; bound via a link protein to polymer of hyaluronic acid
loose CT"areolar tissue;" has relatively more ground substance than collagen and it typically surrounds small blood vessels and occupies areas adjacent to other types of epithelia; adipose loose CT are large cells and small amounts of ECF clusters
Dense irregular CTfilled primarily with randomly distributed bundles of Type I collagen with some elastic fibers; provding resistance to tearnign from all directions as well as some elasticity
dense regular CTprominent in tendons and ligaments; features bundles of essentially parallel collagen, providing great strength (but little stretch) in binding togheter components of the musculoskeletal system; hardly any GS
interstitial fluidion composition similar to that of blood plasma; contains plasma proteins of low molecular weight that pass through the thin walls of capillaries
hydrostatic pressureHP of the blood caused by the pumping action of the heart, which forces water out across the capillary wall
colloid osmotic pressureproduces lasma proteins such as albumin, which draws water back into the capillaries
reticular CTcrooked; consists of delicate networks of type III collagen (reticulin) and is most abundant in certain lymphoid organs where the fibers form attachment site for lymphocytes and other immune cells
Keloid/hypertrophicout of control, where body just continues to lay down more collagen; may need injections to break down; raised scar like if injury to cartilage in ear; "genetic"-- balance of elastin and cartilage
skin graftdue to replace the epithelium; responsib le for regeneration; may wear compression to keep everything smooth