Connective Tissue Histology

Question 1

connective tissue functions

Answer 1

connect bones via ligaments

forms capsules of rogans and their supporting framework

forms protective barriers from the external environment

transduction in muscles via tendons

controlled moedeling and remodeling processes such as wound healing and growth

pathological processes such as inflammation

Question 2

regular connective tissue

Answer 2

varying amounts of fiber, classified as dense or loose dependingo nthe proportion of fibers

Question 3

special connective tissue

Answer 3

includes cartilage, bone, fat, and blood

Question 4

dense regular connective tissue

Answer 4

dense with parallel collagen fibers, closely packed around fibroblast such as in tendons, compressed nuclei

Question 5

dense irregular connective tissue

Answer 5

irregular arrangement of collagen fibers, refers to the meshwork orientation of fibers as in the dermis of the skin, etc.

Question 6

loose connective tissue

Answer 6

more cellular, relatively fewer fibers, often has high fat content, serves as packing material throughout the body with a variety of cell and fiber types

Question 7

embryonic connective tissue

Answer 7

mesenchyme - a loose connective tissue derived from mesoderm

mucouse connective tissue - fills umbilicord, has mucous, ECM is a gelatinous Wharton’s jelly, ground substance and fine collagen fibers

Question 8

ground substance

Answer 8

consists of GAGs, proteoglycans, and glycoproteins

strong negative charges on the GAGs hydrate the connective tissue and the clycoproteins link the cells, fibers, and matrix molecules to each other

Question 9

connective tissue fibers

Answer 9

classified as collagen, elastic, and reticular fibers

composed of fibrils, aggregates of long molecules

can fibers can be in the form of thick or thin filaments arranged in a meshwork, in patches, or in dense sheets

produced by fibroblasts, smooth muscle cells, and some others

Question 10

organization of collagen

Answer 10

alpha1 and alpha2 chains form triple helices, which form moelecules that are packed into fibrils

regularly repeating lysines, one polypeptide can go from 600 to 1000 amino acids long

gaps are staggered, tensile strength of steel due to hydrogen bonding and disulfide bonds

even repeates of glycines in a glycine,proline-hydroxyproline sequence

Question 11

procollagen

Answer 11

collagen before leaving, inactivated by two globular ends on either side

assembled in the ER and fibrils completed extracellularly

vitamin C is required for the hydrogen bonds to form between alpha chains to stabilize the triple helix of the collagen molecule

Question 12

collagen assembly - nucleus

Answer 12

transcription and post-transcriptional modifications

mRNA formed

Question 13

collagen assembly - rER membrane

Answer 13

pro-alpha chain translation

single alpha chain polypeptides formed with globular heads at each end

hydroxylation of proline and lysine, vitamin C necessary

sugar groups added

Question 14

collagen assembly - rER lumen

Answer 14

procollagen molecule assembled

triple helix formed from the C-terminal end to the N-terminal

hydrogen and disulfide bonds form

procollagen molecule transported to the golgi

Question 15

collagen assembly - golgi

Answer 15

procollagen transport to the cell membrane

procollagen molecules associate into bundles

bundles of procollagen packed into vesicles that release them to extracellular coves bounded by fibroblast cell membrane

Question 16

collagen assembly - extyracellular “coves of fibroblasts

Answer 16

completion of collagen molecule, assembly into fibrils

globular ends cleaved, molecules align and assembled head to tail in quarter stagger to form fibrils

molecules cross-linked with covalent bonds at lysine-hydroxylysine aldehyde groups

other collagen types added to the fibril

Question 17

type I collagen

Answer 17

[(a1(I)2)(a2(I)]

Question 18

type II collagen

Answer 18

[a1(II)]3

Question 19

fibril-associated collagens with interrupted triple helices (FACITs)

Answer 19

have stretches without triple helices, can bend there

usually involved in connecting the fibril to intracellular matrices

role is to connect one fibril to another

Question 20

elastic connective tissue

Answer 20

thin fiber meshwork in loose connective tissue

denser fibers in ligamentum flava of the vertebral column and vocal cords

fenestrated elastic plates interspersed with smooth muscle layers in elastic arteries

Question 21

elastin

Answer 21

molecule that allows for elasticity by coiling up and attaching each other

when stretched, molecules straighten out

Question 22

desmosine and isodesmosine

Answer 22

large amino acids unique to elastic connective tissue, interconnect elastin molecules in a somewhat random pattern

Question 23

fibrillin

Answer 23

part of an elastic fibril, both in its interior and on its surface, forms very fine microfibrils that are depositied first as a template for elastic fibril assembly

without fibrilin, elastin molecules will form sheets rather than fibrils

Question 24

Marfan’s syndrome

Answer 24

defect in the autosomal dominant fibrillin gene, resulting in dysfunctional elastic tissue throughout the body

Question 25

reticular fibers

Answer 25

named for arrangement as a reticulum, a branched, interconnecting meshwork in the loose connective tissue stroma of lyphatic tissues and hemopoietic tissues

surround blood vessels, nerves, fat cells, and mucle cells, at the interface between epithelia and underlying connective tissue

also prominent in the embryo and early wound healing

Question 26

reticular fibrils

Answer 26

composed of type III collagen and have the same banding pattern as type I collagen fibrils, form fibers that are narrower in diameter, wavy, and have a higher sugar content than type I collagen fibers

Question 27

reticular cells

Answer 27

in lymphatic and blood-forming tissues, given name because of their unique relationship to retiucal fibers, surround the fibers they produce with their cytoplasm

Question 28

GAGs

Answer 28

repeating, unbranched disaccharides with negative charges, longest GAG is hyaluronan, gives gel-like quality to connective tissue, cartilage matrix, synovial fluid, and vitreous humor in the eye

Question 29

proteoglycans

Answer 29

GAGs attached to a linear core protein to make a brush-like structure

often linked to hyaluronan to help stiffen cartilage matrix or can be smaller transmembrane molecules that function in cell-matrix interactions

Question 30

multiadhesive glycoproteins

Answer 30

small proteins with a variety of configurations that have binding sites for most components of connective tissues and basal cell membranes of epithelia, help stabilize connective tissues

Question 31

connective tissue cells

Answer 31

most varied in loose connective tissue, can be classified as permanent or transient

responsible for manufacturing and maintining the connective tissue fibers and matrix molecules, wound healing, inflammatory response to injury, participation in immune response

Question 32

fibroblasts

Answer 32

connective tissue workhorse cells that produce all of the fiber and matrix component molecules

myofibroblasts have secretory properties of fibroblasts and contractile properties of smooth muscle

Question 33

macrophages (histiocytes)

Answer 33

phagocytic cells derived from monocyte blood cells

have indented nuclei like monocytes and cellular features characteristic of their function such as numerous lysosomes and endocytotic vesciles with produces of ingestion/digestion

Question 34

mononuclear phagocytic system

Answer 34

consists of phagocytic cells throughout the body that are derived from monocytes

Question 35

mast cells

Answer 35

connective tissue equivalent of basophils in blood, involved in immune responses where the cells release histamine that causes edema from increased permeability of small blood vessels, the anticoagulant heparin, and other factors

Question 36

Name the different resident cells in connective tissue.

Answer 36

fibroblasts, macrophages, mast cells, adipocytes, and adult stem cells

Question 37

monocytes

Answer 37

cells that migrate into connective tissue and differentiates into macrophages

stands for mononuclear leukocyte or a white blood cell with a nucleus that is not lobed

Question 38

plasma cells

Answer 38

differentiate from B-lymphocytes to secrete antibodies into the blood during an immune response

Question 39

lymphocytes

Answer 39

involved in the immune response, migrate into connective tissue in response to antigen presentation, some places they have a more permanent residence

Question 40

B lymphocytes

Answer 40

differentiate into plasma cells that secrete antibodies for a humoral immune response (antibodies in bloodstream)

Question 41

T lymphocytes

Answer 41

participate in cell-mediated immune response where they become killer T-cells that attack bacteria, etc.

Question 42

granulocytes

Answer 42

cells that have lobed nuclei

Question 43

neutrophils

Answer 43

have multilobed nuclei and granules, and are named for their lack of staining

motile phagocytes and the most numerous white blood cells

first wave of cells to leave the blood stream at sites of injury, edema, infection, etc.

ingest and dsestroy infectious agents

Question 44

eosinophils

Answer 44

named for eosinophilic granules, function in allergic reactions, parasitic infections, and sites of chronic inflammation

Question 45

basophils

Answer 45

blood equivalent of mast cells in connective tissue

secrete histamine that increases vascular permability

secretes anticoagulant heparin

Question 46

What are the three major transient cells in connective tissue?