Histology - Connective Tissue

Front 1

connective tissue functions 

Back 1

1.      Connects and anchors

2.      Supports organs

3.      Protection and padding

4.      Repair

5.      Line of defense in the inflammatory and immune systems

Front 2

mesenchyme 

Back 2

the simplest form of embryonic connective

composed of mesenchymalcells, amorphous ground substance and very few fibers

Front 3

mesenchymal cells 

Back 3

stellate-shaped with a minimum number of organelles. These cells are multipotential in that they can differentiate into all types of connective tissue proper as well as cartilage, bone and blood.

Front 4

Extracellular Matrix

Back 4

the substance between cells composed of amorphous ground substance,fibers and fluid. 

Front 5

amorphous ground substance

Back 5

a material without structure that is secreted by and surrounds the cell. 

1) Determines the hardness and viscosity of a tissue

2) Regulates the movement of substances between cells

Front 6

Proteoglycans

Back 6

complex glycoproteins that are formed by a central core protein that is heavily bounded by carbohydrates. The carbohydrate is composed of linear repeating units of disaccharides (two sugars) in which one sugar is in its acid form and the other has an amino group attached. The repeating unit of carbohydrate is called a glycosaminoglycan.

Front 7

glycosaminoglycans (GAGS)

Back 7

complex carbohydrates that are composed of linear repeating units of disaccharides (two sugars) in which one sugar is in its acid form (COOH group) and the other has an amino group (NH2).

Front 8

chchondroitin sulfate 

Back 8

GAG found primarily in cartilage and bone 

Front 9

dermatan sulfate 

Back 9

GAG found primarily in the C.T. of skin 

Front 10

Keratan sulfate 

Back 10

GAG found primarily in cartilage 

Front 11

Heparan sulfate 

Back 11

GAG found primarily in basement membrane 

Front 12

Hyaluronic acid 

Back 12

GAG found primarily in cartilage and loose C.T.

Front 13

Proteoglycan aggregates

Back 13

large glycoprotein molecules in the amorphous ground substance composed of numerous proteoglycan subunits attached to hyaluronic acid.

Front 14

collagen 

Back 14

the most abundant fiber type in the body

high tensile strength, major supporting role 

found in most tendons and ligaments 

Front 15

collagen fibrils 

Back 15

formed by staggered tropocollagen units

appear striated due to overlapping of tropocollagen 

Front 16

type I collagen 

Back 16

collagen found in tendons, ligaments, bone, dentin, and dermis of skin 

Front 17

type II collagen 

Back 17

collagen found in cartilage 

Front 18

type III collagen 

Back 18

collagen found in reticular fibers, dental pulp, lymph nodes, and bone marrow 

Front 19

type IV collagen 

Back 19

collagen found in basement membrane 

Front 20

reticular fibers 

Back 20

-small diameter fibers that form a delicate supporting system for cells particularly in the bone marrow and lymphoid organs

-composed of mostly Type III collagen combined with other glycoproteins

-striated

silver-loving, stain black with silver

Front 21

elastic fibers 

Back 21

give elasticity and recoil to organs, are non-striated and do not have visible subunits

contain an amorphous material called elastin, which is molded into a fiber by small microfibrils. These fibers are abundant in organs that need to stretch and recoil such as the aorta, lungs and elastic cartilage

Front 22

fixed cells 

Back 22

adult C.T. cells that are a permament population of cells that form and maintain the amorphous ground substance and fibers within the C.T.

fibroblasts and adipose cells 

Front 23

wandering cells 

Back 23

adult C.T. cells that are derived from the bone marrow and enter the peripheral circulation to reach connective tissue

mast cells

leukocytes 

Front 24

fibroblasts 

Back 24

the most numerous cells in connective tissue proper. The cell is irregular in shape and contains an abundance of rough endoplasmic reticulum.

synthesis and secrete the building blocks of the fibers and amorphous ground substance found in the extracellular matrix

function of this cell is the maintenance of the extracellular matrix

Front 25

adipose cell

Back 25

fat cell

signet ring shape, nucelus is in a thin ring of cytoplasm around a large fat vacuole 

function is the storage of fat for energy 

Front 26

macrophage 

Back 26

large irregular shaped cells similar in structure to the fibroblast

contain many large, irregularly shaped lysosomes containing acid phosphatase

active phagocyte that engulfs foreign particles and worn out blood cells

derived from monocytes 

Front 27

plasma cell

Back 27

the antibody-forming cells of the immune system. 

oval in shape and is characterized by an eccentric (not in the center) nucleus and an abundance of rough endoplasmic reticulum.

function is to destroy antigens during the humoral immune response by the release of antibodies.

Front 28

mast cells 

Back 28

-large oval-shaped cells with an eccentric (not in the center) nucleus

-aligned along blood vessels

-contain an abundance of secretory granules 

-secrete histamine and heparin 

-function is to increase permeability of blood vessels during the inflammatory response 

Front 29

neutrophils 

Back 29

-the most abundant white blood cell representing 50-60% of the leukocyte population in peripheral blood

-characterized by a segmented nucleus formed by 3-5 lobules.

-contain specific granules containing many hydrolytic enzymes

-first line of cellular defense against bacteria 

Front 30

eosinophils 

Back 30

-compose 1-4% of the leukocytes in normal blood. However, during allergic responses their numbers increase 20-30%

-bilobed nucelus 

-function is to digest certain types of parasites and to phagocytize antigen-antibody complexes

-modulate immune response by neutralizing substances secreted by the lymphocytes and histamine 

Front 31

basophils 

Back 31

-0.5% of leukocytes 

-U-shaped nucelus, blue staining granules 

-contains heparin and histamine like mast cells

-function is to increase permeability of blood vessels during inflamation or immune response 

Front 32

lymphocytes

Back 32

-20-35% of leukocytes in blood

-no granules 

-very small, large nucleus 

-function in immune response 

-two classes: B and T

Front 33

B-lymphocytes 

Back 33

involved in humoral immunity. When stimulated, these cells undergo mitosis and differentiate into plasma cells.

Front 34

T-lymphocytes 

Back 34

-some varities involved in humoral immunity, others in cellular immune response 

-cellular: undergo mitosis and form killer T cells which destroy antigens and release lymphokines that attract macrophages and regulate other leukocytes

-humoral: help B-lymphocytes recognize the difference between foreign anitgens and our own proteins 

Front 35

monocyte 

Back 35

-largest leukocyte, 3-8% in blood

-large, kidney shaped nucleus

-abundant cytoplasm 

-function is to form all the tissue macrophages including osteoclasts and cementoclasts 

Front 36

loose/areolar connective tissue 

Back 36

-C.T. characterized by a loosely woven network of fibers

-mostly collagen, also some elastic and reticular fibers 

-wandering and fixed cells scattered throughout 

-binds structures together

-pathway for blood vessels and nerves

-pathway for body defense cells during immune response 

-generally found under every epithelial surface

-initial site of defense against bacteria 

Front 37

dense irregular connective tissue 

Back 37

-C.T. containing an abundance of interwoven fibers and few cells, mostly fibroblasts

-occurs in sheets surrounding muscles, forms capsules of organs, in dermis and lamina propria of gingiva 

-collagen most abundant fiber, some elastic, no reticular 

-supports and binds tissues together 

Front 38

dense regular connective tissue 

Back 38

-C.T. containing fibers organized in a regular, parallel fastion

-fibers are tightly packed, included fibroblasts are flattened and parallel 

-makes up tendons and ligaments 

-mostly collagen

Front 39

reticular connective tissue 

Back 39

-C.T. unique to lymph organs and bone marrow

-composed of stellate shaped reticular cells held together by reticular fibers in fishnet appearance

-supports lymphocytes or blood cells in corresponding tissue by suspending them in the spaces between cell processes 

Front 40

adipose tissue 

Back 40

-C.T. made of a large aggregation of adipose cells supported by a collagen framework

-stores fat

-insulates body from heat loss

-forms a padding 

Front 41

Back 41

addipose tissue 

Front 42

Back 42

basophil 

Front 43

Back 43

dense regular connective tissue 

Front 44

Back 44

elastic fibers 

Front 45

Back 45

eosinophil 

Front 46

Back 46

adipose cells 

Front 47

Back 47

fibroblasts 

Front 48

Back 48

loose connective tissue 

Front 49

Back 49

lymphocyte 

Front 50

Back 50

mast cell

Front 51

Back 51

mesenchyme 

Front 52

Back 52

monocyte 

Front 53

Back 53

neutrophil 

Front 54

Back 54

plasma cell 

Front 55

Back 55

reticular connective tissue 

Front 56

Back 56

reticular fibers