Intro to CT

Question 1

What are the functions of CT?

Answer 1

Provide and maintain form in the body
Provide a matrix that connects and binds cells and tissues together
Serve as a reservoir for hormones that control cell growth and differentation
Medium through which nutrients and metabolic wastes are exchanged b/w cells and their BS

Question 2

What are the three main components of CT?

Answer 2

1) Cells-many types
2) Fibers-protein polymers—collagen fibers, also reticular and elastic
3) Ground substances-viscous mixture of water, proteoglycans, glycosaminoglycans, and glycoproteins=ECM

Question 3

Mesenchymal Cells

Answer 3

fibroblasts, chondrocytes, osteoblasts, adipocytes, endothelial cells, and smooth muscle cells

Question 4

Hematopoietic Cells (blood)

Answer 4

mast cells, basophils, eosinophils, neutrophils, macrophages, lymphocytes (T & B cells), RBCs

Question 5

Macrophage-like cells

Answer 5

monocytes (blood), macrophage (tissue), multinuclear giant cell (CT), kupffer cell (liver), microglia (CNS), Langerhans cells (skin), dendritic cell (lymph nodes), osteoclasts (bone)

I.E. cells that remove debris and “bad guys”

Question 6

What are the fibers that CT can be?

Answer 6

collagen, reticular, and elastic fibers

–amount and type present in a tissue give characteristics to each particular CT

Question 7

Important CTs include:

Answer 7

Tendons, ligaments, aponeuroses, fascias, dermis, organ capsules, stroma of organs, covering of muscles and nerves, membranes (meninges) surrounding the CNS

Question 8

Collagen Fibers

Answer 8

provides resistance to tensile force: prevent tissues from being pulled apart from each other

There are 25 “collagen types” however 1,2,3,4 are the most abundant
1>3>2>4
Each fiber is made of bundled collagen fibrils

Question 9

Type 1 Collagen

Answer 9

strongest, largest collagen fibers, most abundant type

Question 10

Type 2 Collagen

Answer 10

found in articular cartilage and fibrocartilage

Question 11

Type 3 Collagen

Answer 11

synonymous with reticular fibers; found in skin, artery wall, scar tissue, loose CTs

Question 12

Type 4 Collagen

Answer 12

major filament of basement membranes (basal lamina)

Question 13

Reticular fibers

Answer 13

composed of type 3 collagen fibrils

smaller diameter and “loosely” arranged

• -creates a flexible network for organs that incur volume changes (arteries, spleen, liver, uterus)
• -abundant in smooth muscle, neurons (endoneurium), and hematopoietic organs (bone marrow, lymph nodes, spleen papillary layer of dermis–sits directly under the basement layer)

Question 14

Elastic fibers three types

Answer 14

oxytalan, elaunin, elastin

Question 15

Oxytalan

Answer 15

small fibers that do not actually contain elastin protein but are resistant to tensile forces

Question 16

Elaunin

Answer 16

mixture of elastin protein and oxytalan fibers

Question 17

Elastin

Answer 17

polymers of elastin aggregate in the center of elastic fibers and are surrounded by network of oxytalan and elaunin fibers

Question 18

Ground substance (tissue fluid)

Answer 18

viscous, hydrophilic substance with many macromolecules; occurs BETWEEN cells

Question 19

Macromolecules

Answer 19

(glycosaminoglycans(GAG), proteoglycans, glycoproteins)

bind cell surface receptors to fiber components of ECM
anchor cells w/in ECM; provides tissue strength and rigidity

Question 20

What does ECM=

Answer 20

fibers + ground substance

Question 21

Glycosaminoglycans

Answer 21

Hyaluronic acid = articular cartilage

Chondroitin 4-sulfate = cartilage, bone, skin

Chondroitin 6-sulfate = cartilage, skin, aorta

Dermatan sulfate = skin, tendons

Heparan sulfate = lung, liver, basement membrane

Keratan sulfate = cartilage, nucleus pulposus, annulus fibrosus

Question 22

What is CT proper?

Answer 22

Loose CT
Dense CT (regular or irregular): tendons, ligaments, fascia, some CT of organs

Question 23

Specialized Connective Tissue

Answer 23

adipose, elastic, hematopoietic, and mucous tissue (umbilical cord)

Question 24

Supporting CT

Answer 24

cartilage and bone

Question 25

What does loose CT support?

Answer 25

structures that are normally under low pressure and low friction forces

Question 26

Characteristics of Loose CT

Answer 26

flexible tissue, well vascularized, not very resistant to tensile stress
contain mainly fibroblasts and collagen, w/lesser amounts of elastic and reticular fibers
VERY COMMON

Question 27

Where do you find Loose CT

Answer 27

Epithelium, endomysium, endoneurium, dermis, lining of peritoneal and pleural cavities, surrounding glands, blood vessels and mucous membranes

Question 28

What is dense CT main fxn?

Answer 28

offer resistance to tensile force and protection of tissues

Question 29

Characteristics of Dense CT

Answer 29

fewer cells (fibroblasts) and predominance of collagen fibers compared to loose CT
Minimally flexible and highly resistant to stress (especially tension)
composed of irregular and regular types dependent on arrangement of fibers in ECM

Question 30

Dense regular CT

Answer 30

collagen bundles arranged into a definitive, linear pattern designed to with stand prolonged stresses exerted in the direction of fiber alignment

Examples: Tendons, ligaments

Question 31

Dense irregular CT

Answer 31

Collagen fibers are arranged in bundles w/o a definite orientation
provide resistance to stress in all directions
Example: Dermis (reticular layer)

Question 32

Elastic tissue: yellow

Answer 32

ligamentum flavum is most common site of this
composed of thick, parallel elastic fiber bundles and fibroblasts
thin collagen fibers are scattered among the elastic fiber bundles
provides elasticity to tissues; provides recoil from flexed positions

Question 33

Reticular Tissue

Answer 33

loose CT: specialized

Reticular fibers and cells form a sponge-like structure where cells and fluids can move easily