Connective Tissue I and II

Question 1

what are some general characteristics of connective tissue?

Answer 1

-low cell density, extensive ECM

-tend to be highly vascular —> imp for helping other cells get blood

-most retain stem/mitotic cells (tissue growth and regeneration)

Question 2

what is CT composed of?

Answer 2

-cells
-ECM (ground substance and fibers)
—> determines physical properties; synthesized and secreted by cells

major component: ECM

Question 3

what is ground substance?

Answer 3

-colorless, transparent, gel-like
-highly hydrated

-mixture of macromolecules (proteoglycans and glycosaminoglycans)

Question 4

describe ECM fibers

Answer 4

-made of collagen (thick) and elastic (skinny)

-determines physical properties
-synthesized and secreted by cells

Question 5

describe collagen organization

Answer 5

tendon —-> collagen bundles —> fibers —-> fibrils

Question 6

describe type 1 collagen

Answer 6

-has highest tensile strength
-gross: white
-LM: pink fibers and bundles with H&E

found in: bone, teeth, tendons, etc

Question 7

describe type 2 collagen

Answer 7

-slender fibrils found in cartilage

Question 8

describe type 3 collagen (aka reticular fibers)

Answer 8

-functions to filter fluid

-appears delicate, branching, dark-staining with silver

found in lymph nodes

Question 9

describe elastic fibers

Answer 9

-imparts elasticity
-USUALLY WITH COLLAGEN
-core of elastin surrounded by sheath of microfibrils

LM: darker, thinner than collagen

don’t branch

Question 10

describe fibroblasts

Answer 10

-make fiber
-capable of producing all ECM compartments
-especially active during growth, wound healing, scar tissue formation

-LM: elongated, oval nucleus
-TEM: form at discrete sites along the cell membrane

-constitutive until cell told to stop

Question 11

describe adipocytes and name the 2 types

Answer 11

-white, spheroid cells
-synthesize and store fat

TYPES: unilocular and multilocular

Question 12

describe unilocular adipocyte

Answer 12

-most common adipocyte
-large cell
-eccentric nucleus w/thin rim of cytoplasm (signet ring)
-fat stored as single lipid inclusion (lipid droplet)

Question 13

describe multilocular adipocyte

Answer 13

-located in brown adipose tissue
-fat stored in multiple lipid inclusions
-more mitochondria, heat production

FOUND IN INFANTS

Question 14

describe mast cells

Answer 14

-large cell with round, centrally-placed nucleus
-cytoplasm has many dark (basophilic) granules
-released following exposure to sensitized antigens

-granules: histamine, heparin, leukocyte chemotactic factors

Question 15

where are mast cells found?

Answer 15

near blood vessels in skin, digestive system, respiratory system

WHY: most in contact with bacteria there

Question 16

describe macrophages

Answer 16

-long-living cells that originate in bone marrow and migrate out
-develop from precursors called monocytes
-RESIDE IN CT
-large, very irregular outline

Question 17

describe plasma cells

Answer 17

-transient

-synthesize and secrete antibodies
-eccentric nucleus w/extensive euchromatin
-found mainly in GI and respiratory tracts

Question 18

describe loose (areolar) CT

Answer 18

-sparse, loosely arranged fibers
-abundance of ground substance
-primarily beneath epithelium
-primary site of immune and inflammatory reactions

Question 19

describe dense CT

Answer 19

-abundance of bundled fibers
-little ground substance
-can be regular or irregular

Question 20

describe irregular dense CT

Answer 20

disorganized

strong in all directions (ie: not super strong in any one direction)

Question 21

describe regular dense CT

Answer 21

“box car” nuclei

wavy appearance

Question 22

describe reticular tissue

Answer 22

-delicate, lattice work of reticular fibers
-found in organs that filter: blood or lymph nodes
-also found in endocrine glands