LECTURE 3

functions of connective tissues

* support
* connect
* protect
* battleground of the immune system
* contains nerves, blood and lymphatic vessels
* contains fat and tissue fluid

the three general characteristics of connective tissues

ECM
cells
blood and lymphatic vessels, nerves

what two components make up the ECM

ground substance and fibers

how are CT classified

fiber type and organization

malignant neoplasms from CT elements

sarcomas

three types of fibers that make up the ECM

- collagen (type I)
- reticular fibers (type III)
- elastic fibers

the stuff between the cells, fibers, and blood vessels in the ECM

ground substance

ground substance composed of

* water, electrolytes, +/- edema


* glycosaminoglycans (GAGs)
* proteoglycans

what structure forms a continuous network throughout the body?

interstitium

interconnected spaces are filled with moving fluid and supported by strong flexible proteins

interstitium

where does the fluid from the interstitium empty into?

the lymphatic system

true or false - cancer cells quickly metastasize once they reach the fluid-filled spaces in the CT because the fluid empties into the blood vessels.

false - empties into the lymphatic system

true or false - the 3 basic fiber types are present in all connective tissue.

true

what type of cells secrete fibers and ground substance?

fibroblasts

which of the following is not true of type I (collagen fibers)?
a. they are large fibers formed from type I collagen
b. it is the most common form of collagen
c. their function is for stretch and recoil
d. it is easily seen as acidophilic bundles
e. they are the main component in tendons and ligaments because of their strength and flexibility

c

what is the first fiber to form in the embryo and wounds?

reticular fibers

which of the following is not true of reticular fibers?
a. they are delicate and thin that crosslink to form a meshwork
b. made of type II collagen
c. they are only visible with special silver stains, not H&E
d. they are common in highly cellular lymphoid organs, bone marrow, reticular lamina of BM
e. they form delicate supporting framework for cells

e

what cell secretes reticular lamina?

fibroblasts in CT

true or false - the reticular lamina, along with the basal lamina, make up the BM.

true

what type of fiber is associated with Ehlers-Danlos syndrome?

reticular fibers

which of the following is not true of elastic fibers?
a. they form framework in highly cellular lymphoid organs
b. they are thin branching fibers made of elastin with microfibrillar proteins
c. they are typically not visible. large amounts and special stains are required
d. they are for stretch in recoil
e. they are organized into sheets in the aorta

a

what type of fiber is Marfans syndrome associated with?

elastic

what is described as the inherited disease due to a mutation in a fibrillin protein?

marfans syndrome

what are the two types of CT cells?

fixed and wandering

which of the following is not a fixed CT cell?

a. osteoblast b. endothelial cells

c. adipose cells

d. mast cell

e. fibroblasts

d - wandering CT cell

how are CT classified

predominant fiber type and organization

where is adult CT derived from

mesenchyme

what is the ECM composed of

ground substance and fibers

3 types of fibers in the ECM

collagen (type I)
reticular fibers (type III)
elastic fibers

the stuff btwn the cells, fibers, and blood vessels

ground substance

what is ground substance composed of

water
electrolytes
+/- edema
glycoasminoglycans (GAGs)
proteoglycans

hyaluronic acid

glycoasminoglycans (GAGs)

multi-adhesive sticky glycoproteins

proteoglycans

ex of glycoproteins

laminin and fibronectin

interconnected spaces, filled with moving fluid and supported by strong flexible proteins

interstitium

where does the interstitium empty its fluid

lymphatic system

large fibers formed from type I fibers

collagen

most common form of collagen

collagen fibers

appearance of collagen fibers in H&E

visible acidophilic bundles

very strong and flexible; main component in tendons and ligaments

collagen fibers

delicate, thin fibers made from type III collagen fibers; crosslink to form a meshwork

reticular fibers

appearance in H&E of reticular fibers

visible only with special silver stains

forms delicate supporting framework for cells

reticular fibers

common in highly cellular lymphoid organs

reticular fibers

highly cellular lymphoid organs

spleen
lymph node
bone marrow
liver

forms reticular lamina of BM

reticular fibers

thin, branching fibers made of elastin with microfibrillar proteins

elastic fibers

appearance of H&E in elastic fibers

not visible, unless seen in large amounts
special stains usually needed

stretch and recoil

elastic fibers

fiber in aorta

elastic fibers

banding in type I collagen fibers is due to

overlapping tropocollagen molecules

first fibers to form in embryo and wounds

reticular

type III collagen

reticular fibers

medical terms that indicates the ability to touch the tip of the nose or chin with the tongue

gorlin sign

inherited CT disorder

ehlers-danlos syndrome

mutation in type III collagen

ehlers-danlos syndrome

inherited mutation in a fibrillin protein that results in defective elastic fibers

marfans syndrome

syndrom where pts are tall and thin w extremely long arms, legs, fingers, toes, and hyperflexible jts

marfans syndrome

fibroblasts and adipose cells

fixed CT cells

endothelial cells
mesothelial cells
chrondroblast/cyte
osteoblast/cyte

other fixed CT cells

spindle shaped cell with flat, dark nucleus, cytoplasm usually not visible

fibroblast

largest cell, round and empty in H&E, flat nucleus, signet ring shape

adipose cell

attached to the CT by a basal lamina

adipose cell

principle cell of CT

fibroblasts

flat heterochromatic nucleus

fibroblasts

secretes and maintains matrix

fibroblasts

motile and can reproduce (mitosis)

fibroblasts

assembled in fibril and fibers outside of cell

fibroblasts

produces ground substance and the 3 types of fibers

fibroblasts

growth and wound healing

active fibroblasts

active fibroblasts have a plumper, more \_____________ cytoplasm w a more \__________ nucleus

basophilic; euchromatic

what can fibroblasts differentiate into

myofibroblasts

contractile cells active in wound contraction

myofibroblasts

adipocytes

adipose cells

large cell w a giant lipid droplet (neutral fat)

adipose cells

thin rim of cytoplasm, flat heterochromatic nucleus

adipose cells

unilocular cells

adipose cells

multilocular cells

brown fat

where is brown fat found

fetus and newborns

fx of brown fat

serves as energy source; heat

WBCs are

wandering cells

examples of wandering cells

* lymphocytes
* monocytes
* neutrophils
* eosinophils
* basophils

T cells and B cells

lymphocytes

mast cells and macrophages

monocytes

large amoeboid-like cell with grains filling the cytoplasm, obscuring the round nucleus

mast cell

large amoeboid-like cell with particulate debris in cytoplasm after "eating"

macrophage

small round cell with soccer ball nucleus

plasma cell

stain of plasma cell cytoplasm

basophilic

small round cell with dark nucleus and thin rim of cytoplasm

lymphocyte

small cell with a bilobed nucleus and distinct red grains in the cytoplasm

eosinophil

small cell with kinky, segmented nucleus

neutrophil

small cell with indented nucleus, grayish cytoplasm

monocyte

cytoplasmic secretory vesicles

mast cells

wandering cell that likes to be near blood vessels

mast cells

stain of mast cells

purple/pink

secretes heparin, histamine, and leukotrienes

degranulating mast cell

immediate hypersensitivity rxns, allergy, anaphylaxis, hives, asthma

degranulating mast cells

histocyte from monocytes in blood

tissue macrophage

histocyte from monocytes in blood

macrophage

wandering phagocytic cells

macrophage