Download page 1 of 5 LECTURE OUTLINE: CTP

LECTURE OUTLINE & REVIEW QUESTIONS
LECTURE OUTLINE: CTP
(Connective Tissues Proper) (Ordinary Connective Tissues)
General Definition: Tissues composed of cells embedded in an
extracellular (intercellular) matrix, consisting of ground substance
and protein fibers.
General Functions:
Structural
Capsules & internal frameworks of soft organs
Packing in spaces between organs
Loose connections between structures
Wrapping & bundling structures
Tendons connecting muscles to bones
Ligaments connecting bone to bone
Transport of materials (nutrients, gases, vitamins, hormones, etc.)
to and from cells.
Bloodstream <-> Tissue fluids <-> Cells
Defense
Physical barrier against spread of microorganisms
Removal of damaged cells & tissues
Tissue repair
Immunological reactions
General Composition:
1. Matrix
Ground substance
Glycosaminoglycans (GAGS)
Linear polysaccharides
Proteoglycans
GAGS (~90%) bound to a protein “core” (~10%)
Hydrophilic (attract water)
Structural Glycoproteins
Proteins (predominate) + carbohydrates (not GAGS)
Tissue fluid
Filtrate of blood plasma.
Pathway for materials moving between bloodstream &
cells.
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Most water is hydrated to GAGS.
Different connective tissues differ in their ground substance
composition. Result: different functional characteristics.
Protein Fibers
Collagen
Basic Structure:
3 polypeptide chains  tropocollagen
Linked tropocollagen molecules  collagen fibril
Collagen fibrils  collagen fiber
Collagen fibers  collagen bundles
Twelve types of collagen (I-XII)
Differ in alpha chain amino acid composition
I, II, III, IV most common
In CTP:
Type I: collagenous (white) fibers or bundles
Type III: reticular fibers (massed fibrils)
Elastin
Structure: Fibrils embedded in periphery of amorphous core
to form fibers.
2. Cells (“Resident Population”)
Fibroblasts / Fibrocytes
Most common CTP cell type
Differentiate from mesenchymal cells
Produce and maintain:
Ground substance GAGS, proteoglycans, glycoproteins
Protein fibers (collagenous, reticular, elastic)
Cytological characteristics of protein secreting cells.
Fibroblasts more active; fibrocytes less active.
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LECTURE OUTLINE & REVIEW QUESTIONS
Tissue Macrophages
Terminology: Resident / Elicited / Activated
Functions:
Phagocytosis of dead or damaged cells, tissue
components, invasive microorganisms.
Activation: chemical signal from damaged cells, extracellular
tissues, invasive particulates.
Chemotaxis & Amoeboid motion: Follows chemical trail
to area of damage or invasion.
Phagocytosis and Lysosomal Digestion
APC (Antigen presenting cell) Function
Phagocytosis of bacteria
Activation: chemical signal from bacteria
Chemotaxis & Amoeboid motion
Opsonization
Bacteria coated with complement &
immunoglobulins.
Complement & immunoglobulins lock onto
macrophage plasmalemma receptors.
Phagocytosis: phagosome  intracellular digestion
Presentation of bacterial components to other immune
reaction cells
Secretion
Release a variety of factors affecting the activity of white
blood cells, fibroblasts, and platelets.
Mononuclear Phagocyte System (MPS)
A body-wide system of phagocytic cells that meet the
following requirements:
Bone marrow stem cells differentiate into monocytes
Monocytes transported through bloodstream
Monocytes leave blood stream, enter tissues, and
differentiate into phagocytic cells:
CTP: tissue macrophages
Liver: Kuppfer cells
Lungs: alveolar macrophages
Anatomy 25.mguthrie
ANATOMY 25 - GUTHRIE
Bone: osteoclasts
Brain: microglia
Skin: Langerhans cells
Joints: type A cells
Adipocytes (fat cells)
Origin: mesenchymal cells adipoblasts  unilocular
(white) adipocytes or multilocular (brown) adipocytes
Functions:
White fat cells
Lipid storage
Packing & cushioning
Insulation
Secretion
Brown fat cells
Heat production
Hormones secretion ?
Mast Cells
Origin: bone marrow precursor cells  bloodstream
tissues  mast cells
Cytoplasmic granules: histamine (vasodilator); heparin
(anticoagulant); trypsin & chymase (enzymes);
eosinophilic chemotactic factor; leukotrienes
Functions: Hypersensitivity Reactions
Allergic reactions, asthma, anaphylactic shock
Initial exposure to an antigen:
Antigen  B-lymphocytes  plasma cells  antigen
specific antibody  Antigen-antibody complex
Plasma cells  antigen specific IgE  mast cell
plasmalemma IgE receptors
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LECTURE OUTLINE & REVIEW QUESTIONS
Subsequent exposures
Antigen  plasma cells  antibody
Antigen  mast cells  degranulation
Leukotrienes  bronchiolar constriction
Heparin  anticoagulant
Histamine  capillary dilation & bronchiolar
constriction
ECF  attracts eosinophils
3. Cells (“Wandering Population”)
Plasma cells
Antigen  B-lymphocyte  plasma cells + memory cells.
Plasma cells  antigen specific antibody
Neutrophils (neutrophilic leukocytes)
“Specialists” in bacterial phagocytosis
Eosinophils (eosinophilic leukocytes)
Modulate inflammatory reactions
Phagocytize antigen-antibody complexes
Combat some parasites
Classification: Types of CTP
Loose CT (Areolar Tissue)
“Tossed salad” of collagenous, reticular and elastic fibers +
fibrocytes, macrophages, mast cells, fat cells + plasma cells,
neutrophils and eosinophils as necessary
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Adipose Tissue
White fat
Masses of unilocular fat cells with some loose ct between.
Each cell supported by a “girdle” of reticular fibers
Brown fat
Masses of multilocular fat cells. Highly vascularized.
Dense Irregular CT
Essentially a compacted loose ct. Fibers appear to be randomly
oritented, but actually reflect stresses imposed on them.
Dense Regular CT
Parallel bundles of collagenous fibers wrapped with loose ct.
Fibrocytes - only cells present – squeezed in rows between
bundles.
Forms ligaments & tendons
Elastic Tissue
Dense bundles or sheets of elastic fibers
Examples: ligamentum nuchae; elastic laminae of blood vessels
Mucous Tissue
A “primitive” connective tissue.
Example: Wharton’s jelly in umbilical cord.
Contains stem cells (mesenchymal cells)
Reticular Tissue
Interlacing network of reticular fibrils + fibrocytes (sometimes
called reticulocytes) and macrophages.
Forms a scaffolding for some soft organs.
Example: lymph nodes
Anatomy 25.mguthrie
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LECTURE OUTLINE & REVIEW QUESTIONS
1.
CTP matrix consists of _?_. (a) cells and protein fibers (b) cells
and tissue fluid (c) ground substance and protein fibers (d)
tissue fluids and protein fibers (e) none of these
2.
The ground substance of CTP is a chemical solution that
contains _?_. (a) glycosaminoglycans: polysaccharides (b)
proteoglycans: GAGS bonded to a protein core (c)
glycoproteins: proteins + non-GAG carbohydrates (d) water:
mostly solvated to proteoglycans (e) all of these
3.
Select the incorrect statement about collagen. (a) All collagen
molecules are identical. (b) Collagen fibers are bundles of
collagen fibrils. (c) Collagen fibrils are arrays of tropocollagen
molecules. (d) Tropocollagen molecules consist of three
intertwined polypeptide chains. (e) Collagen is a protein.
4.
Select the correct statement about the matrix protein fibers of
CTP. (a) Collagenous or white fibers are bundles of type I
collagen fibrils. (b) Reticular or argyrophilic fibers are bundles of
type III collagen fibrils. (c) Elastic or yellow fibers consist of a
core of the protein elastin and associated microfibrils. (d) All of
these are correct. (e) None of these is correct.
5.
Select the incorrect statement. Fibroblasts or fibrocytes _?_. (a)
are the least common cell type in CTP (b) are derived from
mesenchymal cells (c) produce the gags, proteoglycans, and
glycoproteins of the ground substance. (d) produce collagenous,
reticular, and elastic fibers. (e) have the cytological characteristics
of protein secreting cells.
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part of the mononuclear phagocyte system (e) All of these are
incorrect.
8.
Activated macrophages do not _?_. (a) phagocytize damaged
cells and tissue components (b) phagocytize bacteria and
particulate foreign materials (c) process and present antigens to
lymphocytes (d) secrete substances that affect white blood cells
and fibroblasts (e) produce circulating antibodies
9.
Which is the second step in the macrophage processing of an
invading bacterium ? (a) opsonization of the bacteria (b)
phagocytosis and phagosome formation (c) binding of the
bacterium to C3 complement and Fc receptors on the
macrophage membrane (d) lysosomal breakdown and processing
of the bacterium (e) presentation of bacterial breakdown
products on the macrophage plasmalemma to lymphocytes
10. Connective tissue mast cells _?_. (a) originate from bone marrow
stem cells (b) contain cytoplasmic granules of histamine,
heparin, enzymes, and ECF (c) are involved in inflammatory
reactions, allergies, and anaphylactic shock (d) interact with
plasma cells (e) all of these
11. Which mast cell factor do you think is most responsible for the
swelling (edema), redness (erythema), and increased warmth
(heat) characteristic of inflammatory reactions ? (a) heparin (b)
histamine (c) eosinophilic chemotactic factor (d) antigenspecific IgE receptors (e) none of these
12. Lipoblasts _?_. (a) are undifferentiated adipocytes (b) are
6.
Which cell type do you think is responsible for scar formation ?
(a) macrophage (b) white adipocyte (c) mast cell (d) fibroblast
(e) neutrophils.
7.
Select the incorrect statement about CTP macrophages. (a) Like
fibroblasts, they develop from mesenchymal cells. (b) They are
activated by chemical signals indicating cell damage, tissue
damage or the presence of invasive organisms (c) They exhibit
chemotaxis, amoeboid motion, and phagocytosis. (d) They are
derived from mesenchymal cells (c) differentiate into either
brown or white fat cells (d) all of these (e) none of these
13. White fat cells _?_. (a) are more common than brown fat cells
Anatomy 25.mguthrie
(b) are unilocular (c)are usually surrounded by a thin girdle of
reticular and collagenous fibers (d) all of these (e) none of these
14. Brown fat cells _?_. (a) are multilocular (b) are more numerous
in infants than in adults (c) have more mitochondria and
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LECTURE OUTLINE & REVIEW QUESTIONS
produce more heat than white fat cells (d) all of these (e) none of
these
15. Plasma cells _?_. (a) are derived from B-lymphocytes (b) are
derived from mast cells (c) produce circulating antibodies (d) a
& c (e) b & c
16. Which white blood cell enters the connective tissues to
phagocytize antigen-antibody complexes ? (a) monocyte (b)
neutrophil (c) eosinophil (d) B-lymphocyte (e) none of these
ANATOMY 25 - GUTHRIE
24. Dense regular connective tissue _?_. (a) contains closely packed,
parallel bundles of collagenous fibers (b) contains only fibrocytes
(c) makes up tendons, ligaments, and aponeuroses (d) all of
these (e) none of these.
25. Select the incorrect statement about most of the adipose tissue in
the body. (a) It consists of closely packed multilocular adipocytes
(b) It is white fat. (c) It is a storage depot for lipids, a source of
energy and raw materials. (d) It packs spaces around organs,
provides protection to various structures, and absorbs shocks. (e)
It provides insulation and helps to conserve body heat.
17. Which white blood cell is a “specialist” in the phagocytosis of
bacteria ? (a) monocyte (b) neutrophil (c) eosinophil (d) Blymphocyte (e) none of these
26. Which CTP is found in the umbilical cord ? (a) areolar (b)
mucous (c) elastic (d) adipose (e) reticular
18. Loose c.t. usually contains _?_. (a) fibroblasts & fibrocytes (b)
mast cells (c) fat cells (d) macrophages (e) all of these
19. Loose c.t. contains _?_. (a) collagenous fibers (type 1 collagen)
(b) reticular fibers (type III collagen) (c) elastic fibers (d) all of
these (e) none of these
20. Loose c.t. is also called _?_ . (a) reticular tissue (b) mesenchymal
tissue (c) elastic tissue (d) areolar tissue (e) mucous tissue
21. _?_ tissue consists of reticular fibers, fibrocytes and macrophages
that form a supporting meshwork for some soft organs. (a)
areolar (b) mucous (c) reticular (d) dense irregular (e) dense
regular
22. Dense irregular c.t. is most similar in its composition to a
compacted _?_. (a) reticular tissue (b) dense regular c.t. (c) loose
c.t. (d) elastic tissue (e) adipose tissue
23. Which connective tissue proper forms capsules and supporting
frameworks for soft organs, fasciae, and most of the dermis of
the skin ? (a) areolar (b) dense regular (c) dense irregular (d)
reticular (e) elastic.
Anatomy 25.mguthrie
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