Chapter 2 Flashcards
What does the abbreviation CT stand for?
Connective Tissue
CT consists of _____ & ______
supportive cells & extracellular matrix
Matrix is composed of:
ground substance & fibers.
Functions of CT:
x4
- provide a structural support
- provide a medium for exchange of nutrients
- defense/protection
- storage of adipose
Characteristics of CT:
x4
- Most derived from mesenchyme
- support cells separated by matrix
- support cells produce matrix
- cells adhere to matrix
Ground Substance is made up of what?
Glycosaminoglycans, Proteoglycans, Adhesive glycoproteins, other.
Glycosaminoglycans = ?
Important Trait
Mucopolysaccharids
Hydrophilic
Glycosaminoglycans are composed of:
Sulfated GAG’s and Non-Sulfated GAG’s
Sulfated GAG’s
examples
keratin sulfate, chondroitin sulfate, heparin sulfate, dermatin sulfate
Sulfated GAG’s
Points of Interest
smaller molecules 10-40 kDA
Covalently bonded to proteins
Non-sulfated GAG’s
examples
Hyaluronic Acid = HA = Hyaluronan
Non-sulfated GAG’s
Points of Interest
Large molecules 100-1000’s kDa
Forms a dense molecular network
Holds much H2O (important for allowing diffusion in some tissues)
Positive aspects of inflammation
- Increased fluidity will aid in cell movement
2. Increases numbers of defensive cells
Negative aspects of inflammation
Excessive swelling can damage blood vessels, nerves & cells.
Edema: excessive fluid remaining in the interstitial spaces
What are proteoglycans?
Protein core with many sulfated GAG’s attached
Adhesive Glycoproteins
examples
laminin, fibronectin
Types of Fibers
Collagen, Elastic, Reticular
Collagen
Characteristics
x4
Many different types
Most common CT protein
Type 1 collagen accounts for ~90% of thet total body collagen
Type 1 is known for its great tensile strength but it does NOT stretch
T/F
Collagen is a very complex molecule that is coded for on many genes in the body. Noncritical pathologies can be associated with improperly produced Collagen I.
False.
serious pathologies are associated with improperly formed Collagen I.
Collagen
Aging x2
- Fiber production slows
2. The fibers are weaker
T/F
Vitamin C is necessary for the proper cross-linking (bonding) within the collagen I fiber
True.
If not enough Vitamin C lack proper placement of bonds. Therefore Collagen I structure is weaker (scurvy)… increased Collagen II breakdown.
T/F
Elastic Fibers = Collagen II
False
Elastic Fibers are DIFFERENT than Collagen Type II
Elastic Fibers
Characteristics:
x5 (composition, stretch, location, production, complexity)
Composed of Elastin & Microfibrils
Can Stretch 150% of its resting length
Important in blood vessels and lungs
Commonly produced by fibroblasts (CT and smooth muscle cells, BV)
Simpler fiber than Collagen I so easier for cells to make
Elastic Fibers
Aging:
Pathologies:
As age increases the number of elastic fibers will decrease (skin as example- wrinkles)
In general: fewer pathologies associated with this fiber type
Marfan’s Syndrome
define
Hereditary condition of CT, bones, muscle, ligaments and skeletal structure. DEFECTIVE ELASTIC FIBERS IN TISSUES.
Marfan’s Syndrome
Characteristics
x4
- Irregular and unsteady gate
- Tall lean body type with long extremities
- Abnormal joint flexibility, flat feet, stooped shoulders and dislocation of optic lens
- Aorta usually dilated and may become weakened, allowing an aneurysm to develop
T/F
Reticular Fibers = Collagen Type III
True
Reticular Fibers
Characteristics
x3 (production, life span, pathologies)
- Easy to produce (produced by reticular cells)
- Last ~3 days
- No known serious pathologies associated with this fiber
Reticular Fibers
Aging:
Wound healing:
Does not affect this fiber
First fiber produced during wound healing
What cells make up CT?
Fibroblasts, Fibrocytes, Myofibroblasts, Adipocytes, Plasma Cells, Macrophages, Mast Cells, Leukocytes, Mesenchyme Cells, & Reticular Cells
Fibroblasts
Characteristics
x5 (derived from, important in, mobility, division, change)
Usually derived from mesenchyme cells
Very important cell type in ordinary CT
Generally a fixed cell but can move about somewhat
May occasionally divide- primarily during wound healing
May change into other cell types under special conditions
Fibroblasts
Examples of change to other cell types:
to adipocytes
to chondrocytes: during fibrocartilage formation
to osteoblasts: certain pathologies
Fibroblasts
Functional Division
Structural and Defensive
Fibroblasts
Structural characteristics
x2
- Produce and maintain matrix (i.e. fibers, ground substance)
- Healing (produce GF, scar formation)
Fibroblasts
Structural- Healing
Scar Formation characteristics:
x4 (make-up [2], strength, locations)
dense irregular CT
When mature, are almost avascular and contain fibrocytes
only ~70% as strong as original tissue
common in tendons, ligaments, epithelium, cartilage, capsules of organs, cardiac ms.
Fibroblasts
Defensive characteristics:
- Produce cytokines & enzymes
2. Can phagocytize when it is really needed
Fibrocyte
Characteristics
x3 (appearance, longevity, capabilities)
Mature less active fibroblast so will appear flatter
Long-lived cell with lower energy and oxygen requirements
Structural cell but have limited capabilities
Macrophages
Produce:
Kupffer cells, alveolar macrophages, monocytes, microglia, Langerhans cells, osteoclasts
Macrophages
Functions
x4
- Phagocytosis of debris & microbes
- Act as an APC (probably a separate population of macrophages, presents info about antigen to T helper cells)
- Create foreign body giant cells
- Release cytokines and other products
What does APC stand for?
Antigen Presenting Cell
Fibrocyte
Function of Macrophages
What is a foreign body giant cell
the permanent fusion of many macrophages
Fibrocytes function of macrophages Why do foreign body giant cells form?
In response to:
- sizeable objects
- some pathogens (ex. TB in lungs)
Mast Cells
characteristics
x6 (size/contain, location, division?, lifespan, derived from [2])
Large cells containing cytoplasmic granules
Found in CT proper, by small blood vessels & under epithelium
Occasionally divide
Lifespan: days to a few months
Derived from bone marrow precursor
Once thought to be derived from basophils
Mast Cells
Function
What events do MCs mediate?
Inflammation
Immediate Hypersensitivity Response (simple allergy)
Anaphylaxis
Asthma- most types
Mast Cells
Function- Mediators (describe & list types)
To release primary mediators- these molecules are in the granules of mast cells and can be released very quickly
Histamine, Heparin, ECF, NCF, Other
Mast Cells
Histamine
Function/Effects
On Switch - flash reaction and then it dies fast
Effects:
Increase permeability of capillaries and venules
Vasodilation of arterioles and small arteries therefore increase in blood flow to the affected site
Contraction of visceral smooth muscle
Mast Cells
Heparin
Function/Effect
Off switch- slow to take effect
Effects:
Binds to and inactivates histamine
Mast Cells
Eosinophil Chemotactic Factor (ECF)
Effect
Attracts Eosinophils- Limit histamine/leukotriene effect- Destroy parasitic worm larvae
Inhibit leukotrienes
Produce a factor that inhibits mast cell degranulations
Phagocytize IgE- allergin complexes and mast cell granules
Secretes histaminase
Mast Cells
Neutrophil Chemotactic Factor
Effect
Attracts neutrophils
Mast Cells Secondary Mediators (describe & list type)
Leukotrienes
Others
Mast Cells
Secondary Mediators
Leukotrienes- Effect
Same as histamine but MUCH more powerful (1000’s of times)
Will extend and amplify the effects of histamine
What stimuli will activate mast cells?
Direct mast cell trauma
Phagocytosis
IgE-Allergin complex
Complement process/molecules
Mast Cells
First Exposure
describe & explain effects
Elicits IgE formation which binds to mast cells
Some degranulation but usually a weak response
B & T memory cells are produced
Mast Cells
Second Exposure to same antigen
Describe & effects
Allergin binds to “sensitized” mast cells and mast cells degranulate
Reaction is quicker, more intense and longer lasting
Mast Cell
Mediated Events
What are they?
Basic Inflammatory Reaction (cut in skin)
Immediate Hypersensitivity Response (simple allergy)
Anaphylaxis
Asthma
Mast Cell Mediated Events
Basic Inflammatory Reaction
Steps x5
- Stimulus = phagocytosis
- Mast cells degranulate - local reaction
- Histamine reacts first (Inc. capillary & venule permeability; dilate arterioles)
- Leukotrienes take effect (extend histamine)
- Heparin and ECF react last (Heparin counteract histamine; ECF attract eosinophils; NCF attract neutrophils)
Mast Cell Mediated Events
Immediate Hypersensitivity Response
Steps
x3
- Stimulus = IgE/Allergin Complex
- Mast Cells degranulate & produce various substances
- Localized inflammatory response at sight of antigen
Mast Cell Mediated Event
Anaphylaxis
Steps
x4
- Stimulus = massive IgE production
- Systemic mast cell and basophil degranulation and secretion
- Systemic inflammatory response
- Anaphylactic shock = circulatory shock (severe = CV collapse)
Mast Cell Mediated Response
Asthma
Types/Definitions/Onset
Extrinsic- allergins typically in the air and often known
Childhood onset
Intrinsic- allergin typically unknown
Adult onset (40+); may follow a respiratory illness
Mast Cell Mediated Response
Asthma
Stimulated by:
A. IgE/Allergin Complex
B. secondary factors: fatigue, stress, endocrine changes, foods, aspirin
Mast Cell Mediated Response
Asthma
Primary/Secondary Problems
Primary Problems- release of leukotrienes; contract smooth muscle in the bronchioles (can close)
Secondary Problems- inflammation in the lung; decrease oxygen uptake and increases fluid uptake
Leukocytes
Classes/Types
Monocytes, Neutrophils, Eosinophils, Basophils, & Lymphocytes
Leukocytes
Monocytes become:
macrophages in CT
Leukocytes
Neutrophils function:
Attracted to:
phagocytize
attracted to sites of acute inflammation
Leukocytes
Eosinophils combat:
attracted to:
combat parasitic worm larvae
attracted to sites of allergic reaction
Leukocytes
Basophils are similar to:
function:
Mast Cells
Initiate, Maintain, & Influence Inflammation
Leukocytes
Lymphocytes function:
Attracted to:
humoral and cell-mediated immunities
attracted to sites of chronic inflammation
Mesenchyme Cells = ?
Adult Stem Cells
Mesenchyme Cells Function? Appearance? Division? Adults/Age?
Function: to change into another cell type
Appearance: cells have sparse pale staining cytoplasm with an oval nucleus
Division: can divide
Adults/Age: DO exist in adults, #s decrease with age
Reticular Cells
Derived from:
Function:
Derived from Mesenchyme cells
Function: to make reticular fibers when needed on a permanent basis.
Classes of CT Proper
A. Loose CT
B. Dense CT
C. Reticular CT
D. Adipose
Classes of Specialized CT
A. Cartilage
B. Blood
C. Bone
Loose CT
Characteristics:
x4 (amount cell vs fiber, ground substance, vascularity)
- Larger number of cells and cell types
- Fewer fibers
- Increased amount of ground substance (GAG’s)
- Quite Vascular
Loose CT
Types and where they’re found:
- Loose areolar: greater and lesser omentum
2. Loose irregular: dermis; papillary layer; beneath epithelium in organs
Dense CT
Characteristics
x4 (amount cells vs fibers, ground substance, vascularity)
- Fewer number of cells and cell types
- Many fibers
- Decreased amounts of ground substance (GAG’s)
- Less vascular
Dense CT
Types and where they’re found
- Dense Irregular: dermis; reticular layer; nerve sheaths & organ capsules
- Dense Regular: tendons; ligaments; and aponeurosis
Reticular CT
Characteristics (cell type, fiber type, support)
Example
Primary cell type: reticular
Primary fiber type: reticular collagen III
Provides support in highly cellular organs (areas)
Ex. Lymphatic and endocrine organs
Adipose
Characteristics (cell type, vascularity)
Example
Primary cell type = adipocyte
Quite vascular
Ex. around kidney and heart; bone marrow; hypodermis
Adipose
Function x3
- Energy
- Thermoregulation
- Cushion/Protect organs
General CT rule #1
An increase in the number of cell types should lead to an increase in healing potential
General CT Rule #2
An increased vascularity should lead to an increased healing potential