Exam 1: Ch.2 CT Flashcards
What does CT consists of?
supportive cells and ass. ECM
What is the ECM composed of?
ground substance and fibers
What are the four general functions of CT?
- Provide structural support
- Provide a medium for exchange
- Defense/protection
- Storage of adipose
What are the four characteristics of CT?
- Most derived from mesenchyme
- Support cells separated by matrix
- Support cells produce matrix
- Cells adhere to matrix
What are the main three component of the ground substance?
- Glycosaminoglycans (GAG’s) = mucopolysaccharides
- Proteoglycans
- Adhesive Glycoproteins
What is the important general trait of GAG’s?
hydrophilic
What are the two types of GAG’s?
- sulfated GAG’s
2. non-sulfated GAG’s
What are examples of the Sulfated GAG’s?
- keratan sulfate
- heparin sulfate
- dermatin sulfate
- chondroitin sulfate
Are the sulfated GAG’s or the non-sulfated GAG’s larger?
Sulfated GAG’s = smaller molecules
Non-sulfated GAG’s = larger molecules
What are examples of non-sulfated GAG’s?
Hyaluronic Acid = HA = Hyaluronan
Which type of GAG’s are covalently bonded to proteins?
Sulfated GAG’s
Which type of GAG’s forms a dense molecular network and holds onto water?
Non-sulfated GAG’s (like Hyaluronic acid)
We know non-sulfated GAG’s, like hyaluronic acid, hold only water, but what is that important?
important for allowing diffusion in some tissues
Give me two positive aspects of inflammation.
- increased fluidity will aid cell movement
2. increases numbers of defensive cells
Give me a negative aspect of inflammation.
excessive swelling (edema) can damage blood vessels, nerves, and cells
Where does the extra fluid and defensive cells come from when there is inflammation?
leaky capillaries and venules ( NOT bigger blood vessels)
What part of the ground substance is the protein core with many sulfated GAG’s attached?
proteoglycans
What are two examples of the adhesive glycoproteins in ground substance?
laminin and fibronectin
What are three types of fibers found in the ground substance?
- collagen
- elastic
- reticular
What is the MC CT protein?
collagen
What type of collagen accounts for ~90% of the total body collagen?
Type I
What is collagen type I known for?
its great tensile strength, but does NOT stretch
What pathology is a group of genetic disorders caused by defective or reduced collagen that involves unstable joints, hypermobility, and easily dislocation?
Ehlers-Danlos Syndrome
often skin and blood vessels affected too
As we age, what two things happens to our collagen fibers?
- fiber production slows
2. fibers produced are weaker
What vitamin is necessary for the proper cross-linking (bonding) w/in the collagen I fiber?
Vitamin C
What happens to the collagen if we have a lack of vitamin C?
weaker collagen I produced –> lead to more rapid fiber break down
What disease is caused by a vitamin C deficiency?
Scurvy
What two things is Elastic fibers composed of?
- elastin
2. microfibrils
Elastic fibers can stretch what percentage of their resting length?
150%
What commonly produces elastic fibers? What are they important in?
fibroblasts and smooth muscle cells
important in blood vessels and lungs
T/F. Elastic fibers are more complex than collagen I fibers, therefore harder for cells to make.
False– elastic fibers are LESS complex than collagen I and therefore are EASIER for cells to make
What affect does aging have on elastic fibers?
as age increases the number of elastic fibers will decrease
T/F. In general there are fewer pathologies associated with elastic fibers.
True
What is the hereditary condition of CT, bones, muscle, ligaments, and skeletal structures that is characterized by undeveloped elastic fibers called? What 4 things does it result in?
Marfan’s Syndrome
- irregular and unsteady gate
- tall lead body type with long extremities
- abnorm. join flexibility, flat feet, stooped shoulders and dislocation of optic lens
- aorta usually dilated and may become weakened, allowing an aneurysm to develop
What type of fibers are easy to produce and are essentially the same as collagen III?
reticular fibers
Where are the common places to find reticular fibers?
liver, bone marrow, and lymph nodes
How long to reticular fibers typically last?
~3 days (need to replace freq.)
How does aging impact reticular fibers?
they are not affected
What is the first fiber produced during wound healing?
reticular fibers
Can you name all 10 cells in CT?
- Fibroblast
- FIbrocyte
- Myofibroblast
- Adipocytes
- Plasma Cells
- Macrophages
- Mast Cells
- Leukocytes
- Mesenchyme cells
- Reticular Cells
What are fibroblasts usually derived from?
mesenchyme cells
What cell type did we emphasize that was a VERY IMPORTANT cell type in ordinary CT?
fibroblasts
fixed cell that can move somewhat, may change into other cell types under special conditions
Fibroblasts only occasionally divide, when would be the case that they do?
during wound healing and when stimulated by local growth factors
What are the two main structural functions of fibroblasts?
- Produce and maintain matrix (fibers, ground substance)
2. Healing
Describe how fibroblasts are involved in wound healing.
- produce growth factors
2. Scar formation
Scar tissue is what type of tissue? Describe its characteristic when mature.
dense irregular CT
almost avascular and contain fibrocytes
T/F. When a scar forms it is 70% stronger than the original tissue.
False–it is 70% AS STRONG as the original tissue (its weaker)
Where are locations that scar tissue is common?
tendons, ligaments, epithelium, cartilage, capsules of organs, cardiac muscle
What are the two defensive functions of fibroblasts?
- Produce cytokines and enzymes
2. Can phagocytize when it is really needed
What is a mature less active fibroblasts that will appear flat and is long-lived?
fibrocytes (have lower energy and oxygen requirements)
What is the function of fibrocytes?
maintain matrix
What can a fibrocyte produce?
Hyaluronic acid, ground substance, and reticular fibers
T/F. Fibrocytes can produce new collagen I and elastic fibers.
FALSE–they can NOT produce these (therefore why tendons and ligaments do not heal well)
What type of cell possesss features of fibroblasts and smooth muscle cells?
myofibroblast
What do myofibroblasts function during?
- wound closure
2. tooth eruption
T/F. Adipocytes do not divide or change into other cell types in adults.
True
What are Adipocytes derived from?
mesenchyme cells producing pre-adipocytes
What are the two general functions of Adipocytes?
- lipid storage
2. regulate energy metabolism–> produce LEPTIN (circulating satiety hormone)
What type of cell in CT derived from B lymphocytes?
Plasma cells (large cells with spherical “clock faced” nucleus)
How long to plasma cells live? Where are they found?
short lived (2-3wks)
CT and lymphatic tissues/organs (not typically found in blood)
What is the function of plasma cells?
Produce Antibodies (“GAMED”)
Please list all the anitbodies and….
????
What are large cells with an indented or kidney bean shaped nucleus, often containing residual bodies in their cytoplasm?
Macrophages
*very important defensive cell
What are macrophages derived from? Can they divide?
monocytes
yes
What system are Macrophages a part of?
Mononuclear Phagocyte System (MPS) / Reticuloendothelial System (RES)
Do cell members of the Mononuclear Phagocyte System (MPS) arise from a common ancestor? What are they all able to do?
yes, common ancestor in bone marrow
able to phagocytize and display particular receptors
What are examples of members in the Mononuclear Phagocyte System (MPS)?
Kupffer cells, alveolar macrophages, monocytes, microglia (CNS), Langerhans cells, osteoclasts
What are the four main functions of macrophages?
- Phagocytosis of Debris and Microbes
- Act as an APC to T helper cells
- Create foreign body giant cells
- Release cytokines and other products
What are foreign body giant cells?
created by macrophages; is the permanent fusion of many macrophages
What do foreign body giant cells form in response to?
- sizable foreign substance
- some pathogens (i.e. TB, leprosy, syphilis, granulomas, yaws)
What type of cell is large and contains cytoplasmic granules and is found in CT proper, by small blood vessels and under epithelium?
Mast cells
How long do Mast cells live? Where are they derived from? What were they once thought to be derived from?
few months
bone marrow precursor
thought were from basophils
What are the three main functions of mast cells?
- Influence/ mediate events (Inflam, simple allergy, Anaphylaxis, Asthma)
- To release primary mediators
- To produce and release secondary mediators
What “events” do Mast cells mediate/influence?
- Inflammation
- Immediate Hypersensitivity Response (=simple allergy)
- Anaphylaxis (sever allergy)
- Asthma (most types)
We know mast cells release primary mediates, what are those primary mediators?
- Histamine
- Heparin
- ECF = Eosinophil Chemotactic Factor
- NCF = Neutrophil Chemotactic Factor
We know mast cells release secondary mediators, what are those secondary mediators?
- Leukotienes
2. others– cytokines
What primary mediator is the on switch and has a flash reaction?
Histamine
What are the effects of histamine? (3)
- increase permeability of capillaries and venules
- vasodilation of arterioles and small arteries (increase blood to area)
- contraction of viscercal smooth muscle
What primary mediator is the off switch and is slow to take effect? What is its effect?
Heparin; binds to and inactivated histamine
What primary mediator attracts eosinophils?
ECF = eostinophil chemotactic factor
ECF will attract eosinophils, but what will the eosinophils do? (4)
- inhibit leukotrienes
- produce factor that inhibits mast cell degranulation
- phagocytize IgE-allergen complexes and mast cell granules
- secretes histaminase
Knowing what eosinophils will do once attracted to the site by ECF, what is the main conclusion?
will help to LIMIT the effects of histamine and leukotrienes
What can destroy parasitic worm larvae?
Eosinophils
What primary mediator attracts neutorophils?
NCF = Neutrophil Chemotactic Factor
What secondary mediator has the same effects as histamine? But what is the exception?
Leukotrienes, but MUCH (1000’s of times) more powerful
What will leukotrienes do?
(= a secondary mediator)
will extend and amplify the effects of histamine **
What are the four stimuli that will activate Mast cells?
- Direct mass cell trauma
- Phagocytosis
- IgE-allergen complex
- Complement process/molecules
Describe the First Exposure: Primary Immune Response of mast cells.
Elicits IgE formation that binds to mast cells
- some degranulation (weak)
- Memory cells (B and T) are produced
Describe the Secondary Exposure to same antigen: Secondary Immune Response.
Allergen binds to “sensitized” mast cells and mast cells degradulate
- Rxn is quicker, more intense, and longer lasting
Describe the order of events when there is a Basic Inflammatory Reaction, like a cut in the skin. (5 steps)
- Stimulus = phagocytosis/direct trauma/ complement system (Ex: dead cells, debris, broken fibers)
- Mast cells degranulate (local rxn)
- Histamine reacts first (increase permeability and dilation)
- Leukotrienes takes effect (extend histamine effect)
- Heparin and ECF react last (so will NCF)
Describe the steps that occur in a Immediate Hypersensitivity Response, a simple allergy.
- Stimulus = IgE/allergen complex (ex: Hay fever)
- Mast cells degranulate and produce various substances
- Localized inflamm. response at site of allergen contact
What are the steps that occur during a Anaphylaxis reaction?
- Stimulus = Massive IgE production (bee venom, peanut oil, shellfish, penicillin, etc.)
- Systemic mast cell and basophil degranulation and secretion
- Systemic inflamm response
- Anaphylactic Shock
What does Anaphylactic Shock lead to? What is it caused by?
leads to circulatory shock –> then cardiovascular collapse
Extensive internal bleeding
What type of asthma is it when the allergens are typically in the air and often are known?
Extrinsic asthma = allergic asthma
When is usually the onset of extrinsic asthma?
childhood
What type of asthma is the allergen typically unknown? When is the onset usually for this type?
Intrinsic asthma
often adult (40+ yrs)
What can intrinsic asthma be divided into?
Chemically induces
EIA (exercise induced)
Nocturnal
What type of asthma has varied causes, such as may follow respiratory illness or due to nerve stimulation?
Intrinsic asthma
What are two things that
asthma may be stimulated by?
- IgE/allergen complex
and/or - Secondary factors: fatigue, endocrine changes, odors, emotions, foods, etc.
What is the Primary Problem associated with asthma? What are secondary difficulties caused by?
- release of leukotrienes
2. inflammation in the lungs
What are all the cells that are leukocytes (WBCs)?
Neutrophils Lymphocytes Monocytes Eosinophils Basophils
(“never let monkeys eat bananas”)
What type of leukocyte (WBC) is the most common?
Neutrophils
What do monocytes do?
become macrophages in CT
What do neutrophils do? Where are they attracted to?
phagocytize and are attracted to sties of acute inflammation
What do eosinophils do? Where are they attracted to?
combat parasitic worm larvae and are attracted to sites of allergic inflammation
What type of leukocyte is similar to mast cells and initiate, maintain, and influence inflammation?
basophils
What is the 2nd MC type of leukocyte?
Lymphocytes
What type of WBCs (leukocytes) are attracted to sites of chronic inflammation? What type of immunity are they involved in?
Lymphocytes; involved in humoral and cell-mediated immunities = acquired immunity
What type of cells are adult stem cells that have sparse pale staining cytoplasm with an oval nucleus?
mesenchyme cells
What is the function of mesenchyme cells?
to change into another type of cell
Can mesenchyme cells divide? Do they exist in adults? Can they produce ECM?
yes can divide;
exist in adults, but numbers decreased
limited ECM production
What type of cells are derived from mesenchyme cells?
Reticular cells
What is the function of reticular cells?
to make reticular fibers when needed on a PERMANENT BASIS
What are the four different classifications of CT proper?
- Loose CT
- Dense CT
- Reticular CT
- Adipose
What are the 4 general characteristics of Loose CT?
- larger number of cells and cell types
- Fewer fibers
- increased amount of ground substance
- Quite vascular
What are the two types of Loose CT and where are they found?
- Loose Areolar
2. Loose irregular
Where is loose areolar CT found?
greater and lesser omenta; considered “filler” CT
i.e. around blood vessels
Where is loose irregular CT found?
dermis– papillary layer; beneath epithelium in organs
What are the 4 general characteristics of Dense CT?
- fewer cells and cell types
- many fibers
- decreased amounts of ground substance
- less vascular (exception)
What is the exception to dense CT being considered less vascular?
dense irregular CT in the dermis –has move vascularity
What is the primary cell type in Reticular CT? Fiber type? What does it provide?
reticular cell; reticular fiber
provides support in highly cellular areas/organs
Give three examples of where reticular CT is found.
lymphatic organs, endocrine organs, and bone marrow
What is the primary cell type in adipose? What does this primary cell type develop from?
Adipocytes; develop from mesenchyme cells
T/F. Adipose CT is quite vascular and contains areas of loose areolar CT.
True
What are the two types of adipose tissue?
- White Adipose
2. Brown Adipose
What is the primary cell type of White Adipose tissue?
unilocular white adipocytes– one large droplet
Where is white adipose found?
- around kidney and heart
- within liver
- bone marrow
- hypodermis
What are the three general functions of White adipose?
- Lipid storage within adipocytes
- Produce adipokines (cytokine hormones)
- Store large amount of lipase
For white adipose, what 3 things does the lipid storage w/in adipocytes serve to do?
- energy
- thermal insulation (i.e. hypodermis of skin)
- Protect/cushion organs (i.e. kidney perinephric fat
What is an important adipokine produced by white adipose? What what are the two major functions of that adipokine?
Leptin
- Inhibit appetite
- regulates formation of new adipocytes
What does the storage of large amounts of lipase in white adipose tissue serve to do?
- break-down triglycerides
2. used to split triglycerides to release free fatty acids for exchange other fatty acids (FAs renewed every 2-3 wks)
T/F. Obesity that onsets during adulthood will involve the increase in number of white adipocytes.
False— existing adipocytes increase in size (DO NOT increase in number)
What do adipocytes produce?
leptin
Describe what occurs with the adipocytes for childhood obesity.
number of adipocytes can increase as well as size
obese children may have 3x more fat cells than normal kids
Describe the cell type of Brown adipose compared to white adipose.
Brown adipocytes are smaller and multiocular
Do adults have a lot of Brown adipose? Where is it primarily found?
Very limited amounts; around kidney, adrenals, aorta, and mediastinum
What percentage of the newborn’s body weight is due to Brown Adipose? Where is it primarily found?
2-5%
back, neck, and shoulders
T/F. Brown adipocyte numbers increase with the cold.
True
What is the function of Brown adipose?
thermogenesis (generates heat)
Does Brown adipocytes receive direct sympathetic innervation?
Yes
- nerves to cells
- ANS promotes brown adipocyte differentiation and prevents cell apoptosis
General Rules for CT:
1. An increase in the number of cell types should lead to an increase in _____ _____.
- An increased _____ should lead to an increased healing potential.
- healing potential
2. vascularity
What are three Specialized CT?
- Cartilage
- Bone
- Blood
