Classes 1-2 Flashcards
Symptoms
Subjective indicator
Sign
Objective indicator of pathology
Nucleocytoplasmic ratio
Ratio of nucleus to cytoplasm
Higher in undifferentiated adult cells, fetal cells, tumour cells.
Mitochondria
Double membrane involved in cellular energy production
Higher energy demands –>
More mitochondria
Undifferentiated cells have fewer mitochondria.
Ribosomes
Small RNA granules involved in protein synthesis.
Free floating (internal purposes) or attached to RER (for export)
Endoplasmic reticulum
Mesh work of membranes continuous with nuclear and plasma membranes.
Rough – have ribosomes – protein synthesis
Smooth – catabolism of drugs, hormones, nutrients.
Golgi apparatus
Adjacent to nucleus
Composed of membrane-blind cisterns
Modified, sorts and packages macromolecules
Lysosomes
Membrane bound digestive organelles
Lytic enzymes
Fuse with vesicles to digest materials.
Passive cell projections
Microvilli
Serve to increase surface area for absorption, but not involved in locomotion etc
Active cell projections
Require energy
Cilia
Flagella.
Three Forms of integration
Autocrine
Paracrine
Endocrine
Autocrine stimulation
Cell secretes substance that stimulates itself
Simplest
Paracrine Stimulation
Cell secretes substance that stimulates a nearby cell
Endocrine stimulation
Cell releases substance into bloodstream that stimulates structure far away
Always hormones
Can involve anatomically distinct organs
Atrophy
Decrease in size of cells resulting in reduced tissue mass
Hypertrophy
Increase in size of individual cells resulting in enlarged tissue mass.
Hyperplasia
Increased number of cells resulting in increased tissue mass
Metaplasia
When one mature cell is replaced by a different mature cell type.
Ex. In smokers ciliates columnar epithelia replaced by stratified squamous.
Dysplasia
Cells vary in size and shape.
Large nuclei.
Rate of mitosis increases
Possibly precancerous.
Intracellular accumulations
May occur as a result of overload of metabolites or exogenous material, or prevention of excretion.
Ex. Black lung or fatty liver.
Apoptosis
Endogenously programmed cell death
Active. Can by triggered by external or internal events.
Typically affects single cells.
Cell divides into smaller apoptic bodies which are phagocytized by macrophages or adjacent cells. (In necrosis the fragments are phagocytized by neutrophils).
Necrosis
Exogenously induced cell death
Four types of necrosis
1 coagulative
2 liquifactive
3 caseous
4 fat
Coagulative necrosis
Most common form.
Occurs when cell proteins altered/destroyed, mostly due to anoxia (ex heart attack)
Rapid inactivation of cytoplasmic hydrolytic enzymes, thus preventing cell lysis
Tissues retain regular form and consistency.
Most common in solid internal organs.
Liquifactive necrosis
Dead cells liquify, tissue becomes soft and diffluent.
Mostly brain. Typical of brain infarct
May be secondary to coagulative.
Caseous necrosis
Typical of TB and some fungal infections.
Coagulative necrosis with limited liquifaction.
Centre becomes yellow and cheesy.
Enzymatic Fat Necrosis
A form of liquifactive necrosis caused by lipolytic enzymes, usually around the pancreas.
Pancreatic enzymes released into fat dissolve tissue into glycerol and free fatty acids (which bind with Ca+ and become soapy)
Gangrene
Dead tissue.
Wet (liquifaction) or dry (mummification)
Can undergo secondary change, such as calcification.
What is a telltale sign of necrosis?
Ruptured cell membrane
Pathological apoptosis
Example. Muscular dystrophy, and the excessive death of muscle cells.
Also, rejected transplanted organs.
Pathological lack of apoptosis
Syndactyly
Chronic lymphomatic leukaemia.
Inflammation
Body’s nonspecific response to injury
Necessary part of healing.
Signs of inflammation
Swelling Heat Altered function Redness Pain
Four components of acute inflammation
- Circulatory changes
- Changes in vessel wall permeability
- Release of SMIs
- Cellular events.
Inflammation: change in blood circulation
First response.
Mechanical stimulus –> constriction followed by relaxation of sphincters –> blood rushes into capillaries –> hyperaemia.
Congestion caused by slowing blood, RBCs forming rouleaux, and WBC’s pavementing along endothelium.
Inflammation: changes in vessel wall permeability
Increased permeability due to:
1 increased pressure (due to congestion),
2 reduced O2 and nutrient supply,
3 adhesion of platelets and WBC to vessel wall
4 release of SMIs
Histamine
SMI. Biogenic amine.
Preformed. Released from mast cells and platelets
Contraction of epithelial cells –> gaps –> increased permeability.
Rapidly deactivated by histaminase
Immediate transient reaction.
Bradykinin
SMI.
Created de novo through activation of Factor 12 (Hageman Factor)
Similar effect as histamines, but slower acting. Also incites pain.
Hageman Factor
AKA Coagulation Factor 12.
In intrinsic pathway, combines with calcium –> activated Factor 10 –> fibrin
Also creates plasmin, which breaks fibrin apart.
And also involved in creation of bradykinin.
Complement system
Circulating proteins, produced by liver, actives in inflammatory response.
Three pathways (classical, lectin and alternative).
Result of the complement system
- Opsonin (make bacteria tasty for phages)
- Anaphylatoxins (mediate release of histamines from mast cells –> increased vascular permeability)
- Chemotaxis.(Attracting leukocytes)
- Membrane Attack Complex (MAC) –> cell lysis.
Arachidonic Acid Derivatives
Mediators of inflammation derived from phospholipids of cell membrane (through action of phospholipase)
What are the two pathways for arachidonic acid?
Lipoxygenase Pathway
Cyclooxygenase Pathway
Lipoxygenase Pathway
From arachidonic acid, forms: 1 leukotrienes (promotes chemotaxis and increases vascular permeability) 2. Lipoxins. (Inhibit chemotaxis)
Cyclooxygenase Pathway
One way arachidonic acid is metabolized.
Creates:
- Prostaglandins (vasodilation, vascular permeability, mediates pain and fever)
- Thromboxane. (Platelet aggregation, thrombosis, vasoconstriction)
- Prostacyclin (counteracts effects of thromboxane).
How do anti-inflammatory drugs work on the arachidonic acid system?
Corticosteroids: interrupt phospholipase, so arachidonic acid is never produced, and entire pathway is aborted.
Cox inhibitors (aspirin, ibuprofen, etc) block cyclooxygenase (first step of cyclooxygenase pathway) so thromboxane, prostaglandins and prostacyclin not produced.
Prostaglandins
Eicosanoids produced in the cyclooxygenase pathway of arachidonic acid metabolism.
Stimulate vasodilation and vascular permeability, and mediate pain and fever (antipyretic)
Thromboxane
Produced by the cyclooxygenase pathway of arachidonic acid metabolism.
Involved in vasoconstriction, platelet aggregation and thrombosis.
Prostacyclin
Eicosanoid. Produced by the cyclooxygenase pathway of arachidonic acid metabolism.
Counters effect of thromboxane.
Inhibits platelet aggregation. Vasodilator.
Leukotrienes
Eicosanoid. Produced by the lipoxygenase pathway of arachidonic acid metabolism.
Promote chemotaxis and increase vascular permeability.
Lipoxin
Eicosanoid. Produced by the lipoxygenase pathway of arachidonic acid metabolism.
Inhibit chemotaxis.
Emigration of Leukocytes
Increased permeability of vessel walls, lasting hours to days, allows for leakage of fluid into the institial space.
Transudate
Leakage of fluid into interstitial spaces due to increased hydrostatic pressure.
Mostly fluid; very few proteins or large solutes
Exudate
Fluid that emigrates across vessel walls during inflammation. Increased permeability of walls means that exudate contains many proteins and large solutes.
Acute stages mostly PMNs
H2O. Fibrinogen. Other coagulative proteins. Immunoglobulin. Complement factors. Macroglobulins. Microglobulin.
Steps in emigration of plasmamorphonuclear neutrophils/Leukocytes (PMNs).
- Adhesion
- Pseudopods inserted between endothelial cells
- Passage through basement membrane
- Movement toward source of inflammation.
Cells of inflammation
Neutrophils Eosinophils Basophils Macrophages Platelets
Polymorphonuclear Neutrophils
PMNs
Most numerous of the circulating WBCs
Multisegmented nuclei
Properties: mobility; bactericidal; phagocytosis; produce and release cytokines
Eosinophils
2-3% of circulating WBCs
Slower mobility, reactivity
Segmented nucleus
Allergic reactions and response to parasites.
Basophils
Less than 1% circulating WBCs
Precursor to mast cells
Important in inflammatory reactions mediated by IgE
Single nucleus.
Macrophages
Tissue cells derived from monocytes
Phagocytic and bactericidal
Appear 3-4 days after onset of inflammation.
Platelets
Contain membrane bound granules that contain histamine, coagulative proteins, cytokines, growth factors etc.
