Pathology/Histopathology Flashcards
What is neoplasia?
Neoplasia refers to “new growth” as an
abnormal growth of tissue which, if it forms a
mass, is commonly referred to as a tumor.
Prior to the abnormal growth of tissue, as
neoplasia, cells often undergo an abnormal
pattern of growth, such as metaplasia or
dysplasia. However, metaplasia or dysplasia
does not always progress to neoplasia.
What occurs in hypertrophy, hyperplasia, atrophy, metaplasia, dysplasia
Hypertrophy – ⇑ cell & tissue size
Hyperplasia – ⇑ cell numbers (cell division)
Atrophy – decrease in cell size, numbers
(cell death), tissue size
Metaplasia – change in cell differentiation,
better equipped for environmental stress
Dysplasia – distorted growth pattern, preneoplastic,
often increased mitoses (may be
considered abnormal hyperplasia). May not be
reversible.
What does disease development depend on?
• Cause and its duration and severity • Cell type, stage of cell cycle, and cell adaptability (consider heart, brain, versus skin, liver) • Disease changes occur only after critical cellular, biochemical and molecular damage
What are the three cell types?
Labile – Continuous cell proliferation (skin, gut,
respiratory tract, bone marrow, seminiferous
tubules in testis, lymph nodes). Particular risk of
cancer and radiation damage.
Stable – Do not normally proliferate (adult),
but are able to undergo cell proliferation (liver,
kidney, smooth muscle)
Permanent – No (or little) capacity to divide in
adult tissue (neurons, cardiac muscle)
What does steatosis/fatty liver show histologically
Large circular cellular inclusions as lipids
What is apoptosis vs necrosis?
Necrosis occurs when cells are irreversibly damaged
by an external trauma. The cells lose energy, plasma
membrane pumps stop working, cells fill with water
and essentially explode.
Apoptosis is thought to be a physiological form of
cell death whereby a cell provokes its own demise
(commits suicide) in response to a stimulus. Cells
shrink, bud, and are phagocytosed (macrophages but
also adjacent cells).
What are the aims of inflammation?
Wall off, remove, dilute and start process of healing
Occurs in vascularized tissue, fluid, protein and leucocytes diffuse out
What happens in fibrosis?
Thickening and scarring of connective tissue, rebuilding of ECM with collagen
What happens in acute appendicitis?
Mucosal ulceration pus within meso-appendix
What are the general signs of acute inflammation?
Heat – because of local reaction Redness – blood slows because vessels dilate Swelling – fluids leak from vessels to dilute the damage Pain and loss of function – this allows time to heal
What are the systemic signs of acute inflammation?
Fever (pyrogens – good or bad) Leukocytosis (↑ leukocyte count – leucocytes are white blood cells) Acute phase proteins Acute phase reactions such as sleepiness, hypotension
What happens in acute inflammation
- CHANGES IN BLOOD VESSELS
- INCREASED FLUID FROM VESSELS
- INCREASED LEUCOCYTES
(NEUTROPHILS, LYMPHOCYTES) IN
INFLAMED AREA
What is chemotaxis?
Chemical substances (chemokines, cytokines)
are released at the site of injury.
These are responsible for the vessel and
cellular changes of acute inflammation.
Chemotaxis leads to movement of inflammatory
cells via a chemical gradient. Concentration of
the chemo-attractant is highest near the
injury.
What happens in meningitis/laryngitis?
Meningitis: viral/bacterial infection in meninges, inflammatory response, oedema. Oedema causes increased pressure. This in turn causes headache, etc. Inflamed (dilated) meningeal blood vessels become occluded. Haemorrhagic infarction of associated brain occurs. Laryngitis: viral/bacterial infection, inflammatory response, oedema, airway obstruction
Why does tuberculosis initiate a chronic response straight away?
Neutrophils are inneffective at removing the virus
What is pulmonary fibrosis?
Coal worker’s pneumoconiosis (CWP)
“Black lung disease”
Inflammation of the lungs, often leading to fibrosis
that is caused by breathing a high concentration of
coal dust (or mixed dust) particles.
How does fibrosis occur?
Consists of:
Proliferation of activated macrophages
Activated fibroblasts (myofibroblasts)
New vessels
Collagen and other ECM proteins in area of
damage.
On surface of wound, pink granular appearance.
What is 1st or 2nd intention healing?
Primary Intention Healing – This occurs where the tissue surfaces have been approximated (closed). This can be with stitches, or staples, or skin glue (like Derma bond), or even with tapes (like steri-strips). This kind of closure is used when there has been very little tissue loss. It is also called “primary union” or “first intention healing.” An example of wound healing by primary intention is a surgical incision.
Second Intention Healing – A wound that is extensive and involves considerable tissue loss, and in which the edges cannot be brought together heals in this manner. This is how pressure ulcers heal. Secondary intention healing differs from primary intention healing in three ways:
The repair time is longer.
The scarring is greater.
The chances of infection are far greater
What are the factors that influence healing?
Nutrition, age, adequate blood supply
(atherosclerosis), disease (diabetes), hormones
(glucocorticoids).
Infection, mechanical factors (movement around
wounds), foreign bodies (sutures, glass,
splinters), size and location (small cut vs blunt
trauma)
Inadequate healing leads to rupture and/or
ulceration.
Excessive healing leads to mounds of collagen
called keloids (hypertrophic scar)
What is the differences between atherosclerosis, atheroma and aneurism?
ATHEROSCLEROSIS = PROCESS OF CHANGES (LIPID, CARBOHYDRATE, CALCIUM ETC) IN INTIMA OF ARTERY ATHEROMA = ATHEROSCLEROTIC PLAQUE IN AN ARTERY ANEURISM = ABNORMAL WIDENING OR BALLOONING IN AN ARTERY WALL, CAUSING WEAKENING
What happens in atherosclerosis?
Macrophages arrive to break up cholestrol
Necrosis occurs
Artery wall becomes hard due to calcification
What does Oil red O do?
stain to show lipids in vessel wall in atherosclerosis
What is an atheroma?
An atheroma is a reversible accumulation of degenerative material in the intimal layer of an artery wall. The material consists of mostly macrophage cells and debris containing lipids, calcium and a variable amount of fibrous connective tissue.
What is an aneurism?
An abnormal, localised, dilatation of an artery
What are the different types of aneurism?
Saccular- bulge on the artery
Fusiform
Dissecting
What is a thrombosis?
The formation or presence of a blood clot in a blood
vessel. The vessel may be any vein or artery. The clot
itself is termed a thrombus.
What are the symptoms of deep vein thrombosis?
Pain and tenderness in the leg
Pain on extending the foot
Swelling of the lower leg, ankle and foot
The skin is red and warm.
What is virchows triad?
Endothelial injury
<> abnormal blood flow
>Hypercoagulability
> all lead to thrombosis, however endothelial injury is the main reason, the others are factors that lead to it
What is a thrombus?
a clot of blood formed
during life within the heart or blood vessels
What is an embolus?
a bit of foreign matter in the
blood stream – like a blood clot (thrombus), air
bubble, cancer cells, fat, cardiac vegetations
What can a thrombus lead to?
Lysis and resolution
Organisation
Recanalisation
Embolism
What is the most common site of occlusion in the heart?
LAD coronary artery
What is an ischeamia vs infarct?
ISCHAEMIA (is-kem’ia) An inadequate blood supply to an organ or part of the body, especially the heart muscles. INFARCT Small localised area of necrosis usually resulting from failure of blood supply.
What is shown on the histology of a myocardial infarct
• Infarcted necrotic area surrounded by cardiac
muscle fibres that are intensely stained by eosin
(eosinophilic) when compared to normal
myocardial fibres.
• Separation of the myocytes by oedema.
• Heavy infiltration of the damaged myocardium
by neutrophils. At this stage, there is no
granulation tissue formation (which would have
come later should the patient have survived)
What are the coomplications of a MI?
• Arrhythmias due to electro conductive tissues like
“bundle branches” dying and being replaced with
non-conductive scar tissue
Bundle branches play an integral role in electrical
conduction in the heart by transmitting cardiac action
potentials from bundle of His to Purkinje fibres
• Aneurisms of the ventricle due to weakness and
dilatation of the muscular wall
What is the difference between aortic valve stenosis and insufficiency?
Aortic valve stenosis is narrowing of the aortic
valve, which normally allows blood to flow from
the left ventricular chamber into the aorta and to
the body. Stenosis prevents the valve from
opening properly. The heart works harder to pump
blood through the valve.
Aortic valve insufficiency, also known as aortic
regurgitation, is the leaking of the aortic valve of
the heart that causes blood to flow in the reverse
direction during ventricular diastole, from the
aorta into the left ventricle.
