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Flashcards in Cell Injury Deck (61):
1

What 7 situations can cause cell injury?

Hypoxia, Chemical agents and drugs, Infections, Immunological agents, Dietary imbalance, Genetic derangement + Physical agents

2

What are the 2 types of cell death and define them

Necrosis - a pathological form of cell death due to disease, injury or inadequate blood supply
Apoptosis - programmed cell death

3

What are the types of necrosis and which one is the most common?

Coagulative, liquefactive, fat, caseous and fibrinoid

Coagulative is the most common

4

What is an infract, what are the different types and where can they be seen?

An infract is a lesion that can be seen as a result of an infarction.

There can be white infarcts which occur in solid organs like the heart, spleen and kidney

There can be red infarcts which occur in organs with a dual blood supply, loose stromal support or numerous anastomoses like the liver and lungs

5

What are the differences between necrosis and apoptosis?

Necrosis affects groups of cells, causes swell enlargement, disrupted plasma membrane and is frequently associated with inflammation

Apoptosis affects single cells, caused cell shrinkage, keeps the plasma membrane intact and is not associated with inflammation

6

What proteins are released from myocardiocytes during myocardial infarction and which one is the best clinical marker and why?

Creatine kinase
Aspartate transaminase
Troponin - best marker because it lasts the longest ~120 hours after heart attack

7

What are some causes of acute inflammation?

Microbial infection, hypersensitive reactions, physical agents,chemicals, tissue necrosis and anything that can cause trauma to the tissue

8

What are the 5 clinical features of acute inflammation?

Redness, swelling, heat, pain and loss of function

9

What is the main leukocyte involved in acute inflammation and what is its function?

Neutrophils

Mainly Phagocytosis
Produce growth factors for repair

10

What is the difference between a transudate and exudate? Describe the formation of an exudate

Both are fluids that fill extra vascular spaces and serous cavities

Transudate - has low protein content

Exudate - has high protein content

11

Give examples of some chemical mediators

Histamine, prostaglandin, serotonin and bradykinin

12

What are the 4 systemic effects of acute inflammation?

Pyrexia, leukocytosis, acute phase response in liver and shock

13

What is alpha-1 antitrypsin deficiency?

An autosomal recessive disorder caused by low levels of alpha-1 antitrypsin resulting in unchecked inflammation which can lead to emphysema and cirrhosis

14

What is chronic inflammation?

A chronic response to cell injury which is usually associated with fibrosis

15

Which leukocyte is mainly involved in chronic inflammation and what are its functions?

Macrophages

Phagocytosis
Antigen presenting to immune system
Synthesis of cytokines
Fibrosis and angiogenesis
Release of growth factors

16

What are giant cells and what are the 3 types?

Giants cells - multinucleated cells made by fusion of macrophages due to frustrated phagocytosis

3 types are: langerhans giant cell, foreign body type and touton type giant cell

17

What are the main effects of chronic inflammation?

Fibrosis, impaired function and atrophy

18

What is granulomatous inflammation and what are the 3 main causes?

Chronic inflammation with granulomas

3 main causes: mildly irritant foreign material, infections and other unknown causes

19

What can cause reduced blood supply to tissue?

Thrombosis, embolism, twisting of blood supply and external compression of blood vessel

20

What is a gangrene and what are the different types?

A clinical term used to describe visible necrosis

3 different types: wet, dry and gas

21

What are the 5 groups of intracellular accumulations?

Water and electrolytes
Lipids
Proteins
Pigments
Carbohydrates

22

What are the 3 different tissue types in terms of regeneration, give an example of each.

Labile tissue - surface epithelia, bone marrow

Stabile tissue - fibrous tissue, liver parenchyma, bone osteoblasts

Permanent tissue - neural tissue, cardiac muscle, skeletal muscle

23

What are the processes of wound healing?

Haemostasis

Inflammation

Regeneration

24

What is granulation tissue and what does it consist of?

Tissue that has a granular appearance and texture

Consists of developing capillaries, fibroblasts, myofibroblasts and chronic inflammatory cells

25

What are the different types of cell signalling mechanisms?

Autocrine - cells respond to signalling molecules that they produce themselves

Paracrine - cells produce signalling molecules that act on adjacent cells

Endocrine - hormones are made by cells and travel through the blood stream to any organ/tissue of choice

26

Why are growth factors important in healing?

They are polypeptides that act on cell surface receptors by binding to them and stimulating transcription of genes that regulate entry of genes into the cell cycle

27

What are some local factors in healing?

Size of wound
Location of wound
Blood supply
Nerve supply
Local infection
Foreign bodies
Mechanical stress

28

What are some systemic factors of healing?

Age
Obesity
Drugs (steroids)
Nutrition
Diseases like diabetes
Vitamin deficiency (vitamin c)

29

What is a keloid scar?

A complication of fibrous repair where there is overproduction of fibrous scar tissue due to overproduction of collagen

30

What is haemostasis and what are the steps involved?

The complex process that stops bleeding, representing a balance between procoagulant and anticoagulant factors

3 stages include: primary haemostasis, secondary haemostasis and fibrinolysis

31

What 4 components does successful haemostasis depends upon?

Vessel wall

Platelets

Coagulation system

Fibrinolytic system

32

Describe the process of haemostasis

Injury occurs > vessel wall constricts > endothelial cells secrete Von willebrand factor > platelets adhere to subendothelial structures via Von willebrand factor > platelets adhere to each other > fibrinogen holds platelets together forming a primary platelet plug > fibrin surrounds platelet plug making it insoluble > after a while, plasminogen is activated into plasmin > plasmin breaks down fibrin into fragments following would healing

33

What is a DVT?

Deep vein thrombosis - a clot within a vein

34

What is a pulmonary embolism?

Blockage of the artery in the lungs caused by the breaking off of a DVT into the bloodstream

35

What is a thrombosis?

The formation of a solid mass made of the constituents of blood within the circulatory system

36

What is Virchow’s triad and what constitutes it?

The 3 categories of factors that are thought to contribute to thrombosis: blood flow, vessel wall and blood components

37

What are the 5 possible outcomes of thrombosis?

Lysis
Propagation
Organisation
Recanalization
Embolism

38

What is an embolism?

The blockage of a blood vessel by solid, liquid or gas at a distant site from its origin

39

Define thrombocytopenia and thrombocytosis

Thrombocytopenia - lack of platelets

Thrombocytosis - abundance of platelets

40

In what ways can the coagulation system be inhibited?

Use of antithrombin 3 - group of enzyme that inhibit serine protease, thrombin and factor 10a

Use of protein C - vitamin k dependent zymogen that cleaves factor 5a and 8a and works together with co factor protein s to degrade them

41

What are the effects of a venous thrombosis?

Congestion
Oedema
Secondary ischaemia
Infarction due to compression of arterial vasculature

42

What are the effects of an arterial thrombosis?

Ischaemia
Infarction which depends on site and collateral circulation

43

What is heparin and its mechanism?

Naturally occurring anticoagulant in the body that increases the effect of Antithrombin 3

44

What is warfarin and its mechanism?

A vitamin k antagonist that aids in anticoagulation by inhibiting the synthesis of clotting factors 2, 7, 9 and 10

45

Define atherosclerosis

The thickening and hardening of the intima and media walls of elastic and large and medium sized muscular arteries due to deposition of intracellular and extra cellular lipid

46

What is ARTERIOSCLEROSIS?

Thickening and hardening of walls of arteries and arterioles usually due to diabetes or hypertension

47

What are the layers of the normal arterial structure?

Endothelium - subendothelial connective tissue - internal elastic lamina - muscular media - external elastic lamina - adventitia

48

In atherosclerosis, hows does plaque develop?

Yellow lipid deposits in the intima form a fatty streak
The fatty streak develops to form a simple plaque which is yellow/white in colour with an irregular outline
Simple plaque undergoes calcification resulting in a complicated plaque

49

What are some common sites for atherosclerosis?

Aorta
Coronary arteries
Carotid arteries
Cerebral arteries
Arteries of the legs - popliteal artery

50

What are some of the microscopic features of atherosclerosis?

Accumulation of foam cells
Proliferation of smooth muscle cells
Extracellular lipid deposition
Scattered T lymphocytes

51

What are the cellular events that lead to atherosclerosis?

Chronic Epithelial injury - causes a chronic inflammatory response
Endothelial dysfunction - caused by chronic epithelial injury
Smooth muscle immigration from media to intima - promoted by PDGF
Macrophages and smooth muscle cells engulf accumulated lipid and form foam cells
Smooth muscle proliferation in response to cytokines, growth factors, collagen, matrix deposition and neovascularisation

52

What are the effects of atherosclerosis of the coronary artery?

Reduced blood flow to myocardiocytes which can result in myocardial infarction, arrhythmias, cardiac failure, angina pectoris and sudden death

53

What is the effect of atherosclerosis of the carotid artery?

Cerebral ischaemia leading to a stroke

54

What is the effect of atherosclerosis of the mesenteric arteries?

Ischaemia of the bowel

55

What are the effects of atherosclerosis in peripheral vasculature?

Intermittent claudication - muscle pain/cramp/ache which occurs after mild exercise, usually in calf muscle
Leriche’s syndrome - group of symptoms caused by a certain type of peripheral arterial disease of the legs
Ischaemia rest pain
Gangrene

56

What are some risk factors for atherosclerosis?

Age - more common in elderly
Gender - more common in males
Hyperlipidemia - mainly LDLs
Cigarette smoking
Hypertension
Diabetes mellitus
Excessive alcohol intake
Infection - mainly bacterial
Geography - lower incidence in South America, Africa and Asia

57

What is atherogenesis and which cells are involved?

Development of plaques within blood vessels

Endothelial cells
Platelets
Smooth muscle cells
Macrophages
Lymphocytes
Neutrophils

58

What are the 3 typical signs of hyperlipidemia?

Corneal arcus
Tendon xanthomas
Xanthelasma

59

What preventative measures can be taken to avoid atherosclerosis?

No smoking
Decrease fat intake - LDLs
Treat hypertension
Intake of aspirin
Regular exercise and control of weight
Lipid lowering drugs e.g. statins
Sensible alcohol intake

60

What does the size of a cell population depend on and what cell regulate it?

Cell proliferation
Cell differentiation
Cell death

Proto-oncogenes regulate it

61

What are the 5 main types of cellular adaptations? Describe them

Regeneration - replacement of cell losses by identical cells
Hyperplasia - increase in tissue/organ size due to increase in cell numbers
Hypertrophy - increase in tissue/organ size due to increase in cell size
Atrophy - shrinkage of a tissue/organ due to acquired decrease in size and/or number of cells
Metaplasia - reversible change of one differentiated cell type to another