Intro to Clinical Sciences Flashcards
Define inflammation
The initial series of tissue reactions to injury which can last from a few hours to a few days
Give an example of acute inflammation
Appendicitis
Frostbite
What is another way of describing acute inflammation?
Neutrophil mediated inflammation
What are the benefits of acute inflammation?
Destroys invading pathogens
Walls off an abscess preventing the spread of infection
What are the limitations of acute inflammation?
An abscess can compress surrounding structures
Fibrosis can destroy or distort tissues
What are the steps of inflammation?
Vascular component: dilation of vessels
Exudative component: leakage of fluid
Neutrophil polymorphs: WBCs recruited to the area
What are the outcomes of acute inflammation?
- Resolution: goes away
- Suppuration: pus formation
- Organisation: healing by granulation to form a fibrous scar
- Progression to chronic inflammation
What can cause acute inflammation?
Microbial infection
Hypersensitivity reactions
Physical agents
Chemicals
Necrosis
What are the 5 cardinal signs of inflammation?
Redness/rubor
Heat/calor
Swelling/ tumor
Pain/dolor
Loss of function
What are the stages of neutrophil migration in acute inflammation?
- Margination of neutrophils: cells flow in plasmatic zone near endothelium
- Adhesion of neutrophils: neutrophils adhere to the endothelium and adhere to each other
- Neutrophil emigration: neutrophils migrate through endothelial walls
- Diapesesis: RBCs escape
- Chemotaxis
What are some chemical mediators of acute inflammation?
Histamine- vasodilation, adhesion
Thrombin- adhesion
Nitric acid- prolongs permeability
Bradykinin- “”
Prostaglandins- vasodilation, pain, fever, prolonged permeability
Cytokines- local endothelial action, systemic- fever, metabolic permeability
What are the systemic effects of acute inflammation?
Pyrexia/fever
Malaise
Nausea
Weight loss
Lymph node and spleen enlargement
Anaemia and increased WBC conc
Amyloidosis
Define chronic inflammation
Subsequent and prolonged tissue response to injury
What can chronic inflammation also be defined as (cells)?
Lymphocytes
Plasma cells
Macrophages
What are some causes of chronic inflammation?
Can develop from acute inflammation
Resistance of infective agent such as TB
Endogenous and exogenous material
Autoimmune disease
Granulomatous disease
Transplant rejection
What are the effects of chronic inflammation?
Fibrosis
Impaired function
Atrophy
Stimulation of immune response
How does acute inflammation progress to chronic inflammation?
-Suppuration: pus forms and abscess, abscess forms wall from granulation and fibrous tissue, fibrous scar forms in pus
-Indigestible material can not be cleared: such as keratin, necrotic material
What are the macroscopic signs of chronic inflammation?
-chronic ulcers and cavities
-walls of hollow organs thicken
-fibrosis
-granulomatous inflammation
What are the microscopic signs of chronic inflammation?
-lymphocytes, plasma cells, macrophages
-macrophage -> giant multinucleate cells
-tissue necrosis (sometimes)
What are the roles of the cells involved in chronic inflammation?
-T-lymphocytes: cytokines after contact with antigen
-B-lymphocytes: transform into plasma cells -> antibodies
-Macrophages: ingest material and respond to chemotaxis
What are 3 different types of macrophages?
Kupffer cells in liver
Alveolar macrophages in lungs
Melanophages in skin
Define Granuloma:
An aggregate of epitheliod histocytes/macrophages surrounded by lymphocytes
What are 4 diseases which display Granuloma?
Leprosy
TB
Sarcoidosis
Crohn’s disease
What can granulomas alongside eosinophils be indicative of?
Parasitic infection
What is secreted in granulomatous disease that can be used as a marker?
ACE/ angiotensin converting enzyme
What are the 2 outcomes of tissue damage?
Resolution: initiating factor removed/ tissue can regenerate or is undamaged
Repair: initiating factor can not be removed/ tissue is damaged
Which cells in the body are able to regenerate?
Hepatocytes, pneumocytes, blood cells, gut epithelium, skin, osteocytes
Which cells in the body are unable to regenerate?
Myocardial cells, neutrons
Define thrombosis
The solidification of blood content that forms in an intact vessel during life
Define clot
Coagulated blood outside of the vascular system after death
Why does blood not clot all of the time?
Laminar flow: cells travel in the middle of the cells
Endothelial cells: healthy cells are not adhesive
Define organisation
The repair of specialised tissue by formation of a fibrous scar
What are the stages of thrombus formation?
- Coronary vasospasm
- Primary platelet plug
- Coagulation cascade
What causes arterial thrombosis
Atheromatic plaque causes a change in the vessel wall which affects blood flow, causing a thrombus
Describe the progression of arterial thrombosis
- Fatty streak grows causing obstruction
- Intimal cell loss and fibrin disposition causes platelets to settle
- Proliferation of smooth muscle cells causes platelet layer to form, traps RBCs
- Grows and disrupts laminar flow
What occurs in venous thrombosis?
Low BP, thrombus begins at valves
What is the main cause of venous thrombosis?
Immobility
What are the effects of venous thrombosis?
Tenderness (ischaemia) redness and swelling
What are the effects of arterial thrombosis?
Distal pulse loss, coldness, pain, paleness, necrosis and gangrene
What are the fates of a thrombus?
Resolves by dissolving
Organisation into scar after clearance of thrombus
Intimal cells proliferate and cause thrombus to fuse into a larger vessel
Embolism-fragments break off
Define embolism
A mass of material in the vascular system that can lodge in a vessel and block the lumen
What are some less common causes of embolism?
Air
Cholesterol crystals
Fat
Tumour amniotic fluid
What are the 3 causes of thrombosis outlined in Virchow’s triad?
Change in vessel wall
Change in blood flow
Change in blood constituents
What can cause a change in vessel wall?
Smoking
Hypertension
MI
Trauma
What can cause changes in blood flow?
Immobility
DVT
AF
What can cause changes in blood constituents?
Pregnancy
Oral contraceptives
Cancer
Inherited thrombophlila
How does aspirin work and what does it do?
Inhibits platelet aggregation so can prevent thrombosis
How does warfarin work and what does it do?
Inhibits vitamin K- many clotting factors dependant on this, can prevent thrombosis
Describe the progression of venous thrombosis
Valves naturally protrude into vessel lumen, mostly upstream of thrombosis
Grows by successive deposition via propagation
Fall in BP causes adhesion to endothelial cell walls
Leads to thrombus
What occurs during an arterial embolism?
An embolus from the arterial system can travel anywhere downstream- can be due to atheromatous plaque or thrombus in the heart due to AF
What type of embolism is a pulmonary embolism?
Venous embolism
How does a pulmonary embolism develop?
Embolism travels to vena cava and moves through the heart to lodge in the pulmonary arteries
Why can a venous embolism not enter the arterial circulation?
The blood vessels in the lung are too small for an embolus to pass through
What are the effects of different sizes of emboli?
-Small: can be lysed in lung or can be organised and cause damage
-Medium: can cause respiratory and cardiac problems that can resolve slowly, or can impair lung function
-Large: can cause sudden death- using from DVT in legs
Define ischaemia
A reduction in blood flow to a tissue or organ caused by blockage or obstruction of the blood vessels supplying it
What 2 factors determine if ischaemia can be reversed?
Duration of the ischaemic period
Metabolic demands of tissue (eg. Myocytes are vulnerable)
Define infarction
Necrosis of part or all of an organ due to the artery supplying it becoming obstructed
What is the most common cause of infarction?
Thrombus
What type of organs are at greater risk of infarction?
Organs with an end arterial supply (supplied by a single artery)
Define gangrene
Whole areas of a limb or region of the gut have their arterial supply cut off and large areas of tissue die
Define atherosclerosis
The formation of an atherosclerotic plaques in systemic arteries
Does atherosclerosis affect veins/outside of the systemic system? Why?
No- low pressure
What are the effects of atherosclerosis?
Cerebral infarction
Carotid atheroma -> TIA
MI
Aortic aneurism
Peripheral vascular disease
Gangrene
Outline the progression of atherosclerosis
Birth: no atherosclerosis
Late teens/early adulthood: fatty streaks begin to form
30s-50s: development of atherosclerotic plaques
40s+: complications of atherosclerotic plaques erupt
What are the risk factors of atherosclerosis?
High cholesterol (most important)
Smoking
Hypertension
Diabetes
Male sex
Increased age
What are the 2 main stages of the development of atherosclerotic plaques?
Endothelial injury
Tissue response to injurious agents
Describe the composition of an atherosclerotic plaque
Central lipid core capped by fibrous tissue covered by an arterial endothelium
-collagen for strength (from smooth muscle cells)
-inflammatory cells: macrophages, T lymphocytes, mast cells
-bordered by foam cells- macrophages that have oxidised lipoproteins
Where do atherosclerotic plaques usually form?
Branching points and bifurcations
Describe the process of the formation of an atherosclerotic plaque
- Injured endothelial cells increase adhesion of monocytes
- Lipid accumulation
- Macrophages engulf LDL and apoptose -> Foam cells
- Smooth muscle proliferation
- Fibrous cap forms
- Plaque rupture and thrombus formation
Which effects of atherosclerosis can cause disease?
1.Progressive lumen narrowing
2. Acute atherothrombotic occlusion: plaque rupture leads to coagulation cascade -> ischaemia -> infarction
3.Embolism of distal arterial bed: parts break off and embolism
4. Ruptured abdominal aneurism
What can prevent atherosclerosis?
Stopping smoking
Control of BP
Losing weight
Low dose aspirin
Statins
What triggers the intrinsic coagulation pathway?
Internal damage to vessel wall
Outline the intrinsic coagulation pathway
Factor 12 activated due to collagen contact
Factor 11 activated
Factor 9 activated
Factor 8 leads to common pathway
What triggers the extrinsic coagulation pathway?
External trauma causing blood to escape the circulation
Outline the extrinsic coagulation pathway
Factor 3 exits the circulation
Factor 7 (tissue factor) is released by damaged cells
Factor VII and III = TF-VIIa complex -> activates factor X
Outline the common coagulation pathway
Activated factor X causes factor II (prothrombin) -> IIa (thrombin)
Thrombin converts factor I (fibrinogen) into insoluble fibrin strands
Strands stabilised by factor XIII
How are fibrin clots removed after healing has occured?
Plasminogen -> plasmin -> fibrin breakdown
Protein C and S degrade factor Va and VIIIa, slows clotting
Calcium regulates calcium dependant factors
Antithrombin degrades thrombin
What are the vitamin K dependant clotting factors?
2, 7, 9, 10
Define apoptosis
Non inflammatory controlled cell death without release of harmful products
Chromatin NOT altered
What is the difference between apoptosis and necrosis?
Necrosis is unintended cell death in response to cell injury, apoptosis can suppress the results of necrosis
Name some inhibitors of apoptosis
Growth factors
Sex steroids
Some viral proteins
Extracellular cell matrix
Name some inducers of apoptosis
Glucocorticoids
Free radicals
Ionising radiation
DNA damage
Outline the intrinsic apoptosis pathway
Bcl-2: inhibits induction
Bax: enhances apoptosis
Ratio determines if a cell will survive or apoptose
Describe the role of the p53 gene in the intrinsic apoptosis pathway
Induces cell cycle arrest and initiates DNA damage repair
Hard to repair damage causes p53 to induce apoptosis via the Bcl-2 pathway
Outline the extrinsic apoptosis pathway
FasL or TNF-L activate CSM receptors -> activate caspases
Caspases= death enzymes
Outline the execution apoptosis pathway
Caspase 8 causes activation of other caspases
Caspases cause degradation of nuclear proteins and cytoskeletal framework
Dead cells either apoptose or are later phagocytosed
Define necrosis
Traumatic cell death which induces inflammation and repair
Chromatin CAN be altered
Why does necrosis induce inflammation and repair?
Rupture of plasm membrane releases cell contents which may induce an immune response
What are the 4 forms of necrosis?
1.Coagulative: most common, caused by ischaemia which causes protein coagulation
2. Liquefactive: occurs due to lack of stroma in brain
3. Caseous necrosis: seen in TB, soft cheese appearance
4. Gangrene: rotting of tissues
Define congenital disease
A disease present at birth
Define inherited genetic disease
Caused by an inherited genetic abnormality
Define spontaneous genetic disease
Disease caused by a spontaneous mutation eg. Downs syndrom
Define acquired disease
Disease caused by non-genetic environmental factors
Define Hypertrophy
An increase in cell size without cell division (ie. No increase in number)
When is Hypertrophy seen?
Muscle Hypertrophy in atheletes
Uterine smooth muscle Hypertrophy
Define hyperplasia
An increase in cell number by mitosis
Define atrophy
The decrease in the size of an organ or cell by reduction in cell size/cell number
When does atrophy occur?
Development of genitourinary tract (Wolfian and Müllerian ducts)
Muscle atrophy due to loss of innervation or malnutrition
Define metaplasia
The change in differentiation from one fully differentiated cell type to another fully differentiated cell type
When does metaplasia occur?
Smokers- respiratory epithelium -> squamous epithelium
Barretts oesophagus: squamous epithelium -> columnar epithelium
Define dysplasia
Morphological changes seen in cells in the progression to becoming cancer
-not cancer yet but can become cancer
What occurs in telomeric shortening?
The telomere at the end of each chromosome shortens each time DNA divides as it is not fully copied
They eventually get so short that the cell is incapable of further division
Who is telomere length determined by?
Father
What are common complications found in older people?
Sarcopenia
Deafness
Senile dementia
Cataracts
Osteoporosis
Dermal elatosis (wrinkles)
Impaired immunity
Define carcinogenesis
The transformation of normal cells to neoplastic cells via permanent genetic alterations or mutations
Define neoplasm
Lesion from autonomous abnormal growth of cells which persists after initial stimulus removed
What are the 4 features of neoplasia?
Autonomous
Abnormal
Persistent
New growth
Define tumour
Any abnormal swelling
-includes: neoplasm, inflammation, Hypertrophy, hyperplasia
What 2 things make up a solid tumour?
Neoplastic cells: nucleated cells, synthesise/secrete collagen, mucin, keratin ect
Stroma: neoplastic cells embedded here, provide support and nutrients. Contains fibroblasts, collagen and blood vessels
How does vascular supply limit tumour size?
If not vasculated, the growth is limited by nutrient diffusion
Angiogenesis is induced by VEGF
What are the features of benign neoplasms?
Localised and non-invasive
Slow growth rate
Resembles normal tissue
Often encapsulated
Expophyic growth
How can benign neoplasm cause mortality and morbidity?
Pressure on adjacent structures
Obstruction of ducts
Hormone production (eg. Thyroid)
Transformation to malignancy
Anxiety and stress
What are borderline neoplasms?
Neither benign or malignant
Defy classification
Usually treated as malignant
What are the features of malignant neoplasms?
Invasive- invade and destroy surrounding tissue
Grow rapidly
Irregular border
Do not resemble parent cell
Increased mitotic activity
Necrosis and ulceration common
Endophytic growth (inwards)
What is metastases?
Secondary malignant tumours
How do malignant neoplasms cause mortality and morbidity?
Pressure and destruction of adjacent tissue
Metastases
Blood loss from ulcers
Obstruction of flow
Hormone production
Weight loss and debility
Anxiety and pain
Define histogenesis
The specific cell or origin of a tumour
What are the major categories of origin of tumours?
Epithelial cells = carcinomas
Connective tissues = sarcomas
Lymphoid = malignant neoplasms
What are the grades of malignant neoplasms?
Grade 1: well differentiated
Grade 2: moderately differentiated
Grade 3: poorly differentiated
-well differentiated resembles the parent tissue more
-poorly differentiated = more agressive
Define papilloma
Benign tumour of non-glandular/secretory epithelium
Define adenoma
Benign tumour of glandular epithelium
Define carcinoma
Malignant tumour of epithelial cells
Define Adenocarcinoma
Malignant tumour of glandular epithelium
Define intraepithelial neoplasia
Carcinoma in situ in an epithelium exhibiting malignant cellular features but has not yet invaded the basement membrane
Define:
Lipoma
Osteoma
Angioma
Neuroma
Benign tumour of adipocytes
Benign tumour of bone
Benign vascular tumour
Benign tumour of the nerve
Define:
Liposarcoma
Osteosarcoma
Neurosarcoma
Chrondrosarcoma
Malignant tumour of adipocytes
Malignant tumour of bone
Malignant tumour of the nerve
Malignant tumour of cartilage
What are some malignant tumours that are not carcinomas or sarcomas?
Melanoma: malignant neoplasm of melanocytes
Mesothelioma: malignant neoplasm of mesothelial cells
Lymphoma: malignant neoplasm of lymphoid cells
Define carcinosarcoma
Mixed malignant tumours with characteristics of epithelial and connective tissue cells
Why can neoplastic cells proliferate endlessly?
Oncogenes
Inactivation of tumour suppressor genes
Abnormal expression of apoptosis inhibiting genes
Telomerase prevents telomeric shortening
Define carcinogenic
Malignant neoplasm causing
Define oncogenic
Tumour/neoplasm causing
What percentage of cancer risk comes from genes vs the environment?
85% is environmental
15% is from genes
What are 5 classes of carcinogens?
- Chemical: most require metabolic conversion
- Viruses: such as HPV -> cervical cancer
- Radiation: UV = skin cancer, ionising = more long term effects
- Biological agents: hormones (oestrogen), parasites, mycotoxins
- Miscellaneous: asbestos