Week 1 Flashcards
Pathophysiology
The study of how the function of cells, tissues and organs are altered in disease, illness or injury.
Represents a breakdown of homeostasis.
Aetiology
Idiopathic
Iatrogenic
The study of the cause(s) of a disease. May be one factor or multifactor.
Idiopathic - cause of disease is unknown.
Iatrogenic - disease unintentionally caused by a medical treatment, diagnostic procedure or an error.
Pathogenesis
Acute disease
Chronic disease
The development of a disease. Mechanisms by which a disease becomes established and progresses.
Acute disease - develops quickly
Chronic disease - develops gradually and lasts for a longer time
Risk factors
places a person at greater risk for developing a particular disease
modifiable risk factor
can be changed (e.g smoking, diet)
non-modifiable risk factor
cannot be altered (e.g age, race)
clinical manifestations
signs
symptoms
changes in function caused by a disease
signs - objective measurement / recording of a disease e.g heart rate, temperature, blood pressure
symptoms - subjective feelings e.g pain and nausea
diagnosis
identification of a specific disease through the evaluation of signs, symptoms, laboratory tests and / or other tools
management
aims to minimise the effects of a disease through illness-specific management, education, and patient support
epidemiology
the study of how disease is distributed within populations and identification of factors that influence distribution of disease
incidence
number of new cases of a disease diagnosed within a defined period
prevalence
total number of cases of a disease at a particular time
morbidity
proportion of a population with a disease
mortality
number of deaths
cell adaptation
reversible
irreversible
- response to persistent or intense stimuli
- cell can adapt to new conditions by changing size (atrophy and hypertrophy), number (hyperplasia) and type (metaplasia)
- if cells cannot adapt, they can become injured
reversible - affected cells recover after removal of stimulus
irreversible - results in cell death
atrophy
a decrease in cell size due to a lower than normal demand being placed on a cell
hypertrophy
an increase in cell size due to a greater than normal demand being placed on a cell
hyperplasia
an increase in cell number in response to increase demand
- due to an increased rate of cellular division
- usually, increase is a combination of hyperplasia and hypertrophy
metaplasia
cells change from one cell type to another cell type
- if stimulus is removed, cells may revert to original type
dysplasia
abnormal differentiation or maturation of tissue
- variation in cell size, shape and organisation which leads to breakdown of tissue
- often a precursor to cancer
- may be benign or malignant
- may be reversed if stimulus is discontinued / removed
reversible cell injury: hydropic swelling
- regulates flow of sodium (Na) and potassium (K) across membrane
- Na+/K+ ATPase pump requires energy produced by mitochondria
reversible cell injury: intracellular accumulation
- substances that can accumulate: normal nutrients, pigments and inorganic particles
- accumulate due to excessive levels and / or metabolic dysfunction
irreversible cell injury
- energy production in the mitochondria below essential minimal requirement and unable to be restored
- disruption of nuclear function: without a viable nucleus the cell cannot survive
- loss of cell integrity, cell membrane ruptures
- results in cell death - necrosis and apoptosis
necrosis
cell injury leads to unplanned cell death and autolysis
fat necrosis
- occurs in adipose tissue
- damaged fat cell membranes release triglycerides into the tissue
- formation of free fatty acids
- calcium ions bind to free fatty acids > calcium soaps
- affected tissue becomes chalky and white
necrotic process
- intracellular enzymes move into extracellular fluid
- eventually diffuse into the bloodstream
- presence indicates necrotic cell death and can be used for clinical diagnosis
- release of chemical mediators triggers inflammatory reaction to remove debris and start the healing process
-types - coagulative, liquefactive, caseous, fat
coagulative necrosis
- most common form of necrosis
- characterised by protein denaturation e.g cooking an egg
- tissues retain original shape and consistency before breaking down
- often caused by ischaemic injury
gangrene
- necrosis of a large amount of tissue due to ischaemia
- often seen in toes and lower extremities, usually caused by peripheral vascular disease
- gangrene of toes and / or foot is common in diabetic patients
liquefactive necrosis
- characterised by dissolution of tissues - cell liquefies
- lysosomal digestive enzymes released in large amounts during cell death
- autolysis - tissue transforms into liquid and pus
- most often occurs in the brain due to irreversible ischaemic brain injury
caseous necrosis
- combination of coagulative and liquefactive processes
- tissue framework is not completely broken down
- consistency is “cottage cheese”
- typically seen in tuberculosis
wet gangrene
liquefactive necrosis of internal organs
dry gangrene
coagulative necrosis that dries out and becomes black and mummified
apoptosis
- programmed cell death that occurs normally in developing and adult tissues
- normal process of tissue maintenance and development
- physiologic: formation of our head, face, gastrointestinal tract and other body parts in utero
- pathologic: certain cancers, parkinson’s disease, alzheimers disease
- occurs in response to a specific stimulus that the cell is no longer required or is redundant
- cell size decreases and nucleus condenses > cell membrane ‘blebs’ > cell fragments > apoptotic bodies form > engulfed by nearby phagocytes
- no inflammatory response
hypoxia and ischaemia
hypoxia: a state of low oxygen
ischaemia: inadequate blood flow to an organ or tissue
- ischaemia leads to hypoxia
- hypoxia can occur without ischaemia
ischaemic injury
- compromised oxygen supply to cells
- ATP production decreases
- anaerobic metabolism used
- low ATP production and increased lactic acid
- failure of the membrane pumps
- sodium ions accumulate inside cell
- water moves into cell
- cells swell and become damaged
- calcium released impairing mitochondria
- cellular waste accumulates leading to cell injury
pharmacology
the study of drugs, including their actions and effects on the body
- a drug is any substance or product that is used, or is intended to be used, to modify or explore physiological systems or pathological states for the benefit of the recipient
pharmakos
medicine or drug
logos
study
pharmacokinetics
the physiological processes that influence drug levels within the body: Absorption, Distribution, Metabolism and Elimination (ADME)
- the action of the body on the drug
- kinetic = movement > the movement of drugs into, through and out of the body
pharmacodynamics
the mechanism by which drugs exert their effects on the body
- the action of the drug on the body
- D = do > what the drugs do to the body for a response to occur
pharmacotherapy
the use of drugs for treating or preventing disease
therapeutic effects
intended effects
adverse drug reactions
undesirable effects that occur with the administration of medicines at normal doses
side effects
very common and are the unintended effects that are not related to the desired drug effects
- due to a lack of specificity of action
idiosyncratic reactions
abnormal reactivity to a medication
- unpredictable, likely genetic factor