Lecture 2 - response to cellular strength Flashcards
What state are labile cells
Cells constantly multiplying
What state are stable cells
Only multiply when needed
What state are quiescent cells
Cells retain the ability to proliferate (reversible state)
What are the 3 main causes of cellular stress
Oxygen deprivation (hypoxia)
Physical trauma
Chemical trauma
What are the types of oxygen deprivation (hypoxia)
Ischemia - most devastating cause (restriction of blood)
Hypoxic hypoxia - insufficient O2 to the lungs -> insufficient blood to the body
Anaemic hypoxia - decreased haemoglobin conc. (decreased or delayed RBC production)
Ischaemic hypoxia - inadequate blood to tissue (generalised heart failure, local vessel obstruction, arteriosclerosis, infarctions)
What types of physical trauma cause cellular stress
Mechanical
thermal (hypo, hyper)
Electrical
radiation (damages DNA)
Changes in atmospheric pressure (blast injury and decompression sickness)
What are the types of chemical chemical trauma
Hypertonicity (glucose), poisons, strong acids/alkalis, environmental pollutants and recreational drugs
(increased temp, increased water consumption, cell swells bursts and dies)
Describe helicobacter pylori
in upper GI tract of 50-75% of people - linked to gastric ulcers (neutralises acid of stomach and damages epithelial cells)
What are the immunological agents of Helicobacter pylori
Hypersensitivity reactions - allergies and autoimmunity
Anaphylactic reaction - allergic response to allergen
what are examples of point mutations
Sickle cell anaemia
INDELS
trinucleotide repeat mutations
Give an example of an autosomal dominant disorder
Huntington’s disease - repeat of CAG in HD gene (35 copies) - gain of function, increased num. of repeats (earlier age of onset), loss of medium spiny striatal neurons that normally dampen motor activity
What is an example of autosomal recessive disorder
Cystic fibrosis
What is an example of an X-linked disorder
Duchenne’s muscular dystrophy
Describe thalassemia
Inherited mutations that decrease alpha or beta-globin synthesis rate -> haemoglobin deficiency
Describe effects of nutritional imbalances
Deficiency of nutrients (protein, minerals, vitamins)
Excess of nutrients (carbohydrates, fat, vitamins, minerals)
What is hypertrophy
Increase in size of individual cells - accumulation of protein (not cellular fluid), increased work load (heart and kidney susceptible)
What is hyperplasia
Increased number of cells (increased rate of cellular division - can lead to cell death)
Compensatory - enables certain organs to regenerate
Hormonal - oestrogen dependent organs (excessive hormone response)
What is metaplasia
Reversible replacement from one mature cell type to another
(less differentiated) - Barrett’s oesophagus
What is atrophy
Reduction in cell size (decreased protein synth. and increased protein degradation) -> organ shrinkage, cell changes
(decreased workload, blood supply, nutrition, hormonal stimulation and aging)
Describe poliomyelitis
damage to anterior hon of motor neurons causes atrophy of limbs - loss of nerve innervation
Describe reversible injury
Able to be repaired - cellular swelling (failure of ATP dependent ion pumps in plasma membrane)
- fatty change (lipid vacuoles in cytoplasm)
