Session 1 - Cell injury and Death Flashcards
Give five causes of cell death
Hypoxia Toxins Micro-organisms Physcial Immune Nutritional Radiation
Define disease
a consequence of failed homeostasis with subsequent morphological and / or functional disturbances
What three factors determine the degree of damage to a cell?
- Type of cell
- Severity of injury
- Type of injury
What happens in some cells if damage is minor?
What happens if it severe?
Cell adaptation
Cell death
What is hypoxia?
Body or some tissue within the body is deprived of oxygen
What are three mechanisms by which hypoxia can occur
Ischaemia
Hypoxaemia
Histocytic hypoxia
Anaemic hypoxia
What is ischaemia?
Interrupted blood supply due to blockage or laceration.
Decrease in oxygen AND substrate
More rapid and severe injury than hypoxia
What is hypoxaemia?
Inadequate O2 getting into blood
Give three factors which may cause hypoxaemia
- Reduced inspired O2 e.g. at the top of a mountain
- Normal inspiration but absorption into the blood is impaired by lung disease
- Reduced carrying capacity of O2 e.g. due to anaemia
What is histocytic hypoxia?
What is Anaemic hypoxia?
Inability of the cells to use O2 due to disable oxidative phosphorylation enzymes e.g. due to cyanide poisoning.
Decreased ability of haemoglobin to carry oxygen (anaemia, CO poisioning)
What are the four main chemical types which cause damage to cells?
Illicit drugs
Over the counter drugs and prescription drugs
Alcohol
Cigarettes
How can paracetamol damage cells?
If overdosed, depletes glutathione, an anti oxidant and NAPQI (Phase one metabolite) causes damage to hepatocytes, causing liver damage
What cells does alcohol affect in particular?
Hepatocytes
How do cigarettes damage cells?
- Particulates cause physical damage to epithelium
* Chemical carcinogen
Where is the impact of infection greatest in society?
Areas of poverty
What are four types of infectious organisms?
Helmiths/worms
Eukaryotes
Prokaryotes
Viruses
How can Helmiths cause damage?
Fillriasis - worms block lymphatic vessels
How can eukaryotes cause damage?
protozoa and fungi e.g. thrush – candida causes a superficial mucosal fungal infection
Give a disease caused by bacteria
Syphilis, among many, many others
Give a disease caused by a virus
HIV, or whatever you just thought in your head
How can cells be damaged physically?
Direct trauma
Extremes of temperature
Pressure changes
Electric currents
Give two ways cells can be damaged by the immune system, and provide examples
- Hypersensitivity reactions: Host cells damaged in overlyreactive immune response
e. g. uticaria (hives) causes inflammation in the skin - Autoimmune reactions: immune system fails to distinguish self from non-self
e. g. Grave’s disease > hyperthyroidism
What are the two nutritional discrepancy’s that can cause damage?
Defiencies
Excess
Give an example of a nutritional defiency causing cell damage
vitamin C > scurvy
Give an example of a nutritional excess causing cell damage
Lipids –> atherosclerosis
What is necrosis?
a spectrum of morphological changes that occur after cell death in living tissue
What is apotosis?
programmed, single cell death
What type or reaction is apotosis?
- Energy requiring process
When can apotosis occur?
- May be physiological e.g. aging cell destruction or pathological
What is a lethal damage stimulus?
One that cannot be recovered or adapted from, which will result in apotosis or necrosis