MoD lectures 8-12 Flashcards
What are the two ways cells heal after inflammation?
regeneration and repair
What is regeneration?
damaged cells replaced by like so tissue returns to normal –> restitution of specialist function
What is repair?
damaged cells cannot be replaced by like so fibrosis and scarring –> loss of specialized function
What are the properties of labile cell populations and name some examples
- high normal cell turnover so maintain their integrity
- active cell populations sitting in the basal zone
- e.g. epithelia
What are the properties of stabile cell populations and name some examples
- low physiological turnover but can switch on turn over when the need arises
- e.g. liver and renal tubules
What are the properties of permanant cell populations and name some examples
- no physiological turnover, very long life cells
- e.g. neuron and muscle cells
Which type of cells are best at regeneration and which are worst?
best: labile
stabile
worst: permanant
What are adult stem cell niches?
reservoirs of adult stem cells present in adult tissues in specific anatomical places–> the survival of this is crucial to regeneration
What does uncontrolled cell division lead to?
neoplasia
Name some examples for how regeneration is controlled
contact inhibition (cells proliferate until they touch each other) and using growth factors, cell-cell and cell-matrix interactions
What is granulation tissue?
new connective tissue that forms on the surfaces of wounds during healing
it matures into a fibrous scar
What 3 components make up granulation tissue?
- new capillary loops
- phagocytic cells to remove dead tissue (neutrophils and macrophages)
- (myo)fibroblasts to lay down matrix components (e.g. collagen)
What is a catabolic state?
state of breaking down larger molecules to smaller ones proteins- amino acids fats- fatty acids glycogen- gluose e.g. corticol steroids. This interacts with the healing process
What is primary intention healing?
-healing of a clean, uninfected surgical wound with good haemostasis with edges apposed
What is organisation?
The formation of a fibrous scar and converting to a fibrous scar
What is secondary intention healing?
the wound edges are not opposed causing more extensive scarring
What cells form a callus?
osteoblasts which lay down woven bone (callus) which is then replaced by lamellar bone
What is the supporting tissue in the brain?
glial cells instead of collagen and fibroblasts etc
What does damaged tissue form in the brain?
a cyst
What is gliosis?
proliferating of astrocytes in the brain (instead of scarring)
Name some local factors which inhibit healing
infection, haematoma, blood supply, foreign bodies, mechanical stress
Name some systemic factors which inhibit healing
age, drugs, anaemia, diabetes, malnutrition, catabolic states, vit c deficiency, trace metal deficiency
What is an akaryote?
cell without a nucleus e.g. RBC
What is a prokaryote?
microscopic single-celled organism which has neither a distinct nucleus with a membrane nor other specialized organelles
What is a eukaryote?
organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus
What are virulent micro-organisms?
microorganisms which cause disease
What is Koch’s postulates?
criteria used to describe if a microorganism caused disease
1 the causative organism must be isolated from every individual suffering from the disease in question
2. the causative organism must be cultivated artificially in pure culture
3. When the causative organism, is inoculated from pure culture, the typical symptoms of the infection must result
4. the causative organism must be recoverable from individuals who are infected experimentally
What organism causes syphilis?
treponema pallidum
What causes typhoid fever?
salmonella typhi
What is the protein coat that surround the nucleic acid core of a virus made up of?
capsomeres
What is a virus envelope made up of?
lipid and usually derived from the cell in which they grow
What is the nucleic acid core of a virus made up of?
DNA or RNA but not both
How are retroviruses different from normal ones?
the virion carries an RNA copy of the genome but upon infection of a host cell a cDNA copy of the virus genome is made using reverse trancriptase
what are bacteriophages?
special class of bacteria which attacks viruses