Cellular Responses to Environmental Signals and Stresses Flashcards
What is fibroblast ‘crawling’?
It extends filaments to ‘push’ the cell membrane in one direction, moving from left to right and degrading cells at the back.
What is the role of cytoskeletal filaments in cells?
They provide dynamic re-organisation during cell division and facilitate cell migration.
What is chemotaxis?
Directed movement of a cell towards or away from a diffusible chemical (chemoattractant).
What are leukocytes?
Immune cells that patrol the blood system and can ‘shape-shift’ to chase infection.
What do GPCRs do?
They are receptors for many chemical signals, binding to chemotactic peptides and initiating a signalling cascade.
What is the function of neutrophils?
They chase, engulf, and incinerate bacteria.
What are pheromones?
Volatile hormones released into the environment to modulate the behaviour or physiology of another animal of the same species.
Who coined the term ‘pheromone’?
Karlson and Luscher in 1959.
What is the vomeronasal organ (VNO)?
It detects pheromones in mammals and is sometimes known as the ‘sexual nose’.
What is the main olfactory epithelium?
A sensory substructure that detects mammalian pheromones.
What is the Flehman Response?
A behaviour where an animal tries to ‘pick up’ more pheromones.
What are G-Protein-Coupled Receptors (GPCRs)?
Physiologically important membrane proteins that sense signalling molecules.
What are mechanoreceptors?
Receptors that detect mechanical signals like pressure, found in most animals.
What is temperature-dependent sex determination (TSD)?
Influence of incubation temperature on the sex of alligators; e.g., 33°C produces mostly males.
What role does the TRPV4 protein play in alligators?
It has a possible role in promoting male development.
What are transient receptor potential (TRP) cation channels?
Environmental sensors primarily functioning through Ca2+ signalling.
What is stress in a biological context?
A generalized, non-specific response to any factor that overwhelms the body’s ability to maintain homeostasis.
What is a stressor?
The factor inducing stress.
List types of stressors.
- Physical: heat, trauma, cold
- Chemical: reduced O2 supply, acid-base imbalance
- Physiological: haemorrhagic shock, pain
- Psychological/Emotional: anxiety, fear
What happens to arterioles in response to heat and cold?
- Heat causes arteriolar vasodilation
- Cold causes arteriolar vasoconstriction
What are heat shock proteins (HSPs)?
A large family of highly conserved molecular chaperone proteins that facilitate protein folding or refolding.
How do HSPs respond to stress?
They are up-regulated in response to sudden temperature elevation and can help other proteins deal with stressors.
What is autophagy?
A process where cytoplasmic components are broken down to supply materials for essential molecule synthesis under nutrient-limiting conditions.
What is the role of autophagosomes?
They engulf cellular components and organelles, fuse with lysosomes, and digest the contents.
