ML Lecture’s Flashcards
(60 cards)
Who is Claude Bernard and what was he known for?
- French physiologist
- Milieu interieur (internal environment) and the associated concept of homeostasis
- Scientific method (especially in medicine)
Who is Walter Bradford Cannon and what was he known for?
- American physiologist
- Fight or flight responses
- Homeostasis theory -> ‘The wisdom of the body’ Book
- First expeirmnet: watch the course of a button down a dogs throat
What is homeostasis?
Homeostasis is the maintenance of constant, or relatively constant, internal conditions irrespective of fluctuating external conditions
What are the three main ways organisms can deal with environmental changes?
Organisms can be conformers, regulators, or use avoidance strategies
What are the key components of a homeostasis system?
Detecter, controller/control system, effector/target
What is negative feedback?
A mechanism where the output of a system acts to oppose changes to the input of the system, with the goal of maintaining homeostasis
How does allostasis differ from homeostasis?
While homeostasis refers to maintaining a ‘rigid’ state, allostasis refers to achieving stability through change, allowing for a ‘variable’ state
What are some examples of factors regulated by homeostasis in animals?
Temp, pH, O2, glucose, protein
Who said “La fixité du milieu interieur, c’est la condition de la vie libre”?
Claude Bernard said this phrase, which translates to “The constancy of the internal environment is the condition for a free life.”
What are the two types of responses animals can have to maintain viability?
Animals can have predictive/anticipatory responses or reactive responses to maintain viability
Why is studying stress physiology important?
Dealing with disturbances is key to survival, as it links to behaviour, and stress responses are evolutionary conserved (selected for)
What is acclimitisation?
Adjustment of set points to a new equilibrium in a natural setting
What is acclimation?
Adjustment of set points to a new equilibrium in a laboratory setting
What is habituation?
Adaptation in a physiological context
What is adaptation>
Different processes in evolutionary biology (many different definitions - proceed with caution when using this term)
What are the main types of first messengers in cell signaling?
Hormones, neurotransmitters, neuromodulators, growth factors, and cytokines
What are the three main types of signaling?
Paracrine, endocrine, and autocrine
Who first reported that ligands often bind to more than one receptor subtype, and with which molecule?
John Langley for acetylcholine
What are the two types of acetylcholine receptors and their effects?
- Nicotonic receptor: Agonist for skeletal muscle (increases activity); blocked by curare
- Muscarinic receptor: Agonist for cardiac muscle (decreases activity); part of parasympathetic ANS; blocked by atropine
Who developed the concept of receptors in signalling, and what key experiments led to this discovery?
John Langley developed the concept through experiments with nicotine and curare on muscle contraction in fowl
What are the two main types of cellular receptors?
Membrane receptors and intracellular receptors
How do ligands bind to their receptors?
Through key-lock conformation and hydrogen bonds
What is the importance of signal transduction?
Signal transduction is the process by which a cell converts an extracellular signal into an intracellular response, allowing cells to respond to their environment and communicate with each other
How can different tissues in the body respond differently to the sample signal (ligand)?
Different tissues can express different receptor subtypes or varying amounts of the same receptor, leading to tissue-specific responses to the same ligand
