Intro Flashcards
What is physiology
The close control of flow and interplay of work and information
Physiology key points:
Dynamic
Precise regulation and control (via molecular or voltage signals)
Pharmacology
Studies defined effect of signalling molecules on the physiological and biochemical work on cells - up until the level of the person
Signalling molecule classifications
Endogenous - within the body eg adrenaline
Exogenous 1 - natural, plant based eg morphine
Exogenous 2 - synthetic, man made, containing many thousands of compounds
Signalling (endo para and auto have in common)
Two or more parts of a system seperated
Communicating intimately and coherently
Synchrony - shared purpose
Achieved via extracellular signalling molecules
Endocrine signalling molecules d
features
Glands produce hormones - secreted to blood
Long distance/through whole body
Need receptors/specific binding sites for action
Neuroendocrine = major regulation of body function
Highly potent - Tight feedback control
Classes of endocrine molecules
Amines - hydrophilic, amino acid derivatives, receptors on membrane
Peptides/proteins - hydrophilic, short chain/long receptors on membrane eg insulin
Steroids - lipophilic, derived from cholesterol, receptors intracellular
Catacholamines
Hydrophilic Half life: seconds Action: seconds/milliseconds Receptor: membrane Mechanism: causes change in membrane potential/synthesis of cytosolic second messengers
Peptides and proteins
Hydrophilic Half life: minutes Action: minutes/hours Receptor: membrane Mechanism: synthesis of cytosolic second messangers/triggers protein kinase
Steroids
Hydrophobic/lipophilic
Half life: hours
Action: hours/days
Receptor: cytosolic/nuclear (inside cell)
Mechanism: receptor-hormone complex controls transcription/stability of mRNA
Paracrine
From cell to cell, nearby Small communication scale Released into extracellular environment Induce changes in receptor cells (behaviour/differentiation) Neurotransmitters (neurone to neurone)
Neurotransmitters features
Synapse is specialised and controlled One way transmission Electrochemical Chemical signal proportional to electric field Msecs transmission time Distance 20nm (SHORT)
Excitatory neurotransmitter
Increase firing rate post synaptically
Inhibitory neurotransmitter
Decrease firing rate post synaptically
Excitatory neurotransmitter examples
Acetylcholine Adrenaline Noradrenaline Serotonin Dopamine (can be both) Glutamate
Inhibitory neurotransmitter examples
Glycine
GABA
dopamine (can be both)
What do exogenous and endogenous signalling molecules do
Bring about a change in functional status of target cells
Produce another chemical/electrochemical signal to contribute to signal processing
Perform a specific task
Interconvert between potential energy and kinetic energy
Endogenous signalling
Engineered via evolution
Optimal fit for the job
Agonists usually (activate receptor)
BATON analogy
Exogenous signalling
Engineered via human design (carry imposter signal) Signal carried but sub-optimal fit Antagonists - block signal Or partial agonists - attenuate signal Side effects
Signalling molecule targets
Receptor Ion channels Transporters Enzymes (RITE)
Exception of drug targets: cancer
Chemotherapy targets DNA or protein
Intents to kill another organism (antibiotics or cancer cells)
Receptor type classes
Kinase Ligand gated Ion Nuclear/Intracellular G-protein coupled (KLING)
Ion channnels regulation
Voltage gated: dependent on change in electrical field density
Ion channel: phosphorylation
Primary active transport
Against concentration gradient
Requires energy in the form ATP
Example - Na/K ATPase pump
(3Na out, 2 K in)
Secondary active transport
Facilitated diffusion via SGLT1
Na travels down concentration gradient
Carries glucose with it up its concentration gradient
Na = high —> low Glucose = low —> high (active)
Transport carriers
Facilitated diffusion Active transport (primary and secondary)
Enzymes function
Signal processing, transformation, synthesis, degradation
Can use inhibitors (allosteric or competitive)
