Lecture 1: Unit Introduction Flashcards
What is physiology?
Study of mechanisms governing purposeful interaction of matter, energy and fields in living systems
What are the categories of signaling molecules?
- Endocrine
- Paracrine
- Autocrine
What are endocrine signaling molecules?
- Secreted by endocrine glands
- Hormones
- Typically act over long distances
- Secreted into blood stream
What are the 4 major groups of endocrine hormones?
- Amine hormones
- Peptide hormones
- Protein hormones
- Steroid hormones
What are the main features of amino hormones?
- They are amino acids with modified groups
- Hydrophilic
- Plasma half-life: seconds
- Time course of action: milliseconds to seconds
- Receptor location: plasma membrane
- Mechanism of action: causes change in membrane potential, triggers synthesis of cytosol second messengers
What are the main features of peptide hormones?
- They are short chain of linked amino acids
- Hydrophilic
- Plasma half-life: minutes
- Time course of action: minutes to hours
- Receptor location: plasma membrane
- Mechanism of action: triggers synthesis of cytosolic second messengers, triggers protein kinase activity
What are the main features of protein hormones?
- They are long chains of linked amino acids
- Hydrophilic
- Plasma half-life: minutes
- Time course of action: minutes to hours
- Receptor location: plasma membrane
- Mechanism of action: triggers synthesis of cytosolic second messengers, triggers protein kinase activity
What are the main features of steroid hormones?
- Derived from the lipid cholesterol
- Liphophilic
- Plasma half-life: hours
- Time course of action: hours to days
- Receptor location: cytosolic or nuclear
- Mechanism of action: receptor-hormone complex controls transcription or stability of mRNAs
What are paracrine signalling molecules?
- Signalling coupled from cell to cell
- Released into extracellular environment
- Induces changes in receptor cells
- Neurotransmitters
What are the three major groups of paracrine neurotransmitters?
- Acetylcholine
- Monoamines
- Amino acids
What are the main features of acetylcholine?
Excitatory at end organ - signal increase firing rate post synaptically
What are the main features of monoamine transmitters?
- Adrenaline (excitatory)
- Noradrenaline (excitatory)
- Dopamine (excitatory and inhibitory)
- Serotonin (excitatory)
What are the main features of amino acid neurotransmitters?
- Glutamate (excitatory)
- Glycine (mainly inhibitory)
- G-Amino Butyric Acid (GABA) (inhibitory)
What are the main classes of therapeutic drug targets?
RITE KLING
Receptors
Ion channels
Transporters
Enzymes
Kinase linked receptors Ligand gated Ion channels Nuclear / intracellular G-protein coupled receptors
