Cells (Interaction and interdependence)
- Chemical signalling (HL)HL only
- Receptors bind specific ligands HL only
- binding site
- conformational change
- quorum sensing: Vibrio fischeri
- Signalling chemical categories HL only
- hormones: distant
- neurotransmitters: localized
- cytokines
- calcium ions
- Chemical diversity HL only
- amines, proteins, steroids
- amino acids, peptides
- nitric oxide
- Transmembrane vs intracellular receptors HL only
- hydrophobic membrane region
- ligand stays outside
- steroids enter cell
- Membrane receptor types HL only
- acetylcholine: ion channel
- GPCR: G protein
- epinephrine: cAMP
- insulin: tyrosine kinase
- Steroid hormones change gene expression HL only
- bind specific DNA
- oestradiol: GnRH cells
- progesterone: endometrium
- Feedback regulation HL only
- negative: insulin, glucose
- positive: oestradiol, GnRH
- Receptors bind specific ligands HL only
- Neural signalling
- Neuron structure
- cell body
- axon: long fibre
- dendrites: short fibres
- Resting potential about −70 mV
- Na⁺/K⁺ pump uses ATP
- 3 Na⁺ out, 2 K⁺ in
- K⁺ leaks out
- Action potentials
- movement of positive ions
- propagated along fibre
- Impulse speed
- wider axon faster
- myelin faster
- r and R²
- Synapses
- Ca²⁺ triggers exocytosis
- acetylcholine binds receptors
- EPSP: depolarization
- one direction only
- Voltage-gated channels and threshold HL only
- Na⁺ in: depolarization
- K⁺ out: repolarization
- local currents
- oscilloscope traces
- Saltatory conduction HL only
- nodes of Ranvier
- node to node
- Synaptic interactions HL only
- neonicotinoids block
- cocaine blocks reuptake
- IPSP: hyperpolarization
- summation, all-or-nothing
- Pain and consciousness HL only
- free nerve endings
- capsaicin, heat, acid
- emergent property
- Neuron structure