The nervous system does not divide into independent topics. A withdrawal response is an afferent limb, a cord segment and an efferent limb acting as one thing; cerebral protection is metabolism, blood flow and intracranial pressure held in balance at the same moment. This module is therefore sequenced causally: each lesson assumes only what an earlier lesson has already settled, and every lesson names which ones those are.
Orientation
What this module covers, and how to work through it
Neurophysiology carries a disproportionate share of the MMed Part I physiology syllabus. The topics that recur are cerebral blood flow and its four graphs, intracranial pressure and its two drawings, the blood-brain barrier, the pain pathway, synaptic classification, the nerve action potential, consciousness and sleep. Every one of those has its own lesson here, at the depth the topic justifies.
The module is built to be used two ways. Read straight through, it is a course: part I gives you the cell, part II the organ, part III the pathways, part IV what the system produces. Used as reference, any single lesson stands alone — it opens with what it assumes, links to those lessons, and states its own learning outcomes so you can tell when you are done with it.
Prerequisites for the module as a whole
These carry material this module builds on directly and does not repeat. Work through them first if they are not already secure:
- Cellular physiology — membranes and transport: diffusion, carrier-mediated transport, active transport and osmosis, which the blood-brain barrier and CSF lessons apply rather than re-derive.
- Cellular physiology — membrane potentials: the resting membrane potential, the Nernst and Goldman-Hodgkin-Katz equations and the generic action potential. Lesson 2 here teaches the nerve-specific case and assumes that one.
- Cardiovascular — the circulation: the pressure-flow-resistance relationship, which the cerebral blood flow lesson specialises.
Syllabus
MMed syllabus mapping
| Syllabus area | Lessons | What is covered |
|---|---|---|
| Organisation of the nervous system | Lessons 1-3 | Divisions, neurons and glia; excitable tissue and the nerve action potential; synaptic transmission and its classification |
| Cerebral physiology | Lessons 4-10 | The meninges, the circle of Willis and the cerebral venous sinuses; functional organisation and cerebral metabolism; the blood-brain barrier; cerebrospinal fluid; cerebral blood flow and its autoregulation; intracranial pressure and compliance; applied intracranial physiology and cerebral protection |
| Spinal cord, sensation and pain | Lessons 11-13 | Cord organisation and tracts; sensory receptors and coding; pain physiology: nociception and the ascending pathway, gate control and descending modulation, sensitisation, visceral and neuropathic pain, and the response to pain |
| Motor and autonomic function | Lessons 14-16 | Motor units and descending tracts; muscle spindles, Golgi tendon organs and spinal reflexes; autonomic organisation, transmission, receptors and reflex integration |
| Higher cerebral function | Lessons 17-20 | Consciousness and the reticular activating system; the electroencephalogram and evoked potentials; sleep; memory, emotion and higher cortical function |
Two adjacent topics deliberately sit elsewhere. Neuromuscular junction physiology is its own syllabus objective and its own future lesson; lesson 3 uses the junction as the worked example of a chemical synapse without annexing the topic. Thermoregulation belongs with metabolic and endocrine physiology, because the questions on it are framed as temperature regulation rather than as neurophysiology — hypothalamic integration is taught inside lessons 16 and 20, which is where the source textbooks put it.
The pathway
All 20 lessons, in order
Part I
Foundations
Nothing later in the module works without these. A synapse cannot be explained before an action potential, and an action potential cannot be explained before a neuron.
- Organisation of the nervous system, neurons and glia
The map you need before any of the mechanisms mean anything: how the nervous system is divided, what a neuron is built from, and what the four glial cell types actually do.
- Neuronal excitability: the nerve action potential, propagation and conduction velocity
The nerve action potential in its own right — not the cardiac one — how it propagates, why myelin makes it faster, and every factor that changes conduction velocity.
- Synaptic transmission: electrical and chemical synapses, summation and inhibition
Electrical against chemical, and ionotropic against metabotropic — then the mechanism: release, receptor, EPSP and IPSP, summation, and the two kinds of inhibition.
Part II
Cerebral physiology
The brain as an organ with a supply problem: what covers it, what supplies it, what it costs to run, what protects it, what surrounds it, and what happens when the box it sits in runs out of room.
- The coverings of the brain and the cerebral circulation
The anatomy every later cerebral lesson assumes: the meninges and the dural folds, the four vessels that supply the brain, the circle of Willis, what each territory costs when it is lost, and the venous route back to the heart.
- Functional organisation of the brain and the special features of cerebral metabolism
Why the brain takes 15% of the cardiac output for 2% of body weight, where that energy goes, and what happens to the cell when the supply stops.
- The blood-brain barrier: structure, transport and function
Three structural elements, five routes across, and the reason a quaternary ammonium compound never reaches the brain.
- Cerebrospinal fluid
Secretion at the choroid plexus, composition against plasma, the functions CSF serves, its fixed circulation route, pressure-dependent absorption and hydrocephalus.
- Cerebral blood flow: measurement, determinants and autoregulation
The four curves you must be able to draw, the equation relating flow to perfusion pressure and resistance, and the difference between autoregulation and carbon dioxide reactivity.
- Intracranial pressure, compliance and cerebral perfusion pressure
The Monro-Kellie doctrine, the elastance curve, the three-peak waveform, and the sequence in which compensation is spent.
- Raised intracranial pressure in anaesthetic practice, and cerebral protection
Every manipulation that raises or lowers ICP, organised by the compartment it acts on, then the physiological basis of cerebral protection.
Part III
Spinal, sensory and motor physiology
The cord first, because every sensory and motor pathway is described by where it runs in it. Then sensation, then pain, then movement and the reflexes that guard it, then the autonomic system that integrates all of it.
- The spinal cord: organisation, ascending and descending tracts
The cross-section you have to be able to draw, the laminae of Rexed, and where each tract runs, crosses and ends.
- Sensory receptors, coding and the somatosensory pathways
How a physical stimulus becomes a train of action potentials, how the nervous system encodes modality, intensity, location and duration, and where that information goes.
- Pain physiology: nociception, pathways, modulation and sensitisation
One lesson from nociceptor to perception: transduction, the fibres and the three-neuron pathway, how the dorsal horn and the brainstem turn the signal down, how injury turns it up, and what pain does to the rest of the body.
- Motor control, motor units and the descending motor tracts
From motor cortex to muscle fibre: the hierarchy, the motor unit and its recruitment, and the efferent limb that completes every reflex.
- Muscle spindles, Golgi tendon organs and spinal reflexes
Two proprioceptors, one wired in parallel and one in series, and the reflex arcs they drive — from the monosynaptic stretch reflex to polysynaptic withdrawal, and the muscle tone that sits on top of them.
- The autonomic nervous system: organisation, transmission and reflex integration
Outflow, ganglia, transmitters, receptors and the reflexes they serve — the system whose behaviour under anaesthesia explains most of what happens to the blood pressure.
Part IV
Higher cerebral function
What the whole system produces: arousal, the electrical signature we monitor it by, sleep, and memory and emotion. Every one of these is something anaesthesia deliberately abolishes.
- Consciousness, arousal and the reticular activating system
Why consciousness resists a one-word definition, the two components it separates into, and the ascending arousal system anaesthesia acts on.
- The electroencephalogram, anaesthetic effects and evoked potentials
Where the signal comes from, the named rhythms with their frequency bands, what anaesthesia does to it, and how evoked potentials are used and abolished.
- Sleep physiology: stages, regulation and physiological changes
The two types of sleep, the hypnogram, what every organ system does in each, and why sleep is not anaesthesia.
- Memory, emotion and higher cerebral function
The last lesson in the module: memory systems and their anatomy, the limbic system, cortical language and the higher functions anaesthesia and ageing disturb.
Objectives
The full objective wording
- Organisation, neurons and gliaOrganisation of the nervous system, and the neurone and glia
- Neuronal excitabilityMembrane excitability and the nerve action potential
- Synaptic transmissionSynaptic transmission and neurotransmitters
- Meninges and cerebral circulationCerebral vascular anatomy and the venous drainage
- Cerebral metabolismCerebral metabolism and cerebral protection
- Blood-brain barrierThe blood–brain barrier and cerebrospinal fluid
- Cerebrospinal fluidCerebrospinal fluid: secretion, circulation, absorption and hydrocephalus
- Cerebral blood flowCerebral blood flow and its regulation
- Intracranial pressureIntracranial pressure and the Monro–Kellie doctrine
- Raised ICP and cerebral protectionAnaesthetic effects on intracranial pressure and cerebral perfusion
- Spinal cord and tractsSpinal cord anatomy and the ascending and descending tracts
- Sensory receptors and codingSensory receptors and the somatosensory pathways
- Pain physiologyPain physiology: nociception, pain pathways, modulation and sensitisation
- Motor controlMotor control: cortex, basal ganglia and cerebellum
- Spindles, GTOs and reflexesSpinal reflexes, muscle spindle and Golgi tendon organ
- Autonomic nervous systemThe autonomic nervous system
- Consciousness and arousalConsciousness and the reticular activating system
- EEG and evoked potentialsThe electroencephalogram and evoked potentials
- Sleep physiologySleep architecture and its regulation
- Memory, emotion and higher functionHigher cortical function, memory and language