Neuroscience and Mental Health Flashcards
Outline the organisation of the Central Nervous system.
Central Nervous System
Peripheral Nervous system
- Autonomous Nervous system - Sympathetic nervous system - Parasympathetic nervous system - Somatic PNS
Define the central nervous system.
Brain and spinal cord
Define the peripheral nervous system.
Nerves and ganglia (clusters of neuronal cell bodies) outside the brain and spinal cord.
What to the branches of the PNS do?
- Somatic PNS: controls motor and sensory function for the body wall e.g. skin, skeletal muscles
- Autonomic NS: regulates function of the viscera (internal organs, smooth involuntary muscle, pupils, sweating, blood vessels, bladder, intestin, glands etc and controls heart and contraction rate. It had two arms (sympathetic and parasympathetic)
What are the different types of neurones with regard to direction of information flow?
- Afferent axons propagate action potential towards the CNS, away from PNS e.g. sensory neurones
- Efferent axons propagate action potentials from the CNS to the PNS e.g. motor neurones
- Inter-neurones are CNS neurons that synapse with other CNS neurons within the brain or spinal cord
Outline the parts of the brain.
- Cerebral cortex: two hemispheres. Each receives sensory info from and control movement of the opposite side of the body
- Cerebellum: Controls coordination of movement
- Brain stem: Primitive, densely packed fibres, regulates vital functions e.g. consciousness, breathing. Damage is usually serious and could be fatal
Where does the CNS end in the spinal cord?
- Ends at the margins of the spinal cord
- Dorsal and ventral roots that emerge are part of the PNS
Outline axon packing in nerves.
- Spinal nerves contain both afferent and efferent axons
- They’re bundled into fascicles surrounded by a perineurium
- Whole nerve encased in tough epineurium capsule
- Individual axons wrapped in myelin and endoneurium, though some are unmyelinated e.g. nociceptive (pain) neurons
What is the function of a neuron?
To transmit and receive action potentials, or stimulate target tissue e.g. contraction of smooth/skeletal muscle, secretion from gland.
What is the difference between PNS and CNS with respect to regeneration?
- Axons in PNS can regenerate after injury. Though recovery is often compromised by non-specific target re-innervation and aberrant axon sprouting. It can leave to neuropathic pain.
- Axons in CNS are unable to regenerate over long enough distance to be useful.
Why can’t axons in the CNS regenerate?
- Inhibitory molecules in CNS not PNS e.g. myelin differences
- Absence of guidance cues that stimulate axon growth during development
- Some loss of intrinsic axon growth capability by neurons
What is white and grey matter?
White matter - Ascending and descending axons
Grey matter - Neuronal cell bodies
What is the difference in the action potential pathways between a reflex response and conscious registering?
- Reflex: Only somatic sensory input to inter-neurons and motor output from spinal cord are required NO communication with sensorimotor cortex
- Conscious registering: Sensory inputs activate sensory neurons in spinal cord grey matter that transmit action potentials upward to sensory cortex of brain. Similarly neurons of motor cortex transmit action potentials downward to synapse with spinal motor neurons for voluntary movement
What is considered when diagnosing neurological problems?
- Presenting signs and symptoms to identify underlying anatomy and characterise the syndrome
- Mode (and speed) of onset to determine underlying aetiology (pathological cause)
- History: previous medical problems, family history, social history, other symptoms
List common causes of neurological problems in order of speed of onset.
- Trauma
- Vascular
- Toxic/metabolic
- Infectious
- Inflammatory/autoimmune
- Genetic-congenital
- Neoplastic
- Degenerative
Give some features of stroke.
- 80% are infarct
- 20% haemorrhage (often related to high bp)
- Can affect any part of brain including brainstem
- Problems in opposite side of lesion (contralateral)
- Risk factors include smoking, family history, diabetes, alcohol
What are the common areas affected by stroke and the syndromes they cause.
- Middle cerebral artery: most common, results in weakness and loss of sensation on the other side (contralateral)
- Posterior cerebral artery: often affect occipital lobe, result in visual loss on contralateral side
- Anterior cerebral artery: often cause contralateral leg weakness
- Brainstem: problems with balance, eye movemetns, speech and swallowing, breathing
What treatments are available for stroke?
Acute:
- intravenous thrombolysis to dissolve clot
- intra-arterial thrombectomy to remove clot
Treat complications:
- neurosurgery for haemorrhage or dangerously high pressure
Prevent further stroke:
- thin blood with aspirin
- treat diabetes and high cholesterol
- treat dangerously narrow carotid arteries
What are the examinations performed to diagnose neurological problems?
- Cognitive/thinking abilites: e.g. mini mental state examination
- Cranial nerves: smell, vision, eye-movements, facial sensation and movements
- Limbs: power, coordination, reflexes and sensation
Describe the mini mental state examination?=.
- Orientation e.g. what year is it?
- Registration e.g. ask patient to recall 3 things you just said (like items)
Trials: - Attention and calculation e.g. spell world backward, or count back in 7s
- Recall e.g recall 3 objects
- Language e.g. follow a 3 stage command
Outline the features of Parkinson’s disease.
- Slowly progressinve degenerative diseas affecting the basal ganglia
- Clinical features; rigidity, tremor, bradykinesia (reduced movement)
- Loss of neurons from substantia nigra to the caudate and putamen
- Dopamine is associated neurotransmitter
- Treated with levodopa which can cross blood brain barrier
- Also with deep brain stimulation
What is Spastic Parapaesis?
- Axonal degeneration that affects the spinal cord and leads to rigidity and weakness in the leg muscles which gets progressively worse
- Causes include: Trauma, inflammatory/autoimmune, neoplastic, degenerative, vitamin deficiency (B12), vascular
What is multiple myeloma?
- tumour of plasma cells (b cells)
- treated with radiotherapy and chemotherapy
What is stocking and glove distribution?
- Peripheral nervous disease
- Around the hands approx up to wrist
- Around the feet approx up to mid-shin
(Where you’d wear gloves and socks)