the nervous system -2 anatomy physiology and pathology
TRANSCRIPT
Blood Supply to the BrainCircle of WillisBlood-Brain barrierAllows – water, Glucose, Essential amino acidsFat soluble substances- O2, CO2, fats,No way in – non-essential amino acids, K+ ions, toxins, micro-organisms, proteins, waste products &chemicals (most drugs)Sneaky ones- Alcohol, narcotics, anaesthetics, nicotine
Cerebrospinal Fluid
Clear watery fluid in sub-arachnoid space
Forms buffer/ cushion
Produced by the ventricles and choroid plexus
Maintains a constant pressure and volume of about 150 ml.
Too much – HYDROCEPHALUS
Tested with lumbar puncture
CommunicationLines of PNS
Sensory
Somatic-Skin, muscles
joints
Visceral-Internal organs
Motor
Somatic orVoluntary NS
Autonomic NS
Sympathetic
Parasympathetic
Cranial nerves
Olfactory – smell
Optic – sight
Occulomotor –eye movement
Trochlear – eye motion- down and in
Trigeminal- Motor – mastication, lateral jaw movement. Sensory- maxillary mandibular and ophthalmic.
Cranial nerves
Abducens – eye motion – lateralFacial – Motor – facial expressions, closing of eye and mouth. Sensory- taste on anterior 2/3 of tongueAuditory or Vestibulochoclear – hearing and balanceGlossopharyngeal – Motor- swallowing. Sensory – posterior 1/3 of tongue taste and eardrum, Eustachian tube and pharynx
Cranial nervesVagus – Motor- thoracic and abdominal organs (promote digestion and regulate heart activity). Sensory – pharynx, larynx, heart, lungs, bronchi, GI tract, external ear.
Spinal accessory – Sternocleidomastoid and upper trapezius muscles
Hypoglossal – tongue movement and sensory impulses from tongue.
Autonomic nervous system
Regulates homeostatic control mechanisms
Outside conscious awareness
Some e.g.. – digestion, constriction of blood vessels, stress responses
Sympathetic and Parasympathetic (Cranio-sacral)
STRESS RESPONSEInjuryInfectionTemperatureEmotionsOverworkPainShock Any one of these will produce cortisol and Adrenalin
Effects of cortisol
Stimulation of protein and fat catabolism
Uptake of amino acids and conversion to glucose
Inhibition of glucose uptake
Vasoconstriction
Inhibition of inflammation and specific immune responses
Action of Adrenalin & Sns
Increased blood coagulation
Faster breathing rate and heart beat
Moving blood from centre to muscles
Less fatigue
More energy/ glucose available for use
Over stimulation is detrimental
Diseases of the Nerves
Injury
Functional disorders
Infections
Degeneration
Structural defects
Tumours
Major nervous symptoms
HeadachesNumbnessTinglingWeaknessSudden loss of sightMemory lossCo-ordination difficultiesMuscle rigidity/ spasms/ tics