<p>9.7 The Synapse</p><p>Synapse – junction between two communicating neurons Nerve pathway – nerve impulse travels from neuron to neuron</p><p>Synaptic Transmission </p><p>Dendrite  cell body  along axon  synapse (gap)</p><p>To complete the signal, a NEUROTRANSMITTER is released at the gap to signal the next neuron</p><p>Excitatory – increase membrane permeability, increases chance for threshold to be achieved Inhibitory – decrease membrane permeability, decrease chance for threshold to be achieved</p><p>Types of Neurotransmitters</p><p>Acetylcholine – stimulates muscle contraction Monoamines – Norepinephrine & Dopamine (sense of feeling good, low levels = depression) Serotonin (sleepiness) Endorphins (reduce pain, inhibit receptors) </p><p>Synapses are highly susceptible to drugs and fatigue </p><p> Curare (poison used by S. American Indians) and atropine stops Acetylcholine from depolarising the post- synaptic membrane, i.e. become paralysed.  Strychnine and some nerve gases inhibit or destroy acetylcholinesterase formation. Prolongs and enhances any stimulus, i.e. leads to convulsions, contraction of muscles upon the slightest stimulus.  Cocaine, morphine, alcohol, ether and chloroform anaesthetise nerve fibers. (inhibitory)  Mescaline and LSD produce their hallucinatory effect by interfering with nor-adrenaline & serotonin</p><p>9.8 Impulse Processing</p><p>Neuronal pool – groups of neurons that make hundreds of synaptic connections and work together to perform a common function</p><p>9.9 Types of Nerves</p><p>Sensory Nerves – conduct impulses into the brain or spinal cord Motor Nerves – carry impulses to muscles of glands Mixed Nerves - contain both sensory and motor nerves 9.10 Nerve Pathways</p><p>Reflex arc – simple pathway, includes only a few neurons (reflexes)</p><p>Reflex Behavior – automatic, subconscious responses to stimulu </p><p>Knee-jerk reflex (patellar tendon reflex) stimulus knee  sensory nerve  spinal cord  motor nerve</p><p>Withdrawal reflex – occurs when you touch something painful</p><p>9.11 Meninges = membranes located between bone and soft tissues of the nervous system</p><p>Dura mater = outmost layer, blood vessels, nerves Arachnoid mater = no blood vessels, located between Pia mater = contains many nerves and blood vessels to nourish cells of brain and spinal cord</p><p>*Cerebrospinal fluid = between arachnoid and pia maters</p><p>9.12 Spinal Cord - nerve column, passes from brain down through the vertebral canal - has 31 segments, each with a pair of spinal nerves</p><p>Cervical enlargement = supplies nerves to upper limbs (neck) Lumbar enlargement = supplies nerves to the lower limbs (lower back)</p><p>FUNCTION: conducting nerve impulses, serves as a center for spinal reflexes</p><p>Ascending tracts = carry sensory info to the brain Descending tracts = carry motor impulses from the brain to the muscles</p><p>Spinal reflexes – reflex arcs pass through the spinal cord 9.13 Brain</p><p>Three Major Parts:</p><p>Cerebrum – largest, sensory and motor functions, higher mental function (memory, reasoning) Cerebellum – coordinate voluntary muscles Brain stem – regulate visceral functions</p><p>DESCRIBE THE FUNCTIONS: 1. Cerebral Hemispheres</p><p>2. Corpus Callosum</p><p>3. Convolutions / Sulcus / Gyrus</p><p>4. Transverse / Lateral / Longitudinal Fissures </p><p>Lobes of the Brain</p><p>5. Frontal Lobe</p><p>6. Parietal Lobe</p><p>7. Temporal Lobe</p><p>8. Occipital Lobe</p><p>9. Cerebral Cortex</p><p>10. Ventricles 11. Cerebrospinal Fluid</p><p>Functional Regions:</p><p>12. Motor </p><p>13. Sensory</p><p>14. Association</p><p>DIENCEPHALON & BRAIN STEM</p><p>1. Diencephalon</p><p>2. Thalamus</p><p>3. Hypothalamus</p><p>4. Optic Tract / Chiasma</p><p>5. Midbrain</p><p>6. Pons</p><p>7. Medulla</p><p>8. Pituitary Gland</p><p>9. Hippocampus</p><p>10. Limbic System</p><p>TYPES OF MEMORY: Episodic | Procedural | Semantic | Working</p>