1 diagram of a synapse is considered as in the

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1. Diagram of a synapse is considered as in the process of neutotransmission if there is any indication that N. T. is releasing into the synaptic cleft. eg. Award 1 full mark to the following diagrams : 2. If diagram is in the process of neurotransmission but there is incorrect concept and / or inaccuracy in the drawing, award only ? mark to diagram. 3. If a series of diagrams were used correctly to show the process of neurotransmission, award only 0.5 mark to diagram. 4. N.T. ≠ cholinesterase 5. Neuromuscular junction acceptable (award mark to alternative labels, but label must correspond to structure). 6. Indicate the mark awarded to diagram by denoting. Markers’ Report
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16 Coordination in Humans Last update: 2019-12-24 - 44 - AL980201a Left (0.5) cerebral cortex (0.5) / motor area of cerebrum initiates (0.5) impulse (0.5) that travels along a neurone (0.5) / axon. Synapse (0.5) with interneurone (0.5) at the spinal cord (0.5). Synapse with a motor neurone (0.5). Efferent motor impulse (0.5) exits the spinal cord via the ventral root (0.5), reaches the muscle (0.5). (max. 5) Markers’ Report AL990107 (a) 1 controls voluntary motor functions whereas 2 controls involuntary motor functions (1) / reflexes. (1) AL010201 b). any one of the following: (1 mark for feature and effect, 1 mark for explanation) • as the diameter of nerve fibre increases the rate of conduction increases (1), a bigger diameter reduces the resistance to the conduction of nervous impulse (1) 2 • rate of conduction increases when nerve fibre is myelinated (1), as myelinated sheath insulates the conduction of electrical current, impulse jumps from node to node (1) c). Similarity: • both are reflex centres (1) 2 • both act to relay ascending and descending impulses (1) Differences: Spinal cord Medulla • no control / regulatory center# • contains other control / regulatory centres (1), that regulates heart rate (1) / breathing rate 2 • no chemoreceptors# • contains chemoreceptors (1) that detect pH / CO 2 level in the body fluid (1) 2 • reflex in trunk and limbs • reflex in head also 1 ______ N.B. No comparison, no mark #Unmatched comparison, ½ mark (max.5) at emergency, sympathetic nervous system increases its output (1), resulted in more noradrenaline released (1) to bring about the following: 2
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16 Coordination in Humans Last update: 2019-12-24 - 45 - AL020205 5. (a) Stimuli reception • cones on retina of eye stimulated by red light (1), + produce sensory impulse (1) 2 • utriculus / sacculus perceives position of head (1), + generate sensory impulse (1) 1 • semi-circular canals perceive rotational movement of the head (1) at deceleration / stopping 1 Signal integration • association centre in the cerebral cortex (1) processes impulses from the visual cortex (1) and medulla (1) / cerebellum, and relay them to the motor centre in the cerebral cortex (1) 4 Response initiation • motor centre in cerebral cortex sends impulses (1) 3 • to the muscles of the hands / legs to stop bicycling (1) • sends impulses to other skeletal muscles to maintain balance (1) (NB. + mark to be given once only, candidates must show that they have attempted in all 3 areas to earn kill mark of 9) (b) Hormonal co-ordination Different situations in life Nervous co-ordination • cope with stimuli which involves gradual change (1), deal with prolonged response (1) • cope with sudden stimuli (1) / emergency situations, and the need for short-duration response (1) 4 (Bonus (1)): for sustaining long term survival / adaptations) Mode of action of the hormonal and nervous systems
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