What is the name of the junction between two neurones?

14.1.1 Describe a nerve impulse as an electrical signal that passes along nerve cells called neurones

14.1.10 State that in a reflex arc the synapses ensure that impulses travel in one direction only

14.1.11 State that many drugs, e.g. heroin, act upon synapses

14.1.2 Describe the human nervous system in terms of: – the central nervous system consisting of brain and spinal cord – the peripheral nervous system – coordination and regulation of body functions

14.1.3 Identify motor (effector), relay (connector) and sensory neurones from diagrams

14.1.4 Describe a simple reflex arc in terms of receptor, sensory neurone, relay neurone, motor neurones and effector

14.1.5 Describe a reflex action as a means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors (muscles and glands)

14.1.6 Define a synapse as a junction between two neurones

14.1.7 Distinguish between voluntary and involuntary actions

14.1.8 Describe the structure of a synapse, including the presence of neurotransmitter containing vesicles, the synaptic cleft and neurotransmitter receptor molecules

14.1.9 Describe how an impulse triggers the release of a neurotransmitter from vesicles into the synaptic gap and how the neurotransmitter diffuses across to bind with receptor molecules, in the membrane of the neurone after the synaptic gap, causing the impulse to continue

14.2.1 Define sense organs as groups of receptor cells responding to specific stimuli: light, sound, touch, temperature and chemicals

14.2.2 Identify the structures of the eye, limited to cornea, iris, pupil, lens, retina, optic nerve and blind spot

14.2.3 Describe the function of each part of the eye, limited to: – cornea – refracts light – iris – controls how much light enters pupil – lens – focuses light onto retina – retina – contains light receptors, some sensitive to light of different colours – optic nerve – carries impulses to the brain

14.2.4 Explain the pupil reflex in terms of light intensity and pupil diameter only

14.2.5 Explain the pupil reflex in terms of light intensity and antagonistic action of circular and radial muscles in the iris

14.2.6 Explain accommodation to view near and distant objects in terms of the contraction and relaxation of the ciliary muscles, tension in the suspensory ligaments, shape of the lens and refraction of light

14.2.7 State the distribution of rods and cones in the retina of a human

14.2.8 Outline the function of rods and cones, limited to greater sensitivity of rods for night vision and three different kinds of cones absorbing light of different colours for colour vision

14.2.9 Identify the position of the fovea