Topic 2 Flashcards
Motor Neurones do what
Carry impulses to effectors
Relay neurones do what
Are short and found in the spinal chord where they link motor and sensory neurones
Synapse
Tiny gap between axon terminal and cell. Pulse turns into neurotransmitter substance detected by the next neurone and turned back into a pulse.
What is the phase after interphase and describe it (1st proper phase)
Prophase
Nucleus break down and spindle fibres start to appear
What is the second phase
Metaphase
Chromosomes are lined up on spindle fibres
What is the third phase
Chromosome copies separate and move to opposite ends of the spindle fibres
What is the fourth phase
Telophase
Membrane forms into nuclei around each set of chromosome copies at either end
What is the final phase
Cytokinesis
Two daughter cells separate
Cell walls form in plant cells
Relay and motor neurones don’t have
Dendrons or dendronites on cell body
Cones are
Receptor cells sensitive to the colour of light some detect red others detect blue or green work well in bright light
Rods are
Receptor cells that detect differences in light intensity work well in dull light
Describe how fusing occurs in the eye
Most focusing is done by the cornea which bens light rays to bring them together. The lens then fine tuned it and ciliary muscles make them fatter to focus light from near objects as it increases refraction.
Short sightedness
Distant objects are blurry
Eyeball is too small so image forms behind retina
Cornea is too curved so refracts light too far
Long shighted
Lens is not curved enough so doesn’t bend light enough
Eyeball is too long so image firms in front of retina
Reflex arc
Pain receptor to sensory to motor in spinal chord bypasses brain to effector cells in muscles moves hand away
