3(j) Co-ordination and response
16 specification points in sub-topic 3(j).
Specification points
3.30: Responding to the environment
Why organisms detect and respond to changes around them to survive.
3.31: Homeostasis
Homeostasis: keeping conditions inside the body, such as water content and temperature, steady.
3.32: Stimulus, receptor and effector
A coordinated response: a stimulus is detected by a receptor and an effector responds.
3.33: Plant responses to stimuli
How plants respond to light, gravity, water and touch.
3.34: Geotropic and phototropic responses
Shoots grow towards light and roots grow down with gravity: phototropism and geotropism.
3.35: Auxin and phototropism in stems
How auxin makes a shoot bend towards light by unequal cell elongation.
3.36: Nervous and hormonal communication
Nerves and hormones compared: how fast, how long and how widely each one acts.
3.37: The central nervous system
The brain and spinal cord form the central nervous system, linked to the body by nerves.
3.38: Impulses and rapid responses
How electrical impulses travel from receptors to the CNS and on to effectors.
3.39: Neurotransmitters at synapses
Synapses: how a chemical neurotransmitter carries the signal from one neurone to the next.
3.40: A simple reflex arc
The reflex arc: a fast, automatic response that does not wait for conscious thought.
3.41: Structure and function of the eye
The parts of the eye and how they form an image on the retina.
3.42: Focusing and responding to light
How the eye focuses on near and far objects and how the pupil controls light entry.
3.43: Skin and temperature regulation
How sweating and blood flow in the skin help control body temperature.
3.44: Adrenaline, insulin, testosterone, progesterone and oestrogen
Where adrenaline, insulin, testosterone, progesterone and oestrogen are made and what they do.
3.45B: ADH, FSH and LH
Where ADH, FSH and LH are made and what they do.