B1.2 Nerves and hormones

 ELeanor Turner
Mind Map by ELeanor Turner, updated more than 1 year ago
 ELeanor Turner
Created by ELeanor Turner almost 4 years ago


GCSE Biology Mind Map on B1.2 Nerves and hormones, created by ELeanor Turner on 04/24/2016.

Resource summary

B1.2 Nerves and hormones
1 The nervous system
1.1 Enables humans to react to their surroundings and coordinate their behaviour
1.2 Receptors
1.2.1 Detect stimuli Changes in environment
1.2.2 In the eyes Sensitive to light Have a nucleus, cytoplasm and a cell membrane like most animal cells
1.2.3 In the ears Sensitive to sound and changes in position (enables us to keep our balance)
1.2.4 In the nose and on the tongue Sensitive to chemicals which allow us to taste and smell
1.2.5 In the skin Touch Pain Pressure Temperature changes
1.3 Simple reflex action
1.3.1 Impulses from receptor pass along sensory neurone Reach a synapse between a sensory neurone and a relay neurone Chemical is released that diffuses through synapse and causes an impulse to be sent along a relay neurone Reaches a synapse between a relay and motor neurone, same process occurs again Impulse sent along motor neurone to the effector Response is brought about by the effector Effector is either a muscle or gland Muscle responds by contracting Gland responses by releasing a chemical substance Synapse is a junction
1.3.2 Coordinated by brain Automatic and rapid
2 Control in the human body
2.1 Internal conditions which are controlled
2.1.1 Water content Leaves through sweat, when we breathe out and through urine
2.1.2 Ion content Lost via sweat and urine
2.1.3 Temperature Enzymes work best at certain temperatures
2.1.4 Blood sugar levels Provide cells with constant energy supply
2.2 Many processes coordinated by hormones
2.2.1 Secreted by glands Transported through the bloodstream Regulate the functions of many organs and cells E.g. the menstrual cycle FSH Secreted by pituitary gland Causes eggs to mature in the ovaries Stimulates the production of oestrogen LH Secreted by pituitary galnd Stimulates egg release from the ovaries Oestrogen Secreted by the ovaries Inhibits production of FSH Hormones can be used in controlling fertility Oral contreceptives Contain oestrogen and progesterone They inhibit FSH production and therefore egg maturation They now contain less oestrogen and more progesterone Women suffered significant side effects from oestrogen pills Progesterone only pills lead to fewer side effects Fertility drugs FSH and LH can be given as fertility drugs Used in IVF IVF Given FSH and LH to stimulate maturation of several eggs Eggs are collected and fertilised by father's sperm Develop into embryos When they are tiny balls of cells, one or two are inserted into the mother's womb
3 Control in plants
3.1 Plants are sensitive to
3.1.1 Light
3.1.2 Moisture
3.1.3 Gravity
3.2 Shoots
3.2.1 Grow towards light
3.2.2 Against the force of gravity
3.3 Roots
3.3.1 Grow towards moisture
3.3.2 In the direction of the force of gravity
3.4 Produce hormones to coordinate and control growth
3.4.1 Auxin controls phototropism and gravitropism
3.4.2 Responses of plant roots and shoots to light, gravity and moisture Due to unequal distribution of hormones, causing unequal growth rates Extra auxin Growth is stopped in the roots Growth is stimulated in the shoots Roots When growing sideways, auxin will accumulate on the lower side Auxin causes The cells to stop growing, meaning the cells at the tips grow faster and as a result bend downwards When exposed to moisture, more auxin accumulates on the side with more moisture Shoots When a shoot is exposed to light More auxin accumulates on the side that is in the shade Auxin causes The cells to grow faster (elongate more) on the shaded side, causing it to bend towards the lgiht When a shoot is growing sideways Gravity causes more auxin to accumulate on the lower side, causing it to grow faster and bend upwards
3.5 Plant hormones are used as weed killers and rooting hormones
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