GCSE AQA Biology 1 Nerves & Hormones

Lilac Potato
Mind Map by , created about 4 years ago

Mind map showing information about the nervous system, synapses, reflexes, hormones, the menstrual cycle, controlling fertility and plant hormones...

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Lilac Potato
Created by Lilac Potato about 4 years ago
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GCSE AQA Biology 1 Nerves & Hormones
1 The nervous system
1.1 Sense organs - detect stimuli (changes in the environment)
1.1.1 Contain receptors - groups of cells which are sensitive to stimulus (change stimulus energy into electrical impulses)
1.1.2 Eyes - light receptors
1.1.3 Ears - sound & balance receptors
1.1.4 Nose - smell receptors
1.1.5 Tongue - taste receptors
1.1.6 Skin - sensitive to touch, pressure, pain & temp. change
1.2 The CNS (central nervous system)
1.2.1 Where info from sense organs is sent & reflexes/actions are coordinated
1.2.2 Consists of brain & spinal cord
1.2.3 Neurones transit info quickly to & from CNS
1.2.3.1 Sensory neurones - carry signals from receptors to CNS
1.2.3.2 Relay neurones - carry signals from sensory to motor neurones
1.2.3.3 Motor neurones - carry signals from CNS to effector
1.2.4 Instructions from CNS sent to effectors
1.2.4.1 Muscles & glands - contract or secrete hormones
2 Synapses
2.1 Connect neurones
2.2 Nerve signal transferred by chemicals which diffuse across gap
2.2.1 Chemical set off new electrical signal in next neurone
3 Reflexes
3.1 Automatic responses to certain stimuli - reduce chances of being injured
3.2 Reflex arc - passage of info in a reflex
3.2.1 Neurones go through spinal cord or unconscious part of brain
3.2.2 1) STIMULUS - detected by receptors
3.2.2.1 2) SENSORY NEURONE - impulses sent along to CNS
3.2.2.1.1 3) RELAY NEURONE - impulses reach synapse between sensory & relay, chemicals cause impulses to be sent along relay neurone
3.2.2.1.1.1 4) MOTOR NEURONE - impulses reach synapse between relay and motor, chemicals cause impulses to be sent along motor neurone
3.2.2.1.1.1.1 5) EFFECTOR - impulses travel to effector
3.2.2.1.1.1.1.1 6) RESPONSE - muscle contracts/gland secretes
4 Hormones
4.1 Definition: Chemical messengers which travel in the blood to activate target cells
4.2 Control things in organs & cells that need constant adjustment
4.3 Produced & secreted by glands e.g. pituitary & ovaries
4.4 Long-lasting effects
5 Comparing nerves & hormones
5.1 Nerves
5.1.1 Very fast action
5.1.2 Act for very short time
5.1.3 Act on very precise area
5.2 Hormones
5.2.1 Slower action
5.2.2 Act for long time
5.2.3 Act in more general way
6 The menstrual cycle
6.1 4 stages
6.1.1 1) Bleeding starts - uterus lining breaks down
6.1.1.1 2) Uterus lining builds up
6.1.1.1.1 3) Egg is released
6.1.1.1.1.1 4) Wall is maintained
6.2 Hormones
6.2.1 FSH
6.2.1.1 Produced by pituitary gland
6.2.1.1.1 Causes egg to mature
6.2.1.1.1.1 Stimulates release of oestrogen
6.2.2 Oestrogen
6.2.2.1 Produced in ovaries
6.2.2.1.1 Causes pituitary gland to produce LH
6.2.2.1.1.1 Inhibits release of FSH
6.2.3 LH
6.2.3.1 Produced by pituitary gland
6.2.3.1.1 Stimulates release of egg
7 Controlling fertility
7.1 Reducing fertility
7.1.1 Oestrogen can prevent release of egg - inhibits FSH
7.1.2 Progesterone also reduces

Annotations:

  • Produces thick cervical mucus, stops any sperm getting through
7.1.3 The Pill

Annotations:

  • Used to be version with high levels but there was link with blood clots - now contains lower doses of oestrogen
7.1.3.1 Pros

Annotations:

  • * Over 99% effective at preventing pregnancy * Reduces risk of getting some types of cancer
7.1.3.2 Cons

Annotations:

  • * Isn't 100% effective * Can cause side effects * Doesn't protect against STDs
7.2 Increasing fertility
7.2.1 Some women have low levels of FSH - don't cause eggs to mature
7.2.1.1 Can inject FSH & LH to stimulate egg release
7.2.2 Pros

Annotations:

  • * Helps women to get pregnant
7.2.3 Cons

Annotations:

  • * Doesn't always work - may have to do it many times (expensive) * Too many eggs could be stimulated - multiple pregnancies
7.3 IVF
7.3.1 Involves collecting eggs from woman's ovaries and fertilising with man's sperm - grown into embryos
7.3.1.1 Once ball of cells - 1 or 2 transferred to uterus
7.3.1.1.1 FSH & LH given before egg collection
7.3.2 Pros

Annotations:

  • * Can give infertile couple a child
7.3.3 Cons

Annotations:

  • * Some women have strong reaction to hormones e.g. abdominal pain, vomiting & dehydration * Reported increased risk of cancer * Multiple births - risky for mother & babies
8 Plant hormones
8.1 Auxin
8.1.1 Controls growth near tips of shoots & roots
8.1.1.1 In response to light, gravity & moisture
8.1.2 Produced in tips, moves backwards - enlarging

Annotations:

  • If tip is removed, may stop growing
8.1.3 STIMULATES growth in SHOOTS, INHIBITS growth in ROOTS
8.2 Shoots grow towards light

Annotations:

  • * More auxin accumulates on shaded side * Grows faster on that side - shoot bends towards light
8.3 Shoots grow away from gravity

Annotations:

  • * When shoot is growing sideways, gravity produces unequal distribution - it will have more auxin on lower side * Lower side grows faster - bending shoot upwards
8.4 Roots grow towards gravity

Annotations:

  • * Root growing sideways will have more auxin on lower side * Auxin will inhibit growth - top side grows faster, root bends downwards
8.5 Roots grow towards moisture

Annotations:

  • * Uneven amount of moisture produces more auxin on side with more moisture * Inhibits growth - further side grows faster, root bends towards moisture
8.6 Uses in agriculture
8.6.1 Weedkillers

Annotations:

  • Most weeds in crop field broad-leaved (unlike crops), weedkillers made of plant hormones only affect broad-leaved plants (disrupt normal growth patterns - kills them)
8.6.2 Rooting powder

Annotations:

  • Plant cuttings won't alays grow in soil, add rooting powder containing auxin - produces roots rapidly

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