B1.2 Flashcards
Name five receptors and the stimuli they detect.
- eyes-light
- ears-sound
- nose-smell
- tongue-taste
- skin-touch, pain, temperature change
Stages of the reflex arc
Stimulus-receptor-sensory Neuton-relay Neurone- motor neurone-muscle contracts
What are hormones?
Chemical messengers which travel in the blood to activate cells.
What are three hormones in the menstrual cycle?
FSH
Oestrogen
LH
What does FSH do?
- produced in purity gland
- causes an egg to mature
- stimulates ovaries to produce oestrogen
What does oestrogen do?
- produced in ovaries
- caused pituitary gland to produce LH
- inhabits FSH
What does LH do?
- produced in pituitary gland
- stimulates the release of an egg
How can hormones reduce fertility?
- combination pill
- contains oestrogen and progesterone
- taking it everyday keeps oestrogen levels high
- inhabits the productions of FSH
- stops egg development over time
How can hormones increase fertility?
- Women can’t get pregnant due to low levels of FSH
* FSH and LH can be injected into to stimulate egg release in their ovaries
How does auxin contribute to plant growth?
- plant growth hormone near the tips of shoots and roots
- controls the plants response to light gravity and moisture
- moves backwards, stimulating cell elongation
Plant hormones in agriculture
- selective weedkillers-kill weeds with broadleaves, not crops, made with plant growth hormone
- rooting powder to soil-produce new roots that will grow new plants, producing clones, included auxin
What does positive geotropic mean?
Plant grows towards gravity
What does negative geotropic mean?
Grows away from gravity
What does positive phototropic mean?
Grow towards the sun
What does negative phototropic mean?
Grows away from the sun
