B1.2 - Nerves And Hormones Flashcards
What are hormones?
Chemical long term responses to regulate cell/organ function
What is a reflex action?
How does it work?
Quick, involuntary response to protect body
Brian not involved
What do nerve cells do?
Transmit impulses between brain and spine
Central Nervous System
What are the 3 main types of neurones, and the differences between them?
Sensory neurones send receptor signals -> CNS
Relay Neurone - around CNS
Motor Neurone - CNS -> effectors
What is a receptor? Give 3 examples
Detects stimulus -> electric signal -> neurone
Eyes - detect light
Ears - detect sound
Skin - detects pressure, pain and heat
What is a synapse? How does it work?
Tiny gap between neurones
Chemical secrets at end of neurone -> closes synapse (lengthens reaction time)
Allows conscious control of response - can respond to stimulus in many ways
What is an effector?
Muscles contracting or glands release hormones
What the sequence of a regular nerve reaction?
Stimulus Receptor Sensory Neurone Relay Neurone Motor Neurone Effector
Explain step by step how IVF works
1) Woman given FSH -> releases several eggs
2) Eggs removed, fertiliser with partner’s sperm
3) Embryo placed in uterus, sink into lining -> fetus
What does FSH do?
Matures egg in ovaries
What does oestrogen do?
Makes uterus lining thicken
What does LH do?
Stimulates ovary to release egg
Explain the menstrual cycle step by step
1) Pituitary gland -> FSH - egg in ovaries matures, ovary secretes oestrogen
2) Oestrogen -> uterus lining thicken. LOTS of FSH production
3) LH stimulates ovary -> release egg
4) As FSH levels decrease, ovary stops making oestrogen. When oestrogen low, lining breaks down - cycle repeats
What is an auxin?
Plant hormone that makes cells grow
What is phototropism?
How does it work?
Growth response to light
Auxin builds on shady sides, makes cells grow and bend towards light
