Biology section 5 Knowledge organizer Flashcards
What are the nerve reflexes key terms?
CNS
Reflex action
coordination centre
synapse
what is the reflex arc order
Stimulus - receptor - sensory neuron - relay neuron - motor neuron - effector - response
What is the purpose of the reflex arc
The purpose is to protect the body from damage by reacting more quickly
Explain how the synapse work
First an electrical impulse arrives at the synapse then the neurotransmitter molecules are released and diffuse across the synapse finally the neurotransmitter molecules fill receptors and cause an electrical impulse in the next neuron
what are the endocrine glands
pituitary gland
thyroid
adrenal
pancreas
ovary
testes
What does oral contraceptives contain ‘the pill’
oestrogen to inhibit fsh production so eggs do not mature
what are the pros and cons to the pill
+ 99% effective
+ reduces risk of some cancers
- can cause side effects e.g nausea
what is in an injection , implant or skin patch
progesterone which is slowly released to stop eggs maturing or being released
what are the pros and cons of injections, implants and skin patch’s
+ Fewer side effects then the pill
+doesn’t need to be taken daily so less likely to be forgotten
- less effective than pill
what are barrier methods
Condoms or diaphragm to prevent sperm reaching the egg
what are the pros and cons of the barrier method
+ 98% effective (when used correctly)
+ prevents sti’s
- can break or be used incorrectly
What is spermicide
Used with diaphragms to make them more effective kills or disables sperm
what are the pros and cons of spermicide
+ increases effectiveness of of some barriers
- cant be used on its own
What is the ‘rhythm method’
the rhythm method is avoiding intercourse when egg might be in an oviduct
what are the pros a nd cons of the rhythm method
no +
-high risk of becoming pregnant
What is sterilisation
Undergoing surgery to stop sperm or eggs being able to fertilise
what are the pros and cons or sterilization
+ permanently stops pregnancy
- risks from surgery
- expensive and may not work
What is an intra-uterine device
An implant into the uterus that prevents fertilised eggs implanting into the wall of the uterus and releases hormones
what are the pros and cons of iuds
+ long lasting but can be reversed
- small risk of infection or uterus damage when iud is implanted
What are the steps of IVF
- give mother fsh and lh to stimulate production of eggs
- collect eggs , fertilise with sperm in lab
3.fertilised eggs develop into embryos - one or two embryos inserted into uterus
What are ivf disadvantages
Emotionally and physically stressful
success rates are low
can lead to multiple births which are risky for mother and babies
