Biology section 5 Knowledge organizer

Question 1

What are the nerve reflexes key terms?

Answer 1

CNS
Reflex action
coordination centre
synapse

Question 2

what is the reflex arc order

Answer 2

Stimulus - receptor - sensory neuron - relay neuron - motor neuron - effector - response

Question 3

What is the purpose of the reflex arc

Answer 3

The purpose is to protect the body from damage by reacting more quickly

Question 4

Explain how the synapse work

Answer 4

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

Question 5

what are the endocrine glands

Answer 5

pituitary gland
thyroid
adrenal
pancreas
ovary
testes

Question 6

What does oral contraceptives contain ‘the pill’

Answer 6

oestrogen to inhibit fsh production so eggs do not mature

Question 7

what are the pros and cons to the pill

Answer 7

+ 99% effective
+ reduces risk of some cancers
- can cause side effects e.g nausea

Question 8

what is in an injection , implant or skin patch

Answer 8

progesterone which is slowly released to stop eggs maturing or being released

Question 9

what are the pros and cons of injections, implants and skin patch’s

Answer 9

+ Fewer side effects then the pill
+doesn’t need to be taken daily so less likely to be forgotten
- less effective than pill

Question 10

what are barrier methods

Answer 10

Condoms or diaphragm to prevent sperm reaching the egg

Question 11

what are the pros and cons of the barrier method

Answer 11

+ 98% effective (when used correctly)
+ prevents sti’s
- can break or be used incorrectly

Question 12

What is spermicide

Answer 12

Used with diaphragms to make them more effective kills or disables sperm

Question 13

what are the pros and cons of spermicide

Answer 13

+ increases effectiveness of of some barriers
- cant be used on its own

Question 14

What is the ‘rhythm method’

Answer 14

the rhythm method is avoiding intercourse when egg might be in an oviduct

Question 15

what are the pros a nd cons of the rhythm method

Answer 15

no +
-high risk of becoming pregnant

Question 16

What is sterilisation

Answer 16

Undergoing surgery to stop sperm or eggs being able to fertilise

Question 17

what are the pros and cons or sterilization

Answer 17

+ permanently stops pregnancy
- risks from surgery
- expensive and may not work

Question 18

What is an intra-uterine device

Answer 18

An implant into the uterus that prevents fertilised eggs implanting into the wall of the uterus and releases hormones

Question 19

what are the pros and cons of iuds

Answer 19

+ long lasting but can be reversed
- small risk of infection or uterus damage when iud is implanted

Question 20

What are the steps of IVF

Answer 20

1. give mother fsh and lh to stimulate production of eggs
2. collect eggs , fertilise with sperm in lab
   3.fertilised eggs develop into embryos
3. one or two embryos inserted into uterus

Question 21

What are ivf disadvantages

Answer 21

Emotionally and physically stressful
success rates are low
can lead to multiple births which are risky for mother and babies