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Natural sciences

Grade 9

Life processes: healthy life

Module 10

Nerves and sensitivity

  • Sensitivity involves your capacity to react to your changing (internal and external) environment.

1. Indicate the stimulus-reactor path for the process that follows when a bee stings you on the hand.

2. Add the captions to the illustrations of the brain and the neuron.

  1. Write down the functions of the following:

Brain, spinal cord, motor neuron, sensor neuron

  1. Write down the stimulus and sensation of each sense organ:
  • Light rays penetrate the lens to fall on the retina
  • Image is formed
  • Cones and rods stimulated
  • Impulse transmitted to brain via optic nerve
  • Sound waves stimulate receptors in cochlea
  • Impulse to brain via auditory nerve
  • Gas molecule dissolves in mucus membrane
  • Olfactory nerve transmits impulse to the brain
  • Taste buds on the tongue sense only bitter, sweet, sour or salty (other tastes are perceived by the sense of smell)
  • Impulse to brain
  • Receptors in skin pick up mechanical, heat, touch, cold or pain stimuli.
  • Impulses to brain


  • Why :

a) you blink your eyes:

b) your nose runs when you have been crying:

c) your pupils dilate in a dark room:

d) food has no taste when your nose is blocked:

The effects of drugs and alcohol on the brain

When your body is in pain, painkillers mask the pain. You can control the nervous system’s capacity to feel. This means that medication can be applied usefully, but also that it can be misused.

Drugs are used in this way to provide excitement, but this is dangerous because it can lead to DEPENDENCY and result in TOLERANCE for particular levels of the drug. When this happens, more and stronger drugs are needed.

PAIN KILLERS :Morphine and heroin

  • suppress pain

deaden the senses

STIMULANTS :Caffeine, nicotine, ecstasy anti-depressants

  • enhance brain activity
  • anxiety (it causes)

lead to depression

TRANQUILLISERS :Alcohol and sleeping tablets

  • slow down brain activity
  • willpower, judgement and self-control affected

Sluggishness and disturbances of the vision


  • feelings of wellbeing
  • experiencing things that are not real


  • Why do young people turn to drugs?


Could you apply your existing knowledge?

LO 2.4


Learning Outcomes 2 : Constructing Science knowledge

The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

We know this when the learner:

2.4 applies knowledge.


1. impulse/stimulus – receptor – impulse – cns – impulse – effector

2. labels: sketch brain + neurone

4. Complete the table on the senses:

5 a) reflex action to lubricate the eye with a lubricant

b) Tears drain the tear duct that opens at the back of the throat cavity – which is also the back of the nasal cavity

c) opening enlarges to allow more light

d) nasal receptors temporarily out of action; tongue only recognises sweetness, saltiness, acidity, and bitterness

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Berger describes sociologists as concerned with
Mueller Reply
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Source:  OpenStax, Natural sciences grade 9. OpenStax CNX. Sep 15, 2009 Download for free at http://cnx.org/content/col11069/1.1
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