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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

5. FIND OUT:

  • 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

HALLUCINOGENICS :Dagga and LSD

  • feelings of wellbeing
  • experiencing things that are not real

Schizophrenia

  • Why do young people turn to drugs?

Assessment: APPLICATION

Could you apply your existing knowledge?

LO 2.4

Assessment

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.

Memorandum

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 does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
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
Daniel
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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
how to synthesize TiO2 nanoparticles by chemical methods
Zubear
how did you get the value of 2000N.What calculations are needed to arrive at it
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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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