<< Chapter < Page Chapter >> Page >

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

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.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
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
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
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Berger describes sociologists as concerned with
Mueller Reply
Got questions? Join the online conversation and get instant answers!
QuizOver.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Natural sciences grade 9. OpenStax CNX. Sep 15, 2009 Download for free at http://cnx.org/content/col11069/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Natural sciences grade 9' conversation and receive update notifications?

Ask