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Chapter 2: Body Coordination
Types of Reex action:
(a) Cerebral refex (c) Cranial refex(b) Spinal refex (d) Conditioned refex(c) Cranial refex
IRIS control the light intensity at the retina (Pupil reex) cereral reex
1. Cereral reex: refex action that is controlled by the brain.Eg: Pupil refex
2. The echanis is about ho! iris control its uscle to control aount o" lighteg:#utonoic ner$ous syste (%efex action) &no!n as 'pupil refex
igh light intensity*bright light +o! light intensity*di light
Circular uscle contract
,Parasypathetic -S)
%adical uscle contract
(Sypathetic -S)
Pupil reduced in sie (constrict) Pupil is open !ider (dilates)
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!nee"#er$ (Spinal reex)
Spinal reex: the refex action that is controlled by the spinalcord
Path%ay: Stiuli sensory neurone spinal cord otor neurone
&& 'thers:
Cranial
reex
%efex that occurs in brain and head region. Eg: sal$ation and eyes blin&ing
Condition
ed reex
The action that is due to long practice and experience
Eg: riding a bicycle
Synapse
1. Synapse: site !here t!o neurons or a neuron and an e6ector cell counicate.
;nee3er& tested by
&noc&ing at the &neecap
caise a refex contraction at
the <uadriceps uscle inthe upper tight leg &ic&s.
,n this refex path!ay5 a
stretch receptors(proprioceptors) in the
tendon is stiulated by the
tap and it sends signal tothe sensory neurone and to
the spinal cord.
The ipulse is then send toa otor neurone "ro spinal
cord to <uadriceps.
8ailure o" the leg respond tothe tap ay be due to
disease*daage to one or
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*xercise
1. o! any neurones are in$ol$ed in &nee er&= -ae the neurones
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A. -ae a refex that do not in$ol$es relay neurones
B. >hat receptors are used to detect taste=
2+ Proprioceptors
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, Proprioceptors: receptors !hich are connected to sensory neurones." ;no!n as -stretch receptors." Sensiti/e to 0o/e0ent1 pressure
or stretching %ithin the ody
" #cts as internal sensory organs carry outacti$ities !ithout being !atched.
3 8ound in the uscles5 tendons5 ligaents and
oints
1. 4uried under the s&eletal
uscle are uscle
spindles (sensory stretchreceptors) that lie parallel!ith the rest o" the bres
in uscle.
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, !inaesthetic: using proprioceptors to help to sense and detect lib0s position and
o$eent.
2 This !ill help the body to coordinate the o$eent and the balance o" the body.
oint: location at !hich the bones
are connected
Tendons: tough band brous
connecti$e tissues that connectsuscle to the bone (can !ithstand
tension)
3iga0ents: brous tissues thatconnects bones to the other bones
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Chapter 2: Body Coordination
24 5u0an Brain
+e"t heisphere:
Control the rightside o" the body
%ight heisphere:
Control the le"t sideo" the body.
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1. The brain is protected by craniu and ? ebranes (eninges)2. /eninges "unction as shoc& absorber "or the brain?. The brain has 2 hal$es that is called as cerebral heispheres (le"t heisphere and right
heisphere)
+e"t
heisphere
Controls side o" the body
%ight
heisphere
Control the side o" the body
9. The brain is di$ided into ? ain parts that are:(a) Cerebru (c) /edulla oblongata
(b) CerebelluCereru09
6orerain
+argest part o" the brain
6unctions: control the eory5 thin&ing and all $oluntary actions%ecei$es ipulses "ro receptors in the eyes5 ears5 nose5 tongue and
s&in Transit ipulses to uscles and glands
Futer layer o" the cerebru cortex4elo! cortex !hite atterCortex:
3 Consists o" grey atter ade up o" cell bodies o" neurones3 Cortex ebrane is greatly "olded increase the sur"ace area to
hold ore cell bodieshite 8atter:
/ade up o" neurone0a axon
Cereellu095indrain
as t!o heisphereas a "olded sur"ace to increase its sur"ace area
Futer region rey atter,nner region >hite atter
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;oluntary action ;s In/oluntary action
;oluntary action In/oluntary actionSiilarities
3 4oth are ner$ous coordination3 4oth in$ol$e peripheral and central ner$ous syste
<i7erences:Part o" the brain
that is in$ol$ed:
Controlled by cerebellu Controlled by edulla oblongata
>ill control
ability:
Controlled by our !ill Cannot be controlled by our !ill
#!areness: #!are o" the action beingplanned or ta&en
Ta&e place continuously andautoatically in the body !ithout us
being consciously a!are o" the
-er$ousipulsepath!ay:
Path%ay:%eceptor spinal cord cerebru
E6ector
Path%ay:%eceptor spinal cord /edullaoblongata
E6ectorSpeed o" action: Speed o" action can be
<uic&ened or slo!ed do!n
Speed o" action is "ast
Exaples Eg: !riting5 dancing5 reading5
clibing5 carrying outexperient
putting do!n a hot obect ==
Eg: peristalsis5 heart beating5 "ood
digestion5 breathing rate
3ael the diagra0
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*xercise
1. >hy are the groo$e on the sur"ace o" the huan brain=
2. >hy is an in$oluntary action <uic&er than a $oluntary action=
?. # $icti inures his brain and becoes paralyed and speechless in an accident but
his heart still beats and he can still breathe. >hich parts o" his brain are inured and
!hich part is not=
9. ,n !hat !ay is the huan brain superior to other aalian brains=
@. -ae the 2 structures that protect the brain
A. >hich part o" the brain is called the sall brain=
B. >hy is it iportant "or the brain to ha$e the grey atter on the outer side=
I. >hat is !hite atter ade up o"=
J. >hat is eant by the otor area o" the brain=
17.Kou are !atching a TH prograe. ,s this a $oluntary action or an in$oluntary action=>hy=
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SP8 2=,=
Diagra belo! sho!s 2 types o"
neurone
(a) -ae the type o" neurone:-eurone #:
-eurone 4:
(b) -ae the structure labelled L at neurone 4
(c) >hat is the "unction o" the structure L=
(d) 8ill in the boxes belo! !ith the correct neurone "or the
ipulse path!ay
%eceptor Central -S E6ector
(e) Diagra belo! sho!s the part o" a huan brain
# student has lost his body balance and could not
coordinate his leg and hand o$eent. ,n the diagra
belo!5 ar& √ the part o" the brain !hich is inured
SP8 2==>
Diagra belo! sho!s the structure o" a neurone
(a) 4ase on diagra abo$e5 ar& √ the type o" neurone in
the box pro$ided
Sensory neurone %elay neurone /otor neurone
(b) -ae L:
(c) State 2 "unctions o" L
(d) Diagra sho!s the path!ay o" an ipulse. /ar& the √
location o" neurone in the diagra
%eceptor C-S
E6ector
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