2. 3.1 Understanding
response and coordination
A student is able to:
list the changes in external and internal environment faced by an
organism,
state why organisms have to be sensitive to changes in internal and
external environment,
clarify through examples the meaning of ‘stimulus’ and ‘response’,
state the main components and pathways involved in detecting and
responding to changes in external environment,
state the main components and pathways involved in detecting and
regulating changes in internal environment,
clarify through examples the meaning of ‘coordination’.
5. all organs and systems in a healthy
human body are co-ordinated
co-ordinated means :
they co-operate with one another and
work together efficiently
6. The changes which cause response
in the body are called stimuli
(stimulus)
Stimuli: changes in the environment
- Internal & external environment
13. Consider the tennis player about to hit
the ball:
Physical activity is one function
that requires co-ordination
1 Eyes see ball.
2
3
Information goes to
brain & is processed.
Brain sends messages to
muscles to hit the ball.
17. 3.2 Analysing the role of human nervous
system
A student is able to:
state the role of nervous system,
draw and label a diagram to show the organisation of the nervous
system,
name the main parts of the brain and state their functions,
draw and label a diagram of a cross section of the spinal cord,
state the main functions of the spinal cord,
label the structure of an efferent neurone,
identify the type of the neurone from diagrams given,
state the function of each type of neurone,
state the mode of transmission of information along the neurone,
18. 3.2 Analysing the role of human nervous
system
A student is able to:
describe briefly the pathway of transmission of information from
receptors to effectors,
draw and label a simple diagram of a synapse,
describe the transmission of information across synapses,
state the role of the synapse in transmission,
give examples of voluntary action,
give examples of involuntary action,
outline the transmission of information in voluntary action,
outline the transmission of information in involuntary action,
draw a schematic diagram showing a reflex arc,
give examples of nervous system related diseases.
20. Question:
1. What is the main function of the nervous
system? (2)
The NS contains a network of specialised
cells called neurones that coordinate the
actions of an animal / human and
transmit signals between different parts of
its body.
22. Nervous systems process information in
three stages
Sensor
Effector
Motor output
Integration
Sensory input
Peripheral nervous
system (PNS)
Central nervous
system (CNS)
23. The Nervous System receives
messages from:
Receptors in Sense
organs
CNS
27. Organization of the human nervous system
BRAIN
SPINAL
NERVES
(31 pairs)
CRANIAL
NERVES
(12 pairs)
AUTONOMIC
NERVOUS
SYSTEM
SPINAL CORD
CENTRAL NERVOUS
SYSTEM
HUMAN NERVOUS
SYSTEM
PERIPHERAL NERVOUS
SYSTEM
SOMATIC
NERVOUS
SYSTEM
SYMPATHETIC
SYSTEM
PARASYMPATHETIC
SYSTEM
29. Brain & Spinal cord:
the main parts of the NS
are called the CNS
30. How is the CNS connected to the various parts
of the body?
31. Basic unit of the nervous system
Nerve cells = Neurones
Neurones
transmit
electrical
impulses
36. Meninges surround Brain & Spinal Cord
Function of the Meninges:
1. stabilise neural tissue
2. protect from bruising against bones
37. Meningitis: caused by an infection of the
meninges
Bacteria
Virus
Streptococcus
meningitis infection
38. Cerebrospinal Fluid (CSF) fills the:
1. hollow cavities of
the brain
[ventricles]
2. spinal cord
Left lateral view
39. Functions of the cerebrospinal
fluid:
1. acts as a shock absorber
2. to allow oxygen and
nutrients to diffuse
through it to nourish
neurones
3. to allow removal of
wastes
40. CSF must be drained all the time
CSF accumulates and exerts pressure
on the brain if not allowed to drain
41. Parts of the brain:
Cerebrum / cerebral hemisphere
Cerebellum
Medulla
oblongata
Pituitary
gland
Hypothalamus
42. What happened to the size of the cerebrum
as more complex nervous systems evolved?
The cerebrum came to make up a larger
proportion of the brain.
43. The cerebrum is highly folded
Many neurones can be
packed into a small
space.
45. Regions of the Brain: Cerebrum
• Layers of the cerebrum
Grey matter:
- outer layer in the
cerebral cortex
- composed mostly of
neurone cell bodies
White matter:
- inner layer in the
cerebral cortex
- composed of myelinated
nerve fibres
46. Position of Grey and White Matter
Grey
matter
Brain
Spinal Cord
White
matter
47. The Cerebrum is the site of:
1) consciousness, our sense of self
49. Regions of the Cerebral Cortex
receives and
processes visual
information
concerned with
planning and
decision making
receives and
processes auditory
information
deals with incoming
information from
the body
50. Three Kinds of Functional Areas in Cerebral Cortex:
2. Sensory areas
Receive impulses from
sensory receptors
1. Motor areas
Send impulses to
skeletal muscles
62. has centres which control mood and emotions
such as aggression, rage, fear and pleasure
is the most vascular region of the
brain
monitors:
i) metabolite and hormone levels of the blood
ii) blood temperature
The Hypothalamus
66. Question:
1. List the function of each of the following
parts within the central nervous system:
i. cerebrum; (2)
ii. cerebellum; (2)
iii. medulla oblongata. (2)
2. In humans the cerebrum is very large and
highly folded. Explain why. (2)
67. Question:
This question concerns the nervous system of humans.
Give the main function of the following structures within the
brain: (4)
1) Medulla
controls heart rate, blood pressure, breathing rate
2) Cerebellum
controls posture and balance, co-ordinates muscle
action
3) Cerebrum
responsible for voluntary action, store memory,
involved in learning
4) Hypothalamus
responsible for homeostasis, acts as an integration
centre for the endocrine and nervous systems
70. The Spinal Cord is a cylinder of
nervous tissue
runs from the base of the brain down the back
71. Two functions of the Spinal Cord:
1)acts as a coordinating centre for:
reflex actions
2) provides a means of
communication between the:
spinal nerves and
the brain
72. The Structure of the Spinal Cord & its Roots
GREY MATTER
contains
cell bodies
dendrites
synapses
WHITE MATTER
contains
myelinated nerve
fibres
73. Myelin = FAT = white
Grey matter
White matter
TS spinal cord
Why is the white
matter white?
due to nerve fibres
covered by myelin
74. Grey matter
White matter
due to nuclei present
in cell bodies TS spinal cord
Remember nuclei look
DARK.
Why is the grey
matter grey?
83. Basic plan of a nervous system
receptor afferent neurones efferent neurones
interneurones
in
central
nervous
system
stimulus
change in the environment
of the receptor
generates
nerve
impulses
The functional unit of the nervous system is the neurone.
muscle or gland
response
effector
85. The Structure And Function Of A Typical
Neurone
Dendrites
Neurilemma
• Forms the cell
membrane of a neurone
Muscle fibres
Myelin sheath
• Insulates the axon and
speeds up the transmission
of impulses
Axon (Transmits impulse away
from the cell body)
Dendron (Transmits impulse
towards the cell body)
Nucleus
Cell body
• Contains a nucleus, cytoplasm
and other organelles
Nodes of Ranvier
• Where the neurilemma
constricts, helps to speed up
transmission of nerve impulse
• Serves as a control centre
91. Function of the myelin sheath
Protects the nerve fibre
insulates the nerve fibre
speeds up the impulses
Myelin sheath:
FAT
92. Nodes of Ranvier: gaps along the axon
facilitate the rapid conduction of nerve impulses
impulsesimpulses occur at intervals of 1 to 2 m
93. Differences in structure between a:
1. Long axon
2. No receptor
3. Cell body terminal &
has dendrites
4. Many short dendrons
1. Short axon
2. Receptor
3. Cell body at the side;
no dendrites
4. One long dendron
receptor axon
axon
dendron
Afferent neuroneEfferent neurone
C
N
S
C
N
S
94. Differences in function between a:
receptor
Afferent neuroneEfferent neurone
C
N
S
C
N
S
Carries
impulse from
the receptor
to the CNS
Carries
impulse from
the CNS to
the effector
97. Connections between afferent neurone,
interneurone and efferent neurone.
Neurones DO NOT touch each other
Afferent
neurone
Efferent
neurone
Inter
neurone
98. A synapse is a tiny gap between
neurones
synapse
105. What happens at a chemical synapse?
• Calcium ions cause synaptic vesicles to fuse
with the presynaptic membrane, releasing
neurotransmitters into the synaptic cleft.
2
106. What happens at a chemical synapse?
• neurotransmitters diffuses across the
synaptic cleft and binds to specific
neuroreceptor sites in the post synaptic
membrane.
3
107. Neurotransmitters are
cleared from the cleft.
Why is it important to
remove them from the
synaptic cleft?
To stop their action.
What happens to the neurotransmitter
after its release?
108. 1. Diffusion
The neurotransmitter is cleared from the
synaptic cleft in three ways:
2. Reuptake by
adjacent cells
3. Enzymes present
in the cleft may
destroy them: e.g.
acetylcholinesterase
acts on
acetylcholine (ACh)
110. All skeletal muscle motor neurones
Some neurones in the autonomic NS
Acetylcholine (ACh) is released by:
111. Blocks ACh receptors
Circular iris muscles do not contract
Atropine from belladonna
112. Explain the possible effects of the following
neurotoxins based on their mode of action:
1.nerve gases used in warfare (e.g. sarin) and
organophosphate insecticides (e.g.
parathion) inhibit acetylcholinesterase; (1)
The neurotransmitter is not destroyed by
acetylcholinesterase and continues to act
on the postsynaptic membrane. Thus
impulses are continuously being fired.
Question:
113. Explain the possible effects of the following
neurotoxins based on their mode of action:
Question:
2.various toxins, such as
botulinum toxin, prevent
the release of
acetylcholine. (1)
No impulse can be fired in
the postsynaptic
membrane and the person
remains paralysed.
115. Amphetamine & Nicotine are stimulants
have an excitatory effect
cause brain to release more
dopamine [neurotransmitter]
dopamine causes neurones to fire more often
than normal:
= euphoric feeling
116. But when the effect wears
off person feels down
Effect of Amphetamines
117. Amphetamine stimulates dopamine synapses:
- by increasing
the release of
dopamine
from the
presynaptic
terminal
DAT – dopamine transporter
118. Nicotine binds to the presynaptic receptors:
exciting the neurone to fire more action
potentials causing an increase in dopamine
release
121. Types Of Coordinated Response
Two types of actions controlled by the human
nervous system
Voluntary Action
Involuntary Action
Controlled by cerebrum
Controlled by medulla oblongata
122. Voluntary Action
Initiated by the motor centres of the cerebral corfex
The pathway of transmission of information in voluntary action
Receptors
Sensory areas
of the cerebral
cortex
Motor area of
the cerebral
cortex
Effector
Afferent nerve
Efferent nerve
Stimulus
Response
123. Involuntary Action
The brain is not conscious of an involuntary action.
Example of involuntary action involving skeletal muscle
knee jerk reflex
withdrawal of the hand from a hot object
Example of involuntary action involving smooth muscle
cardiac muscle or glands
regulation of blood pressure
rate of breathing
blood glucose level
130. A Reflex Action is a
rapid, automatic, involuntary response to a
stimulus which is not under the voluntary
control of the brain
The pupil
reflex
131. A Reflex Action
is the simplest form of response in the nervous
system
the same stimulus produces the same response
every time
Sneeze Swallow
Snail retreats inside
shell
137. b. List the stimulus and response for each of
the following reflex actions:
i. swallowing; (3)
Stimulus: food in mouth
Response: food goes down oesophagus
ii. coughing. (2)
Stimulus: foreign particles in trachea
Response: removal of foreign object from
trachea
138. Question:
A student accidentally touches a beaker of hot
water. The student pulled her hand away from
the hot water very quickly. This is an example
of a reflex action.
a) Define the term reflex action. (2)
139. Question:
b) List TWO examples of reflex actions taking
place in newborn babies. (4)
Suckling reflex
Grip reflex
Stepping
reflex
Crying
reflex
140. Reflex Arc is the:
nervous pathway taken by nerve
impulses in the reflex action
142. Two Types of Reflex Action:
1.Monosynaptic 2. Polysynaptic
e.g. knee jerk reflex
Has a SINGLE synapse
between the sensory
and motor neurones
e.g. hand withdrawal reflex
Has TWO or more
synapses
lex
151. A Reflex Arc
- nerve pathway in a reflex action
stimulus
receptor
afferent neurone
spinal
cord of
central
nervous
system
interneurone
efferent neurone
effector
response
152. REMEMBER: Reflex Arc
Some involve 3 neurones – afferent neurone,
interneurone & efferent neurone
Eg. withdrawal of the hand from a hot object
Some involve 2 neurones – afferent neurone
& efferent neurone
Eg. knee jerk
155. Question
A transverse section through the spinal cord is
examined under the high power of the
microscope. Part of it looks like diagram A and part
looks like diagram B. Which is grey matter and
which is white matter?
Give reasons for your decision.
A B
156. Answer
Diagram A represents nerve fibres cut in cross-
section and therefore comes from white
matter.
Diagram B shows many cell bodies which
constitute much of the grey matter.
A B
157. Label the diagram. Draw arrows to
show direction of impulse
A – receptor
B – sensory neurone
C – motor neurone
D – synapse
158. Question:
6d) The following diagram demonstrates the rapid
and automatic removal of a finger from a
flame.
i) Complete the diagram by drawing and naming
the neurones that bring about this reflex action.
159. ii) Use arrows to show the pathway of the
nerve impulse along the neurones. (4)
160. e) Some individuals suffer from a motor neurone
disease in which the neurones gradually
degenerate. How is this likely to interfere with the
efficiency of reflex actions? (2)
Reflex actions take
longer to occur – they
become less efficient.
161. Label the two neurones. What is the
function of each?
162. Question:
The diagram in the figure below shows part of
the spinal cord of a human in transverse
section
a)Identify the structures labelled A through D.
(2)
A: white matter
B: dorsal root ganglion
C: grey matter
D: ventral root
E: central canal
163. Question:
Touching a hot surface would generally cause a
person to contract their biceps, retracting the
arm and hand away from the stimulus. This
reflex action involves three neurones.
b) What is a reflex action? (1)
A reflex action is a rapid automatic response
to a stimulus. An action which is not learned.
164. Question:
c) Name the three types of neurones involved in
a reflex action and indicate the approximate
position of each on the diagram. (3)
165. Question:
d) State ONE function of the fluid found in
structure E. (1)
Shock absorber / provides nutrients to the
nerve cells / removes wastes of nerve cells
167. Organization of the human nervous system
BRAIN
SPINAL
NERVES
(31 pairs)
CRANIAL
NERVES
(12 pairs)
AUTONOMIC
NERVOUS
SYSTEM
SPINAL CORD
CENTRAL NERVOUS
SYSTEM
HUMAN NERVOUS
SYSTEM
PERIPHERAL NERVOUS
SYSTEM
SOMATIC
NERVOUS
SYSTEM
SYMPATHETIC
SYSTEM
PARASYMPATHETIC
SYSTEM
168. Peripheral Nervous System
Cranial & Spinal Nerveshe nervous system of a vertebrate
mixed nerves
What does
this mean?
31 pairs
12 pairs
170. AUTONOMIC NERVOUS SYSTEM
The part of the nervous system responsible for control of
the bodily functions not consciously directed, such as
breathing, the heartbeat, and digestive processes.
171. Organization of the human nervous system
BRAIN
SPINAL
NERVES
(31 pairs)
CRANIAL
NERVES
(12 pairs)
AUTONOMIC
NERVOUS
SYSTEM
SPINAL CORD
CENTRAL NERVOUS
SYSTEM
HUMAN NERVOUS
SYSTEM
PERIPHERAL NERVOUS
SYSTEM
SOMATIC
NERVOUS
SYSTEM
SYMPATHETIC
SYSTEM
PARASYMPATHETIC
SYSTEM
172. Autonomic Nervous System also known as the
involuntary Nervous System
Regulates activities of:
cardiac & smooth muscles
glands
FUNCTION:
controls involuntary
functions e.g. sweating
173. The overall control of the autonomic NS
is maintained by centres in the :
medulla
&
hypothalamus
175. Effect on the Heart:
Organ Sympathetic Parasympathetic
Heart Increases
amplitude and
rate of heart
beat
Decreases
amplitude and
rate of heart beat
181. Parkinson’s disease
Affects nerve cells in the brain that produce neurotransmitter
dopamine.
Symptoms : muscle rigidity, tremors, and changes in speech and
gait.
After diagnosis, treatments can help relieve symptoms, but there
is no cure.
186. Nerve gases
Nerve gases, or nerve agents
odorless , colorless or yellow-brown liquids
eg Sarin and VX.
Even in small quantities, nerve gases inhibit
the enzyme acetylcholinesterase and disrupt
the transmission of nerve impulses in the
body.
187. Effects of sarin
Runny nose, Watery eyes, Small, pinpoint pupils, Eye pain,
Blurred vision, Drooling and excessive sweating, Cough,
Chest tightness
Rapid breathing, Diarrhea, Nausea, vomiting, and/or
abdominal pain, Increased urination
Confusion, Drowsiness, Weakness, Headache, Slow or fast
heart rate, Low or high blood pressure
Even a small drop of sarin on the skin can cause sweating
and muscle twitching where sarin touched the skin.
Exposure to large doses of sarin by any route may result in
the following harmful health effects:
Loss of consciousness, Convulsions, Paralysis, Respiratory
failure possibly leading to death
190. BOTOX
Botox is a drug made from a toxin produced by the
bacterium Clostridium botulinum.
causes a life-threatening type of food poisoning
called botulism.
191. BOTOX
Doctors use it in small doses to treat health problems, including
Temporary smoothing of facial wrinkles and improving your
appearance
Severe underarm sweating
Cervical dystonia - a neurological disorder that causes severe
neck and shoulder muscle contractions
Blepharospasm - uncontrollable blinking
Strabismus - misaligned eyes
Chronic migraine
Overactive bladder
Botox injections work by weakening or paralyzing certain
muscles or by blocking certain nerves. The effects last about
three to twelve months, depending on what you are treating.
The most common side effects are pain, swelling, or bruising at
the injection site. You could also have flu-like symptoms,