2.  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

3.  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.

4. Co-ordination of body functions
involves:

5. NERVOUS CONTROL:
THE NERVOUS SYSTEM

6. Brain & Spinal cord:
 the main parts of the NS
 are called the CNS

7. Vertebrae protect the spinal cord
Spinal
cord
Vertebra
Vertebral
column

8. How is the CNS connected to the various parts
of the body?

9. The Nervous System receives
messages from:
Sense organs
CNS

10. The Nervous System sends
messages to:
 Muscles
 Glands
Effectors
CNS
Salivary
glands

12. Flow of information
What are
‘stimuli’?

13. A stimulus is:
 a change in the environment that can be
detected by a sense organ and brings about a
response

14. Stimuli [stimulus = singular]
Cold
Heat
Sound
Chemicals
in air
Pain

15. Neurones and nerves
Neurone = nerve cell
Nerve = a bundle of nerve cells
neurones

16. Neurones can be very long

17. Sensory neurones
Motor neurones
Intermediate or
Relay neurones
Three types of Neurone

18. Structure of a sensory neurone

19. Function of the myelin sheath
to insulate the fibre
speeds up the impulses
Myelin sheath:
FAT

20. Direction of impulse along a
sensory neurone
Axon carries impulse:
Away from the cell body

21. Fig. 4 A motor neurone.
[axon terminal]
Direction of
impulse

22. 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
Sensory neuroneMotor neurone
C
N
S
C
N
S

23. Differences in function between a:
receptor
Sensory neuroneMotor neurone
C
N
S
C
N
S
Carries the
impulse
towards
the CNS
Carries the
impulse away
from the
CNS

25. Fig. 5 Connections between a sensory, a
relay and a motor neurone.
 Neurones DO NOT touch each other
Sensory
neurone
Motor
neurone
Relay
neurone

26. A synapse is a tiny gap between
neurones
synapse

27. Impulses
travel in
direction
across a
synapse
Sensory neurone
Motor neurone
Relay neurone
Effector
Receptor

28. How many synapses on one cell
body? 1,000 to 10,000!!

29. Fig. 6 A synapse.

32. A Reflex Action is a
 rapid, automatic, involuntary response to a
stimulus

33. Examples of reflex actions:
 Sneezing

34.  Blinking
 Coughing
 Removing the leg
when stepping on a pin

35. Examples of reflex actions:
 withdrawing your hand from a hot
object

36. Why are reflex actions useful to
the body?

37. Question: SEP 2010
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 and transmit signals
between different parts of its body.

38. 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

39. Question: MAY, 2011 [2B]
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)

40. Question: MAY, 2011 [2B]
b) List TWO examples of reflex actions taking
place in newborn babies. (4)
Suckling reflex
Grip reflex
Stepping
reflex
Crying
reflex

41. The reflex arc is:
 the path along which a nerve impulse travels
from the receptor to the effector
 e.g. :
 Knee jerk reflex arc
 The hand withdrawal reflex arc

42. The knee jerk is a reflex action

43. The knee jerk reflex arc
MuscleSpinal cord

44. Dorsal [back]
TS spinal cord
Ventral [front]

45. A sensory neurone always
enters via the DORSAL
ROOT

46. Dorsal root ganglion is a
collection of cell bodies of the
sensory neurones

47. Fig. 7 The hand withdrawal reflex arc.

48. Myelin = FAT = white
Grey matter
White matter
TS spinal cord
Why is the white
matter white?
 due to nerve fibres
covered by myelin

49. Grey matter
White matter
 due to nuclei present
in cell bodies TS spinal cord
Remember nuclei look
DARK.
Why is the grey
matter grey?

50. 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

51. 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

52. Label the diagram. Draw arrows to
show direction of impulse
A – receptor
B – sensory neurone
C – motor neurone
D – synapse

53. Question: SEP, 2004
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.

54. ii) Use arrows to show the pathway of the
nerve impulse along the neurones. (4)

55. 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.

56. Label the two neurones. What is the
function of each?

57. Question: SEP 2010
Draw a labelled diagram showing the reflex arc
that takes place in a knee jerk reflex. On the
diagram indicate clearly the direction of flow of
impulses. (You are not expected to draw the
muscles involved or the spinal cord).
(6)

59. Question: MAY, 2011 [2A]
A student accidentally touches a beaker of hot
boiling water. The student pulled away her hand
within a few milliseconds. This is an example of a
reflex action.
a) Write a brief description about the events
leading to the student pulling away her hand.
(5)
b) Draw a diagram showing the reflex arc
responsible for producing this reflex action. In
your diagram include arrows to show the direction
of nerve impulses travelling along the neurones.
(6)

62. The skull protects the brain

63. The cerebrum is highly folded
Many neurones can be
packed into a small
space.

64. Two Cerebral hemispheres =
cerebrum

65. The cerebrum
 controls our:
 sensations
 movements
 is responsible for:
 memory
 thought
 intelligence
Cerebrum

66. The cerebrum contains
2. Sensory areas:
 for sensation
1. Motor areas:
 for movement
3. Association areas :
 for thinking

67. Parts of the brain:
Cerebrum / cerebral hemisphere
Cerebellum
Medulla
oblongata
Pituitary
gland
Hypothalamus

68. Functions of:
 releases
hormones
 homeostasis

69. Functions of the cerebellum:
 controls balance and
muscular co-ordination

70. Functions of the medulla oblongata:
 controls various automatic processes such as:
 the rate of breathing
 heartbeat

71. 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

72. Meninges
 are layers of tissue that surround the CNS

73. Meningitis
 is an infection of the meninges

74. Question: SEP 2010
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)

75. HORMONAL
CONTROL:
THE ENDOCRINE
SYSTEM

76. Glands in the body are:
secrete an enzyme
into a duct
 secrete hormones
 have no duct (ductless)
 have a rich blood supply
Exocrine
gland
Endocrine
gland

77. What is a hormone?
 a chemical which is produced by one part of
the body, travels in the bloodstream and
has an effect on the target organ

78. Fig. 14 Position of the main endocrine
glands in the human body.

79. The main human endocrine glands
and their secretions.
Gland Hormone Function
Thyroid Thyroxine
Controls the
metabolic rate

80. Gland Hormone Function
Adrenals Adrenaline
Prepares the
body for action
Kidneys
Adrenal glands

81. Adrenaline, the emergency
hormone

82. Adrenaline prepares the body for
action
Muscles need ENERGY to contract!!

83. Which process releases energy?
glucose + oxygen carbon
dioxide
+ water + energy
glucose
oxygen
muscle energy
How can MORE glucose + oxygen
reach the muscle?

84. Effects of adrenaline
Heart beat increases
Breathing rate
increases

85. Effects of adrenaline
 Arteries to muscles widen
What is the effect of this?

86. 5 litres of blood in an adult
If more blood
flows to muscles
less must flow to
other organs.
Which?

87. Gut & Skin get less blood
 As arteries narrow
A person becomes pale
when afraid. Why?

88. Glycogen
Glucose in the blood increases
Glycogen is converted
to glucose
Effects of adrenaline

89. Effects of adrenaline include:
1. Heart beat increases
2. Breathing rate increases
3. Arteries to gut and skin narrow
4. Arteries to muscles widen
5. The pupils of the eyes widen
6. Glycogen is converted to glucose

90. Gland Hormone Function
Pancreas
Insulin
Decreases the blood
sugar level
Glucagon
Increases the blood
sugar level

91. Control of blood sugar

93. Question: MAY, 2011
Give a biological explanation for the following
situation:
A diabetic person received an insulin shot after
intake of a meal rich in carbohydrates. (2)
A diabetic person does not
produce insulin. The insulin
injected helps the person to
reduce the sugar level in the
blood back to normal.

94. Gland Hormone Function
Ovaries
Female sex hormones
e.g. oestrogen
Control sexual
development
Testes
Male sex hormones e.g.
testosterone
Control sexual
development

95. Gland Hormone Function
Pituitary
Growth hormone Speeds up growth
FSH
Causes follicle to
develop into a Graafian
follicle
LH
Causes ovulation
ADH Causes kidneys to
reabsorb water

96. Differences between nervous and
endocrine co-ordination.
Nervous Chemical
Information passes as
electrical impulses along
nerve fibres
Information passes as a
chemical substance
through the bloodstream
Rapid transmission Slow transmission
Response is immediate
Response is usually slow
e.g. growth
Response is short-lived Response is long-lasting
Response is very exact
Response is usually
widespread

98. Negative feedback control:
 produces an effect which is the opposite of
what has been happening before
 e.g. if body temperature rises, sweat is
produced to cool it down
 is important to keep conditions constant in
the body

99. Control of blood sugar as an
example of:
NORM
Excess
Deficiency
Corrective
mechanism
Corrective
mechanism
NORM
Negative
feedback
Negative
feedback

100. THE END