(BIOLOGY-COORDINATION QUESTIONS & ANSWER'S)

1}.Figure 1 shows the spinal cord.

Figure 4

a. Name parts labelled L, M and N.

L: __sensory neurone (1 mark)
M: _grey matter_____(1 mark)
N: __white matter_________ (1 mark)
b. Give the structural difference between M and N.
__M has the highest concentration of the cell bodies and N has the highest
concentration of axons and dendrons__ (1 mark)
c. (i) On the diagram mark X, as the part attacked by polio. (1 mark)
(ii) What causes polio?
___virus__ (1 mark)
(iii) Give one way, how polio can be prevented.
_vaccination_ (1 mark)
d. Give any two functions of the fluid found in part labelled O.
i. _it acts as the shock absorber(1 mark)
ii. _it provides the nutrients to the brain and the spinal cord__ (1 mark)
 iii. Draw arrows that show the direction of the nerve impulse during the
reflex action.
(1mark)

2} Figure 2 is a diagram showing an example of a reflex action in humans. Use

it to answer the questions that follow.

a. State the example of the reflex action.

_spinal reflex action___(1 mark)
b. Explain the role of the spinal cord in a reflex action.
_it receives the nerve impulses from the sense organ and interpret the
impulses and send them through the motor neuron to the effectors __(2
marks)
c. State the function of part N.
__it contains the cerebral spinal fluid that provides nutrients (1 mark)
d. Explain why a polio patient does not feel pain after touching a hot object.
 _this is because the sensory neuron is destroyed that can carry nerve
impulses from the sense organ to the brain or the spinal cord so that the
impulse can be interpreted for the person to feel pain _(2 marks)

e. explain how the person withdraws the hand from the fire in the diagram
above

_the sense organ senses the change in an environment as increase in

temperature, then the impulse travels through the sensory neuron to the spinal
cord where the impulse is interpreted and sent to effectors through the motor
neuron. The impulse causes the biceps to contract and the triceps to relax thus
causing the arm to withdraw from the fire (4marks)

3} Figure 3 shows position of endocrine glands in the human body. Use it to answer
the questions that follow.

a. Name the hormone produced by part marked M.

__thyroxine hormone___ (1 mark)
b. Explain why the hormone produced by part marked N is called the flight or
Fight hormone.
_it prepares the body for an action either to run away or to fight__(2 marks)
c. (i) What would happen to the levels of glucose in the body if part O was
Removed?

_the levels of glucose will be high__(1 mark)

(ii) Explain your answer in 9.c (i)

_this is because the hormone produced by O converts the excess glucose to

glycogen_(2marks

4(a) Give reason why pituitary gland is sometimes referred to as “the master
gland”.

_it controls the activities of other hormones(1 mark

(b) Explain how hormones from endocrine glands reach their target organs.
_they flow in the blood and the target organ has specific receptors that these
hormones will bind which the hormones will bind thus effecting the
change_(2 marks)
(c) Explain how the body limits the duration of hormones response from
persisting indefinitely.
_they are destroyed___ (2 marks)

5a} State one difference between the way the nervous system and endocrine
system brings about response.
 _the nervous system uses the nerve impulses while the endocrine system
uses the hormones._(1mark)
b. Explain one reason why the surface of cerebrum of higher animals is deeply
folded
_this is because the animals are associated with and thinking capacity
hence the cerebrum has to be highly folded _(2marks)

6a} Define a reflex action.

Is the rapid and automatic response to the stimuli_____ (1 mark)

b) State any five components of a reflex arc.

i. sense organ, sensory neuron, motor neuron, spinal cord

and effectors_(5marks
c) Briefly explain which parts are involved specifically in a knee
jerk reflex arc.
The hit on the knee the impulse is taken through the sensory neuron to the spinal
cord where the impulse is interpreted and then sent back through the motor neuron
to the muscles where the muscles will contract and other muscle will relax this
cause the knee jerk _ (4 marks)

d; Explain the effect of each of the following structures on movement of an

impulse in neurones.
(i) Myelin sheath
__it prevents the interference during the nerve transmission hence allowing the
nerve transmission to be faster____ (2 Marks)
(ii) Node of Ranvier _it speeds up the rate of the nerve transmission____ (2
Marks)
7} What is the difference between exocrine and endocrine glands?
_the exocrine glands releases the substances outside the body while the
endocrine glands releases the substances within the body ____2.marks
(ii) Give one example of
a. Endocrine gland: ___adrenal gland______
b. Exocrine : _sweat gland____
(iii) Name a grand which is both exocrine and endocrine
__pancreas______ 1.mark

8} The diagram below shows the position of some endocrine glands in the
body.

A hormone secreted by one of the glands has the following effects:

▪ Heartbeat increases_________________________
▪ Arteries supplying the gut constrict____________
▪ Arteries supplying the muscles dilate________
▪ Pupil size increases________
 a. Identify the letter and name of the gland that secretes the hormone that
brings about the above changes.
______________D_(1mark)

b. Explain the significance of each of the following changes:

i. Heartbeat increases. this is to allow more blood to be taken from the

alveoli which contains oygen to all the body parts that will need oxygen for
respiration so as to generate energy. And also it allows more deoxygenated
blood to be brought to the alveoli where it can diffuse out from the blood _(3)

ii. Arteries supplying the gut constrict so as to allow less blood to flow to the
gut preventing the absorption of glucose from the gut that can br converted to
glycogen in the liver. This ensures that the body uses the glucose that has been
stored for respiration.(3marks)

iii. Pupil size increases _to allow more light to enter the eye enabling the
person to see properly a distance from the person (2mark

9} An athlete involved in a cross-country competition, was running at a speed

of 2 metres per second. As she passed through a forest, she met a leopard and
her speed immediately rose to 6 metres per second.

i. Name the hormone that caused the change in speed.

Adrenaline hormone____(1mark)

ii. Explain how the hormone led to the change in speed in 9.

 _the hormone once released it triggers massive gaseous exchange in the
alveoli allowing more oxygen to be used for respiration to generate energy
in the muscles. This energy is then used for running thus increasing the
speed_(3marks)

a) Mention the two main parts of the central Nervous system

i. ___the brain and spinal cord___(2 marks

b) Explain why a heavy blow would be fatal if done to the medulla oblongata
than if done to the cerebrum

_this is because the medulla oblongata controls involuntary processes like

breathing which allows air to be drawn in and to be used for respiration _ (2
marks)

10} Figure 4 shows a cross section of the spinal cord. Use it to answer the
questions that follow.
a. Name the part marked K.

_sensory neurone________ (1 mark)

b. Mention one disease that attacks neurone X.

____polio______(1 mark)

c. Give one function of the fluid found in the neural canal.

_____it contains cerebral spinal fluid________ (1 mark)

11} Define a “conditioned reflex action”.

_it is the response that a person will do due to past experience___ (1 mark)

a. Mention the three main steps involved in conditioning organism. (3 marks)

Step 1 activity and a stimulus___
Step2: __repetition of the activity and stimulus ________________

Step3 activity only_______

b. What is the difference between “a conditioned reflex” and “a single reflex

action”?

__conditioned reflex is due to past experience while simple reflex is not

associated with past experience__(1 mark)

11.Table 1 shows results of an experiment where a person was blindfolded

and asked to locate the direction of sound produced by a clock placed at
different distances.
a. What two variables were kept constant in this experiment?

__aperson and the bell_ (2 marks

b. What was the aim of the experiment?

___the effect of the distance on hearing _____ (1 mark)

c. What conclusion can be drawn from the results shown in Table 1?

__the closer the sound is the more likely aperson will hear from all
positions______ (1

12.Figure 5 is a diagram showing a transverse section of the spinal cord. Use it

to answer the questions that follow.
a. Name the parts labelled B and C.

____ventral root and C is the dorsal root (2 marks)

b. State the structural difference between parts labelled A and D.

___A consits nerve fibres while D consists of cell bodies_____ (1 mark)

c. What is the function of the substance found in the part labelled E?

__acting as a shock absorber and providing nutrients to the brain and spinal
cord___ (1 mark)

d.with an aid of the diagram explain 2 differences between the motor and sensory
neuron

(5marks)
13.Figure 6 is a diagram showing a synapse between two nerve cells. Use it to
answer the questions that follow.

a. Use an arrow to indicate the direction of the nerve impulse in the diagram.

(1mark)

b. State any three function of the synapse to the work of neurons.

__acting as a valve

Preventing low frequency impulses from passing through

__ (3mark)

c. Explain one effect of smoking Indian hemp to the nervous system.

It impairs the transmission of the nerve impulse_____ (2 marks)

Figure 7 is a diagram of a nerve cell. Use it to answer the questions that follow:
a. Name the parts marked T and S.

_____T is the mylein sheath and S is axon_ (2 marks)

b. Name the type of nerve cell shown in Figure 8.

_motor neuron___ (1 mark)

c. Explain what could happen if the cell body was damaged.

_no action will be taken by the effectors_ (2 marks)

d. Explain any one adaptation that enables the nerve cell to conduct impulses at
high speed.

__it has mylein sheath that act as an insulator preventing interference that may
affect the transmission of nerve impulses___ (2 marks)

14.(a) State any two examples of cranial reflex action.

_blinking and sneezing (2 marks)

b) State the function of central canal in spinal cord.

____it contains the cerebral spinal final fluid ___ (1 mark)

c) State two structural differences between a motor neurone and sensory

neurone.
__sensory neuron has a dendron while motor doesn't have.
Cell body is on the sides of the sensory neuron and along the nerve fibre in
the motor neuron_(2 marks)
Essay questions

15} Write an essay on the problems associated with nervous system

Polio.caused by avirus attacts the sensory neuron ther by affexting the transmission
of the nerve impulses to the central nervous system

Meningitis.is caused when the menenges layer is attached by virus.it affects the
transmission of the nerve impulses. Characterised by stiffness of the neck

Multiple sceoliris.is the condition where by the mylein sheath is deatroyed. This
results is slow transmission of the nerve impulses_

Cerebral malaria.occurs when the plasmodium matures in the cerebrum.that affect

the transmission of the nerve impulses in the brain.

Paralysis.this condition leads to the in the ineffectiveness in the transmission of

nerve impulses in the muscles.

10marks)

16} Discuss five differences between nervous and hormonal coordination

On composition; nervous system is made of neurons while Hormonal

system is made of secretory cells.

Message transmission in nervous system are transmitted in form of

electrical impulse while in hormonal they are transmitted in form of
chemicals called hormones.

Messages in nervous system travel quickly while Messages in hormonal

system travel slowly.

Mode of message transmission in nervous system are transmitted along

nerve fibres while Messages in hormonal system are transmitted
through blood system.

Duration of effect of message in nervous system lasts for a short time

while effect of the message in hormonal system lasts longer

OR

While endocrine system is slow, nervous impulse is immediate/rapid.

Hormones are transported chemically through blood, nervous impulses

are transported electrochemically through nerve fibres.

Hormones affect different organs of the body and has a widespread

effect, while nervous impulses afeect only a particular part of the body.
Hormonal effect is long lasting whereas nervous effect is short lived.

Hormones can bring about a metabolic change but nervous impulse

impulses cannot bring about a metabolic change.

17} Write an essay on effects of time of a day on memorizing a list of

words, you should include materials, procedure , results & conclusion.

On materials collect Textbook, student, stop watch and experimenter.

As a procedures, let the student collect the textbook for memorization

and tell the student to start studying the list of words for the maximum
time of 2 hours. The experimenter or supervisor should set questions
from the list of words the student has memorized and give them to the
student.

Observe how he or she performs and repeat the steps but for this
time with maximum of 6 hours and observe how he or she performs.

On expected results you will find that The marks that the student will
get will be different depending on the time he/she spends on
memorizing a list of words.
In conclusion, The more time you spend on memorizing a list of words,
the more the brain stores information so that memorization can be
modified according to past experience.

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