Download State that the nervous system consists of the central nervous system

6.5 Study Guide the Nervous System
Instructions: Read pages 173 to 184 in you IB Biology Textbook. Then define all the vocabulary words and Address all
the assessment statements below:
Vocabulary Words:
Central Nervous system
Peripheral Nervous system
Nerves
Neurons
Dendrites
Axon
Myelin sheath
Nodes of Ranvier
Motor end plates
Nerve Impulse
Resting potential
Action Potential
Depolarization
Repolarization
Relay neurons
Motor neurons
Synapsis
Synaptic transmission
Protein Channels
Sodium ions
Potassium ions
Active transport
Facilitated diffusion
Neurotransmitter
Ion channel
Vesicles
Exocytosis
Presynaptic neuron
Postsynaptic neuron
Homeostasis
Hypothalamus
Glucose
Glucagon
Insulin
Glycogen
Pancreas
Alpha Cells
Beta cells
Hydrolysis
Diabetes type I
Diabetes type 2
Assessment Statements:
6.5.1 State that the nervous system consists of the central nervous system (CNS) and peripheral nerves, and is
composed of cells called neurons that can carry rapid electrical impulses.
6.5.2 Draw and label a diagram of the structure of a motor neuron. Include dendrites, cell body with nucleus, axon,
myelin sheath, nodes of Ranvier and motor end plates.
6.5.3 State that nerve impulses are conducted from receptors to the CNS by sensory neurons, within the CNS by
relay neurons, and from the CNS to effectors by motor neurons.
6.5.4 Define resting potential and action potential (depolarization and repolarization).
6.5.5 Explain how a nerve impulse passes along a non-myelinated neuron. Include the movement of Na+ and K+
ions to create a resting potential and an action potential.
6.5.6 Explain the principles of synaptic transmission. Include the release, diffusion and binding of the
neurotransmitter, initiation of an action potential in the post-synaptic membrane, and subsequent removal
of the neurotransmitter.
6.5.7 State that the endocrine system consists of glands that release hormones that are transported in the blood.
6.5.8 State that homeostasis involves maintaining the internal environment between limits, including blood pH,
carbon dioxide concentration, blood glucose concentration, body temperature and water balance.
6.5.9 Explain that homeostasis involves monitoring levels of variables and correcting changes in levels by negative
feedback mechanisms.
6.5.10 Explain the control of body temperature, including the transfer of heat in blood, and the roles of the
hypothalamus, sweat glands, skin arterioles and shivering.
6.5.11 Explain the control of blood glucose concentration, including the roles of glucagon, insulin and α and β cells in
the pancreatic islets.
6.5.12 Distinguish between type I and type II diabetes.
Practice Questions (options):
1. Define the following:
Central nervous system
The brain and spinal cord. (1)
Peripheral nervous system
Neuron
Synapse
Neurotransmitter
Resting potential
Action potential
2. State the name and function of each of the labeled structures of this motor neuron.
A = Dendrite
Function:
B=
Function:
C=
Function:
D=
Function:
E=
Function: speeds up propagation of action potential and saves energy
F=
Function:
Essential Biology 6.5 Nerves, Hormones, Homeostasis
Due Date:
Candidate Number: 002171-
Student Name:
3. This diagram shows a simple reflex arc.
Identify the structures labeled A-D and state the actions 1-3.
A
B
C
D
1
2
3
4. Resting potential is the electrical potential across the membrane of a neuron that is not
conducting an impulse. It is used to repolarize (reset) a neuron in between impulses.
a. List two ions used in neurons.
b. Define electrical potential
c. State the specific method of membrane transport used to maintain resting potential
d. Explain how a resting potential is maintained, including why it is negative.
 Sodium ions are pumped out of the neuron
 By




Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 6.5 Nerves, Hormones, Homeostasis
Student Name:
Due Date:
Candidate Number: 002171-
5. Action potential (AP) is the depolarization and repolarization of the neuron to conduct an
electrical impulse.
a. Use the following cues to explain how an AP is transmitted along the neuron.
Resting potential
Is maintained through...
Depolarisation
Is trigged by…
Which causes
Voltage-gated Na+ channels
“all or nothing response”
K+ channels
Refractory period
b. Explain the significance of the labeled features of this graph, showing an action potential.
1
2
3
4
5
c. Outline how a one-way direction of nerve impulse is maintained.
d. Compare resting potential and action potentials.
Resting potential
Also known as…
-polarisation
Action potential
- polarisation
Internal potential is… (positive/ negative)
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 6.5 Nerves, Hormones, Homeostasis
Due Date:
Candidate Number: 002171-
Student Name:
Sodium ions are…
Potassium ions are…
Membrane proteins used
(voltage-gated sodium channels or sodium potassium pump?)
6. A synapse is a junction between neurons. This is a small gap between the terminal end of the
pre-synaptic neuron and the dendritic end of the post-synaptic neuron. The electrical signal of
the action potential is converted to a chemical signal, which passes across the synapse and
stimulates an action potential in the post-synaptic neuron. Whew.
a. Label these features of the synapse.
A
B
C
D
E
F
G
H
b. Explain the process of synaptic transmission, referring to all of the labeled structures above.
 AP reaches terminal end of pre-synaptic neuron
 This causes voltage-gated Ca2+ channels to open






Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 6.5 Nerves, Hormones, Homeostasis
Student Name:
Due Date:
Candidate Number: 002171-
c. Explain the need for high numbers of mitochondria in the pre-synaptic neuron.
d. Predict the effect of a drug which acts as a competitive inhibitor of a neurotransmitter.
7. Define the following.
Endocrine system
Hormone
Gland
Target cell
Homeostasis
Negative feedback
8. State the function of the following hormones
Insulin
Glucagon
Adrenalin
Testosterone
FSH
LH
Oestrogen
Progesterone
HCG
Oxytocin
9. List five internal conditions in the human body maintained through homeostasis.
10. Explain how homeostasis is based on a system of negative feedback control.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 6.5 Nerves, Hormones, Homeostasis
Student Name:
Due Date:
Candidate Number: 002171-
11. Complete the flow chart below to show how the hypothalamus controls body temperature
through hormones. What are the body’s responses?
12. Blood glucose levels are maintained by hormones produced in the pancreas.
Complete the table to show glucoregulation.
High Blood Sugar
Pancreatic cells used
Low Blood Sugar
Beta cells
…which secrete…
… carried in blood to….
&
… causing conversion of..
… to …
Overall effect:
Stephen Taylor
Glucose removed from blood
Bandung International School
Glucose released into blood
http://sciencevideos.wordpress.com
Essential Biology 6.5 Nerves, Hormones, Homeostasis
Student Name:
Due Date:
Candidate Number: 002171-
13. Diabetes mellitus is a disease in which regulation of blood glucose is difficult.
Distinguish between type I and type II diabetes.
Type I
Type II
Cause
Effect
Risk factors
Treatment
14. Explain how we can tell from this table that the patient is diabetic.
15. Distinguish between nerves and hormones.
Nerves
Hormones
Through:
Route
Direct from coordinator to effector
From:
To:
Signal type
Chemical
Time to take action
longer
Duration of effects
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 6.5 Nerves, Hormones, Homeostasis
Due Date:
Candidate Number: 002171-
Student Name:
16. Identify the part of the brain are nerve impulses converted to hormonal signals.
17. Complete the steps below to show how the nervous and endocrine systems work together to
regulate body temperature.
Stimulus
Sensory
neuron
Relay
Effector
Hormone 1
Gland
Target cells
Effect
Release of Thyroid hormone
Target cells
Effect
Data-based question practice, from the QuestionBank CDRom
18. The sense of taste is normally caused by the stimulation of chemoreceptors in the taste
buds of the tongue. There are four main 'tastes': sweet, salty, bitter and sour. The tongue
also has receptors for temperature. It is known that the taste of food can vary according
to whether it is cold, warm or hot. Scientists discovered that just warming or cooling parts
of the tongue, even when no food was present, also caused a sensation of taste.
Scientists experimented with a group of people. They gradually cooled the tips of
their tongues and measured the intensity of the taste felt by each member of the
group. The experiment was repeated, this time warming the tip of the tongue. The
graphs show the average values for the group.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 6.5 Nerves, Hormones, Homeostasis
Due Date:
Candidate Number: 002171-
Student Name:
Cooling the tongue tip
Warming the tongue tip
Taste intensity felt
/ arbitrary units
moderate
weak
just
detectable
35 25 35 20 35 15 35 10 35 5 20 25
Decrease in temperature from 35 ºC
Key:
Salty
Bitter
20 30
20 35
20 40
Increase in temperature from 20 ºC
Sweet
Sour
[Source: modified from Cruz and Green, Nature (2003) 403, page 889]
(a)
Identify which taste was felt most strongly when the tip of the tongue was
(i)
cooled:
(ii)
warmed:
(1)
(b)
Compare the effects on the taste of sweetness, of warming and cooling the tip
of the tongue.
(2)
(c)
It is important that such experiments use a population sample that is
representative. Suggest two biological criteria the scientists would have used to
select the people to be tested.
(1)
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 6.5 Nerves, Hormones, Homeostasis
Due Date:
Candidate Number: 002171-
Student Name:
(d)
Explain whether cooling or warming the tip of the tongue has the greater effect
on the sensation of taste.
(2)
The scientists discovered that there were two types of chemoreceptor in the tongue
tip. They called these A and B. They tested these chemoreceptors using solutions of
sucrose to find out the type of taste and the intensity felt. The results are shown in the
bar chart.
moderate
weak
Taste intensity felt
/ arbitrary units
just detectable
sweet detected
Key:
(e)
sour detected
A
B
Compare the effects of sucrose on the A and B chemoreceptors by giving two
similarities and two differences.
Similarities


Differences


(4)
(Total 10 marks)
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 6.5 Nerves, Hormones, Homeostasis
Student Name:
Due Date:
Candidate Number: 002171-
Works Cited
1. Taylor, Stephen. Nerves, Hormones and Homeostasis (presentation). Science Video Resources.
[Online] Wordpress, 2010. http://sciencevideos.wordpress.com/bis-ib-diploma-programme-biology/06human-health-physiology/nerves-hormones-homeostasis/.
2. Allott, Andrew. IB Study Guide: Biology for the IB Diploma. s.l. : Oxford University Press, 2007. 978-019-915143-1.
3. Mindorff, D and Allott, A. Biology Course Companion. Oxford : Oxford University Press, 2007. 978099151240.
4. Clegg, CJ. Biology for the IB Diploma. London : Hodder Murray, 2007. 978-0340926529.
5. Campbell N., Reece J., Taylor M., Simon. E. Biology Concepts and Connections. San Fransisco :
Pearson Benjamin Cummings, 2006. 0-8053-7160-5.
6. Burrell, John. Click4Biology. [Online] 2010. http://click4biology.info/.
7. IBO. Biology Subject Guide. [Online] 2007. http://xmltwo.ibo.org/publications/migrated/productionapp2.ibo.org/publication/7/part/2/chapter/1.html.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com