Essential Biology 6.5 Nerves, Hormones, Homeostasis / Due Date: /
Student Name: / Candidate Number:

1.  Define the following:

Central nervous system / The brain and spinal cord.
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:

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

· 

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 / Action potential
Also known as… / -polarisation / - polarisation
Internal potential is… (positive/ negative)
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

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.

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 / Low Blood Sugar
Pancreatic cells used / Beta cells
…which secrete…
… carried in blood to….
… causing conversion of..
… to …
Overall effect: / Glucose removed from blood / Glucose released into blood

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
Route / Direct from coordinator to effector / Through:
From:
To:
Signal type / Chemical
Time to take action / longer
Duration of effects

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.

[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)

(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.

(e) Compare the effects of sucrose on the A and B chemoreceptors by giving two similarities and two differences.

Similarities

Differences


(4)

(Total 10 marks)

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/06-human-health-physiology/nerves-hormones-homeostasis/.

2. Allott, Andrew. IB Study Guide: Biology for the IB Diploma. s.l.: Oxford University Press, 2007. 978-0-19-915143-1.

3. Mindorff, D and Allott, A. Biology Course Companion. Oxford: Oxford University Press, 2007. 978-099151240.

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/production-app2.ibo.org/publication/7/part/2/chapter/1.html.

Self Assessment:

Essential Biology / Assessment
Criterion / Complete (2) / Partially complete (1) / Self / MrT
Presentation & Organisation / NA / Complete and neat. All command terms highlighted, tables and diagrams well presented.
Academic Honesty / NA / Sources cited using the CSE (ISO 690 numerical) method, with Works Cited section complete and correct.
Objective 1 understanding / All answers for the following command terms correct: / Most answers for the following command terms correct:
Define Draw Label List Measure State
Objective 2 understanding / All answers for the following command terms correct: / Most answers for the following command terms correct:
Annotate Apply Calculate Describe Distinguish Estimate Identify Outline
Objective3
understanding / All answers for the following command terms correct: / Most answers for the following command terms correct:
Analyse Comment Compare Construct Deduce Derive Design Determine Discuss
Evaluate Explain Predict Show Solve Sketch Suggest
Logic, notation, mathematical working / NA / Answers are presented in a logical and concise manner. SI units used most times, with correct unit symbols and definitions of terms. All mathematical working shown.
Further research / NA / Evidence is apparent of research and reading beyond the textbook and presentations to find correct answers to challenging questions. If any questions are unanswered, this criterion scores zero.
Total (max 10):

Ms. Fargo

Stephen Taylor Bandung International School