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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 systemNeuronSynapseNeurotransmitterResting potentialAction potential

2. State the name and function of each of the labeled structures of this motor neuron.

A = DendriteFunction:

B = Function:

C= Function:

D = Function:

E = Function: speeds up propagation of action potential and saves energy

F = Function:

Ms. Fargo Stephen Taylor Bandung International School


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 causesVoltage-gated Na+ channels“all or nothing response”K+ channelsRefractory 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 systemHormoneGlandTarget cellHomeostasisNegative feedback

8. State the function of the following hormones

InsulinGlucagonAdrenalinTestosteroneFSHLHOestrogenProgesteroneHCGOxytocin

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 IICause

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 effectorThrough: 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.



K ey: S a lty B itte r S w eet S o u r

C o o lin g th e to n g u e tip

D ec rease in te m p eratu re from 3 5 ºC In c rease in tem p era tu re fro m 2 0 ºC

m o d era te

w eak

ju std e tec tab le

Tast

e in

tens

ity fe

lt/ a

rbitr

ary

units

W a rm in g th e to n g u e tip

3 5 2 5 2 0 2 5 2 0 3 0 2 0 3 5 2 0 4 03 5 2 0 3 5 1 5 3 5 1 0 3 5 5

[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.

Taste in te n sity fe lt/ a rb itra ry u n its

m o d era te

w eak

ju s t d e te c tab le

sw ee t d e tec ted so u r d e tec ted

K ey: A B

(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 Cited1. 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 AssessmentCriterion 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

Objective3understanding

All answers for the following command terms correct: Most answers for the following command terms correct:

Analyse Comment Compare Construct Deduce Derive Design Determine DiscussEvaluate Explain Predict Show Solve Sketch Suggest

Logic, notation, mathematical

workingNA

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):


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