Unit 1 F214 Communication, homeostasis and energyModule1: Communication and homeostasis

Name: Target grade:Module 1 4.1.1 Communication Learning outcomes In

classNotes Practice

exam questions

Revision

Outline the need for communication systems within multicellular organisms, with reference to the need to respond to changes in the internal and external environment and to co-ordinate the activities of different organs;State that cells need to communicate with each other by a process called cell signalling;State that neuronal and hormonal systems are examples of cell signalling;Define the terms negative feedback, positive feedback and homeostasis;Explain the principles of homeostasis in terms of receptors, effectors and negative feedback;

Describe the physiological and behavioural responses that maintain a constant core body temperature in ectotherms and endotherms, with reference to peripheral temperature receptors, the hypothalamus and effectors in skin and muscles.

Module 1 4.1.2 Nerves Outline the roles of sensory receptors in mammals in converting different forms of energy into nerve impulses;Describe, with the aid of diagrams, the structure and functions of sensory and motor neurones;Describe and explain how the resting potential is established and maintained;Describe and explain how an action potential is generated;Describe and explain how an action potential is transmitted in a myelinated neurone, with reference to the roles of voltage-gated sodium ion and potassium ion channels;Interpret graphs of the voltage changes taking place during the generation and transmission of an action potential;Outline the significance of the frequency of impulse transmissionCompare and contrast the structure and function of myelinated and non-myelinated neurones;Describe, with the aid of diagrams, the structure of a cholinergic synapse;

Outline the role of neurotransmitters in the transmission of action potentials;Outline the roles of synapses in the nervous system.

4.1.3 Hormones Define the terms endocrine gland, exocrine gland, hormone and target tissue;Explain the meaning of the terms first messenger and second messenger, with reference to adrenaline and cyclic AMP (cAMP);Describe the functions of the adrenal glands;Describe, with the aid of diagrams and photographs, the histology of the pancreas, and outline its roleExplain how blood glucose concentration is regulated, with reference to insulin, glucagon and the liver;Outline how insulin secretion is controlled, with reference to potassium channels and calcium channels in beta cells;Compare and contrast the causes of Type 1 (insulin-dependent) and Type 2 (non-insulin-dependent) diabetes mellitus;Discuss the use of insulin produced by genetically modified bacteria, and the potential use of stem cells, to treat diabetes mellitusOutline the hormonal and nervous mechanisms involved in the control of heart rate in humans.

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End of topic test nerves

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End of topic test hormones

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End of Module1: Communication and homeostasis test

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Module 1 4.1.1-4 CommunicationOCR Book pages 4-11

Extension reading: Biological Sciences review articles: Homeostasis May 2000Keywords:

Homeostasis, stimulus, response, receptor, effector, excretion, cell signalling, Neuronal system, hormonal system, hormones, negative feedback, optimum, positive feedback, oxytocin, ectotherm, endotherm, physiological, anatomical, hypothalamus, arterioles.Tasks:

1. By the end of the unit you should have compiled a glossary to include all the key terms above, and any others that help you understand this module.

2. Why do cells need to maintain a certain limited set of conditions inside their cells?3. Define stimulus and response.4. Complete the word fill exercise on stimulus and response:

External environment:

All living organisms have an ______________environment that consists of the : ____________, _______________,____________________around them.

This external environment will change, as it changes it may place _______________on the living organism. Such as, a cooler environment will cause greater heat loss.

If the organism is to remain ______________ and ______________, the changes in the environment must be monitored and the organism must change its _____________ or _________________ to reduce the stress.

The environment change is a __________________ and the way in which the organism changes its behaviour or physiology is its _______________. The environment may change ______________, such as the seasons or Global warming

These changes will elicit a ____________ _____________. However the environment may change more __________________. The change (stimulus) must be ________________________the organism must respond to the change

Internal environment:

Most ________________ _______________have a range of tissues and organs. Many of these are not exposed to the external environment, they are protected by ______________ _______________and ______________. (e.g. skin and bark.)

In animals the internal cells and tissues are bathed in _____________________ _______________. This is the environment of the cells. As cells undergo their various _________________ ___________________they use up _______________ and produce _________________. Some of these may be unwanted or ___________________These substances ___________________ of the cells into the___________________________. Therefore, the activities of the cells alter their own environment. One waste product is ______________________If this is allowed to build up in the tissue fluid outside the cells it could disrupt the action of _____________________ by changing the __________________ of the environment around the cell. Accumulation of waste or toxins in this

internal environment must act as _______________________to cause removal of these wastes. This may act directly on the cells which __________________________________their activities so that less waste is produced. However, this response may not be good for the whole organism.

5. Find 2 examples of a stimulus and response to environmental changes and two for the internal environment.

6. State the key features of a good communication system7. Revise cell signalling from AS and summarise your understanding into 6 bullet points. (page

20-21) 8. Give a definition for Homeostasis and list some of the factors that need to be kept constant

in the body. 9. Define Negative feedback, draw a flow chart to explain and give an example. 10. Define positive feedback, draw a flow chart to explain and give an example.

EXTENSION: Can you give an example of positive feedback that is not harmful? 11. Give a definition for ectotherm and name 5 examples.12. Describe the advantages and disadvantages of being an ectotherm.13. Research your own behavioural and physiological adaptations of ectotherms and complete

into a table: Do not use the examples from the text book.

Adaptation How it helps regulate temperature Type of adaptation

Example

14. Give a definition for endotherm and name 5 examples. 15. Describe the advantages and disadvantages of being an endotherm. 16. Using the figure below: Summary of temperature regulation

a) What is the norm value for human body temperature? b) Using different colours, shade in and label the boxes in Figure 1 that represent the

stimulus receptors, control mechanism, effectors and responses involved in this example of homeostasis.

c) Which response by effectors occurs in humans but produces little effect and is more significant in most other mammals?

d) What behavioural changes could a person make to prevent their temperature dropping? e) Complete the tables To explain the responses if it is too hot or too cold:

If TOO COLD:

Thermoregulation Thermoregulation Thermoregulation Thermoregulation

Receptor Thermo receptors in skin and

hypothalamus

Thermo receptors in skin and

hypothalamus

Thermo receptors in skin and

hypothalamus

Thermo receptors in skin and

hypothalamus

Processing centre

Effector Skeletal muscle Liver and muscle tissue

Smooth muscle in skin and blood

vessels

Hair erector muscles muscles

Effect

If TOO HOT: Thermoregulation Thermoregulation Thermoregulation ThermoregulationReceptor Thermoreceptors in

skin and hypothalamus

Thermoreceptors in skin and

hypothalamus

Thermoreceptors in skin and

hypothalamus

Thermoreceptors in skin and

hypothalamus

Processing centre

Effector Skeletal muscle Liver and muscle tissue

Smooth muscle in skin and blood

vessels

Sweat glands in the skin

Effect

Summary of temperature

regulation

17. Complete review exam question on this attached 18. Review the Learning outcomes for Module 1 4.1.1-4 Communication19. Ask for the exam question pack for this module to be e-mailed to you to complete as final

review of this topic.

Module 1.1. 5-9 NervesOCR Book pages 12-21

Extension reading: Biological Sciences review articles: Refractory period April 2008Pacinian corpuscle January 200

Keywords:Sensory receptors, transducers, neurones, sensory neurones, motor neurones, polarised, depolarised,

hyperpolarised, generator potential, resting potential, action potential, voltage gated channels, threshold potential, repolarisation, refractory period, local currents, salutatory conduction, myelin

sheath, nodes of Ranvier, synapse, cholinergic, neurotransmitter, synaptic knob, presynaptic membrane, post synaptic membrane, acetylcholinesterase, exocytosis, synaptic cleft, summation,

temporal summation, spatial summationTasks:

1. By the end of the unit you should have compiled a glossary to include all the key terms above, and any others that help you understand this module.

2. Outline the roles of sensory receptors in mammals in converting different forms of energy into nerve impulses: page 12. a. Complete the table below to show the receptors and the energy changes they detect

Type of receptor Stimulated by Receptor Energy change detected

Chemoreceptor Volatile chemicals

Chemoreceptor Soluble chemicals

Mechanoreceptor Vibrations

Photoreceptor Light

Thermoreceptor Heat/cold

Pressure receptor Pressure on skin

Proprioreceptor Muscle length, and muscle tension,

b. What happens to the stimulus from all these receptors? What word is used to describe this?

3. Describe, with the aid of diagrams, the structure and functions of sensory and motor neurones: page 12-13Neurones are cells specialised to transmit electrical signals of nerve impulses very quickly from one part of the body to another.

a. What features of a neurone are typical of Eukaryotic cells? b. What types of neurone are there and what are their functions?c. Draw and label a motor and sensory neurone d. Describe how a motor neurone and a sensory neurone are adapted to their function:

State the adaptation and describe its function e. Complete the table to compare the structure, location and function of Motor and

Sensory neurones:

Motor Sensory

General structure

Location of cell body relative to

CNS

Dendrites

Axons

Function

4. Describe and explain how the resting potential is established and maintained: page 14a. SYNOPTIC: remind yourself here of AS: How can molecules move across

membranes? State the processes and the structures involved. b. What is the resting potential? c. What is the role of the organic anions inside the neurone? d. By what processes do the ions move across the membrane in a resting potential? e. Explain the changes in the potential difference during the resting potential by

producing a flow chart with 10 bullet points. These are the key words that should be used and explained: Resting potential, polarised, sodium-potassium pump, plasma membrane, permeable, diffusion, electrochemical gradients, negative potential, equilibrium, -70Mv, Na+ gated channels, K+ gated channels, protein channels

5. Describe and explain how an action potential is generated: page 14-15a. Give a definition for action potential b. What is a generator potential? c. Why are action potentials described as ‘all or nothing’? d. List the key words you would need to use and understand to describe an action

potential: e. Sort the statements in the table below to the correct order to ‘Describe how an action

potential is generated’:

Statement OrderVoltage-gated sodium ion channels open and many Na+ ions enter. As more Na+ ions enter, the more positively charged inside the cell becomes compared to outside.Na+ ion channels open and some Na+ ions diffuse into the cellK+ ions diffuse out of the cell, bringing the potential difference back to negative inside compared with the outside; this is repolarisation.The original potential difference is restored, so the cell returns to its resting state.The potential difference overshoots slightly, making the cell hyperpolarised.The membrane is at resting state; -60mV inside compared to outside: polarised.The Na+ ion channels shut and the K+ ion channels open.The membrane depolarises- it become less negative with respect to the outside and reaches the threshold potential of -50mV.The potential difference across the membrane reaches +40mV. The inside is now positive compared to the outside. This is the action potential

f. By what process in an action potential do the ions move across the membrane? g. What causes the voltage-gated channels to open in an action potential? h. After each action potential there is a period of time when another action

potential cannot be stimulated in a cell membrane. What is this known as and why is it important?

6. Describe and explain how an action potential is transmitted in a myelinated neurone, with reference to the roles of voltage-gated sodium ion and potassium ion channels: pages 16-a. Complete the following:b. Axons and dendrons have cells wrapped around them that nourish and protect

them, these are called ___________ ___________ In mammals these cells are wrapped many times around, producing multiple layers of the cell surface membrane which is called the _____________ _____________The gaps between the individual cells are called the ___________________________________

c. What is the function of the myelin sheath? d. What is saltatory conduction? e. What are the advantages of salutatory conduction? f. How does the action potential travel along the neurone? Sort the statements

below to explain:1) This creates a concentration gradient to the adjacent areas which have a low

concentration of sodium ions, causing the ions to diffuse along sideways to these areas 2) An action potential is generated at one point in the membrane as sodium voltage-

gated channels open3) The outside of the cell at that area to become more negative due to the loss of

positively-charged Na+ 4) As the Na+ ions enter the cell, the concentration at that point increases inside the cell5) Na+ ions diffuse into the cell as they are at a higher concentration outside the cell. This

depolarises the membrane at that point 6) This leads to another concentration gradient of sodium ions to the next area along the

membrane and the process repeats – transmitting the impulse all along the membrane

7) This in turn depolarises slightly that part of the membrane, causing the voltage-gated sodium channels to open in that area, so even more sodium ions diffuse into the cell, depolarising the membrane further – inducing an action potential

7. Interpret graphs of the voltage changes taking place during the generation and transmission of an action potential: page 15a. Onto the diagram below annotate to describe what is happening in the conduction of an

impulse. Ensure you include all of the following:Stimulus, Na/K pump, Threshold,Resting potential, action potential, Voltage dependent Na+ channels, Voltage dependent K+ channels, Polarised, depolarised, hyperpolarised, -50Mv, +40Mv, K+ Protein channel, refractory period

b. Look on line and find a good link that helps you visualise what is happening in the conduction of an impulse. E-mail any good ones to me to forward to the class. Look at these too, which we looked at in class:http://media.pearsoncmg.com/intl/snab_2009/topic_8/interactives/8_2/topic_8_2.html https://www.youtube.com/watch?v=YP_P6bYvEjE https://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html http://www.mrothery.co.uk/images/nerveimpulse.swf

c. What are A,B,C,D, E and F on the graph:

8. Outline the significance of the frequency of impulse transmission: pages 14,21Action potentials do not change in size as they travel – an action potential will always reach + 30 mV all the way along an axon. A neurone will either conduct an action potential or not; this is described as an ___________ ________________ _________. A stimulus at the higher intensity does not cause a larger impulse; they will cause the sensory neurons to produce more _________________ ______________so more frequent action potentials in the sensory neurone. This means more vesicles released at the synapse, a higher frequency of action potentials in the postsynaptic neurone and a higher frequency of impulses to the brain.

9. Compare and contrast the structure and function of myelinated and non-myelinated neurones: page 21a. Compare the structure and function of myelinated and non-myelinated neurones by

producing a table with comparative pointsAnswer:

Myelinated neurones Non-myelinated neurones

10. Describe, with the aid of diagrams, the structure of a cholinergic synapse: pages 18-19 Outline the role of neurotransmitters in the transmission of action potentials: page 19

a. Watch this link at any point during independent study, I would suggest at the beginning and at the end: http://media.pearsoncmg.com/intl/snab_2009/topic_8/interactives/8_4/ topic_8_4.html

b. What is a synapse? c. What is the synaptic cleft? d. What is a neurotransmitter? e. What is a cholinergic synapse? f. How is the presynaptic knob adapted to its function? g. How is the post synaptic membrane adapted to its function? h. What is acetylcholinesterase?

i. Why is it important that the synaptic cleft contains acetylcholinesterase? j. Onto the diagram below, with numbered points describe the ‘transmission of a signal across

the synaptic cleft from the arrival of the impulse’. Ensure the following key words are added/labelled/used: Synaptic knob, presynaptic membrane, post synaptic membrane, mitochondria, smooth endoplasmic reticulum, vesicle, acetylcholine, myelin sheath, calcium ion channel, Ca2+, Action potential, diffuse, exocytosis, receptor sites, sodium ion channels, generator potential, excitatory post synaptic potential, threshold, action potential, acetylcholinesterase,

11. Outline the roles of synapses in the nervous system: page 20a. What is the main role of synapses? b. Use the diagram below to explain synaptic

divergence:

c. Use the diagram below to explain synaptic convergence:.

d. How do synapses ensure signals are transmitted e. How do they filter out low level stimulus? Why is this important? f. Use the diagrams below to explain what summation is and the differences between

temporal and spatial summation:

g. Explain why we get used to a smell, or the aeroplanes flying above us, the class of chatty pupils. Why is this advantage?

h. Why is the creation of specific pathways important? 12. Review the Learning outcomes for Module 1.1. 5-9 Nerves WWW/EBI?13. Ask for the exam question pack for this module to be e-mailed to you to complete as final

review of this topic.

4.1.3 10-13 HormonesOCR Book pages 22-29

Extension reading: Biological Sciences review articles:

Keywords:Hormones, endocrine, target cells, adenyl cyclase, adrenal gland, adrenaline, alpha cells, beta

cells, pancreas, islets of Langerhans, insulin, hepatocytes, glycogenesis, gluconeogenesis, glycogenolysis, blood glucose concentration, cAMP, diabetes mellitus,Type I, Type II,

hyperglycaemia, hypoglycaemia, genetically engineered, stem cells, cell metabolism, myogenic, pacemaker, SAN,medulla oblongata, cardiovascular control centre, blood pressure, second

messenger.1. By the end of the unit you should have compiled a glossary to include all the key terms

above, and any others that help you understand this module.2. Define the terms endocrine gland, exocrine gland, hormone and target tissue: pages 22-23

a. Define these terms aboveb. Secretion is carried out by glands. There are two main categories of gland, compare in

the table below:

Endocrine Gland Exocrine Gland

c. Endocrine Glands On the diagram below identify some of the organs of the endocrine system and name some of the hormones they secrete

d. There are 2 types of hormone: Complete the table to compare:

Type of molecule

Can it pass through a membrane?

Location of receptor

Examples

3. Describe the functions of the adrenal glands: pages 22-23a. Where are the adrenal glands?b. Describe the structure of the adrenal glands.c. Using the diagram explain the roles of the adrenal medulla and the adrenal cortex

4. Explain the meaning of the terms first messenger and second messenger, with reference to adrenaline and cyclic AMP (cAMP): pages 22-3a. What is a first and second messenger?b. Use the diagram and your text book to explain how the hormone causes an effect inside

the cell?

5. Describe, with the aid of diagrams and photographs, the histology of the pancreas, and outline its role: page 24a. Where is the pancreas located?b. What is the role of the Pancreas?c. Find good diagrams and photographs to put into your independent learning pack to

show the histology of the Pancreas.d. Clearly label these diagrams to show you understand.

6. Explain how blood glucose concentration is regulated, with reference to insulin, glucagon and the liver: pages24-5

a. Complete the following diagram, showing how we are able to control blood sugar levels. Name the organ(s) where each stage occurs.

Adrenaline in the blood binds to a _____________________ receptor on the cell surface membrane. The adrenaline molecule is the _________

________________________. When it binds to the receptor it activates an enzyme called adenyl cyclase. The enzyme converts ATP to cAMP, which is the ___________________ ___________________ inside the cell.

The cAMP can then cause an effect inside the cell by activating enzyme action.

b. Define the following terms:

Term Definition Occurs when blood

concentration is HIGH

Occurs when blood

concentration is LOW

Glucose

Glycogen

Glucagon

Glycogenesis

Gluconeogenesis

Glycogenolysis

TIP: What does neo mean? Lysis mean?Genesis mean?

7. Outline how insulin secretion is controlled, with reference to potassium channels and calcium channels in beta cells: page 26

a. Complete the flow chart and add numbers to the diagram to show how insulin secretion by beta cells is regulated.

Rise in blood glucose

concentration

Glucose concentration

falls

Fall in blood glucose

concentration

Glucose concentration

increases

Normal blood glucose concentration:

8. Compare and contrast the causes of Type 1 (insulin-dependent) and Type 2 (non-insulin-dependent) diabetes mellitus page 27a. Complete a table to compare the 2 types of diabetes and their cure; ensure you have a

comparative statement e.g.

Type 1 diabetes is insulin-dependent diabetes

Type 11 diabetes is non-insulin-dependent diabetes.

b. Why is insulin injected rather than taken in tablet form?c. Complete the boxes to explain the shape of the curve: page 27

1

2

3

4

5

6

7

9. Discuss the use of insulin produced by genetically modified bacteria, and the potential use of stem cells, to treat diabetes mellitus page 27a. What are genetically engineered bacteria?b. What are stem cells?c. Describe the use of insulin produced by genetically modified bacteria.d. What are the advantages/issues?e. Describe the use of stem cells to produce insulin.f. What are the advantages/issues?

10. Outline the hormonal and nervous mechanisms involved in the control of heart rate in humans pages28-29

a. What is cell metabolism?b. Why is it important that the heart should be able to adapt its rate?c. Define myogenic?d. What is the pacemaker of the heart?e. Describe what happens when the pacemaker generates an action potentialf. What can affect the frequency of contraction of the pacemaker?g. What factors can affect heart rate?h. What is the cardiovascular centre?i. What hormone can affect the heart rate?j. Draw flow diagrams explaining :

i. The effect of a low pH on heart rateii. The effect of a high pH on heart rate

iii. The effect of high blood pressure on heart rateiv. The effect of low blood pressure on heart rate

k. Draw a time line explaining the development of pacemakers.11. Check the learning outcomes for this section12. Request the exam questions for this module as a final check of your understanding.

THE ENDHOW WELL PREPARED ARE YOU FOR YOUR TEST???

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