Unit 1 F214 Communication, homeostasis and energy
Module1: Communication and homeostasis
Name:
Target grade:
Module 1 4.1.1 Communication
Learning outcomes
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
transmission
Compare and contrast the structure and function of
myelinated and non-myelinated neurones;
Describe, with the aid of diagrams, the structure of a
cholinergic synapse;
In
class
Notes
Practice Revision
exam
questions
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 role
Explain 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 (insulindependent) 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 mellitus
Outline the hormonal and nervous mechanisms
involved in the control of heart rate in humans.
End of topic test Communication:
Mark: /30
%:
Grade:
%:
Grade:
WWW
EBI
End of topic test nerves
Mark: /30
WWW
EBI
End of topic test hormones
Mark: /30
%:
Grade:
WWW
EBI
End of Module1: Communication and homeostasis test
Mark: /50
WWW
EBI
%:
Grade:
Module 1 4.1.1-4 Communication
OCR Book pages 4-11
Extension reading: Biological Sciences review articles: Homeostasis May 2000
Keywords:
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 system
7. 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
Example
adaptation
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:
Receptor
Processing
centre
Effector
Effect
Thermoregulation
Thermoregulation
Thermoregulation
Thermoregulation
Thermo receptors in
skin and
hypothalamus
Thermo receptors in
skin and
hypothalamus
Thermo receptors in
skin and
hypothalamus
Thermo receptors in
skin and
hypothalamus
Skeletal muscle
Liver and muscle
tissue
Smooth muscle in
skin and blood
vessels
Hair erector muscles
muscles
If TOO HOT:
Receptor
Processing
centre
Effector
Thermoregulation
Thermoreceptors in
skin and
hypothalamus
Thermoregulation
Thermoreceptors in
skin and
hypothalamus
Thermoregulation
Thermoreceptors in
skin and
hypothalamus
Thermoregulation
Thermoreceptors in
skin and
hypothalamus
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 Communication
19. 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 Nerves
OCR Book pages 12-21
Extension reading: Biological Sciences review articles:
Refractory period April 2008
Pacinian 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 summation
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. 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
Chemoreceptor
Volatile chemicals
Chemoreceptor
Soluble chemicals
Mechanoreceptor
Vibrations
Photoreceptor
Light
Thermoreceptor
Heat/cold
Pressure receptor
Pressure on skin
Proprioreceptor
Receptor
Energy change
detected
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 12-13
Neurones are cells specialised to transmit electrical signals of nerve impulses very quickly
from one part of the body to another.
a.
b.
c.
d.
What features of a neurone are typical of Eukaryotic cells?
What types of neurone are there and what are their functions?
Draw and label a motor and sensory neurone
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 14
a. 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 14-15
a. 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
Order
Voltage-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 cell
K+ 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 16a. Complete the following:
b. Axons and dendrons have cells wrapped
c.
d.
e.
f.
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
___________________________________
What is the function of the myelin sheath?
What is saltatory conduction?
What are the advantages of salutatory
conduction?
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 voltagegated channels open
3) 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 cell
5) 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 15
a. 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.mcgrawhill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.h
tml
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 14,21
Action 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 21
a. Compare the structure and function of myelinated and non-myelinated neurones by
producing a table with comparative points
Answer:
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.
c.
d.
e.
f.
g.
h.
i.
j.
What is a synapse?
What is the synaptic cleft?
What is a neurotransmitter?
What is a cholinergic synapse?
How is the presynaptic knob adapted to its function?
How is the post synaptic membrane adapted to its function?
What is acetylcholinesterase?
Why is it important that the synaptic cleft contains acetylcholinesterase?
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 20
a. 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 in the right direction?.
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 Hormones
OCR 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 above
b. 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.
a.
b.
c.
Describe the functions of the adrenal glands: pages 22-23
Where are the adrenal glands?
Describe the structure of the adrenal glands.
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 22-3
a. 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?
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.
5. Describe, with the aid of diagrams and photographs, the histology of the pancreas, and
outline its role: page 24
a. 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.
Rise in blood
glucose
concentration
Glucose
concentration
falls
Normal blood glucose concentration:
Glucose
concentration
increases
Fall in blood
glucose
concentration
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.
1
2
3
4
5
6
7
8. Compare and contrast the causes of Type 1 (insulin-dependent) and Type 2 (non-insulindependent) diabetes mellitus page 27
a. 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
9. Discuss the use of insulin produced by genetically modified bacteria, and the potential use
of stem cells, to treat diabetes mellitus page 27
a. 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 potential
f. 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 rate
ii.
The effect of a high pH on heart rate
iii.
The effect of high blood pressure on heart rate
iv.
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 section
12. Request the exam questions for this module as a final check of your understanding.
THE END
HOW WELL PREPARED ARE YOU FOR YOUR TEST???
WWW/EBI