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Title: Homeostasis
Description: The notes are an overall outlook onto homeostasis and feedback loops serrated into three case studies. Case study one focuses just on feedback loops, case study 2 does the same but within animals and case study three is an analysis of diabetes. The notes would be aimed for student completing senior school (10-12) and are useful to extract notes from. A bibliography is already provided and the addition of intent referencing

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TOPIC: Keeping the balance
Case  Study  1:  Feedback  loops  and  how  they  link  within  the  body  

 
Numerous  of  
molecular  and  
physiological  
processes  in  the  
body  are  
controlled  by  
what  is  known  as  
a  feedback  loop
...
     
 
They  work  
through  a  
“looping’  
process
...
 
 
 A  stimulus  produces  a  change  in  a  variable  within  the  body,  the  change  is  
detected  by  the  receptor
...
   Output  then  sends  the  information,  
along  an  efferent  path,  from  the  control  centre  to  the  effector  where  a  response  
from  the  effector  balances  out  the  original  stimulus  to  maintain  homeostasis
...
 
 
In  biology,  there  are  two  feedback  loops
...
 [NA/2016]  Negative  feedback  is  by  far  the  most  common  of  the  
two
...
 When  a  variable  changes  in  the  
body  to  make  the  temperature  rise  or  fall,  or  a  change  in  persons  blood  glucose  
concentration,  this  triggers  the  process  that  then  counteracts  the  body’s  change
...
 For  example,  “When  blood  sugar  rises,  insulin  sends  a  signal  to  the  
liver,  muscles  and  other  cells  to  store  the  excess  glucose
...
   When  certain  variables  in  the  body  change,  
positive  feedback  loops  acts  to  exacerbate  and  amplify  it
...
 Positive  feedback  
commonly  will  occur  during  a  women’s  pregnancy  or  the  causes  of  a  stroke
...
 It  is  a  
steroid  hormone,  
released  by  the  Corpus  Lutem
...
   It  causes  the  
endometrium  (lining  of  the  uterus)  to  ‘secrete  special  proteins  throughout  the  
second  half  of  the  menstrual  cycle,  where  from  there  it  prepares  to  receive  and  
nourish  an  implanted  fertilized  egg
...
’    [2016 National Women's Health
Resource Center,]  
If  a  fertilized  egg  is  implanted  within  the  endometrium,  progesterone  is  then  
produced  in  the  placenta  and  the  levels  remain  elevated  throughout  the  duration  
of  the  pregnancy
...
   
Progesterone  plays  a  key  role  in  feedback  loop
...
 Oestrogen  then  
stimulates  the  release  of  LH  (luteinizing hormone),  which  turns  in  turn  
controls,  the  production  of  progesterone
...
 [Encyclopaedia  Britannica,  2016]
...
 Progesterone  
levels  remain  high  unless  
the  egg  goes  unfertilized,  
in  which  case  the  egg  is  
re-­‐absorbed  and  
progesterone  levels  fall
...
 This  turning  
point  almost  always  occurs  14  days  after  ovulation
...
0  

58
...
5  

5
...
5  

78
...
5  

15
...
5  

24
...
0+5
...
5  
Water  losses=  46
...
5+15
...
5  
Water  gains-­‐  water  losses  =  -­‐2  
 
Mammal  2:  
Water  gains=  58
...
5=  63
...
5+15
...
5=  118
...
 From  this  given  data,  mammal  is  best  
adapted  to  living  in  the  dry  environment  due  to  it  only  requiring  2mL  of  water  to  
obtain  a  sufficient  water  level  in  comparison  to  Mammal  2’s  55mL
...
 The  data  shows  that  mammal  1  loses  most  of  it’s  water  through  
evaporation,  46
...
5mL
...
5mL  but  2  loses  15
...
 Mammal  1  loses  
15
...
5mL
...
 
The  kidneys  of  a  desert  mammal  must  have  a  longer  loops  of  Henle  to  make  the  
animals’  urine  as  concentrated  as  possible  and  to  limit  the  amount  of  water  and  
salt  they  loose  in  order  to  keep  their  bodies  hydrated  whilst  living  in  such  hot  
conditions
...
 As  urine  enters  the  descending  loop,  the  loop's  penetrable  
walls  absorb  water
...
”  [faculty
...
   
 
Desert  Mammal;  requires  a  small  glomerus  due  to  its  lack  of  nutrients  in  tis  
environment
...
 
With  a  lack  of  water,  the  animal  would  benefit  from  a  long  proximal  convoluted  
tubule  and  distal  tubule  as  this  allows  the  animal  to  reabsorb  more  water
...
 With  a  lack  of  water,  the  animal  would  benefit  from  a  long  
proximal  convoluted  tubule  and  distal  tubule  as  this  allows  the  animal  to  
reabsorb  more  water
...
 Due  to  the  animal  being  in  freshwater  a  
short  proximal  convoluted  tubule  and  distal  tubule  is  required
...
 In  analysing  the  data  
and  the  graph’s  trend,  it  is  evident  to  see  the  frog  leaves  the  water  in  days  90-­‐92  
as  the  data  shows  a  significant  decrease  in  ammonia  found  in  its  excretory  
material
...
   

   

For  the  tadpole  to  live  comfortable  within  the  water,  it  must  excrete  ammonia
...
 Ammonia  is  the  by-­‐
product  of  protein  metabolism  and  is  realised  through  the  gills  into  the  water
...
 
 
 

Another  suggestion  for  the  decrease  of  ammonia  may  be  due  to  the  size  of  the  
tadpole’s  kidney  changing  as  it  grows  into  a  frog
...
 The  tadpole  
excreted  ammonia  as  the  glomerulus  in  its  nephrons  are  small
...
 When  the  tadpole  
becomes  a  frog  and  it’s  glomeruli  is  larger,  their  excretory  material  is  filtered  
more  and  therefore  more  water  is  present
...
 Without  a  sufficient  amount  of  insulin,  glucose  builds  up
...
 Type  1  (  insulin  dependent)  ,  Type  2  (non  
insulin  dependent)  and  Gestational  Diabetes  (occurs  through  pregnancy  )
...
 Dr  Lesley  Russel,  gave  an  insight  to  this  
epidemic  stating  “  the  Australian  public  needed  to  be  made  much  more  fearful  of  
the  consequences  of  obesity  and  diabetes
...
5  million  people  in  
Australia  had  diabetes  and  2  million  had  pre-­‐diabetes
...
 
That’s  estimated  as  one  person  every  five  minutes
...
7  million  
Australians  have  diabetes
...
2  
million  known  and  registered)  as  well  as  silent,  undiagnosed  type  2  diabetes  (up  
to  500,000  estimated)
...
diabetesaustralia/2015]  The  WHO  projects  that  diabetes  
will  be  the  7th  leading  cause  of  death  by  2030
...
 Taking  into  
consideration  the  genetic  predisposition  of  a  person,  the  prevention  techniques  
may  differ  for  each  person
...
 [Polonsky,2001]  In  type  2  diabetes,  the  
pancreatic  cells  become  progressively  less  able  to  secrete  sufficient  insulin  to  
maintain  normal  carbohydrate  and  lipid  homeostasis
...
 Many  studies  show  that  lifestyle  changes,  such  as  losing  weight,  eating  
healthy  and  increasing  physical  activity  can  dramatically  reduce  the  progression  
of  type  2  diabetes  and  are  important  to  controlling  type  1  diabetes
...
 [American  Heart  Association,2016]  In  many  instances,  lifestyle  
changes  must  be  complemented  by  a  regimen  of  medication  to  then  control  
blood  glucose  levels,  high  blood  pressure  and  cholesterol
...
 With  the  overall  
rate  of  obesity  increasing,  
this  is  making  people  more  
susceptibility  to  developing  
diabetes
...
 More  than  two  thirds  
of  people  with  diabetes  in  
Africa  are  undiagnosed,  
Every  1  in  8  in  the  North  
America  and  Caribbean  
Region  has  diabetes,  Europe  
has  the  highest  prevalence  of  
children  living  with  type  1  diabetes,  In  South  East  Asia,  one  quarter  of  all  births  
are  affected  by  high  blood  glucose  in  pregnancy,  37%  of  all  adults  with  diabetes  
live  in  the  Western  Pacific,  In  the  Middle  East  and  North  Africa,  four  out  of  ten  
adults  with  diabetes  are  undiagnosed  and  By  2014,  the  number  of  people  with  
diabetes  will  increase  by  65%  in  South  and  Central  America  [International  
Diabetes  Federation  Diabetes  Atlas  Key  Findings/2015]
...
 With  this  major  increase  of  diabetes  on  
an  international  scale,  it  is  capable  of  coming  to  the  conclusion  of  diabetes  being  
a  worldwide  issue
...
 Type  2  diabetes  
can  be  reversed  with  a  change  in  lifestyle,  in  accordance  to  Medical  Express
...
 When  
teaching  Australian  public  about  the  prevalence  and  management  of  diabetes,  
the  topic  of  alcohol  and  tobacco  consumption  should  be  discussed  in  relation  too  
not  in  taking  any  of  the  substances
...
   
 
 
 
 
 
 
 
 

Bibliography:  
 
Evidence_Brief_Obesity_Prevalence_Trends_Australia  PDF:  
Australian Health Survey (also known as National Health Survey) 2011-12
http://www
...
gov
...
nsf/home/australian+health+s
urvey
Australian Aboriginal and Torres Strait Islander Health Survey 2012-13
http://www
...
gov
...
nsf/Lookup/4727
...
55
...
health
...
gov
...
html
NSW Population Health Survey 2010
http://www
...
nsw
...
au/surveys/adult/Pages/adult_results
...
health
...
gov
...
htm
Queensland Self Reported Health Status 2011-12
http://www
...
qld
...
au/epidemiology/documents/srhs-localgovarea2011-2012
...
oecd
...
htm
 
Diabetes globally
...
Diabetes globally
...
diabetesaustralia
...
au/diabetes-globally
...

Diabetes (AIHW)
...
Diabetes (AIHW)
...
aihw
...
au/diabetes/
...

Diabetes in Australia
...
Diabetes in Australia
...
diabetesaustralia
...
au/diabetes-in-australia
...

Examples of Negative Feedback
...
Examples of Negative Feedback
...
yourdictionary
...
html
...

BBC - GCSE Bitesize Science - Life goes on : Revision, Page 5
...
BBC GCSE Bitesize Science - Life goes on : Revision, Page 5
...
bbc
...
uk/schools/gcsebitesize/science/triple_ocr_gateway/the_l
iving_body/life_goes_on/revision/5/
...


Genetics of Diabetes and Its Complications
...
Genetics of Diabetes and
Its Complications
...
asnjournals
...
full#ref-7
...

Prevention & Treatment of Diabetes
...
Prevention & Treatment of
Diabetes
...
heart
...
jsp#
...
[Accessed 20 March
2016]
...
2016
...
[ONLINE] Available at:
http://www
...
org/condition/progesterone
...

Positive and Negative Feedback
...
Positive and Negative Feedback
...
mheducation
...
html
...

 
WHO  |  Diabetes
...
 WHO  |  Diabetes
...
who
...
 [Accessed  20  March  
2016]
...
 2016
...
 [ONLINE]  Available  at:  
http://medicalxpress
...
html
...
 
 
Annotated  Bibliographies:  
 
1
...
2016
...
[ONLINE] Available at:
http://www
...
gov
...
[Accessed 20 March 2016]
...
 The  article  gave  a  detailed  
description  into  why  diabetes  is  a  growing  epidemic  and  gave  past  and  present  
data  to  back  up  their  thesis  of  the  statement  being  true
...
 It  
gave  many  doctors  opinions  making  it  useful  to  reference  within  the  assignment
...
   
 
Validity  of  source:  

This  source  was  considered  to  be  valid
...
 With  the  use  of  
referencing  doctor’s  opinions  in  the  source,  it  makes  the  validity  easier  to  believe  
as  there  are  expert  opinions  within  the  source
...
 
Reference:  
WHO  |  Diabetes
...
 WHO  |  Diabetes
...
who
...
 [Accessed  20  March  
2016]
...
 
 
Description  of  Usefulness:  
The  information  was  useful  to  discuss  what  each  of  the  diabetes  types  are  and  
the  prevalence  of  them
...
 It  was  published  in  2015  making  it  very  
recent
...
 
 
 
3
...
 2016
...
 [ONLINE]  Available  at:  
http://medicalxpress
...
html
...
 
 
Outline  of  the  Article:  
Gives  an  outline  to  how  type  2  diabetes  can  be  prevented  and  reversed  with  
correct  diet  and  lifestyle
...
 It  was  published  in  2016  making  it  very  
recent
...
 With  this,  it  makes  it  vert  
evident  the  website  is  based  to  take  about  the  body  and  medical  topics
...
 
Reference:  
Genetics of Diabetes and Its Complications
...
Genetics of Diabetes and
Its Complications
...
asnjournals
...
full#ref-7
...

 
Outline  of  the  Article:  
Gives  an  outline  to  how  genetics  can  effect  a  person  chances  of  developing  
diabetes  and  discusses  options  to  keep  diabetes  under  control  
 
Description  of  Usefulness:  
The  information  was  useful  to  discuss  the  prevalence  of  diabetes  and  ways  onto  
making  sure  diabetes  either  doesn’t  get  worse  of  doesn’t  occur  at  all  as  well  as  
include  genetic  preposition
...
 It  was  published  in  2016  making  it  very  
recent
...
   With  this,  it  implies  that  it  
discuss  different  topics  for  study  
 
5
...
2016
...
[ONLINE] Available at:
https://www
...
com
...
[Accessed 20
March 2016]
...
 
 
Description  of  Usefulness:  
The  information  was  useful  to  discuss  the  overall  topic  of  diabetes  and  to  help  
provide  present  data  detail  on  diabetes
...
 It  was  published  in  2016  making  it  very  
recent
...
 
 
5
...
2016
...
[ONLINE] Available at:
https://www
...
com
...
[Accessed 20
March 2016]
...
 It  gave  
insight  into  the  diabetes  rates  in  other  countries  
 
Description  of  Usefulness:  
The  information  was  useful  to  compare  data  around  the  world  to  discover  if  
diabetes  is  a  national  or  international  epidemic  
 
Validity  of  source:  
This  source  was  considered  to  be  valid
...
   The  website  is  a  well-­‐known,  and  highly  recommended  site  when  
searching  for  information  on  diabetes,  making  it  very  valid
Title: Homeostasis
Description: The notes are an overall outlook onto homeostasis and feedback loops serrated into three case studies. Case study one focuses just on feedback loops, case study 2 does the same but within animals and case study three is an analysis of diabetes. The notes would be aimed for student completing senior school (10-12) and are useful to extract notes from. A bibliography is already provided and the addition of intent referencing