The document discusses homeostasis and how the body responds to exercise. It begins by explaining the concept of homeostasis as maintaining a constant internal environment despite external changes. It then asks the reader to: 1) Describe homeostatic mechanisms regulating heart rate, breathing rate, body temperature, and blood glucose levels. 2) Explain how these homeostatic responses change during exercise and how the body works to maintain homeostasis. 3) Evaluate the importance of homeostasis in maintaining healthy body functioning and what would happen if it did not occur. The document provides resources and additional content to help the reader complete the tasks, including describing specific homeostatic mechanisms, explaining how they relate to exercise, and discussing the consequences of losing homeostasis

1. TASK 4 HOMEOSTATIC
MECHANISMS AND THE
MAINTENANCE OF AN INTERNAL
ENVIRONMENT.
HOMEOSTASIS AND HOW THE BODY RESPONDS TO EXERCISE (P5, M2, D2)
 TO SECURE KNOWLEDGE BY EXPLAINING THE CONCEPT OF HOMEOSTASIS
 TO FURTHER DEVELOP KNOWLEDGE BY DISCUSSING THE PROBABLE HOMEOSTATIC RESPONSES TO CHANGES IN THE
INTERNAL ENVIRONMENT DURING EXERCISE
 TO SHOW EXCELLENCE BY EVALUATING THE IMPORTANCE OF HOMEOSTASIS IN MAINTAINING THE HEALTHY
FUNCTIONING OF THE BODY.

2. Task ref. Evidence
submitted
Page numbers or
description
P5 explain the concept of
homeostasis
M2 discuss the probable
homeostatic responses
to changes in the internal
environment during exercise
D2 evaluate the importance of
homeostasis in maintaining
the healthy functioning of the
body.
Additional comments to the Assessor:

3. HOMEOSTATIC MECHANISMS AND THE
MAINTENANCE OF AN INTERNAL
ENVIRONMENT.HOMEOSTASIS IS THE PROCESS OF MAINTAINING A CONSTANT INTERNAL ENVIRONMENT DESPITE
EXTERNAL CHANGES.
FOR THIS TASK YOU NEED TO;
(A) DESCRIBE THE HOMEOSTATIC MECHANISMS THAT REGULATE;
• HEART RATE
• BREATHING RATE
• BODY TEMPERATURE
• BLOOD GLUCOSE LEVELS.
INCLUDE ANNOTATED DIAGRAMS WITH SUPPORTING DESCRIPTIONS.
(B) EXPLAIN HOW THESE HOMEOSTATIC RESPONSES CHANGE IN THE INTERNAL ENVIRONMENT
DURING EXERCISE. USE THE SCENARIO GIVEN AND SHOW HOW THE BODY WORKS TO MAINTAIN
HOMEOSTASIS.
(C ) EXPLAIN THE IMPORTANCE OF HOMEOSTASIS IN MAINTAINING THE HEALTHY FUNCTIONING OF
THE BODY. WHAT WOULD HAPPEN IF HOMEOSTASIS DID NOT OCCUR? HOW WOULD THE BODY COPE?

4. RANGE OF CONTENT:
3 UNDERSTAND HOW HOMEOSTATIC
MECHANISMS OPERATE IN THE MAINTENANCE
OF AN INTERNAL ENVIRONMENT
• HOMEOSTASIS: DEFINITION OF HOMEOSTASIS, INTERNAL ENVIRONMENT, CONCEPT OF NEGATIVE
FEEDBACK AS A REGULATORY MECHANISM
• HOMEOSTATIC MECHANISMS FOR REGULATION OF: HEART RATE: ROLES OF INTERNAL RECEPTORS,
AUTONOMIC NERVOUS SYSTEM-SYMPATHETIC AND PARASYMPATHETIC NERVE SUPPLY, CARDIAC
CENTRE, SINOATRIAL NODE; EFFECTS OF INCREASED BODY TEMPERATURE AND ADRENALINE ON
• HEART RATE BREATHING RATE: ROLES OF INTERNAL RECEPTORS, AUTONOMIC NERVOUS SYSTEM –
SYMPATHETIC AND PARASYMPATHETIC NERVE SUPPLY, RESPIRATORY CENTRE, DIAPHRAGM AND
INTERCOSTAL MUSCLES BODY TEMPERATURE: PRODUCTION OF HEAT BY THE BODY, E.G. THROUGH
METABOLIC PROCESSES; LOSS OF HEAT BY THE BODY – RADIATION, CONDUCTION, CONVECTION,
EVAPORATION; ROLES OF HYPOTHALAMUS, AUTONOMIC NERVOUS SYSTEM – SYMPATHETIC AND
PARASYMPATHETIC, SKIN – ROLE OF ARTERIOLES AND SWEAT GLANDS; EFFECTS OF SHIVERING;
IMPLICATIONS OF SURFACE AREA TO VOLUME RATIOS, E.G. IN THE CARE OF BABIES; FEVER BLOOD
GLUCOSE LEVELS: ROLES OF PANCREAS, LIVER, INSULIN, GLUCAGON

5. A)HOMEOSTASIS IS…..
THE PROCESS OF MAINTAINING A CONSTANT
INTERNAL ENVIRONMENT DESPITE EXTERNAL
CHANGES.
• HEART RATE
• ROLE OF INTERNAL RECEPTORS
• ROLE OF AUTONOMIC NERVOUS SYSTEM
• EFFECTS OF BODY TEMPERATURE
• EFFECTS OF ADRENALINE
• BREATHING RATE
• ROLE OF INTERNAL RECEPTORS
• ROLE OF AUTONOMIC NERVOUS SYSTEM
• ROLE OF DIAPHRAGM AND INTERCOSTAL MUSCLES
• EFFECTS OF ADRENALINE
• BODY TEMPERATURE
• EFFECT OF METABOLIC PROCESSES
• ROLE OF THE SKIN
• HOW HEAT IS LOST
• ROLE OF AUTONOMIC NERVOUS SYSTEM
• BLOOD GLUCOSE
• ROLE OF PANCREAS
• ROLE OF LIVER
• EFFECTS OF INSULIN
• EFFECTS OF GLUCAGON
Watch the following video
http://study.com/academy/lesson/what-is-
homeostasis-definition-examples-quiz.html

6. HEART RATE EXPLAIN HOW EACH OF THE
FOLLOWING IS INVOLVED WITHIN
HOMEOSTASIS
• ROLE OF INTERNAL RECEPTORS
• WHAT ARE THEY? HOW DO THEY
WORK?
• HTTPS://WWW.BOUNDLESS.COM/PHYSIOLOG
Y/TEXTBOOKS/BOUNDLESS-ANATOMY-
AND-PHYSIOLOGY-
TEXTBOOK/INTRODUCTION-TO-HUMAN-
ANATOMY-AND-PHYSIOLOGY-
1/HOMEOSTASIS-32/HOMEOSTATIC-
CONTROL-284-3141/
• HTTP://WWW.NCBI.NLM.NIH.GOV/PUBMED/1
5255616
• HTTP://WWW.NURSINGTIMES.NET/CLINICAL
-SUBJECTS/RESPIRATORY/HOMEOSTASIS-
PART-1-ANATOMY-AND-
PHYSIOLOGY/203292.FULLARTICLE

7. HEART RATE
• ROLE OF AUTONOMIC NERVOUS
SYSTEM
• WHAT IS IT?
• HTTP://WWW.S-
COOL.CO.UK/GCSE/PE/HOW-THE-
BODY-IS-CONTROLLED/REVISE-
IT/THE-AUTONOMIC-NERVOUS-
SYSTEM

8. HEART RATE EXPLAIN HOW THE HEART RATE
AFFECTS EACH.
• EFFECTS OF BODY TEMPERATURE
BLOOD PRESSURE
THE HUMAN BODY USES HOMEOSTASIS TO REGULATE ITSELF
INTERNALLY, DESPITE WHATEVER ACTIVITY THE PERSON IS ENGAGED IN
OR ENVIRONMENTAL ISSUES HE IS ENCOUNTERING. BLOOD PRESSURE
REGULATION IS PART OF HOMEOSTASIS. A NORMAL BLOOD PRESSURE
SHOULD BE APPROXIMATELY 120 OVER 80, ACCORDING TO CREIGHTON
UNIVERSITY MEDICAL CENTER. DEPENDING ON THE OUTSIDE
TEMPERATURE, BLOOD VESSELS WILL EITHER DILATE OR CONTRACT. A
DILATION OF THE BLOOD VESSELS WILL CAUSE A DROP IN BLOOD
PRESSURE, AND THIS LOWERS BODY TEMPERATURE. CONTRACTING
VESSELS INCREASE BLOOD PRESSURE, RESULTING IN INCREASING CORE
TEMPERATURE.
• HTTP://WWW.LIVESTRONG.COM/ARTICLE/228784-THE-EFFECTS-
OF-BODY-TEMPERATURE-ON-HEART-RATE/
• EFFECTS OF ADRENALINE
ADRENALINE, ALSO CALLED EPINEPHRINE, IS A
HORMONE SECRETED BY YOUR ADRENAL
GLANDS, WHICH SIT ON TOP OF EACH OF YOUR
KIDNEYS. ONCE RELEASED BY THESE GLANDS,
ADRENALINE PRODUCES A VARIETY OF EFFECTS
ON YOUR BODY, INCLUDING INCREASES IN YOUR
HEART RATE. THESE EFFECTS ARE TRIGGERED
THROUGH INTERACTIONS WITH CERTAIN
PORTALS ON THE SURFACES OF YOUR CELLS
CALLED ADRENERGIC RECEPTORS.
• HTTP://WWW.LIVESTRONG.COM/ARTICLE/355
672-WHY-ADRENALINE-SPEEDS-UP-HEART-
RATE/

9. BREATHING RATE
EXPLAIN EACH OF THE FOLLOWING;
• ROLE OF INTERNAL RECEPTORS
• ROLE OF AUTONOMIC NERVOUS
SYSTEM
• ROLE OF DIAPHRAGM AND
INTERCOSTAL MUSCLES
• EFFECTS OF ADRENALINE

10. WHAT IS HAPPENING IN
THIS IMAGE?
HTTP://WWW.LIVESTRON
G.COM/ARTICLE/30209-
BREATHING-
REGULATED/

11. BODY TEMPERATURE
HTTP://WWW.BBC.CO.UK/SCHOOLS/GCSEBITESIZE/SCIENC
E/ADD_OCR_PRE_2011/HOMEOSTASIS/BODYTEMPREV1.SH
TML
• EFFECT OF METABOLIC PROCESSES
• ROLE OF THE SKIN
• HOW HEAT IS LOST
• ROLE OF AUTONOMIC NERVOUS SYSTEM
• THE HUMAN BODY IS DESIGNED TO FUNCTION MOST EFFICIENTLY AT 37ºC. THIS IS CONTROLLED TO MAINTAIN THE TEMPERATURE AT WHICH THE BODY’S
ENZYMES WORK BEST.
• IF YOU BECOME TOO HOT OR TOO COLD, THERE ARE WAYS IN WHICH YOUR BODY TEMPERATURE CAN BE CONTROLLED.
TOO HOT
WHEN WE GET TOO HOT:
• SWEAT GLANDS IN THE SKIN RELEASE MORE SWEAT. THE SWEAT EVAPORATES, REMOVING HEAT ENERGY FROM THE SKIN.
• BLOOD VESSELS LEADING TO THE SKIN CAPILLARIES BECOME WIDER - THEY DILATE - ALLOWING MORE BLOOD TO FLOW THROUGH THE SKIN, AND MORE HEAT TO
BE LOST.
TOO COLD
WHEN WE GET TOO COLD:
• MUSCLES CONTRACT RAPIDLY - WE SHIVER. THESE CONTRACTIONS NEED ENERGY FROM RESPIRATION, AND SOME OF THIS IS RELEASED AS HEAT.
• BLOOD VESSELS LEADING TO THE SKIN CAPILLARIES BECOME NARROWER - THEY CONSTRICT - LETTING LESS BLOOD FLOW THROUGH THE SKIN AND CONSERVING
HEAT IN THE BODY.
• THE SKIN
• THE HAIRS ON THE SKIN ALSO HELP TO CONTROL BODY TEMPERATURE. THEY LIE FLAT WHEN WE ARE WARM, AND RISE WHEN WE ARE COLD. THE HAIRS TRAP A
LAYER OF AIR ABOVE THE SKIN, WHICH HELPS TO INSULATE THE SKIN AGAINST HEAT LOSS.
• THE HYPOTHALAMUS IS THE PART OF THE BRAIN WHICH MONITORS THE BODY'S TEMPERATURE. IT RECEIVES INFORMATION FROM TEMPERATURE-SENSITIVE
RECEPTORS IN THE SKIN AND CIRCULATORY SYSTEM.
• THE HYPOTHALAMUS RESPONDS TO THIS INFORMATION BY SENDING NERVE IMPULSES TO EFFECTORS TO MAINTAIN BODY TEMPERATURE.

12. WATCH THE VIDEO
• HTTP://STUDY.COM/ACADEMY/LESS
ON/HOMEOSTASIS-AND-
TEMPERATURE-REGULATION-IN-
HUMANS.HTML

13. For example, if we become too cold, the hair erector muscles
contract. This raises the skin hairs and traps a layer of air next to the
skin.
Skin hairs lie flat when we are hot and stand upright when we are
cold

14. Negative feedback mechanisms
control body temperature. They
include the amount of:
•shivering (rapid muscle
contractions release heat)
•sweating (evaporation of water
in sweat causes cooling)
•blood flowing in the skin
capillaries

15. Too cold Too hot
Process Vasoconstriction Vasodilation
Arterioles Get narrower Get wider
Blood flow in skin capillaries Decreases Increases
Heat loss from skin Decreases Increases
Vasoconstriction and vasodilation
The amount of blood flowing through the skin capillaries is altered by vasoconstriction and vasodilation.

16. BLOOD GLUCOSE
• GLUCOSE IS NEEDED BY CELLS FOR
RESPIRATION. IT IS IMPORTANT THAT
THE CONCENTRATION OF GLUCOSE
IN THE BLOOD IS MAINTAINED AT A
CONSTANT LEVEL. INSULIN IS A
HORMONE - PRODUCED BY THE
PANCREAS - THAT REGULATES
GLUCOSE LEVELS IN THE BLOOD.
• BLOOD SUGAR LEVEL
• THIS IS CONTROLLED TO PROVIDE
CELLS WITH A CONSTANT SUPPLY OF
GLUCOSE FOR RESPIRATION. IT IS
CONTROLLED BY THE RELEASE AND
STORAGE OF GLUCOSE, WHICH IS IN
TURN CONTROLLED BY INSULIN.
Low glucose High glucose
Effect on pancreas
Insulin not secreted into the
blood
Insulin secreted into the
blood
Effect on liver
Does not convert glucose into
glycogen
Converts glucose into
glycogen
Effect on blood glucose level Increases Decreases
Action of insulin

17. http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel/
responses_to_environment/homeostasisrev6.shtml find out
more!

18. Diabetes
Diabetes is a condition in which the blood glucose levels remain too high.
It can be treated by injecting insulin. The extra insulin causes the liver to
convert glucose into glycogen, which reduces the blood glucose level.
There are two types of diabetes - Type 1 and Type 2.
Type 1 diabetes
Type 1 diabetes is caused by a lack of insulin. It can be controlled by:
•monitoring the diet
•injecting insulin
People with Type 1 diabetes have to monitor their blood sugar levels throughout
the day. Their levels of physical activity and their diet affect the amount of insulin
needed.
They can help to control their blood glucose level by being careful with their diet
(eating foods that will not cause big spikes in their blood sugar level) and by
exercising (which can lower blood glucose levels due to increased respiration in
the muscles).

19. Type 2 diabetes
Type 2 diabetes is caused by a
person’s body becoming
resistant to insulin. It can be
controlled by diet and exercise.
There is a link between rising
levels of obesity and increasing
levels of Type 2 diabetes.
Changes in obesity and Type 2 diabetes
Watch the video
http://study.com/academy/lesson/homeostasis-
glucose-levels-and-osmolarity-hormonal-
control.html

20. WATER CONTENT
• THIS IS CONTROLLED TO PROTECT
CELLS BY STOPPING TOO MUCH WATER
FROM ENTERING OR LEAVING THEM.
WATER CONTENT IS CONTROLLED BY
WATER LOSS FROM:
• THE LUNGS - WHEN WE EXHALE
• THE SKIN - BY SWEATING
• THE BODY - IN URINE PRODUCED BY
THE KIDNEYS
• HTTP://WWW.BBC.CO.UK/SCHOOLS/G
CSEBITESIZE/SCIENCE/ADD_OCR_PRE_
2011/HOMEOSTASIS/WATERBALREV1.
SHTML
• EXPLAIN WHAT IS HAPPENING IN
EACH ORGAN.

21. Negative feedback
Homeostatic control is achieved using negative feedback mechanisms:
•if the level of something rises, control systems reduce it again
•if the level of something falls, control systems raise it again

22. ADDITIONAL RESOURCES
• HTTP://WWW.BBC.CO.UK/EDUCATION
/GUIDES/Z4KHVCW/REVISION
• HTTP://WWW.S-
COOL.CO.UK/GCSE/BIOLOGY/HOMEO
STASIS/REVISE-IT/WHAT-IS-
HOMEOSTASIS
• HTTP://WWW.ABPISCHOOLS.ORG.UK/
PAGE/MODULES/HOMEOSTASIS_KIDN
EYS/INDEX.CFM?COSITENAVIGATION_
ALLTOPIC=1
• HTTP://WWW.BBC.CO.UK/BITESIZE/HI
GHER/BIOLOGY/CONTROL_REGULATI
ON/HOMEOSTATIC_CONTROL/REVISI
ON/1/
• HTTPS://WWW.YOUTUBE.COM/WATC
H?V=VB7TSHQR1EY

23. B)HOW AND WHY DO HOMEOSTATIC RESPONSES
CHANGE IN THE INTERNAL ENVIRONMENT DURING
EXERCISE. USE THE SCENARIO GIVEN AND SHOW
HOW THE BODY WORKS TO MAINTAIN
HOMEOSTASIS.• WHEN YOU SWEAT, BREATHE HEAVILY AND FEEL YOUR
HEART POUNDING, IT DOESN’T JUST MEAN YOU ARE
HAVING A GOOD WORKOUT. THESE PHYSIOLOGICAL
FACTORS ARE ALSO VITAL TO YOUR BODY
MAINTAINING A STATE OF HOMEOSTASIS.
HOMEOSTASIS IS DEFINED AS A CONSTANT, STEADY
ENVIRONMENT DESPITE EXTERNAL CHANGES, SUCH AS
EXERCISE. EXERCISE AFFECTS YOUR BODY
TEMPERATURE, BLOOD OXYGEN LEVELS, SUGAR
LEVELS AND HYDRATION – ALL PROPERTIES
NECESSARY FOR YOUR SURVIVAL. YOUR BODY USES
AN AUTOMATIC FEEDBACK SYSTEM TO PRESERVE
NORMAL TEMPERATURE AND WATER LEVELS, SO YOU
CAN KEEP EXERCISING. EAT PROPERLY AND DRINK
PLENTY OF FLUIDS TO HELP YOUR BODY MAINTAIN
HOMEOSTASIS.
Find out more at
http://www.livestrong.com/article/369714-how-
does-the-body-maintain-homeostasis-in-
response-to-exercise/

24. C) COMPLETE THE TABLE BELOW IN AS MUCH
DETAIL AS POSSIBLE WRITE UP IN A REPORT.
Body system How does
Homeostasis help
maintain the system?
What would happen
if homeostasis did
not occur? What
would go wrong?
How would the body
cope? What changes
would occur?
Cardiovascular
Respiratory
Digestive
Renal
Nervous
Muscular-skeletal
Immune/Lymph/
Endocrine
Reproductive