# Applied Science AQA/Homeostasis
## Topic Title

THIS TOPIC MIGHT BENEFIT FROM BREAKING UP INTO SMALLER CHUNKS.

### Setting Applied context

Health professionals need to be able to relate the principles of homeostasis to health and illness, and maintaining a patient’s homeostasis is one of the most important roles of a nurse. Many of the tests that a nurse performs on a patient, such as measuring temperature or blood pressure, determine whether the patient’s body is in homeostasis or in distress. Nurses need to know about the importance of maintaining insulin levels in people suffering from diabetes, in order to prevent severe consequences of blood sugar imbalance.
* Syllabus Content
* •    how homeostasis involves physiological control systems that maintain the internal environment within restricted limits:
* •    body temperature range (35.8 – 37.5 °C)
* •    blood glucose range (82 – 110 mg/dL)
* •    blood pH range (7.35 – 7.45)
* •    negative feedback as a homeostatic mechanism, eg controlling water retention using anti-diuretic hormone (ADH, also known as vasopressin) produced by the pituitary gland
* •    the role of different hormones in body function, including:
* •    insulin
* •    glucagon
* •    ADH
* •    aldosterone
* •    the roles of the pancreas and liver in regulating blood glucose concentration
* •    the body’s normal system for regulating blood glucose concentration:
* •    the action of insulin in activating enzymes to convert glucose to glycogen
* •    the action of glucagon in activating enzymes to convert glycogen to glucose
* •    the action of adrenaline in activating enzymes to convert glycogen to glucose
* •    the causes of Types I and II diabetes
* •    the control of Types I and II diabetes
* •    how health professionals and patients with diabetes use physiological measurements to inform diagnosis and treatment of diabetes, including the use of:
* •    fasting glucose levels
* •    urine dipsticks
* •    blood glucose ‘pinprick’ tests
* •    the roles of the hypothalamus, pituitary and ADH in osmoregulation
* •    the different parts of the nephron and their roles, including:
* •    Bowman’s capsule as an ultrafiltration unit
* •    convoluted tubules in selective reabsorption of glucose, sodium ions and water
* •    the roles of the adrenal cortex, convoluted tubules and aldosterone in the reabsorption of sodium ions
* •    the consequences of sodium chloride (salt) deficiency in the short term, and the long-term effects on health
* •    the circumstances in which certain people may be at risk of losing too much salt
* •    why excess salt in the diet might create health problems
* •    the consequences of excess/deficiency of ions and hormones on health.

### Exploration of key ideas (must be original text, not C&P) – level checked by AQA

In general, point students towards the approach to take, as opposed to just giving them information.

#### Concept 1 - Physiological control systems

The body temperature is kept constant (from 35.8 - 37.5°C). This is done through the hypothalamus in the brain which detects changes in the temperature of the blood. The body has a range of systems that can regulate temperature, For Example, Hairs on the skin can stand upright to reduce heat loss or glands on the skin secrete sweat to increase heat loss through evaporation.
Blood Gluscose range is kept constant from 82-110 mg/dl through insulin being secreted into the blood via the pancreas, this makes the liver convert the gluscose glycogen, this makes the glusacose level go down, conversely when gluscose levels are too low the pancreas releasees glucagon this causes the cells in the liver to turn glycogen into glucose, this causes the gluscose levels to rise, this is an example of negative feedback
Blood pH range is kept constant (7.35-7.45) through breathing, skin and urine. This is done through breathing by the release of CO$_2$ which rids the body of acid but also when you hyperventilate you breathe in too much and increase the alkaline concentration. This is also done through the Skin via sweat and urine by the release of Urea which decreases the acidic concentration of the blood.

#### Concept 2 - Roles of Hormones

explanation 2

#### Concept 3

explanation 3

#### Concept 4

explanation 4

### Study Task

Work to do to understand this topic e.g. research, analysis

### Careers and Organisations

Carry out some research into these jobs in this area. (Feel free to add other jobs you find.)
| Research these roles: | What are the benefits of this role to society? | What organisations would employ someone in this role?  (Where would they work?) | What would someone in this role have to do within the organisation? | What scientifically-related skills do they need to have?  What techniques do they need to have mastered? | What experience is needed to undertake this role and its responsibilities within an organisation? | What other science personnel will they work with in their organisation. |
| rseu | | | | | | |
| Job 2 | | | | | | |

### Relevant practical/s

– relating to criteria skills

### Quick questions

Example:
quick questions
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### Exam-style questions

– can we use old AQA qs… e.g. from more than 5 years ago? With Examiner comments
click to reveal answer

### Links

to other sections within this book
to good external websites (including AQA website, wikipedia, relevant applications / companies) - also considering links in spec

### References / Bibliography

of recommended text books
including mapped refs to existing books
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