HSC Biology notes Mod 8: Non-infectious disease and disorders  Homeostasis IQ: How is an organism’s internal environment maintained in response to a changing external environment?  • Construct and interpret negative feedback loops that 

show homeostasis by using a range of sources including 

Homeostasis- similar state eg. Body temp, glucose levels, blood pressure, iron etc. Not conscious decision. Body can monitor, analyse and adjust.   Body control of homeostasis involves: Stimulus - Initial change in environment internal or external) Receptors - detects change Control centre - Analyses change eg. Brain, spinal cord Effectors - Carry out reaction to the change e.g. muscle, glands 

Response - reaction to the initial change    

• Investigate the various mechanisms used by organisms to maintain their internal environment within tolerance limits including 

- Trends and patterns in behavioural, structural and physiological adaptations one endotherms that assist in maintaining homeostasis 

Adaptation type 

Name of endotherm 

Adaptation  Explanation 

Structural   Australian fur seal 

Fur  Woolly underfur traps in the heat and insulates internal temperatures, preventing heat from escaping. 

Bilby  Large, thin ears  Large thin surface area in ears allows more blood to flow, allowing the heat to radiate to the external environment, therefore maintaining homeostasis.  

Behavioural  Mountain pygmy possum 

Curls up in a ball and draws in appendages 

By reducing surface area, you are reducing blood flow to the extremities, therefore reducing exposure to the cold, therefore reducing heat loss, therefore maintaining homeostatic blood temperature. 

Spinifex hopping mouse 

Dig burrow in desert habitat  

By seeking shelter, sun exposure is being reduce, reducing heat exposure, therefore maintaining homeostasis.  

Physiological  Fairy penguin  Restricts blood flow to feet 

Heat moves from hotter to colder, therefore heat would be lost to the external cold environment. To counteract this, the fairy penguin reduces blood to the feet, therefore conserving internal body heat from being lost, maintaining homeostasis. 

Red kangaroo  Vasodilation of capillaries close to forearm surface 

Vasodilation allows more blood to flow, as the forearm capillaries are close to the surface this increased blood flow allows for heat to radiate and be lost to the external environment, reducing internal temperature, therefore maintaining homeostasis.  

  - Internal coordination systems that allow homeostasis to be maintained, including hormones and 

neural pathways  Hormones 

- Produced in glands and transported around the body in the circulatory/lymph system glucagon  

- Maintains glucose levels (blood sugar) - Made in the pancreas - Reduces glucose consumption by the liver  - Works with insulin  - Too much can cause a rare cancer 

 Neural pathways 

- The nervous system works to regulate and maintain an animals internal environment and response to the external environment.   

- It works with another system called the endocrine system which produces hormones in response to certain stimuli. These two systems are essential to maintain homeostasis. 

- A nerve impulse can be detected as a change in voltage. The impulse is transmitted as a wave of electrical changes that travel along the cell membrane of the neuron.   

central nervous system (CNS) - The control centre for all body responses - Coordinates all responses  

Made of the brain and the spinal cord - Receives, interprets and initiates a response.   

peripheral nervous system (PNS) - Branching system of nerves  - Connects receptors and effectors  - Transmits messages to and from the CNS 

    - Mechanisms in plants that allow water balance to be maintained 

Controlled stomata opening and closing The plant controls when opens its stomata to the early morning and late afternoon (cooler temperature; sunlight less intense) and closes in the heat of the day, avoiding dehydration. 

Thick, waxy cuticle The plants have thick cuticles which reduce the internal temperature by insulating the water from excessive sunlight, thus reducing the rate of evaporation and potential dehydration. 

 

eg. Eucalyptus tree  

eg. Eucalyptus and Banksia  

Shiny Leaves The plants have shiny leaves that help reflect sunlight energy, reduce the internal temperature, minimise the rate of transpiration and help minimise dehydration. 

Hairs on leaf and stem The plant has hairs on its leaves and stem that help trap a thin layer of humid air, reducing diffusion of water out of the plant’s cell, reducing transpiration and minimising dehydration. 

 

eg. Eucalyptus plants   eg. paper daisy  

Leaf Fall The plants drop their leaves during the hot and dry summer, therefore lowering the total surface area of the tree exposed, minimising the heat that is absorbed, lowering the rate of transpiration is lowered and reducing its risk of dehydration. 

Hanging leaf orientation The plant has its leaves hanging in a vertical position, so it reduces the surface area in which the leaves are exposed to the sun’s heat in the middle of the day when it is higher overhead. This reduces the tree’s risk of dehydration. 

 

eg. eucalyptus tree  

 

eg. eucalyptus tree  

Curling of leaves The plant curls its leaves when temperature is high, reducing the air flow across the stomate which are located on the inside of the roll, as well as trapping a thin layer of humid air in the coil. Both mechanisms help reduce transpiration and possible dehydration. 

CAM Pathway The plant uses the CAM pathway to close its stomata during the heat of the day and open it during night to get CO2. The plant has large vacuoles to store the CO2 until it photosynthesises in the sunlight of the day. This minimises water loss via the stomata. 

eg. Flax Lily   eg. Stag Horn Fern 

  

Causes and effects (depth study) IQ: Do non-infectious diseases cause more deaths than infectious diseases?  Non- infectious disease - not caused by pathogens and not transmitted from one organism to another (non-communicable)  • Investigate the causes and effects of non-infectious diseases in humans, including but not limited 

to: - Genetic diseases 

Caused by a mutation of the genes or chromosomes of an individual. Also a result of abnormal cell division by mitosis or meiosis resulting in an incorrect number of chromosomes or abnormal chromosomes. Eg. Cystic fibrosis (gene mutation) 

- Diseases caused by environmental exposure Can be lifestyle disease (eg. CD or smoking-related diseases), diseases caused by physical factors (eg. Skin cancer from exercise UV exposure), or disease caused by chemical exposure in the environment (eg. Lead poisoning) 

- Nutritional diseases Caused by diets lacking proper nutritional balance. Can also be phycological conditions that lead to inappropriate diets (anorexia nervosa or bulimia nervosa). This imbalance can lead to malnutrition. Can be undernutrition (EG. Iron deficiency) or overnutrition (obesity) 

- Cancer Abnormal cells divide in an uncontrollable way. Can invade body tissue, spread a 

Melanoma (environmental) 

Treatment- Stage 0-2 (localised) can be treated through surgery. Stage 3 (in nearby lymph nodes or tissue) can also be treated by surgery, removing affected lymph nodes and tissue as well as additional treatments eg. radiation therapy, chemotherapy immunotherapy or targeted therapy. 

Management- Palliative treatment aims to manage symptoms of melanoma. Slows the spread of the cancer. Includes radiation or drug therapy. Palliative treatment includes a team of professionals to meet your physical, practical, emotional, spiritual and social needs. 

Future research- Cells in melanoma tutors have high levels of BET proteins, which turn on genes that help grow and become cancerous. New drugs can inhibit the BET proteins and kill some melanomas. nd disrupt normal body functioning. Cell division controlled by genes in DNA: DNA repair genes (code for proteins that stop cell cycle while other proteins remove and replace damaged DNA), Proto-oncogenes (code for proteins the stimulate cell growth and mitosis) and Tumor suppressor genes (code for proteins that slow down or stop cell growth and mitosis, and cell death). Mutations in these genes cause cells to not differentiate, and grow rapidly creating tumors.  

Non-infectious disease 

Definition  Example  Cause  Effects 

Genetic disease 

Something that is inherited 

Trisomy 21 Caused by trisomy 21 (3 chromosome 21’s) caused by abnormal cell division.  

Heart defects, hearing/vision problems, learning problems, and facial features. 

Environmental disease  

Disease caused by factor in the environment  

Hay fever  Allergic reaction to allergens in the environment.  

cold-like signs and symptoms, such as a runny nose, itchy eyes, congestion, sneezing and sinus pressure 

Nutritional disease 

Lack or excess of nutrient either micro or macro 

Iron deficiency  Blood loss, lack of iron in diet, inability to absorb iron or pregnancy 

Fatigue, pale skin, brittle nails and muscle pain 

Cancer  Uncontrollable cell division  

Melonoma  Likely combination of environmental and genetic factors.  

Illness and death 

  • Collect and represent data to show the incidence, prevalence and mortality rates of non-infectious 

diseases, for example  Incidence- number of new cases of a disease reported over a specific time period Prevalence- number of people in a particular population with a specific disease Mortality- number of deaths due to a particular disease in a specific time period Morbidity- number of cases of the disease  Can be used to determine:  ● Trends associated with particular diseases ● Whether certain groups are more susceptible to particular disease ● Weather methods in use for preventing and treating the disease are successful ● Pathway for research and areas to concentrate on in terms of public health  

- Nutritional diseases 

- Diseases caused by environmental exposure   Epidemiology IQ: Why are epidemiological studies used?  Epidemiology- study of disease in a population that asks how many, who, where, when, how and why. Uses numbers, ratios, proportions and rates.   • Analyse patterns of non-infectious diseases in populations, including their incidence and 

prevalence, including but not limited to - Nutritional diseases              - Diseases caused by environmental diseases      

  • Investigate the treatment/management, and possible direction for future research, of a 

non-infectious disease using an example from one non-infectious diseases categorise listed above  Treatment- the administration of remedies (pharmaceutical, behavioural, surgical) to a person suffering from a disease with the aim to cure Management- care and attention given to an individual suffering from a disease. It may include treatment, but often focuses on quality of life where cure is improbable. 

• Evaluate the method used in an example of an epidemiological study Epidemiological study: Skin cancer/melanoma A study conducted by 2 research groups in 2016 on Melanoma in Australia. Group 1 (cohort study) followed 

a group of people from 3 high schools from year 12 to age 50. For each student they recorded current 

state of health, exposure to environmental and nutritional factors. The group was split into 2- high UV 

radiation exposure and low UV radiation exposure. Participants were checked annually and data would 

give correlation between UV exposure and melanoma. Group 2 went to three hospitals and surveyed all 

admitted patients. They divided people into two groups- those with melanoma and those without. They 

recorded all patients current state of health, exposure to environmental an nutritional factors. They then 

compared the number of people in each group who had high exposure to UV radiation and determined if 

the data showed a correlation between exposure to UV radiation and melanoma. 

 

11. A) what type of study was carried out by group 1? Cohort B) Identify one problem associated with this type of study. It takes a long time to get results as melanoma especially usually develops later in life, years after exposure.  12. A) what type of study was carried out by group 2? Case control B) Identify one problem associated with this type of study. They are subject to systematic errors- bias shifting results away from true results due to selection or information bias  • Evaluate, using examples, the benefits of engaging in an epidemiological study ● Help determine cause of disease and which populations are affected eg. Through epidemiological 

studies we know that Melanoma is caused by high UV exposure and develops later in life putting men (on average work more outdoor jobs) and people over 50 at greater risk 

● Guides the development of strategies to control disease and improve public health eg. Identifies risks of melanoma and enables public health campaigns to promote the strategies to reduce these risks through limiting sun exposure 

● Evaluates the effectiveness of strategies in place to treat/control disease eg. We now know that although incidence in melanoma is still increasing mortality rates have plateaued indicating effectiveness of melanoma treatment 

 Prevention IQ: How can non-infectious diseases be prevented?  

• Use secondary sources to evaluate the effectiveness of current 

disease-prevention methods and develop strategies for the prevention of a non-infectious disease, including but not limited to 

 Disease prevention improves quality of life and overall health and wellbeing of a population as well as reduces financial burden on the individual and health system. Incidence of non-infectious disease has increased. In 2014-15 50% of Australians had at least one chronic condition and 23% had two or more. Such as Arthritis, asthma, back pain, cancer, cardiovascular disease, chronic obstructive pulmonary disease, diabetes and mental health conditions.   Government legislation - asbestos legislation In 2003 the Australian government completely banned all asbestos as it can lead to asbestosis, lung cancer and mesothelioma. Use of asbestos can lead to fines of up to $7,500 or $15,000 for companies, showing the severe enforcement of this law to increase public health safety and reduce incidence of non-infectious disease.  - Educational programs and campaigns Many non-infectious diseases are lifestyle related diseases, educational programs an campaigns provide information and education about the effects of disease and the risk factors for disease and how to reduce those risk factors often through healthy diet, exercise and reducing risks such as smoking and drinking.  Educational program - Crunch and sip By educating primary school age student K-6 on the benefits of a healthy diet through both theory and practical education, they can be informed to make healthier choices to recuse their risk of lifestyle diseases such as diabetes, childhood obesity and cardiovascular disease.  Campaign - Quit campaigns Encourages people to stop smoking through ads and increasing public awareness of the dangers of smoking, reducing incidence of the lung cancer associated with smoking.  - Genetic engineering The ability to manipulate genes has enabled us to prevent certain non-infectious diseases.   Golden rice Genetically engineered ‘golden rice’ contains a gene from corn and soil bacterium which produces beta-carotene which can be used by the body to produce vitamin A. Half a million children suffer from blindness due to vitamin A deficiency in Africa and Asia which could be prevented with ‘golden rice’.     

Technology and disorders IQ: How can technologies be used to assist people who experience disorders?  • Explain a range of causes of disorders by investigating the structures and 

functions of the relevant organs, for example 

• Investigate technologies that are used to assist with the effects pf a disorder, including but not limited to 

 - Hearing loss  Pinna- collects and funnels sound waves to ear canal and drum Ear drum- sound energy hits ear drum causing it to vibrate Ossicles- ear drum vibrates ossicles causing energy to amplify Cochlea- stirrup (ossicle) causes cochlea fluid to move Cochlea hairs- fluid moves hairs (cilia) Auditory nerve- hairs detect and convert into electrical impulses to travel to brain to be processed  Causes Age- high frequency hairs at front of cochlea are more exposed and therefor degenerate first causing high frequency hearing loss with age  - Hearing loss: cochlear implants- used for severe to profoundly deaf people with missing or damaged hair cells in cochlea. Worn externally to detect and convert sound to digital code then into electrical impulses send by electrodes into cochlea. Impulses directly stimulate the cochlea and are recognised by the brain. Cochlea must still function to work.  Bone conduction implants- Used for outer or middle ear problems. Uses external sound processor attached with titanium implant that is surgicall Type of hearing problem  Location of the source of problem  Possible causes 

Conductive hearing loss  Outer or middle - vibrations aren’t transferred  

Object (eg earwax) preventing vibration, burst eardrum 

Sensorineural hearing loss  Inner - cilia/nerve not detecting and converting 

Loss of cochlea hair function 

Auditory processing disorder  Brain - can’t decode  Genetic, problem during foetal development 

Mixed hearing loss  Both conductive and sensorineural   y placed in bone behind ear. Detects and converts sound mot vibration which are transferred directly to cochlea. Inner ear and cochlea must still function to work.  Hearing aids- Electronic devices the amplify sounds entering external ear. Microphone detect and converts sound to electrical signal directing sound into external ear. Can be programmed and used for mild hearing loss. Technology  Pros  Cons 

Cochlea implant  Helps severe hearing loss, replaces outer, middle and inner ear 

Expensive and invasive, does not fully reproduce sounds 

Bone conductor implant  Can be trialled before surgery  Invasive, relies on battery, 

Hearing aid  Relatively cheap, improves hearing, easily controlled, non-invasive 

Only for mild hearing loss, background noise, doesn’t pick up all frequencies 

   - Visual disorders  Refractive surfaces in eye focus light to retina to send images to brain.  

Name of disorder  Myopic (short sighted)  Hyperopic (long sighted) 

Vision  Blurry vision for objects far away  Blurry vision for objects close 

Where does light focus?  In front of retina  Behind the retina 

Cause of the disorder  Shape of eye too long or curve of cornea too steep 

Shape of eye is too short or curve of cornea too flat 

  Astigmatism Where light focuses in multiple points making vision blurry  Corneal- cornea is asymmetrical Lenticular- curve is asymmetrical  Presbyopia As we age, sense stiffens making eye cilary muscles work harder to pull eye to focus on objects. Occurs in 40’s.  Glasses and contacts Used to correct refractive errors. Hyperopia uses convex lenses and myopia concave lenses to refract light to hit the retina. Presbyopia often requires multi-focal’s. Astigmatisms require sense with varied curvature to counteract the asymmetry of the cornea.    Laser surgery LASIK- Uses cool lasers to correct refractive errors. Short procedure where eye is numbed with local anaesthetic, eye lid held open by device, ultra thin flap is made in top 

surface or cornea using laser, cool laser then removes corneal tissue to correct shape of cornea before closing flap and covering eye for the next day.  Disadvantages - risk of vision loss, flap may become displaced or break, dry eye, more expensive and invasive Advantages - improved vision, fast healing, don’t have to wear glasses  - Loss of kidney function  Kidney failure also known as end-stage kidney disease (ESKD) refers to both kidneys being unable to effectively balance salads and water in blood and remove waste and is life threatening. When developed slowly over time is called chronic kidney failure, when occurs suddenly is acute kidney failure. Can be caused by  - Trauma - Diabetes - High blood pressure - Medullary cystic disease - Acute or chronic kidney disease (AKD & CKD) - Medications - Polycystic kidney disease - Glomerulonephritis (inflammation of glomerulus often due to infection eg HIV)  - Kidney dialysis Preferred treatment for kidney disease is a kidney transplant however is often hard to get. Kidney dialysis is a life-prolonging treatment. Most common form is haemodialysis. Needs to be done at least three times per week lasting for 4-5 hours. Involves patients blood being pumped through dialyser where blood passes through many semi-permeable tubes surrounded by dialysate (fluid). Allows small substances (waste) to pass by diffusion to cleanse/dialyse blood of waste to regulate homeostasis.   Benefits  Limitations 

- Keeps patients alive - Maintains homeostasis of body fluids - Not painful 

- Time consuming - Invasive - Expensive - Restricts lifestyle - Risk of infection - Not 100% effective (does not cure)