Module 8: Non-Infectious diseases

Question 1

What is homeostasis?

Answer 1

The process by which the body maintains a constant internal environment, which is important as many bodily processes only work under certain conditions.

Question 2

What are tolerance limits?

Answer 2

The range of acceptable deviation of the internal environment of the body.

Question 3

What is the stimulus and respoinse model?

Answer 3

The body’s way of detecting a change in its external or internal environment, and its subsequent response.

Question 4

Steps of the stimulus response model?

Answer 4

1. Stimulus - Change in environment
2. Receptor - Recognise changes to internal condition
3. Control Centre - CNS (Brain and spinal cord) where information is interpreted to figure out how to respond.
4. Effector - What is involved in fixing imbalance, either muscles expanding/contracting or glands releasing a secretion.
5. Response

Question 5

How does the control centre send signals to effectors?

Answer 5

Either:
- The nervous system
Travels via electrical impulses along nerve cells
- Endocrine system
Through homones that act as chemical messengers travelling through blood

Question 6

What is the negative feedback loop?

Answer 6

Information produced by the feedback causes a reversal in the effect of the stimulus.

Question 7

What is thermoregulation?

Answer 7

Intenral regulation of an animal’s body temperature, which is crucial in maintaining the body’s bodily functions. It works through a negative feedback loop.

Question 8

Where are thermoreceptors found?

Answer 8

On the skin, which detect external temperature change and trigger frequently.
Also in the hypothalamus, as a cluster of temperature-sensitive cells which monitor the body’s internal temperature by measuring the temperature of the blood.

Question 9

What responses do we have to temperature decreases?

Answer 9

Physiological:
Piloerection (goosebumps) erect hairs on the skin, trapping air close to the skin and preventing heat loss via the convection of air.
Vasoconstriction causes less blood to travel near the skin’s surface, resulting in less heat being lost from the blood.
Muscle cells perform respiration in order to break down glucose to make energy. As respiration is an exothermic process, it releases heat, warming up the body.
Also, thyroid-stimulating hormones are secreted by the pituitary gland, acting on the thyroid gland to release thyroid hormones that increases metabolic processes.
Behavioural:
Seeking shelter
Putting on clothing
Increasing movement

Question 10

What responses do we have to temperature increases?

Answer 10

Physiological:
Vasodilation causes blood to actively lose heat to the environment.
Sweating comes from the eccrine and aprocine gland, which draws heat from the skin in order to evaporate the sweat.
Hypothalamus decreases secretion of thyroid hormone which reduces the rate of cellular respiration in the body’s organs.
Behavioural:
Decreased activity
Covering body in water
Move into shade

Question 11

How to plants maintain osmoregulation in dry environments?

Answer 11

If there is not a steady water supply, water loss, can result in plants losing their turgor, and dying. Plants can:
- Close their stomata, pores on the skin that allow for gas exchange between plant tissues and the environment, preventing transpiration which the the loss of water vapour in plants. Controlled by hormone abscisic acid, and typically closes when it is hottest.
- Waxy cuticle lines the exterior of plants that provides a waterproof barrier which helps reduce water loss.
- Vacuoles, organelles which store large amounts of water.

Question 12

What are the different classifications of plants based on their adaptations to the moistness of their environments?

Answer 12

Mesophytes: Adapted to neither wet or dry. E.g. Roses and Corn plants
Xerophytes - Adapted to arid environments. E.g. Eucalyptus tree, banksia, spinifex grass
Have fewer stomata, less potential for transpiration
Drooping leaves, sunked stomata and hairy leaves trap air around stomata and saturate air with moisture, further preventing water from being pulled out of the plant.
Hydrophytes - Adapted to wet environments. E.g. water lillies
Higher numbers of stomata
Large, flat leaves increases surface area to promote water loss.

Question 13

How do plant cells close stomata?

Answer 13

Decreasing water in guard cells causes them to go flacid, and close the gap. Uses absicsic acid hormone

Question 14

Why are salty environments harsh?

Answer 14

Due to osmosis, plants that exist in salty environments must combat the movement of water out of their roots into the salty surroundings. Also, excess salt can be toxic to cells.

Question 15

How do halphytes exist in salty environments?

Answer 15

Mechanisms include:
- Salt exclusion, where special tissues in roots and the lower stem stop salt from entering the plant but allow water uptake. For example, red and grey mangroves use this.
- Salt excretion, where plant actively concentrates salt which is then excreted through special glands on the leaves, which crystallises and is washed or blown away. Used by grey and river mangoves.
- Salt accumulation, where the plant deposits absorbed salt into older tissues like leaves, which are shed from the plant, removing the salt from the tree. Used by the milky mangrove.
- Mangrove soil also has low oxygen, so surface roots not only cover a large surface area in search of water, but allows cells to respire by sticking about the ground.

Question 16

What are the components of the nervous system?

Answer 16

CNS gathers information from all over the body and coordinates responses.
Peripheral NS are the neurones that connect the CNS to the rest of the body.

Question 17

Components of PNS?

Answer 17

Somatic:
Voluntary, conscious portion of the nervous system.
Made up of nerves that connect to:
- Skin
- Sensory organs
- Skeletal muscles
Its function is to process sensory information that arrives via external stimuli and coordinate voluntary movement.
Autonomic:
Involvuntary, uncscious poprtion pof the nevrous system.
Made up of nerves that connect to:
- Cardiac muscle in the heart
- Smooth muscle in the organs
It’s function is to control everything we don’t think about, like heart rate, digestion, sweating, pupil diameter.

Question 18

Components of the autonomic system?

Answer 18

Parasympathetic: (Rest and digest system)
Nervous system releases acetylcholine, a neurotransmitter that communicates the body to relax, slowing heart rate and digestive system to digest food.
Sympathetic: (FIght or Flight Response)
The nervous system releases adrenaline, a hormone that causes the heart to speed up to distribute oxygen to all of the body’s muscles, and stops digestion to focus energy towards survival.

Question 19

Different types of neurons, where they are found and function and important points on structure.

Answer 19

• Sensory neurons
  Part of somatic system, they carry electrical impulses from receptor to CNS. They have long dendrites as receive from receptor cells are far away from the brain.
• Motor neurons
  Somatic and autonomic system. Transmit electrical impulses from CNS to effectors. They have short dendrites but very long axons to carry received information to the effector cells. Like a backwards sensory neuron.
• Interneurons (relay or connector neuron)
  Found in CNS. They transmite electrical impulses between sensory and motor. They have many, short dendrites to carry nerve impulses from sensory to cell body and many short axons to carry impulses from cell body to motor neurons.

Question 20

What is a neuron and its structure?

Answer 20

Neurons are the functional units of the nervous system which carry signals around the body. They are made up of BDAMS.
B - Cell Body, main spherical part of neuron that contains nucleus.
D - Dendrites, the branches that extend off the cell body, and connect neurons. They are responsible for receiving information and passing it towards the cell body
A - Axon, long, thread-like projection responsible for carrying information away from the cell body.
M - Myelin sheath which coats the axon to protect and insulate it.
S - Synaptic knobs, branches at the end of the axon that connect to dendrites

Question 21

What is the endrocrine system? Specifics of hormones and an example.

Answer 21

Made up of a ground of glands which secrete hormones, small chemicals that cause a response in another region of the body. Hormones diffuse out of glands and into blood to be transported around the body. Hormones only bind to specific receptors found on target cells, where the number of recepters the target cell has, the more dramatic the response. Examples of an important hormone is insulin, which acts on liver, muscle and fat cells to maintain glucose levels.

Question 22

Endorcine vs nervous

Answer 22

Question 23

What is antidiuretic hormone?

Answer 23

ADH increases water reabsorption into the blood from the kidneys. This makes urine more concentrated as more water is retained than excreted.

Question 24

What are glands

Answer 24

Groups of hormone-secreting cells or organs.

Question 25

List (5) endocrine glands and the hormones they produce in the body

Answer 25

- Hypothalamus Controls many metabolic processes, determines whether internal conditions are being maintained and produces many hormones, such as TRH. - Pituitary gland Found in the brain and controlled by the hormone secretions of hypothalamus. Releases several hormones that regulate the secretion of hormones from other glands. - Pineal gland Found in the brain, it releases melatonin which helps control our circadian rhythms, telling us when to eat and sleep and is regulated by light levels. - Thymus Responsible for development of the immune system by secreting thymosin, which stimulates development of T cells. - Pancreas Found behind stomach, controls blood glucose levels through the hormones glucagon and insulin.

Question 26

How is the endocrine system stimulated?

Answer 26

Nerve impulse Change in concentration of hormone Change in concentration of substance in blood

Question 27

How is blood glucose controlled?

Answer 27

Constantly monitored by sensor cells in the pancreas.

Question 28

What happens when BGL is too high?

Answer 28

Beta cells in Islets of Langerhans in the pancreas release the hormone insuline when BGL gets too high, which travels to the liver and skeletal muscle cells. It can: - Stimulate the conversion of glucose into glycogen - When liver cells are filled with glycogen, insulin can convert glucose into fatty acids.

Question 28

What happens when BGL is too low?

Answer 28

Excess glucose is stored as glycogen in the liver and skeletal muscle cells. When sensor cells detect low BGL, alpha cells located in the Islets of Langerhans in the pancreas release glucagon into the bloodstream. When glucagon reaches liver and muscle cells, it attaches to receptors on the membranes of the cells, triggering enzymatic reactions that break glycogen down into glucose, which gets released into the bloodstream.

Question 29

What is cortisol?

Answer 29

A hormone produced by the adrenal glands that stimulates the breakdown of proteins into glucose, which is released during times of stress. This ensures the body is prepared if a fight or flight response is initiated.

Question 30

What are the types of non-infectious disease?

Answer 30

- Genetic disorders - Environmentally induced - Cancer - Nutritional disorders

Question 31

What is a genetic disorder? (example)

Answer 31

Altered or incorrect expression of a gene that causes disease is passed on. Example, cystic firbrosis caused by the a mutation in the CFTR gene causes the CFTR channel in the outer cell membrane to become faulty, causing sticky mucus to build up that leads to breathing problems and increases risk of infection.

Question 32

What are environmental exposure diseases?

Answer 32

Hypersensitivity reactions, overreaction of the immune system in respsonse to antigens in the environment. For example, allergies.

Question 33

What is cancer?

Answer 33

Group of diseases that involve unregulated and abnromal cell growth and divison. It can be caused by random mutations or environmental agents. Mutations can damage tumour-suppressor genes, increase cell division and suppress apoptosis function in the body, resulting in tumours. Mutagens that cause cancer are referred to carcinogens, such as tobacco smoke and UV radiation.

Question 34

What is a nutritional disorder and how can it take form?

Answer 34

A deficiency, imbalance or excess of carbs, fats and proteins, vitamins, minerals and water. Undernutrition can take form in: - Stunting - Wasting (low weight for height) - Underweight (low weight for age) Overnutrition can take form in: - Obsesity

Question 35

Info about lung disease

Answer 35

Lung cancer is the leading cause of cancer-related death in Australia. Cigarette smoking is the number one risk factor for lung cancer, and is linked to about 80% to 90% of lung cancer deaths. There is an estimated 12,700 new cases and 9000 deaths per year.

Question 36

What is epidemiology? What does it identify and help us with?

Answer 36

The study of the distribution, patterns and causes of disease in a population. Epidemiological studies identify assocaitions between risk factors and disease, helping us to make future predictions about disease distribution and helps shape preventative measures.

Question 37

What is prevalence?

Answer 37

The number of living people diagonosed with a disease at a given time.

Question 38

What is incidence?

Answer 38

The number of new cases of a disease DIAGNOSED within a specific time period.

Question 38

What is mortality?

Answer 38

The number of deaths occuring as a result of the disease during a specific time period.

Question 39

Pitfalls of epidemiology?

Answer 39

Fails to: - Provide a holistic view on health, focuses on physical health - Explain sociocultural factors that contribute to poor health - Explain the reasons why health inequalities exist It can show patterns and trends, but it does not explain the reasons behind these trends.

Question 39

Information about nutrional diseases?

Answer 39

In 2012, 806 million people (11.3%) of people worldwide were undernourished. This was 821 million people (10.9%) in 2017. In 1975, 4% of children were overweight/obese. This has risen to 18% of children in 2016.

Question 40

How is data collected in an epidemiological study, and how should it be improved? (5)

Answer 40

Typically collected through interviews and questionnaires. To improve the effectiveness, the following are crucial: - Large sample sizes and data sets reinforce the associations between a disease and investigated factors - Sampling method must broad not just in quantity, but demographically, so age, ethnicity, gender. - Experiments must be performed under controlled conditions to test the hypothesis - Final data should be peer reviewed - Further studies must be implemented to enhance the accuracy of the studies.

Question 41

What is passive immunotherapy?

Answer 41

Involves the administration of agents that are a natural component of the immune system. For example, monoclonal antibodies can be used, which reduce harm to healthy cells. The three main types are: - Standard Bind to specific antigens on cancer cells, which flag the cell to be destoyed by the immune system, or block active sites so they cannot proliferate. - Conjugated Attached to a drug, toxin, or radioactive particle. When a conjugated monoclonal antibody binds to a cancer cell, it is able to deliver the toxic substances into the cells and destroy them. - Bispecific Made up of two different monoclonal antibodies have two different binding sites. One is for a cancer cell and one is for an immune cell, allowing for the direct delivery of a cancerous cell to an immune cell that can destroy.

Question 42

How is cancer commonly treated?

Answer 42

- Chemotherapy Involves drugs which target and kill rapidly multiplying cells. However, some normal, healthy cells also grow quickly, such as bone marrow and hair follicle cells. As a result, these healthy cells are also destroyed and have a significant impact on the patient's health and wellbeing. - Radiotherapy Involves high doses of high energy radiation, which damages the DNA inside cancerous cells in the aim of kill cancer cells in a tumour. However, radiotherapy doesn't specifically target cancer cells, and damage to healthy cells in the surrounding tissue is unavoidable. - Surgery Physically removes a tumour from the body. However, it is often difficult to ensure that all cancer cells have been eliminated.

Question 43

What is cancer immunotherapy?

Answer 43

Treatment that harnesses the immune system in order to fight cancer. It is split into two types, passive and active.

Question 44

What is active immunotherapy?

Answer 44

Attemps to stimulate the patient's own immune system to attack cancer cells. These include: - Cancer Vaccines Contain antigens from cancer cells that produce memory cells against cancer cells. They an either be preventative or therapeutic.

Question 45

What is the ear divided into?

Answer 45

Outer Ear Middle Ear Inner Ear

Question 45

What does outer ear consist of?

Answer 45

- Pinna Fleshy, external tissue consisting of a flap of cartilage and skin. Funnels sound waves into the ear canal. - Ear Canal A passage comprised of skin and bone, that leads soundwaves to the eardrum - Ear drum Thin membrane between outer membrane and middle ear. Vibrates at the same frequency of sound waves that enter, transferring vibrations to the ossicles.

Question 45

What does the middle ear consist of?

Answer 45

- Ossicles Three tiny bones, malleus, incus and stapes (smallest bones in the body). They amplify and transmit vibrations from the eardrum to the oval window. - Oval Window Thin, flexible membrane that transmits vibrations from the stapes to the fluid in the cochlea. - Round Window Thin membrane between middle and inner ear that bulges outwards to allow for the equalisation of pressure in the cochlea when the oval window vibrates. - Eustachian tube Tube that connects middle ear to the pharynx at the back of the throat. It equalises air pressure on both sides of the eardrum so that it is not overly stretched.

Question 46

What does the inner ear consist of?

Answer 46

- Cochlea Fluid filled, snail shaped tube. This middle chamber of the cochlea consists of hair cells attached to the basilar membrane, referred to as the Organ of Corti. Hair cells act as sound receptors, as when they are bent, they generate nerve impulses. They get bent when the oval window vibrates, which vibrates the fluid in the cochlea, flexing the basilar membrane in response and bending the hair cells. - Vestibular apparatus Part of the cochlea, is involved in maintaining balance, not involved in detecting sound. - Auditory nerve The nerve impulse from the bent hairs is transmitted to the brain via the auditory nerve, so that the sound can be processed and interpreted.

Question 47

Types of hearing loss?

Answer 47

Conductive Sensorineural Auditory processing Tinnitus

Question 48

What is conductive hearing loss?

Answer 48

Deafness caused by damage to outer or middle ear. Results in reduced or muffled sound. Caused by: - Aging - Malformed structure at birth - Noise strain - Injury - Infection - Blockage during to earwax, tumour or foreign item Most can be corrected by surgery or medication

Question 49

What is sensorineural hearing loss?

Answer 49

Deafness caused by damage to inner ear/neural pathways. Results in faint or muffled sound. Caused by: - Malformed inner ear at birth - Exposure to damaging noise that kills hair cells in cochlea - Head injury Often can't be corrected.

Question 50

Treatments for hearing loss?

Answer 50

Hearing aids Bone conduction implant Cochlear implant

Question 50

What is auditory processing hearing loss?

Answer 50

Not due to damage or defects in structure of the ear. Instead, caused by processing problems in auditory areas of the brain, resulting in inability to detect the direction of a sound. Limited therapies to help treat.

Question 51

What is a hearing aid?

Answer 51

Battery powered electronic device that fits into the hollow outside of the ear canal. Microphone receives soundwaves and converts into electrical energy, while an amplifier makes sound waves stronger within the ear canal, thus the eardrum, ossicles and cochlead must still have an adequate level of function so sound can be registered and converted into signal. A receiver changes electrical energy to sound energy, and a speaker directs the sound energy into the ear canal. Used for people with conductive or sensoirneural hearing loss.

Question 51

What is tinnitus?

Answer 51

When you hear a ringing sound in the ears. Caused by: - Exposure to loud sound - Injury - Aging

Question 51

Pros and cons of hearing aids?

Answer 51

Pros: - Relatively cheap - Easy to install Cons: Amplify all sounds, including background noise, and can cause pain. Does not help people with severe inner ear or auditory nerve damage.

Question 52

What is a bone conduction implant?

Answer 52

Works by creating sound vibrations, conducted directly into the cochlea, thus treating conductive hearing loss.

Question 53

What are cochlear implants?

Answer 53

Used by people with severe hearing loss in any region. It converts sound into electrical signals and directly stimulates the auditory nerve. The microphone picks up sound, while a speech processor converts the sound into an electrical signal. Transmitting coil sends the message as a radio signal to the receiver, which is surgically implanted into skull, with fine wires that attach it to the cochlea.

Question 54

Pros and cons of cochlear implants:

Answer 54

Pros: Provides hearing to profoundly deaf people. Cons: Highly expensive Operation side effects (Infection, drooping face, numb tongue due to nerve damage) Wearer must learn to interpret sounds Success of implant is limited if auditory nerve or region of the brain is damaged

Question 55

How does the eye see?

Answer 55

Reflected visible light rays enter the eye through the pupil, pass through the lens and the jelly like fluid in the eye and detected by photoreceptors in the back of the eye, called the retina. When photoreceptors are activated, they generate nerve impulses that are sent to the brain via the optic nerve.

Question 56

Key structures of the eye?

Answer 56

- Iris Ring of pigmented muscle tissue, which works to control pupil size, and hence the amount of light entering the eye. Bright light can damage the photoreceptors in the eye, while dim light may not stimulate photoreceptors enough to form an image. - Lens Transparent biconvex protein disc, which adjusts its thickness to bend light so it focuses directly on the retina. The closer the object, the more light rays diverge and the more bending required. This is called accomodation. - Retina Thin layer of photoreceptor cells which line the inner back surface of the eye, specialised neurons that contain light-sensitive pigments called rods which work better at night and cones which work better at day. These receptors change their shape when exposed to light, and generate an electrochemical signal to be interpreted by the brain.

Question 57

Types of visual disorders?

Answer 57

Refractive errors - when light is not bent onto the retina properly so vision is blurred. - Myopia - Hyperopia Retina Conditions: - Retinopathy - Macular Degeneration - Colour blindness

Question 58

What is myopia?

Answer 58

Causes image to form in front of retina, short sightedness. Caused by a lens that is too thick or eyeball is too long.

Question 59

What is hyperopia?

Answer 59

Long sightedness, where image is focused behind the retina, caused by a lens that is too thin, or eyeball is too short.

Question 60

What is retinopathy?

Answer 60

Damage to the retina, caused by changes to blood vessels surrounding the region.

Question 61

What is colourblindess?

Answer 61

Occurs when one of the three types of colour detecting cone cells isn't working.

Question 61

What is macular degeneration?

Answer 61

Caused by distortion or absence of the fovea, one of the most sensitive parts of the retina. Dry macular degeneration is the most common, leading to gradual loss of central vision, while wet is caused by abnormal growth of blood vessels under the retina, leading to fluid leakage and sudden loss of vision.

Question 62

Treatments for visual disorders?

Answer 62

Glasses Laser Surgery

Question 63

How do glasses work?

Answer 63

They have lenses that are shaped for individual needs, compensating for misshapen eye lenses or eyeballs. Concave lenses are for myopia which causes light rays to diverge so the image forms further back, convex are for hyperopia, which causes light to converge, so the image forms further forward.

Question 64

How does laser eye surgery work?

Answer 64

Most common procedure is LASIK, where a laser is used to reshape the cornea, decreased curvature for myopia and increased curvature for hyperopia.

Question 65

Kidney structure?

Answer 65

Capsule is the protective outer covering of the kidney. Directly underneath is the cortext, while the light pink 'toe shaped' tissue is called the medulla. Cream coloured tissue is called the pelvis. The nephron is within the medulla, which acts as the main functional unit of the kidney.

Question 66

Kidney function how is it done?

Answer 66

Responsible for filtering the blood, and excreting the excess wastes, salts and water in order to maintain homeostasis. Blood enters the kidney through the renal artery, which flows towards glomerulus in nephrons. Blood pressure forces plasma out of the blood into the Bowman's capsule. The plasma, now called the filtrate, flows through the semi permeable tubules, where useful substances are passively reabsorbed into blood. By the end of the tubule, is a fluid called urine filled with urea, excess salt and water, which is removed via the ureter and stored in the bladder. Released by urethra in urination.

Question 67

Structure of nephrons?

Answer 67

Wrench shaped structure is called bowman's capsule, surrounding a dense clump of blood capillaries called glomerulus.

Question 68

Types of kidney disorders?

Answer 68

Glomerulonephritis Diabetic nephropathy Polycystic kidney disease Kidney stones

Question 69

Glomerulonephritis

Answer 69

Inflammation of the glomerulus, often occurs after a bacterial infection.

Question 70

Diabetic nephropathy

Answer 70

Kidney damage caused by diabetes, as kidneys become fatigued and damaged by strain. Results in less efficient removal of wastes and larger substances being filtered out of blood that shouldn't be.

Question 71

Kidney stones

Answer 71

When waste products crystallise into lumps, which are incredibly painfal and cause blockages. Factors that increase a person's risk are: - Dehydration - Poor diet - Hereditary factors

Question 72

Polycystic kidney disease

Answer 72

Causes cysts to grow in the kidneys, an inherited condition, which can enlarge and damage the kidneys.

Question 73

Treatments for kidney disorders

Answer 73

Dialysis Kidney transplants

Question 73

What is dialysis?

Answer 73

Removal of waste products and excess fluid from blood by an external machine called a dialyser. Blood is fed into the dialyser from an artery, where it flows through semi permeable tubing, and immersed in dialysing solution, filtering blood which is circulated back into the body through a vein.

Question 74

What is dialysing solution?

Answer 74

Higher concentration of glucose and ions to prevent diffusion. Low concentration of wastes to promote diffusion. The dialysing solution is continually replenished to maintain the concentration gradient.

Question 75

Pros and cons of dialysis?

Answer 75

Pros: - Improved quality of life Cons: - Time consuming, must be connected to dialysis for 2 hours two to three times a week. - Invasion into individual's blood vessels can cause blood clotting, bleeding and infections.

Question 76

Pros and cons of kidney transplants?

Answer 76

Pros: - Improved quality of life - Efficient procedure, with surgery only taking 2-3 hours and recovery only taking days. Cons: - Immunosuppresive drugs must be taken for the rest of the individual's life, leaving them vulnerable to future infections. - Long waiting lists