Module 8: Non-Infectious diseases Flashcards
Homeostasis Causes and Effects Epidemiology Prevention
What is homeostasis?
The process by which the body maintains a constant internal environment, which is important as many bodily processes only work under certain conditions.
What are tolerance limits?
The range of acceptable deviation of the internal environment of the body.
What is the stimulus and respoinse model?
The body’s way of detecting a change in its external or internal environment, and its subsequent response.
Steps of the stimulus response model?
- Stimulus - Change in environment
- Receptor - Recognise changes to internal condition
- Control Centre - CNS (Brain and spinal cord) where information is interpreted to figure out how to respond.
- Effector - What is involved in fixing imbalance, either muscles expanding/contracting or glands releasing a secretion.
- Response
How does the control centre send signals to effectors?
Either:
- The nervous system
Travels via electrical impulses along nerve cells
- Endocrine system
Through homones that act as chemical messengers travelling through blood
What is the negative feedback loop?
Information produced by the feedback causes a reversal in the effect of the stimulus.
What is thermoregulation?
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.
Where are thermoreceptors found?
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.
What responses do we have to temperature decreases?
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
What responses do we have to temperature increases?
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
How to plants maintain osmoregulation in dry environments?
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.
What are the different classifications of plants based on their adaptations to the moistness of their environments?
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.
How do plant cells close stomata?
Decreasing water in guard cells causes them to go flacid, and close the gap. Uses absicsic acid hormone
Why are salty environments harsh?
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.
How do halphytes exist in salty environments?
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.
What are the components of the nervous system?
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.
Components of PNS?
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.
Components of the autonomic system?
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.
Different types of neurons, where they are found and function and important points on structure.
- 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.
What is a neuron and its structure?
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
What is the endrocrine system? Specifics of hormones and an example.
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.
Endorcine vs nervous
What is antidiuretic hormone?
ADH increases water reabsorption into the blood from the kidneys. This makes urine more concentrated as more water is retained than excreted.
What are glands
Groups of hormone-secreting cells or organs.
List (5) endocrine glands and the hormones they produce in the body
- 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.
How is the endocrine system stimulated?
Nerve impulse
Change in concentration of hormone
Change in concentration of substance in blood
How is blood glucose controlled?
Constantly monitored by sensor cells in the pancreas.
What happens when BGL is too high?
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.
What happens when BGL is too low?
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.
What is cortisol?
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.
What are the types of non-infectious disease?
- Genetic disorders
- Environmentally induced
- Cancer
- Nutritional disorders
What is a genetic disorder? (example)
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.
What are environmental exposure diseases?
Hypersensitivity reactions, overreaction of the immune system in respsonse to antigens in the environment.
For example, allergies.
What is cancer?
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.
What is a nutritional disorder and how can it take form?
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
Info about lung disease
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.
What is epidemiology? What does it identify and help us with?
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.
What is prevalence?
The number of living people diagonosed with a disease at a given time.
What is incidence?
The number of new cases of a disease DIAGNOSED within a specific time period.
What is mortality?
The number of deaths occuring as a result of the disease during a specific time period.
Pitfalls of epidemiology?
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.
Information about nutrional diseases?
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.
How is data collected in an epidemiological study, and how should it be improved? (5)
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.
What is passive immunotherapy?
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.
How is cancer commonly treated?
- 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.
What is cancer immunotherapy?
Treatment that harnesses the immune system in order to fight cancer. It is split into two types, passive and active.
What is active immunotherapy?
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.
What is the ear divided into?
Outer Ear
Middle Ear
Inner Ear
What does outer ear consist of?
- 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.
What does the middle ear consist of?
- 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.
What does the inner ear consist of?
- 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.
Types of hearing loss?
Conductive
Sensorineural
Auditory processing
Tinnitus
What is conductive hearing loss?
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
What is sensorineural hearing loss?
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.
Treatments for hearing loss?
Hearing aids
Bone conduction implant
Cochlear implant
What is auditory processing hearing loss?
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.
What is a hearing aid?
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.
What is tinnitus?
When you hear a ringing sound in the ears. Caused by:
- Exposure to loud sound
- Injury
- Aging
Pros and cons of hearing aids?
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.
What is a bone conduction implant?
Works by creating sound vibrations, conducted directly into the cochlea, thus treating conductive hearing loss.
What are cochlear implants?
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.
Pros and cons of cochlear implants:
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
How does the eye see?
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.
Key structures of the eye?
- 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.
Types of visual disorders?
Refractive errors - when light is not bent onto the retina properly so vision is blurred.
- Myopia
- Hyperopia
Retina Conditions:
- Retinopathy
- Macular Degeneration
- Colour blindness
What is myopia?
Causes image to form in front of retina, short sightedness. Caused by a lens that is too thick or eyeball is too long.
What is hyperopia?
Long sightedness, where image is focused behind the retina, caused by a lens that is too thin, or eyeball is too short.
What is retinopathy?
Damage to the retina, caused by changes to blood vessels surrounding the region.
What is colourblindess?
Occurs when one of the three types of colour detecting cone cells isn’t working.
What is macular degeneration?
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.
Treatments for visual disorders?
Glasses
Laser Surgery
How do glasses work?
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.
How does laser eye surgery work?
Most common procedure is LASIK, where a laser is used to reshape the cornea, decreased curvature for myopia and increased curvature for hyperopia.
Kidney structure?
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.
Kidney function how is it done?
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.
Structure of nephrons?
Wrench shaped structure is called bowman’s capsule, surrounding a dense clump of blood capillaries called glomerulus.
Types of kidney disorders?
Glomerulonephritis
Diabetic nephropathy
Polycystic kidney disease
Kidney stones
Glomerulonephritis
Inflammation of the glomerulus, often occurs after a bacterial infection.
Diabetic nephropathy
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.
Kidney stones
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
Polycystic kidney disease
Causes cysts to grow in the kidneys, an inherited condition, which can enlarge and damage the kidneys.
Treatments for kidney disorders
Dialysis
Kidney transplants
What is dialysis?
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.
What is dialysing solution?
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.
Pros and cons of dialysis?
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.
Pros and cons of kidney transplants?
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
