Homeostasis in Biology
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Questions and Answers

What is the primary purpose of homeostasis in organisms?

  • To increase metabolic rates in all conditions
  • To maintain a relatively stable internal environment (correct)
  • To eliminate all external stimuli
  • To adapt to every environmental change permanently

    • What initiates the process of homeostasis?

  • The actions of the central nervous system alone
  • The transmission of information via motor neurons
  • Detection of changes known as stimuli (correct)
  • The role of effectors in creating responses

    • Which component of the homeostasis process is responsible for receiving stimuli?

  • Sensory neurons
  • Receptors (correct)
  • Effectors
  • Central nervous system

    • What is the correct sequence in the stimulus-response pathway?

    <p>Stimulus → Receptor → Messenger → Effector → Response</p> Signup and view all the answers

    What type of receptors are primarily focused on changes in light?

    <p>Photoreceptors</p> Signup and view all the answers

    What role does the central nervous system play in maintaining homeostasis?

    <p>Sending messages to effectors based on stimulus information</p> Signup and view all the answers

    Which example illustrates the detection and response in the homeostasis process?

    <p>Receptors detecting light changes and adjusting pupil size</p> Signup and view all the answers

    In the context of homeostasis, what is the role of effectors?

    <p>To counteract changes and implement responses</p> Signup and view all the answers

    What is the minimum electrical charge required for an action potential to be generated?

    <p>-55</p> Signup and view all the answers

    Which process involves positively charged sodium ions entering the cell?

    <p>2</p> Signup and view all the answers

    How does the brain coordinate appropriate responses to sensory signals?

    <p>By interpreting information and sending impulses to muscles and glands</p> Signup and view all the answers

    What role do hormones play in homeostasis?

    <p>They act as chemical messengers affecting cell activity</p> Signup and view all the answers

    What happens to ADH production when blood volume is too high?

    <p>ADH production will stop</p> Signup and view all the answers

    What is the primary function of aldosterone?

    <p>To regulate blood pressure by reabsorbing salt</p> Signup and view all the answers

    What fluid surrounds cells and aids in the removal of waste products?

    <p>Interstitial fluid</p> Signup and view all the answers

    What happens to a plant cell if it dehydrates?

    <p>It wilts</p> Signup and view all the answers

    What is the function of stomata in plants?

    <p>To regulate gas exchange</p> Signup and view all the answers

    How can hormonal signals influence enzymes in cells?

    <p>By selectively activating or inhibiting specific enzymes</p> Signup and view all the answers

    What occurs when blood glucose levels rise above the normal set point?

    <p>Insulin is secreted to move glucose from blood to cells</p> Signup and view all the answers

    How does the body respond to rising temperatures?

    <p>Vasodilation of blood vessels occurs</p> Signup and view all the answers

    What is the primary function of glucagon when blood glucose levels fall?

    <p>Convert glycogen back to glucose in the liver</p> Signup and view all the answers

    What characterizes Type 1 diabetes?

    <p>It is caused by the immune system attacking pancreatic cells</p> Signup and view all the answers

    What is the role of the hypothalamus in thermoregulation?

    <p>It integrates sensory information and regulates body temperature</p> Signup and view all the answers

    What mechanism is primarily responsible for stabilizing body temperature?

    <p>Negative feedback</p> Signup and view all the answers

    In response to a drop in skin temperature, which action occurs?

    <p>Blood vessels constrict to retain body heat</p> Signup and view all the answers

    Which statement accurately describes a positive feedback mechanism?

    <p>It drives processes away from a set equilibrium</p> Signup and view all the answers

    How is insulin related to blood glucose regulation?

    <p>It facilitates the uptake of glucose by cells</p> Signup and view all the answers

    What occurs if blood pressure falls too low in the body?

    <p>The control center issues a command to increase blood pressure</p> Signup and view all the answers

    What is the main purpose of using golden rice?

    <p>To prevent deficiency of Vitamin A</p> Signup and view all the answers

    What does gene therapy primarily aim to achieve?

    <p>To replace or repair defective genes</p> Signup and view all the answers

    Which method is often used for gene transfer in gene therapy?

    <p>Viral vectors</p> Signup and view all the answers

    What is a potential limitation of gene therapy?

    <p>Therapeutic cells are limited compared to body cells</p> Signup and view all the answers

    What role do CRISPR techniques play in genetics?

    <p>They are used for developing gene editing strategies</p> Signup and view all the answers

    How is sound represented in physical terms?

    <p>As longitudinal waves</p> Signup and view all the answers

    Which part of the ear is responsible for funneling sound waves into the auditory canal?

    <p>Pinna (auricle)</p> Signup and view all the answers

    What do the ossicles in the middle ear do?

    <p>Amplify sound waves</p> Signup and view all the answers

    Which of the following describes in-vivo gene transfer?

    <p>Gene transfer that occurs inside the body</p> Signup and view all the answers

    What is the frequency of sound associated with, in terms of pitches?

    <p>Pitch of the sound</p> Signup and view all the answers

    What physiological adaptation helps reduce body heat in a red kangaroo during hot conditions?

    <p>Lies in the shade out of direct sunlight</p> Signup and view all the answers

    Which system is responsible for the rapid response to internal and external stimuli?

    <p>Nervous system</p> Signup and view all the answers

    What is the primary role of sensory neurons?

    <p>Receive signals from the environment</p> Signup and view all the answers

    What adaptation allows the fat-tailed dwarf lemur to survive in hot conditions?

    <p>Aestivates in a tree</p> Signup and view all the answers

    Which component of a neuron carries signals towards the cell body?

    <p>Dendrites</p> Signup and view all the answers

    What mechanism helps in the maintenance of body temperature according to the muscular system?

    <p>Produces heat</p> Signup and view all the answers

    During which phase does a mountain pygmy possum primarily reduce its energy consumption?

    <p>Hibernation in winter</p> Signup and view all the answers

    What is primarily affected in the respiratory system to regulate acid-base balance in the blood?

    <p>Carbon dioxide elimination</p> Signup and view all the answers

    What specific adaptation does a common wombat employ to manage heat on hot days?

    <p>Slows metabolism to ⅓ of normal</p> Signup and view all the answers

    Which structure in a neuron transmits electrical signals away from the cell body?

    <p>Axon</p> Signup and view all the answers

    Which type of neuron primarily connects sensory and motor neurons?

    <p>Interneurons</p> Signup and view all the answers

    What effect does panting have on the body during hot weather?

    <p>Enhances evaporative cooling</p> Signup and view all the answers

    What is the primary purpose of the endocrine system in relation to homeostasis?

    <p>Secretes hormones for long-term regulation</p> Signup and view all the answers

    What characteristic structure of the tail in some animals helps with efficient heat loss?

    <p>Large surface area to volume ratio</p> Signup and view all the answers

    What type of adaptation involves behavioral changes to reduce heat absorption?

    <p>Behavioral adaptation</p> Signup and view all the answers

    What can excessive exposure to UV light lead to in skin cells?

    <p>Abnormal cell division</p> Signup and view all the answers

    Which of the following is a symptom of lead poisoning?

    <p>Slurred speech</p> Signup and view all the answers

    In which condition does the lack of protein in the diet directly lead to severe health issues, particularly in children?

    <p>Kwashiorkor</p> Signup and view all the answers

    What is the main cause of nutritional deficiency diseases?

    <p>Psychological conditions affecting diet</p> Signup and view all the answers

    What is a characteristic of obesity?

    <p>Excess calories stored as fat</p> Signup and view all the answers

    How does a mutation in proto-oncogenes affect cell growth?

    <p>It causes uncontrolled cell production</p> Signup and view all the answers

    What role do tumor suppressor genes play in cell growth?

    <p>Induce cell death in damaged cells</p> Signup and view all the answers

    What condition is characterized by impaired wound healing and joint pain due to vitamin deficiency?

    <p>Scurvy</p> Signup and view all the answers

    Which environmental exposure is directly linked to the formation of melanoma?

    <p>Excessive UV radiation</p> Signup and view all the answers

    What health issue can result from a lack of Vitamin A?

    <p>Blindness and dry skin</p> Signup and view all the answers

    What role does oxytocin play during childbirth?

    <p>Stimulates uterine contractions</p> Signup and view all the answers

    How do endotherms primarily maintain their internal temperature?

    <p>By generating heat through metabolic processes</p> Signup and view all the answers

    Which of the following is an effect of anorexia nervosa?

    <p>Tiredness and anorexia</p> Signup and view all the answers

    Which adaptation helps endotherms reduce heat loss?

    <p>Huddling together</p> Signup and view all the answers

    What type of malnutrition results from excessive intake of food?

    <p>Overnutrition</p> Signup and view all the answers

    What is a consequence of uncontrolled cell division in cancer?

    <p>Spread to other tissues</p> Signup and view all the answers

    What is a behavioral adaptation of red kangaroos to cope with heat?

    <p>Seeking shade</p> Signup and view all the answers

    High blood pressure, or hypertension, can be caused by which of the following?

    <p>Build-up of plaque in arteries</p> Signup and view all the answers

    What is the significance of the surface area to volume ratio in large animals?

    <p>Smaller ratio reduces heat loss</p> Signup and view all the answers

    What behavior do some organisms exhibit to avoid the hottest part of the day?

    <p>Nocturnal activity</p> Signup and view all the answers

    Which substances are primarily reabsorbed in the proximal tubule?

    <p>Water, sodium, and glucose</p> Signup and view all the answers

    Countercurrent heat exchange is an adaptation found in which type of organisms?

    <p>Marine mammals like dolphins</p> Signup and view all the answers

    What is the primary function of the descending limb of the Loop of Henle?

    <p>Reabsorb water only</p> Signup and view all the answers

    Which of the following is NOT a structural adaptation for maintaining temperature in endotherms?

    <p>Nocturnal behavior</p> Signup and view all the answers

    What impact does aldosterone have on the distal tubule?

    <p>Increases the permeability to sodium</p> Signup and view all the answers

    Which of the following diseases can lead to chronic kidney disease?

    <p>Diabetes</p> Signup and view all the answers

    What process allows small animals to cope with the cold when they cannot increase their metabolic rate?

    <p>Torpor or hibernation</p> Signup and view all the answers

    Ecotherms are best defined as organisms that:

    <p>Depend largely on environmental temperatures for heat</p> Signup and view all the answers

    What is a primary characteristic of haemodialysis?

    <p>Redirects blood through a dialysis machine externally</p> Signup and view all the answers

    Which therapy uses drugs to interrupt the pathways causing uncontrolled division of melanoma cells?

    <p>Targeted therapies</p> Signup and view all the answers

    Which mechanism aids in maintaining water balance in plants?

    <p>Transpiration</p> Signup and view all the answers

    During which process does active transport primarily occur in the nephron?

    <p>Reabsorption of sodium in the distal tubule</p> Signup and view all the answers

    What is the main reason patients on dialysis must follow strict dietary restrictions?

    <p>To help maintain the balance of electrolytes</p> Signup and view all the answers

    What type of study first investigates the cause of disease by providing information about its patterns?

    <p>Descriptive studies</p> Signup and view all the answers

    What adaptation can help animals minimize exposure to extreme temperatures?

    <p>Behavioral changes in activity times</p> Signup and view all the answers

    Which is an inherent disadvantage for ectotherms compared to endotherms?

    <p>Inability to maintain activity levels across temperatures</p> Signup and view all the answers

    What is a significant challenge in current immunotherapy for melanoma?

    <p>Only two existing drugs are available</p> Signup and view all the answers

    What happens to blood in peritoneal dialysis?

    <p>Waste products migrate into the dialysis fluid from the peritoneum</p> Signup and view all the answers

    Why do darker-colored animals tend to absorb more heat?

    <p>Darker pigments absorb more light</p> Signup and view all the answers

    What primarily distinguishes case control studies from cohort studies?

    <p>The study of individuals with and without the disease</p> Signup and view all the answers

    Which component of blood is typically retained and not filtered into the Bowman’s capsule?

    <p>Red blood cells</p> Signup and view all the answers

    Which type of error in studies is referred to as bias?

    <p>Systematic errors</p> Signup and view all the answers

    How should epidemiological studies optimally sample participants?

    <p>Include a range of people and factors that may skew results</p> Signup and view all the answers

    What does immunotherapy aim to leverage in the fight against melanoma?

    <p>The body's own immune system</p> Signup and view all the answers

    Which type of epidemiological study is used primarily to test the effectiveness of treatments?

    <p>Intervention studies</p> Signup and view all the answers

    What is a common problem leading to loss to follow-up bias in studies?

    <p>Participants relocating or dropping out</p> Signup and view all the answers

    Which of the following best describes cohort studies?

    <p>They observe effects on groups exposed to a potential risk factor</p> Signup and view all the answers

    What is one important factor for ensuring the validity of an epidemiological study?

    <p>Use a control group for comparisons</p> Signup and view all the answers

    How can researchers reduce measurement bias in studies?

    <p>Take repeated measurements and have multiple observers</p> Signup and view all the answers

    What is the primary focus of analytical studies in epidemiology?

    <p>Testing hypotheses regarding disease causes</p> Signup and view all the answers

    What is a significant limitation of chemotherapy in treating melanoma?

    <p>It is ineffective against melanoma cells</p> Signup and view all the answers

    What role does abscisic acid (ABA) play in plants experiencing water loss?

    <p>It helps close stomata to reduce water loss.</p> Signup and view all the answers

    Which structure or adaptation helps xerophytes reduce water loss?

    <p>Sunken stomata.</p> Signup and view all the answers

    Which of the following genetic diseases is caused by a single-gene mutation?

    <p>Both B and C.</p> Signup and view all the answers

    What is a consequence of cell disruption related to cancer?

    <p>Cells cannot differentiate and perform specialized functions</p> Signup and view all the answers

    Which of the following is a known risk factor for developing melanoma?

    <p>Exposure to UV light</p> Signup and view all the answers

    What is a common characteristic of environmental diseases?

    <p>They can stem from both man-made and natural factors.</p> Signup and view all the answers

    What does the term 'metastasis' refer to?

    <p>The spread of cancer to other organs</p> Signup and view all the answers

    What is the primary risk factor for developing non-infectious diseases?

    <p>Genetic factors.</p> Signup and view all the answers

    What is the primary cause of type 2 diabetes incidents being higher in females than in males?

    <p>Lower physical activity levels</p> Signup and view all the answers

    Which adaptation helps the Eucalyptus tree minimize moisture loss?

    <p>Thick waxy cuticle.</p> Signup and view all the answers

    What does PKU result from?

    <p>A buildup of phenylalanine in the blood.</p> Signup and view all the answers

    Which statement correctly describes the mortality rate of type 2 diabetes?

    <p>It was the leading cause of death in 2016</p> Signup and view all the answers

    How does having curled leaves benefit xerophytes?

    <p>It traps moisture and slows down evaporation.</p> Signup and view all the answers

    Which treatment is often sufficient for early-stage melanoma?

    <p>Surgery</p> Signup and view all the answers

    Which of the following is NOT a factor that can contribute to cancer?

    <p>Regular physical exercise</p> Signup and view all the answers

    What causes cystic fibrosis?

    <p>A mutation on chromosome 7 affecting ion regulation.</p> Signup and view all the answers

    Which lifestyle choice is a significant risk factor for cardiovascular diseases?

    <p>Tobacco use.</p> Signup and view all the answers

    What does the prevalence of a disease refer to?

    <p>The number of existing cases at a given time</p> Signup and view all the answers

    What physical characteristic is most commonly associated with Down syndrome?

    <p>Characteristic facial features.</p> Signup and view all the answers

    What type of disease is primarily responsible for 70% of deaths globally?

    <p>Non-infectious diseases</p> Signup and view all the answers

    Which is NOT a method used to evaluate the effectiveness of disease control strategies?

    <p>Improvement of lifestyle habits</p> Signup and view all the answers

    What adaptation do Spinifex Grass and Prickly Pears have in common?

    <p>Water-storing capabilities.</p> Signup and view all the answers

    What environmental factor can lead to skin cancer?

    <p>Exposure to ultraviolet light.</p> Signup and view all the answers

    How has the incidence of melanoma changed since 1982?

    <p>Increased by 93%</p> Signup and view all the answers

    Which statement best describes the relationship between non-infectious diseases and lifestyle factors?

    <p>Lifestyle choices can increase the risk of developing non-infectious diseases.</p> Signup and view all the answers

    Which demographic is more likely to develop melanoma?

    <p>Males</p> Signup and view all the answers

    What role do epidemiological studies play in public health?

    <p>They help identify patterns and causes of diseases</p> Signup and view all the answers

    What type of cells cannot repair their DNA as easily as normal cells during radiation treatment?

    <p>Cancer cells</p> Signup and view all the answers

    What is the main function of the sound processor in a BAHA system?

    <p>To process sound and transmit signals to the implant</p> Signup and view all the answers

    What type of hearing loss is a cochlear implant primarily designed to assist?

    <p>Severe to profound sensorineural hearing loss</p> Signup and view all the answers

    What characteristic of cochlear implants makes them different from traditional hearing aids?

    <p>Cochlear implants require invasive surgical implantation</p> Signup and view all the answers

    Which structure of the eye helps direct light toward the retina?

    <p>Cornea</p> Signup and view all the answers

    What is the primary role of the iris in vision?

    <p>To control the amount of light entering the eye</p> Signup and view all the answers

    Which component of a cochlear implant directly stimulates the auditory nerves?

    <p>Electrode array</p> Signup and view all the answers

    Which type of photoreceptor is most sensitive to low light conditions?

    <p>Rod cells</p> Signup and view all the answers

    What challenge might a user face when wearing hearing aids in a noisy environment?

    <p>Hearing aids amplify all sounds, making it hard to focus</p> Signup and view all the answers

    What anatomical feature of the eye is responsible for nutrient supply?

    <p>Choroid</p> Signup and view all the answers

    What is the primary benefit of conducting an epidemiological study?

    <p>To discover or provide evidence for significant risk factors associated with a non-infectious disease</p> Signup and view all the answers

    What does the ciliary body do in relation to the lens of the eye?

    <p>Holds the lens in place and adjusts its shape</p> Signup and view all the answers

    Why might a cochlear implant be considered a permanent choice in hearing assistance?

    <p>It can destroy remaining natural hair cells in the cochlea</p> Signup and view all the answers

    Which method is NOT mentioned as a way to prevent non-infectious diseases?

    <p>Surgical interventions</p> Signup and view all the answers

    What outcome did the QUIT campaign achieve regarding smoking prevalence?

    <p>A 1.8-3.1% reduction in smoking prevalence within 18 months</p> Signup and view all the answers

    What is the primary function of the retina?

    <p>To convert light energy into electrical impulses</p> Signup and view all the answers

    What significant factor contributed to a higher incidence of type 2 diabetes in Australia?

    <p>High life expectancy</p> Signup and view all the answers

    What is one potential side effect of using hearing aids?

    <p>Excessive amplification of unwanted sounds</p> Signup and view all the answers

    Which of the following is NOT a component of a successful public health campaign?

    <p>Strict financial penalties</p> Signup and view all the answers

    Which statement about the QUIT campaign is correct?

    <p>Graphic images and slogans were part of its strategy</p> Signup and view all the answers

    How does pre-implantation genetic testing prevent genetic diseases?

    <p>By screening embryos before implantation to ensure they are free of mutated genes</p> Signup and view all the answers

    What is one goal of intervention epidemiology?

    <p>To measure the effectiveness of preventive and control measures</p> Signup and view all the answers

    What role does legislation play in disease prevention?

    <p>It may increase taxes or restrict marketing related to health risks</p> Signup and view all the answers

    What is one limitation of treatment methods for non-infectious diseases?

    <p>They can involve drugs that have side effects leading to additional problems</p> Signup and view all the answers

    Which method is indicated to reduce vitamin deficiencies in developing countries?

    <p>Transgenic crops that incorporate essential vitamins</p> Signup and view all the answers

    Why is prevention of disease considered better than treatment?

    <p>It can reduce suffering and improve overall quality of life</p> Signup and view all the answers

    What trend is observed regarding smoking rates in males and females?

    <p>Males have historically had higher smoking rates but are quitting sooner</p> Signup and view all the answers

    What critical factor is used in the success of health promotions?

    <p>Community engagement and trust in sources</p> Signup and view all the answers

    What type of cells are responsible for night vision?

    <p>Rods</p> Signup and view all the answers

    What is the primary function of cones in the human eye?

    <p>Provide color vision</p> Signup and view all the answers

    Which photopigment is present in all rod cells?

    <p>Rhodopsin</p> Signup and view all the answers

    What causes myopia in the human eye?

    <p>Eyeball is too long</p> Signup and view all the answers

    What is the role of the ciliary body during accommodation?

    <p>Thins the lens for distant vision</p> Signup and view all the answers

    Which optical device would be recommended for someone with hyperopia?

    <p>Convex lenses</p> Signup and view all the answers

    What is the term for the bending of light as it passes through different media?

    <p>Refraction</p> Signup and view all the answers

    Light rays that are divergent require what adjustment for proper focus on the retina?

    <p>Thickening of the lens</p> Signup and view all the answers

    What could cause hyperopia?

    <p>Too short of an eyeball</p> Signup and view all the answers

    What corrective procedure could be used for refractive disorders?

    <p>Laser eye surgery</p> Signup and view all the answers

    How many types of cone cells are there and what colors do they primarily detect?

    <p>Three: Blue, Green, and Red</p> Signup and view all the answers

    What is the primary optical device used to compensate for myopia?

    <p>Concave lenses</p> Signup and view all the answers

    What part of the eye has the greatest refractive power?

    <p>Cornea</p> Signup and view all the answers

    What role does the Eustachian tube play in hearing?

    <p>It connects the middle ear to the nasal cavity.</p> Signup and view all the answers

    What mechanism allows hair cells to convert vibrations into electrical signals?

    <p>Vibrations displace the tectorial membrane.</p> Signup and view all the answers

    What is the main difference between conductive and sensorineural hearing loss?

    <p>Conductive hearing loss is due to issues in outer or middle ear.</p> Signup and view all the answers

    Which part of the cochlea is activated by low-frequency sounds?

    <p>Apex of the cochlea.</p> Signup and view all the answers

    What is the primary function of hearing aids?

    <p>To magnify sound vibrations.</p> Signup and view all the answers

    What is a common underlying cause of sensorineural hearing loss?

    <p>Excessive noise exposure.</p> Signup and view all the answers

    How does a cochlear implant function?

    <p>By directly bypassing the hair cells in the cochlea.</p> Signup and view all the answers

    What is the role of the organ of Corti in the cochlea?

    <p>It contains hair cells for sound detection.</p> Signup and view all the answers

    Which channel of the cochlea is filled with endolymph?

    <p>Cochlear duct.</p> Signup and view all the answers

    What do hair cells at the base of the cochlea respond to?

    <p>High-frequency sounds.</p> Signup and view all the answers

    How is hearing sensitivity measured?

    <p>Through an audiogram.</p> Signup and view all the answers

    What is the purpose of the round window in the ear?

    <p>To relieve pressure within the cochlea.</p> Signup and view all the answers

    What feature of some hearing aids assists with receiving sound in certain environments?

    <p>Telecoil.</p> Signup and view all the answers

    What happens to the eardrum when the Eustachian tube is blocked?

    <p>It cannot vibrate correctly.</p> Signup and view all the answers

    What is the main purpose of the ossicles in the middle ear?

    <p>To transmit sound vibrations.</p> Signup and view all the answers

    What is the primary purpose of LASIK eye surgery?

    <p>To modify the shape of the cornea</p> Signup and view all the answers

    How do contact lenses correct hyperopia?

    <p>By being thicker at the center</p> Signup and view all the answers

    What is the function of nephrons within the kidney?

    <p>To filter waste materials from blood</p> Signup and view all the answers

    Which of the following statements about the excretory system is true?

    <p>The ureters transport urine from the kidneys to the bladder</p> Signup and view all the answers

    What occurs during the secretion process in nephron function?

    <p>Unwanted substances move into the nephron</p> Signup and view all the answers

    What forms as a result of the breakdown of amino acids in humans?

    <p>Ammonia</p> Signup and view all the answers

    Why is urea less toxic than ammonia?

    <p>It can be stored for longer periods</p> Signup and view all the answers

    Which part of the nephron is responsible for filtration?

    <p>The glomerulus</p> Signup and view all the answers

    What shape does the renal cortex typically have?

    <p>Dark brown and vascular</p> Signup and view all the answers

    In which part of the nephron does reabsorption primarily occur?

    <p>In the convoluted tubules</p> Signup and view all the answers

    What is the role of the renal artery in the kidney's function?

    <p>To bring unfiltered blood into the kidney</p> Signup and view all the answers

    Which substances are typically found in urine?

    <p>Water, ions, and drugs</p> Signup and view all the answers

    What process occurs when the kidneys maintain the body's acid-base balance?

    <p>Osmoregulation</p> Signup and view all the answers

    What keeps the eye steady during LASIK surgery?

    <p>Suction ring applied to the eye</p> Signup and view all the answers

    Study Notes

    Homeostasis

    • Homeostasis is the process of maintaining a stable internal environment despite external changes. Organisms maintain: temperature, nutrient concentration (glucose), oxygen/carbon dioxide levels, and waste concentration.
    • Homeostasis facilitates short-term environmental adaptation.
    • Homeostatic stages:
      • Stage 1: Detecting change. Receptors (cells sensitive to stimuli) detect internal/external changes (stimuli). Sense organs have high receptor concentrations (e.g., photoreceptors in eyes). Internal receptors constantly monitor internal environment.
      • Stage 2: Countering change. Information from receptors travels to the central nervous system (CNS) via sensory neurons. The CNS determines a response and sends a message to effectors (muscles or glands) via motor neurons. This is the stimulus-response pathway.

    Negative Feedback Loops

    • Most homeostatic systems use negative feedback. The response reduces or counteracts the initial stimulus. A change away from the typical status is prevented – e.g., temperature, water, glucose levels.
    • Temperature Regulation:
      • Receptors: Thermoreceptors (skin, brain)
      • Control Center: Hypothalamus
      • Effectors: Sweat glands, smooth muscles (arrector pili), blood vessels (arterioles)
      • Temperature rising: Sweat evaporation (high specific heat capacity) cools the body. Arrector pili relax/hairs flatten. Arterioles dilate (vasodilation).
      • Temperature falling: Shivering warms the body. Arrector pili contract/hairs raise to trap warm air. Arterioles constrict (vasoconstriction) to retain heat.
    • Blood Glucose Regulation:
      • Receptors: Pancreas (islet cells)
      • Control Center: Hypothalamus
      • Effectors: Liver, cells
      • High blood glucose: Insulin promotes glucose uptake by cells, converting glucose to glycogen in the liver – decreasing blood sugar.
      • Low blood glucose: Glucagon converts glycogen to glucose in the liver, increasing blood sugar. Insulin secretion is inhibited.

    Diabetes

    • Diabetes occurs when blood glucose regulation is ineffective. It's caused by insufficient insulin production.
    • Types:
      • Type 1: Autoimmune disorder (inherited). Immune cells attack beta islet cells, reducing insulin production.
      • Type 2: Lifestyle factors (diet, inactivity) impair insulin production/use.
      • Gestational: Pregnancy can disrupt insulin regulation. Elevated glucose levels can impact fetal development.

    Positive Feedback Mechanisms

    • Positive feedback reinforces a change. The response continues, and the process accelerates. Not common in homeostasis, but occurs in childbirth (oxytocin release stimulates contractions).

    Endotherm vs. Ectotherm

    • Endotherms (mammals, birds): Internal body temperature is stable, independent of external temperature. Generate heat through metabolism.
    • Ectotherms (invertebrates, fish, reptiles): Body temperature matches the environment. Limited ability to regulate internal temperature.

    Adaptations in Endotherms

    • Behavioral: Seeking shade, altering posture, nocturnal activity, migration.
    • Structural: Insulation (fur, feathers, blubber), surface area to volume ratio (smaller SA/V ratio means less heat loss).
    • Physiological: Shivering, torpor (short-term), hibernation (extended decrease).

    Internal Coordination Systems

    • Nervous system: Rapid response, detects/coordinates responses (brain, spinal cord, sensory/motor neurons).
    • Endocrine system: Slower but prolonged response. Hormones coordinate body activities.
      • Examples: ADH (water balance), aldosterone (salt balance).

    Plant Adaptations for Water Balance

    • Stomata: Openings in leaves for gas exchange and transpiration. Regulate water loss.
    • Xerophytes (dry environments): Adaptations to minimize water loss include:
      • Small surface area to volume ratios, waxy cuticles, and sunken stomata.
      • Rolled leaves, hairs, and reflective surfaces.

    Non-Infectious Diseases: Causes and Effects

    • Non-infectious diseases are not caused by pathogens. Factors like age, genetics, lifestyle, nutrition, and environment influence susceptibility.
    • Genetic diseases:
      • Single-gene abnormalities: Mutations in genes from parents (e.g. cystic fibrosis, sickle cell anemia).
      • Chromosomal abnormalities: Incorrect number/structure of chromosomes (e.g. Down syndrome)
    • Environmental exposure: Lifestyle and environmental toxins, stress, UV light exposure.
    • Lifestyle diseases: Result from lifestyle choices impacting organ function (e.g., cardiovascular disease, Type 2 diabetes)
    • Nutritional diseases: Imbalances in nutrient intake.
      • Undernutrition: Lack of sufficient nutrients.
      • Overnutrition: Excessive nutrient intake.
    • Cancer: Uncontrolled cell division due to mutations in DNA repair, proto-oncogenes, or tumour suppressor genes.

    Epidemiology and Non-Infectious Diseases

    • Epidemiology is the study of disease patterns. Collects and analyzes data (incidence, prevalence, mortality) to study patterns and causes of diseases.
    • Types of Epidemiological Studies:
      • Descriptive: Identify patterns/frequency of disease.
      • Analytical: Test hypotheses about disease causes (case-control, cohort).
      • Intervention: Evaluate treatments/prevention strategies (experimental, quasi-experimental).

    Treatment/Management of Non-Infectious Diseases

    • Treatment methods vary by disease. Examples include surgery (early melanoma), radiation, chemotherapy, targeted therapies, immunotherapy (advanced melanoma), and dialysis (kidney failure).

    Technologies and Disorders

    • Hearing Loss: Conductive or sensorineural loss. Hearing aids, cochlear implants.
    • Visual Disorders: Refractive errors (myopia, hyperopia). Glasses, contact lenses, laser eye surgery.
    • Kidney Function Loss: Chronic kidney disease. Dialysis, kidney transplant.

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    Test your knowledge on the mechanisms of homeostasis in organisms. This quiz covers the primary functions, pathways, and components involved in maintaining physiological balance. Ideal for students studying biology and physiology.

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