Physiology: Homeostasis and Feedback Mechanisms
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Physiology: Homeostasis and Feedback Mechanisms

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Questions and Answers

What is the primary mechanism the body uses to maintain homeostasis?

  • Negative feedback (correct)
  • Vasodilation
  • Hormonal regulation
  • Positive feedback

    • Which of the following is an example of negative feedback in the body?

  • Vasodilation on a hot day (correct)
  • Uterine contractions during childbirth
  • Milk production during breastfeeding
  • Blood clot formation

    • What occurs during positive feedback mechanisms?

  • The body maintains stability by reversing changes
  • The body undergoes constant adjustments to homeostasis
  • The body amplifies changes in the same direction (correct)
  • The body entirely resets its functions

    • In which situation would the body most likely utilize a positive feedback mechanism?

    <p>Increasing uterine contractions during labor</p> Signup and view all the answers

    Which physiological change is likely to occur when the body temperature rises on a hot day?

    <p>Vasodilation and sweating</p> Signup and view all the answers

    Which of the following best describes a self-amplifying response in the body?

    <p>Stretch receptor activation during childbirth</p> Signup and view all the answers

    How does the body typically respond to a decrease in blood pH?

    <p>Increase in breathing rate to expel carbon dioxide</p> Signup and view all the answers

    Which condition indicates a loss of homeostasis in the body?

    <p>Uncontrolled blood sugar levels</p> Signup and view all the answers

    What happens to an atom when it has unequal numbers of protons and electrons?

    <p>It becomes an ion</p> Signup and view all the answers

    Which type of bond is characterized by the transfer of electrons from one atom to another?

    <p>Ionic bond</p> Signup and view all the answers

    What type of molecule is formed when two identical atoms bond and share electrons equally?

    <p>Non-polar molecule</p> Signup and view all the answers

    What type of ion is formed when an atom gains electrons?

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

    Which statement about hydrogen bonds is true?

    <p>They are very weak and easily broken.</p> Signup and view all the answers

    What characteristic makes covalent bonds the strongest among the bond types discussed?

    <p>They involve the sharing of electrons.</p> Signup and view all the answers

    What best describes a cation?

    <p>An atom that has lost electrons</p> Signup and view all the answers

    Which of the following is NOT a type of chemical bond mentioned?

    <p>Peptide bond</p> Signup and view all the answers

    What is the primary function of ribosomes within the cell?

    <p>To translate RNA messages into proteins</p> Signup and view all the answers

    Which organelle is responsible for breaking down fats, proteins, and carbohydrates?

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

    What role do peroxisomes play in the cell?

    <p>They metabolize organic compounds using oxidative enzymes.</p> Signup and view all the answers

    Which function does the Golgi apparatus serve in the cell?

    <p>It modifies and packages proteins for transport.</p> Signup and view all the answers

    How do lysosomes contribute to the immune response?

    <p>They degrade phagocytosed bacteria, viruses, and damaged cells.</p> Signup and view all the answers

    What specifies the phenotype when an individual has one dominant and one recessive allele?

    <p>The individual is a carrier with a normal phenotype.</p> Signup and view all the answers

    When would the mutation in the CFTR gene lead to the expression of cystic fibrosis?

    <p>If two recessive alleles are present.</p> Signup and view all the answers

    What describes a situation where two different dominant alleles lead to a blended phenotype?

    <p>Incomplete dominance.</p> Signup and view all the answers

    Which blood type can be expressed by an individual with the genotype AO?

    <p>Type A</p> Signup and view all the answers

    Which factor characterizes polygenic inheritance?

    <p>Multiple genes contribute to a particular phenotype.</p> Signup and view all the answers

    What is defined as the diffusion of water down its concentration gradient?

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

    Which type of solution has a greater concentration of solute outside the cell than inside?

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

    What term is used to describe when solute concentration is the same inside and outside the cell?

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

    When water moves into a cell due to a lower concentration of solute outside the cell, which solution is created?

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

    Which type of molecules are typically unable to pass through cell membranes easily?

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

    How does water behave in a hypertonic solution?

    <p>Water diffuses out of the cell</p> Signup and view all the answers

    Cell membranes are selectively permeable. What does this mean?

    <p>Some substances can pass while others cannot</p> Signup and view all the answers

    What is considered a solute in a biological solution?

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

    Study Notes

    Homeostasis

    • The body continuously monitors and adjusts various physiological parameters: temperature, blood pH, blood sugar levels, and blood pressure.
    • Loss of homeostasis can lead to various pathologies and diseases.
    • Key focus in physiology is understanding body responses and regulatory mechanisms.

    Feedback Mechanisms

    • Negative Feedback

      • Detects adverse changes and initiates processes to reverse them.
      • Primary method for maintaining homeostasis.
      • Example: When body temperature rises, vasodilation and sweating occur, leading to heat loss and normalization of temperature.

    • Positive Feedback

      • Detects changes and triggers greater responses in the same direction.
      • Less common but plays critical roles, such as in childbirth.
      • Example: Baby pressure against cervix leads to increased contractions, enhancing the birthing process.

    Chemical Reactions

    • Billions of chemical reactions occur within the body, essential for functions like seeing, hearing, breathing, and thinking.
    • Tryptophan, an amino acid, is produced through specific chemical reactions in the body.

    Atomic Structure

    • Electrons possess a negative charge, protons a positive charge, and neutrons have no charge.
    • An atom becomes an ion when it has unequal numbers of protons and electrons.
    • Cations are positively charged ions, while anions are negatively charged ions.

    Polarity of Molecules

    • Bonding between atoms can result in non-polar molecules (equal electron sharing) or polar molecules (unequal sharing).
    • Polar molecules have distinct charge distributions, with one end being positive and the other negative.

    Types of Chemical Bonds

    • Hydrogen Bonds

      • Weak bonds crucial for biological processes.

    • Ionic Bonds

      • Form through the attraction of cations and anions; relatively weak and easily broken.

    • Covalent Bonds

      • Strong bonds formed through the sharing of electrons; not easily broken.

    Osmosis and Cell Membrane Transport

    • A solution is a mixture of solute (particulate matter) and solvent (liquid).
    • Osmosis: Diffusion of water from low to high solute concentration.
    • Cell membranes are selectively permeable, allowing free passage for certain substances while restricting others.

    Tonicity

    • Hypertonic: Higher solute concentration outside the cell.
    • Isotonic: Equal solute concentration inside and outside the cell.
    • Hypotonic: Lower solute concentration outside the cell.
    • Water moves to equalize solute concentrations, impacting cell shape and function.

    Cellular Structures

    • Ribosomes: Complexes of protein and RNA found in the nucleolus, rough ER, and cytoplasm, translating RNA into proteins.

    • Lysosomes: Membrane-bound vesicles containing enzymes that degrade fats, proteins, and nucleic acids; utilized by white blood cells.

    • Peroxisomes: Similar to lysosomes, containing oxidative enzymes for metabolizing organic compounds.

    • Golgi Apparatus: Synthesizes carbohydrates, modifies proteins from the rough ER, and packages them for transport.

    Genetics and Alleles

    • Dominant Alleles: Expressed in phenotype and can mask recessive alleles.

    • Recessive Alleles: Expressed only when both alleles are recessive.

    • Example: Mutation in CFTR gene can cause cystic fibrosis; carriers have one dominant and one recessive allele.

    • Codominance: Two different dominant alleles are expressed simultaneously (e.g., blood types A and B).

    • Incomplete Dominance: Results in a blended phenotype (e.g., pink flowers from red and white parents).

    • Polygenic Inheritance: Multiple genes contribute to traits like eye color and conditions such as heart disease or cancer.

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    Description

    Explore the intricate processes of homeostasis in the human body and how it regulates vital functions like temperature and blood pressure. This quiz delves into both positive and negative feedback mechanisms essential for maintaining balance and overall health. Understand the implications of losing homeostasis and its impact on pathology and disease.

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