Pharmacology for EMS Week 2: Homeostasis
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Questions and Answers

What is the primary goal of homeostasis?

  • To maintain cellular dehydration
  • To eliminate all external stressors
  • To create fluctuating physiological states
  • To maintain a constant internal environment (correct)

    • Which physiological variable does NOT have a specific normal range mentioned?

  • Temperature
  • Carbon dioxide (correct)
  • Sodium
  • Glucose

    • What happens when a homeostatic mechanism fails for one variable?

  • It resolves itself automatically
  • It has no impact on other variables
  • It strengthens other homeostatic mechanisms
  • It can lead to changes in other variables (correct)

    • Which of the following best describes the dynamic nature of homeostasis?

    <p>Physiological processes fluctuate yet stabilize</p> Signup and view all the answers

    What factors regulate homeostasis in the body?

    <p>Control systems including feedback mechanisms, reflexes, hormones, and others</p> Signup and view all the answers

    How does the body respond when normal physiological responses are altered?

    <p>By requiring exogenous interventions</p> Signup and view all the answers

    Which of these substances is considered hydrophobic?

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

    What is a key component that must be regulated for normal cellular function?

    <p>Oxygen levels</p> Signup and view all the answers

    What happens to protein structure when exposed to heat and extreme pH?

    <p>It may undergo temporary or permanent structural alteration.</p> Signup and view all the answers

    How is pH mathematically defined in relation to hydrogen ion concentration?

    <p>pH = -log [H+]</p> Signup and view all the answers

    Which of the following statements is true regarding acidity and hydrogen ion concentration?

    <p>Higher hydrogen ion concentration correlates with lower pH.</p> Signup and view all the answers

    What normally describes the pH of intracellular fluid (ICF)?

    <p>pH 7.0 - 7.2</p> Signup and view all the answers

    What is the definition of an acid in terms of its behavior in solution?

    <p>A molecule that releases protons.</p> Signup and view all the answers

    What is the primary result of diffusion in a liquid or gas?

    <p>Uniform distribution of solute</p> Signup and view all the answers

    How does osmosis differ from diffusion?

    <p>Osmosis specifically moves water from low to high solute concentration</p> Signup and view all the answers

    What does the rate of diffusion depend on?

    <p>Magnitude of concentration difference</p> Signup and view all the answers

    What is meant by dynamic equilibrium in cellular homeostasis?

    <p>Constant movement of ions maintaining balance</p> Signup and view all the answers

    What role does the electrochemical potential play in the equilibrium of living cells?

    <p>It contributes to the concentration and movement of ions</p> Signup and view all the answers

    Which statement best describes the semi-permeable membrane's function in osmosis?

    <p>It only permits the movement of water while blocking solutes</p> Signup and view all the answers

    What can result from an alteration in concentration gradients in living organisms?

    <p>Complications in molecular pathology</p> Signup and view all the answers

    Which of the following best explains the relationship between concentration gradients and hydrostatic pressure during equilibrium?

    <p>They must be balanced to achieve equilibrium</p> Signup and view all the answers

    What do cells combat to maintain concentration gradients?

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

    What is the osmolarity concentration range for human intracellular fluid (ICF)?

    <p>280 mOsmol/L</p> Signup and view all the answers

    What happens to red blood cells (RBCs) placed in a hypertonic solution?

    <p>They may lyse and shrivel.</p> Signup and view all the answers

    What does the term 'osmolarity' relate to?

    <p>Measure of solute concentration</p> Signup and view all the answers

    What is the primary role of cells in maintaining electrochemical equilibrium?

    <p>To actively transport ions into and out of the cell</p> Signup and view all the answers

    What effect does the administration of hypertonic solutions have on cells?

    <p>Can lead to cellular damage</p> Signup and view all the answers

    During equilibrium, what occurs in terms of water or molecule movement?

    <p>There is no net movement of water or molecules</p> Signup and view all the answers

    Which process refers to the assisted movement of some molecules through the cell membrane?

    <p>Facilitated transport</p> Signup and view all the answers

    What characterizes a strong acid compared to a weak acid?

    <p>Strong acids completely dissociate into ions.</p> Signup and view all the answers

    What do hydrophilic substances have that allows them to dissolve in water?

    <p>They possess polar bonds and/or ionized groups.</p> Signup and view all the answers

    What role does negative feedback play in biological systems?

    <p>It prevents excessive responses to changes in homeostasis.</p> Signup and view all the answers

    What occurs when molecular charge is altered?

    <p>It leads to changes in functional characteristics.</p> Signup and view all the answers

    What defines hydrophobic substances?

    <p>They primarily contain electrically neutral covalent bonds.</p> Signup and view all the answers

    How do enzymes typically respond to pH changes?

    <p>Their activity is optimal within narrow pH ranges.</p> Signup and view all the answers

    What is produced when carbonic acid dissociates?

    <p>It releases hydrogen ions and bicarbonate.</p> Signup and view all the answers

    What happens to small changes in hydrogen ion concentration?

    <p>They can cause significant changes in molecular interactions.</p> Signup and view all the answers

    What is the primary role of negative feedback in physiological processes?

    <p>To maintain physiological properties within a narrow optimum range</p> Signup and view all the answers

    Which hormone released during negative feedback decreases blood glucose levels?

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

    In the context of positive feedback, what initiates uterine contraction during labor?

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

    Which of the following best describes the nature of positive feedback?

    <p>It amplifies the original stimulus without a clear termination.</p> Signup and view all the answers

    What is the function of glucagon in relation to blood glucose levels?

    <p>To increase blood glucose levels</p> Signup and view all the answers

    Which physiological response is involved in the negative feedback mechanism to lower blood glucose?

    <p>Increased glucose uptake by cells</p> Signup and view all the answers

    What is an example of a physiological process governed by positive feedback?

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

    Which type of feedback mechanism is more commonly found in physiological processes?

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

    Study Notes

    Pharmacology for EMS - Week 2: Introduction to Homeostasis

    • Objectives:

      • Describe homeostasis and transport mechanisms for normal cellular function
      • Discuss properties of hydrophilic and hydrophobic substances
      • Describe protein synthesis and protein roles in the body
      • Describe enzyme role and function
      • Describe and give examples of positive and negative feedback mechanisms

    • Homeostasis:

      • Maintaining a stable internal environment despite external stressors
      • A dynamic process, not constant over time (e.g., temperature, pH, glucose levels)
      • Considered individually for each physiological variable
      • Homeostatic failure in one variable can affect others
      • Regulated by control systems (feedback mechanisms, reflexes, hormones, chemical messengers, biological rhythms)
      • Cells have specific requirements or "normal ranges" for glucose, oxygen, salts, pH, waste products, and temperature (e.g., temperature 36.5-37.5°C, pH 7.35-7.45)

    • Drug Administration and Homeostasis:

      • Administering drugs implies the body's homeostatic and feedback mechanisms are not functioning correctly
      • Drugs are administered exogenously (from outside the body) to intervene

    • Transport:

      • Cells maintain electrical and chemical differences between intracellular and extracellular environments to allow reaction and interaction
      • Maintaining concentration gradients in cells requires a constant battle against diffusion
      • Some molecules easily pass through cell membranes; others need assistance (facilitated diffusion), or active transport against concentration gradients

    • Equilibrium:

      • Cells maintain osmolarity and electrochemical equilibrium between the extracellular fluid (ECF) and intracellular fluid (ICF) with no net movement of water or molecules under normal conditions.
      • There is a difference in ion concentration and an electrochemical charge due to active transport into and out of cells

    • Diffusion:

      • All molecules are constantly vibrating
      • Higher energy state leads to more movement
      • Diffusion results in even distribution of molecules within a container until concentration is uniform in the container
      • The rate of diffusion is related to concentration differences between compartments

    • Diffusion in Living Organisms:

      • Essential for processes like oxygen, carbon dioxide, salt, ion, and glucose diffusion
      • Complicated pathology or drug action often results from altered concentration gradients or impaired diffusion at the molecular level

    • Diffusion Across a Semi-Permeable Membrane:

      • Osmosis is water diffusion from low solute concentration to high solute concentration through a semipermeable membrane.
      • Equilibrium occurs when competing forces of concentration (osmotic) gradient and hydrostatic pressure are in balance
      • Electrochemical potential difference also considered for equilibrium

    • Transport across cell membranes:
      -Cells maintain concentration gradients despite continuous diffusion

    • Enzymes:

      • Proteins that act as catalysts, lowering activation energy for chemical reactions
      • Not consumed by reactions, allowing repeated use with additional substrates
      • Subject to specificity, affinity, competition, and saturation in their binding
      • Accelerate both forward and reverse chemical reactions

    • Enzymes and Drug Metabolism:

      • Most drugs are metabolized or modified by enzymes
      • Common mechanisms of drug action include altered enzyme induction/inhibition or kinetics. This will be discussed in greater detail in future lectures

    • Proteins:

      • Involved in all physiological processes; Some are enzymes
      • Receptors can be regulated
      • Protein structure is not static, and changes in structure affect protein properties
      • Protein structure can be affected by heat and extremes in pH

    • Hydrogen Ions, pH, and Acidity:

      • pH measures acidity/basicity (lower pH means more acidic)
      • Pure water pH = 7.0
      • ICF pH ~ 7.0-7.2 and ECF pH ~ 7.35-7.45
      • Acidity refers to free/unbound hydrogen ion concentration
      • Hydrogen ion concentration is expressed as a negative log Small changes in pH can have a large effect on molecular interactions

    • Feedback Mechanisms:

      • Positive feedback leads to accelerating amplification of initial stimulus.
      • Negative feedback leads to the inhibition of further reaction
        • Negative feedback regulates homeostasis
      • Most physiological processes use negative feedback to maintain physiological properties and concentrations within narrow ranges.
      • Drugs can affect the body's natural feedback mechanisms

    • Drugs Revision for Week 3:

      • Study ibuprofen, paracetamol, and Entonox with emphasis on dose, presentation, indications, and contraindications

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    EHS 202 Week 1 Homeostasis 2023-2024 PDF

    Description

    This quiz covers the essential concepts of homeostasis related to pharmacology for emergency medical services. Key topics include transport mechanisms, properties of substances, protein synthesis, enzyme functions, and feedback mechanisms. Understanding these principles is crucial for maintaining a stable internal environment in medical practice.

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