Medical Physiology: Introduction to Medicine (INMD 2011)
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Questions and Answers

Who coined the term 'Physiology' and what did it originally mean?

Aristotle coined the term 'Physiology', which meant the study of nature or natural history.

Who began modern experimental physiology by studying the body parts of animals?

  • Hippocrates
  • Empedocles
  • William Harvey
  • Claudius Galen (correct)

    • William Harvey correctly described the direction of circulation of blood in 1628.

    True

    Maintaining the internal environment of living systems in a more or less constant state is known as ________.

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

    Match the following: Fields of Physiology with their related topics.

    <p>Human Physiology = cell physiology, CV physiology, renal physiology, respiratory physiology, GI physiology, endocrine physiology, CNS physiology, etc Synthetic Physiology = Organization of physiological processes into whole body performances Analytic Physiology = Dissecting the functions of the systems into its component processes</p> Signup and view all the answers

    What are the components of the cell coat (glycocalyx)?

    <p>glycolipids and glycoproteins</p> Signup and view all the answers

    Which substances can penetrate the lipid bilayer of the cell membrane?

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

    Diffusion is passive movement of substances down their concentration gradient, from an area of high concentration to low concentration. Factors affecting the net rate of diffusion include lipid solubility of the substance, membrane permeability, concentration difference or pressure difference, and electrical potential difference of ions.

    <p>Membrane Thickness</p> Signup and view all the answers

    Exocytosis is the process by which a cell takes in material from its surroundings.

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

    What is the concentration of osmotically active particles per kg of water?

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

    What is the osmolality of an isotonic solution relative to plasma?

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

    Hypertonic solution has a higher osmolality than ________.

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

    Edema can be either pitting or cellular.

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

    Match the type of edema with its cause:

    <p>Cellular or non-pitting edema = Increase in intracellular fluid volume Extracellular or pitting edema = Increase in interstitial fluid volume</p> Signup and view all the answers

    Which of the following is a function of the cell membrane?

    <p>All of the above</p> Signup and view all the answers

    At what altitude does Haemoglobin stop increasing?

    <p>6000 meters</p> Signup and view all the answers

    What is the primary cause of the significant increase in red blood cells and haemoglobin at high altitudes?

    <p>Elevated level of erythropoietin and hypoxia's stimulant action on blood forming organs</p> Signup and view all the answers

    High altitude exposure leads to an increase in systemic blood pressure in Ethiopians.

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

    The intense vascularization of the myocardium leads to a decrease in Coronary Blood Flow due to an increase in coronary __________ resistance.

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

    Match the following hormones with their elevated levels at high altitudes:

    <p>Glucocorticoids, Thyroid hormones, Catecholamines = - Elevated levels Aldosterone, Antidiuretic hormone, Atrial natriuretic peptide = - Altered secretion due to diuretic effect Progesterone, Oestrogen = - Decreased levels Testosterone, LH, FSH = - Changes in secretion Insulin sensitivity, Rate of glucose utilization = - Increased levels</p> Signup and view all the answers

    What category of system responses occur in loops?

    <p>Responses to different stimuli</p> Signup and view all the answers

    Which of the following are components of a Closed Loop System (feedback loop)?

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

    In a Closed Loop System, the input is affected by the output.

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

    ______ regulation is an example of a Closed loop system involving negative feedback.

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

    Match the following types of regulation with their examples:

    <p>Negative Feedback = Temperature regulation Positive Feedback = Severe shock</p> Signup and view all the answers

    What does Allostatic Load refer to?

    <p>The cost of adaptation to a stressful environment eliciting repeated and sometimes prolonged adaptive responses.</p> Signup and view all the answers

    Which of the following are indicators of allostatic overload?

    <p>Immune dysfunction</p> Signup and view all the answers

    What is the concept of Adaptation also known as?

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

    What is the resting membrane potential typically observed in large nerve fibers?

    <p>-90 millivolts</p> Signup and view all the answers

    Which types of synapses exist?

    <p>Both a and b</p> Signup and view all the answers

    Excitatory postsynaptic potentials (EPSP) cause hyperpolarization in the postsynaptic cell.

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

    Inhibitory postsynaptic potentials (IPSP) are caused by opening __ channels.

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

    Match the following neurotransmitters with their types:

    <p>Acetylcholine, Norepinephrine, Epinephrine = Excitatory neurotransmitters GABA, Glycine = Inhibitory neurotransmitters</p> Signup and view all the answers

    What are the three processes that rapidly terminate transmitter action at chemical synapses?

    <p>Diffusion, enzymatic degradation by extracellular enzyme (in the case of acetylcholine), uptake of transmitter into the nerve ending or other cell</p> Signup and view all the answers

    What is the synapse between a motor neuron and a skeletal muscle called?

    <p>Neuromuscular junction</p> Signup and view all the answers

    Nicotinic receptors function as selective sodium channels.

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

    Each quantum of ACh produces a small depolarization of the muscle membrane, called a miniature end-plate potential. Depolarizations from many quanta summate to produce a full end-plate potential in the muscle membrane, known as ______________.

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

    Match the following types of NT receptors with their descriptions:

    <p>Ion channel coupled receptors = usually by amino acid and amine NT (fast acting = Ionotropic) G-protein coupled receptors = by proteins NT (slow acting, affecting metabolism thus metabotropic receptors) Autoreceptors = located on presynaptic neurons and inhibit NT synthesis and release (presynaptically)</p> Signup and view all the answers

    Match the following adrenergic receptors with their response and mechanism:

    <p>α1 receptor = Excitation, stimulation of metabolism; Mechanism: Activation of enzymes, release of intracellular Ca2+ α2 receptor = Inhibition of effector cell; Mechanism: Reduction of cAMP concentrations β1 receptor = Stimulation, increased energy consumption; Mechanism: Enzyme activation β2 receptor = Inhibition, relaxation; Mechanism: Enzyme activation</p> Signup and view all the answers

    Neuroendocrine hormones are secreted by neurons into the circulating blood and influence the function of cells in the body. Paracrines are secreted by cells into the extracellular fluid and affect neighbouring cells of a different type. Autocrines are secreted by cells into the extracellular fluid and affect the function of the same cells that produce them by binding to cell surface receptors.

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

    What is the main function of hormones in the body?

    <p>Water and electrolyte balance</p> Signup and view all the answers

    What is the significance of cAMP in some hormonal actions?

    <p>cAMP plays a role as a secondary messenger in mediating the effects of certain hormones on target tissues.</p> Signup and view all the answers

    Study Notes

    Course Objectives

    • Describe the basic organization and functions of cells and intracellular organelles
    • Describe the benefits of homeostasis for the survival of organisms
    • Describe the nature and organization of the major systems of the human body

    Course Contents

    • Definition and approach to study physiology
    • Functional organization of the human body and control of the internal environment (homeostasis, allostasis, and heterostasis)
    • Cell physiology (body fluid compartment and composition, plasma membrane and membrane transport mechanism)
    • Introduction to physiology of nervous system

    Teaching-Learning Methodology

    • Interactive lecture
    • Integrated biomedical laboratory
    • E-learning
    • Self-directed learning

    Physiology

    • Study of nature (Physi - nature, physiologic; natural, relating to physics)
    • Study of living organisms (i.e., studying practically everything in the universe and in the human body)
    • Extends from physical and chemical processes in cells and tissues to whole animals

    Physiological Processes

    • Chemical reactions that occur in cells
    • Transmission of nerve impulses
    • Contraction of muscles
    • Mechanisms by which the living body sees, moves, digests, keeps warm, etc.
    • Transformation of energy from one form to another

    Fields of Physiology

    • Human physiology (cell physiology, CV physiology, renal physiology, respiratory physiology, GI physiology, endocrine physiology, CNS physiology, etc)
    • Relationship between physiology and other sciences (anatomy, biochemistry, pathology, pharmacology, etc)

    Homeostasis

    • Dynamic steady state of the internal environment
    • Process that maintains the internal environment of living systems in a more or less constant state
    • Departures from the steady state are opposed by negative feedback regulation

    Regulation of Physiological Parameters

    • Maintenance of normal blood pressure requires the integration of several organ systems
    • Control of body fluid volume and blood pressure
    • Regulation of electrolyte balance
    • Regulation of acid-base balance

    Historical Development of Regulatory Mechanisms

    • Empedocles (Greek philosopher, 504-433 B.C)
    • Hippocrates (460-370 B.C)
    • William Harvey (1628)
    • Claude Bernard (1813-1878)
    • W.B. Cannon (1929)
    • Miller (1957)

    Levels of Physiological Regulation

    • Sub-cellular autoregulation
    • Cellular auto-regulation
    • Local (tissue) level regulation
    • Distant (organ/system) regulatory mechanisms

    Components of Distant Physiological Regulation

    • Detector (sensor)
    • Amplifier (integrating center)
    • Effector (output)
    • Feedback (return of information)

    Types of Feedback

    • Negative feedback ( stabilizes the system)
    • Positive feedback (amplifies the response)

    Allostasis and Allostatic Load

    • Allostasis: the ability of the body to adapt to changing environments
    • Allostatic load: the cumulative cost of adaptation to repeated stress
    • Manifestations of allostatic load: decreased cognitive function during aging, abdominal obesity, increased risk for hypertension, cardiovascular disease, insulin-dependent diabetes, decreased immune responses, etc.

    Types of Allostatic Overload

    • Overstimulation by frequent stress
    • Failure to inhibit allostatic responses when not needed
    • Inability to stimulate allostatic responses when neededHere are the study notes for the provided text:
    • Adaptation and Acclimatization*
    • Indicators of allostatic overload:
      • Cardiovascular pathology
      • Metabolic deterioration
      • Brain atrophy
      • Immune dysfunction and vulnerability to viral impact
      • Bone demineralization
      • Vulnerability to preterm delivery
      • Changes in sensitization processes
    • Concept of Adaptation (Heterostasis):
      • External world problems to be solved through structural evolutionary changes
      • Adaptation is a bilateral process where the organism adapts to the environment, and the environment is modified
      • Examples: Grazing animals vs. herbs, trees vs. soil, and birds adapting to high altitudes
    • Adaptation to Climatic Changes*
    • Long-term adaptation to cold:
      • Physiological adaptation: reduced BMR, cooling of peripheral and deep lying tissues, and reduced thermal conductivity
      • Cultural adaptation: housing, clothing, and food habits (e.g., Eskimos)
    • Long-term adaptation to heat:
      • Genetic: body shape, long limbs, protruding organs
      • Physiological: activity of sweat glands, increased ability of sweating
      • Cultural: clothing (e.g., Arabian Bedouins)
    • Adaptation to High Altitude*
    • Adjustment to high altitude:
      • Homeostatic responses: CVS, Resp. System
      • Adaptive responses: hyperhaemoglobinaemia, hypervascularization, hyperactivity of cell enzymes
    • Respiratory responses to high altitude:
      • Initial increase in ventilation, followed by acclimatization
      • Changes in MV, VC, FVC, and RR
    • Regulation of ventilation at high altitude:
      • Initial increase in ventilation triggered by hypoxia
      • Long-term adaptation: increased DG, PaO2, and decreased A-a difference
    • Haematologic responses:
      • Increased Hb and red blood cell count
      • Changes in blood picture observed in humans at sea level and high altitude
    • Cardiovascular responses:
      • Decreased SV, CO, and BP
      • Increased HR and vasodilatation
    • Endocrine responses:
      • Changes in hormone levels, including glucocorticoids, thyroid hormones, catecholamines, and insulin
    • Neural responses:
      • Impaired sensory, perceptual, and motor performance
      • Effect of high altitude on mental concentration and muscular coordination
    • Body Fluid Compartments*
    • Composition of human body:
      • Water (60%)
      • Proteins (18%)
      • Fats (15%)
      • Minerals (7%)
    • Fluid compartments:
      • Extracellular fluid (ECF): 20% of body weight, including plasma, interstitial fluid, and transcellular fluid
      • Intracellular fluid (ICF): 40% of body weight
      • Blood volume: 8% of body weight
    • Importance of water in the body:
      • Solvent for electrolytes and nutrients
      • Digestion and absorption
      • Transportation of materials
      • Temperature regulation
    • Measurement of body fluids:
      • Direct and indirect methods
      • Indicator dilution method
    • Water balance:
      • Intake: drinks, food, and metabolic water
      • Output: urine, feces, sweat, and insensible losses
    • Osmolality and osmolality:
      • Concentration of osmotically active particles
      • Measurement in mOsm/L or mmol/L
    • Fluid Transfer and Balance*
    • Routes of fluid transfer:
      • Entry point: mouth and GIT
      • Exit routes: skin, lung, intestine, and kidney
    • Organs involved in water and electrolyte homeostasis:
      • Hypothalamus
      • Kidneys
      • Adrenal glands
    • Regulation of water intake:
      • Thirst mechanism
      • Antidiuretic hormone (ADH)
    • Role of ADH in fluid volume regulation:
      • Release from hypothalamus
      • Stimulates water reabsorption in collecting ducts
      • Regulates water-electrolyte balance

    Let me know if you need further clarification or have any questions!### Edema and Osmotic Pressure

    • Localized increased venous pressure leads to increased filtration and edema
    • Cellular non-pitting edema can be caused by:
      • Depression of cellular metabolism, leading to increased sodium influx and water entry into the cell
      • Inflammation, which increases membrane permeability to sodium and other ions, leading to edema
    • Water intoxication can occur when excessive volumes of water are absorbed too quickly, leading to nausea, vomiting, and shock

    Dehydration and Electrolyte Imbalance

    • Dehydration occurs when water loss exceeds water intake, leading to negative fluid balance
    • Causes of dehydration include:
      • Hemorrhage
      • Severe burns
      • Prolonged vomiting
      • Diarrhea
      • Profuse sweating
      • Water deprivation
      • Diuretic abuse
    • Signs and symptoms of dehydration include:
      • Weight loss
      • Fever
      • Mental confusion
      • Hypovolemic shock
      • Loss of electrolytes

    Cellular Composition

    • Proteins make up 50-60% of the dry mass of a typical cell
    • Lipids make up 40% of the dry mass of a typical cell
    • Carbohydrates make up 3% of the dry mass of a typical cell
    • Nucleic acids, such as DNA and RNA, are also present in cells

    Cell Membrane Composition

    • Cell membranes are composed of a lipid bilayer with proteins inserted into it
    • Proteins can be:
      • Peripheral (extrinsic), which are hydrophilic and loosely attached to the membrane
      • Integral (intrinsic), which are anchored to the membrane through hydrophobic interactions
    • Lipids in the cell membrane include:
      • Phospholipids, which have a glycerol backbone and are amphiphilic
      • Cholesterol, which determines the rigidity of the membrane
      • Neutral fats, which are also present in the membrane

    Cell Membrane Functions

    • The cell membrane:
      • Separates cellular contents from the extracellular fluid
      • Regulates the passage of substances in and out of the cell
      • Provides receptors for neurotransmitters, hormones, and drugs
      • Facilitates cell-to-cell contact
      • Plays a role in the generation and transmission of electrical impulses in nerve and muscle cells
      • Is involved in the regulation of cell growth and proliferation

    Transport Across the Cell Membrane

    • Simple diffusion:
      • Occurs down a concentration gradient
      • Does not require energy
      • Is affected by factors such as viscosity, molecular weight, and lipid solubility
    • Osmosis:
      • Is the movement of water from an area of high concentration to an area of low concentration
      • Occurs through a selectively permeable membrane
    • Facilitated diffusion:
      • Is carrier-mediated transport
      • Occurs down a concentration gradient
      • Does not require energy
      • Is affected by factors such as saturation, competition, and lipophilicity
    • Active transport:
      • Is the transport of substances against a concentration gradient
      • Requires energy
      • Can be primary (directly uses ATP) or secondary (uses energy from the Na+ gradient)

    Carrier Proteins

    • Carrier proteins:
      • Are involved in facilitated diffusion
      • Are specific to the substance being transported
      • Can be saturable, competitive, and inhibited by certain substances
    • Types of carrier proteins:
      • Uniport carriers, which transport a single substance in one direction
      • Antiport carriers, which transport two substances in opposite directions
      • Symport carriers, which transport two substances in the same direction

    Pump Transport Mechanisms

    • Primary active transport:
      • Uses energy from ATP
      • Examples include the Na+/K+ pump, Ca2+ pump, and H+/K+ pump
    • Secondary active transport:
      • Uses energy from the Na+ gradient
      • Examples include Na+/glucose co-transport and Na+/K+/2Cl- co-transport

    Ion Channels

    • Ion channels:
      • Are integral membrane proteins
      • Allow for the selective passage of ions across the cell membrane
      • Can be gated, allowing for regulation of ion movement

    Vesicular Transport

    • Vesicular transport:
      • Involves the movement of substances in vesicles
      • Can be:
        • Endocytosis, which involves the engulfing of materials by the cell membrane
        • Exocytosis, which involves the release of substances from the cell
    • Examples of vesicular transport include:
      • Phagocytosis, which involves the engulfing of large particles
      • Pinocytosis, which involves the engulfing of fluid and small molecules
      • Receptor-mediated endocytosis, which involves the specific binding of substances to receptors on the cell membrane

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    Description

    This quiz assesses the understanding of medical physiology, covering the basics of cells and intracellular organelles, and the importance of homeostasis. It is designed for PC1 students at Debre Berhan University.

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