Human Physiology Week 4 - Notes
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Questions and Answers

What is the formula for calculating Cardiac Output?

  • Stroke Volume x Heart Rate (correct)
  • Heart Rate - Stroke Volume
  • Stroke Volume + End Diastolic Volume
  • End Diastolic Volume - End Systolic Volume
  • Which component is responsible for the greatest rate of self-excitation in the heart?

  • SA Node (correct)
  • Purkinje fibers
  • Bundle of His
  • AV Node
  • During which phase does the aortic valve open?

  • Systole (correct)
  • Atrial systole
  • Isovolumic relaxation
  • End Diastolic Volume
  • What term describes the amount of blood remaining in the ventricle after contraction?

    <p>End Systolic Volume</p> Signup and view all the answers

    Which of the following represents the relationship between Stroke Volume and End Diastolic Volume?

    <p>Stroke Volume = EDV - ESV</p> Signup and view all the answers

    If the SA Node fails, which structure takes over as the primary pacemaker?

    <p>AV Node</p> Signup and view all the answers

    What effect does the sympathetic nervous system have on cardiac contractility?

    <p>Increases contractility</p> Signup and view all the answers

    What does an Ejection Fraction of 60% indicate?

    <p>Normal contractility</p> Signup and view all the answers

    What primarily influences the preload in the heart?

    <p>Volume of blood in the ventricles</p> Signup and view all the answers

    Which term describes a slow resting heart rate?

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

    What is a major pathophysiological characteristic of rhabdomyolysis?

    <p>Increase in intracellular calcium</p> Signup and view all the answers

    Which of the following symptoms is not typically associated with myocarditis?

    <p>Severe muscle pain</p> Signup and view all the answers

    Which of the following factors increases the risk of exertional rhabdomyolysis in athletes?

    <p>Lack of rest</p> Signup and view all the answers

    What physiological effect can result from myocarditis?

    <p>Decreased heart muscle function</p> Signup and view all the answers

    What can be a consequence of increased myoglobin in the blood due to rhabdomyolysis?

    <p>Decreased renal function</p> Signup and view all the answers

    What is the primary role of ATP in the body?

    <p>To serve as a primary energy carrier</p> Signup and view all the answers

    What is the basal metabolic rate?

    <p>The number of calories required for maintaining homeostasis</p> Signup and view all the answers

    Which factor is NOT associated with an increase in metabolic rate?

    <p>Sedentary lifestyle</p> Signup and view all the answers

    How is daily energy expenditure primarily affected?

    <p>By physical activity levels and metabolic factors</p> Signup and view all the answers

    Which thermometer method is considered the gold standard for measuring body temperature?

    <p>Esophageal probe</p> Signup and view all the answers

    What physiological purpose does fever serve?

    <p>To raise the resting body temperature</p> Signup and view all the answers

    What type of molecule causes the hypothalamus to change the body's temperature set point?

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

    What is thermogenesis?

    <p>The body's process of producing heat</p> Signup and view all the answers

    What prevents back-flow during ventricular systole in the heart?

    <p>Chordae tendineae</p> Signup and view all the answers

    In which part of the heart does blood enter through the Mitral valve?

    <p>Left atrium</p> Signup and view all the answers

    Which type of muscle is cardiac muscle classified as?

    <p>Striated muscle</p> Signup and view all the answers

    Where does blood go after passing through the pulmonary arteries?

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

    Which valves are classified as atrio-ventricular valves?

    <p>Tricuspid and mitral valves</p> Signup and view all the answers

    What structure separates the atria from the ventricles in the heart?

    <p>Fibrous insulator</p> Signup and view all the answers

    What is the role of papillary muscles in the heart?

    <p>Prevent back flow during systole</p> Signup and view all the answers

    Which structures in cardiac muscle are especially permeable to the movement of ions?

    <p>Intercalated discs</p> Signup and view all the answers

    What type of blood enters the right atrium of the heart?

    <p>Deoxygenated blood</p> Signup and view all the answers

    Which of the following describes the nature of the right and left atria?

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

    Study Notes

    Metabolism

    • Calorie: Energy needed to raise 1 gram of water by 1 degree Celsius.
    • Kilocalorie (kcal): Unit for measuring energy content in food or energy expenditure in humans.
    • ATP: Central energy molecule for muscle contractions, nerve conduction, and active transport.

    Daily Energy Expenditure

    • Basal Metabolic Rate (BMR): Calories used to maintain homeostasis.
    • Metabolic rate increases during sleep; the brain remains highly active.

    Factors Affecting Metabolic Rate

    • Activity level, lean body mass, and hormonal factors (thyroid, growth hormone, testosterone).
    • Environmental factors: fever, cold climate, small body size (enhanced heat loss).

    Body Temperature Measurement

    • Normal healthy range: 97 to 99 degrees Fahrenheit.
    • Core temperature (biotemperature) can be measured using esophageal probes or rectal thermometers.
    • Oral temperature measurement can be affected by intake of hot/cold substances.

    Heat Sources

    • Thermogenesis: Body's heat production process.
    • Fever: Physiological response mediated by pyrogens, influencing the hypothalamus to raise body temperature.

    Cardiac Anatomy

    • Blood flow pathway: Right atrium → tricuspid valve → right ventricle → pulmonary arteries → lungs → left atrium → pulmonary veins → left ventricle → aortic valve → aorta.
    • Right and left atria function as syncytia, facilitating coordinated electrical activity.

    Heart Valves

    • Mitral and tricuspid valves are atrioventricular (AV) valves that prevent backflow during ventricular systole.
    • Chordae tendineae and papillary muscles assist in valve function.

    Cardiac Cycle

    • Phonocardiogram and electrocardiogram (ECG) provide information on heart sounds and electrical activity.
    • End Diastolic Volume (EDV): 130 ml; End Systolic Volume (ESV): 50 ml; important for calculating stroke volume (SV).

    Cardiac Output

    • Stroke Volume (SV): EDV - ESV.
    • Cardiac Output (CO) = Heart Rate x SV.
    • Ejection Fraction (EF) = SV/EDV indicates heart efficiency.

    Blood Pressure Fundamentals

    • Arterial blood pressure is influenced by cardiac output and peripheral resistance.
    • Control mechanisms include heart rate modulation and vascular resistance adjustments.

    Cardiac Conduction System

    • SA Node: Pacemaker of the heart, located in the right atrium, initiates action potentials facilitating atrial contraction.
    • AV Node: Delays signal to ventricles, allowing for synchronized contractions.

    Electrocardiogram (ECG) Basics

    • Electrical cardiac events monitored through P wave (atrial depolarization), QRS complex (ventricular depolarization), and T wave (ventricular repolarization).

    Heart Rate Control

    • Bradycardia: Slow heart rate; Tachycardia: Fast heart rate.
    • Autonomic nervous system balances heart rate through sympathetic (increase) and parasympathetic (decrease) actions.

    Cardiac Contractility

    • Influenced by preload (ventricular filling) and afterload (resistance against ventricular ejection).
    • Positive inotropic effects enhance contractility; negative inotropic effects diminish it, regulated by calcium levels.

    Rhabdomyolysis

    • Condition of severe skeletal muscle damage leading to toxic release into circulation.
    • Symptoms include brown urine, pain, weakness; risk factors involve dehydration and high exercise intensity.

    Myocarditis

    • Inflammation of the heart muscle resulting in possible scar formation.
    • Symptoms may include referred pain, fatigue, shortness of breath, and irregular heartbeats.

    Physiological Effects of Myocarditis

    • Can lead to low blood pressure, increased heart workload, cellular death, and potential arrhythmias.

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    Description

    Test your understanding of metabolism and metabolic rates with this quiz. Explore key definitions and concepts including calorie, kilocalorie, and the role of ATP in bodily functions. Perfect for students studying biology or health sciences.

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