Human Physiology I Lecture Notes

Eric Woode, PhD, BPharm - Human Physiology I Lecture Notes

Course Information

  • Instructor: Eric Woode, PhD, BPharm
  • Department: Pharmacology & Toxicology, UHAS, Ho
  • Course Title: SOPH 143 Human Physiology I
  • Date: 1/25/2026

Introduction

  • Introduction to Human Physiology focusing on General & Cellular Physiology.

Homeostasis

  • Definition: Maintenance of a relatively stable internal environment despite continuous external and internal changes.
  • Origin of the term: Greek words "homeo" (similar) and "stasis" (standing).
  • Historical contributions:
    • Claude Bernard - Concept of the internal environment (milieu intérieur).
    • Walter Cannon - Expanded the concept to physiological regulation (temperature, pH, glucose levels).

Cell Structure

  • Basic units of life.

Transport Across Membranes

  • Mechanisms governing the movement of substances into and out of cells.

Physiology: Etymology

  • The term "Physiology" comes from Ancient Greek:
    • φύσις (phúsis) - nature, origin
    • -λογία (-logía) - study of
  • Definition: The scientific study of functions and mechanisms in living systems.

What is Physiology?

  • Definition: “Physiology is the science of life. It is the branch of biology that aims to understand the mechanisms of living things, from the basis of cell function at the ionic and molecular levels to the integrated behavior of the whole body and the influence of the external environment.”
  • Importance: Helps understand body responses in health and disease, facilitating new treatments and health guidelines.

Why Study Physiology?

1. Understanding Drug Action
  • Physiology provides insight into normal bodily functions, enabling pharmacy students to understand drug interactions that restore homeostasis.
2. Mechanisms of Disease
  • Physiology enables understanding of pathophysiological changes in diseases, informing drug selection and therapy management.
3. Pharmacokinetics & Pharmacodynamics
  • Essential for understanding drug absorption, distribution, metabolism, and excretion (ADME) and their effects at cellular and systemic levels.
4. Rational Drug Therapy
  • Understanding physiology assists in predicting drug effects, side effects, and contraindications for safe medication use.
5. Clinical Decision-Making
  • Physiological knowledge aids pharmacists in interpreting laboratory results, monitoring therapy, and making patient-centered recommendations.

Bibliography

  • Tortora & Derrickson (2022) Principles of Anatomy & Physiology, 16th Ed
  • Martini, Nath & Bartholomew (2023) Fundamentals of Anatomy & Physiology, 12th Ed
  • Marieb & Keller (2022) Essentials of Human Anatomy & Physiology, 13th Ed
  • Caon, M (2020). Examination Questions and Answers in Basic Anatomy and Physiology, 2000 Multiple Choice Questions, 3rd Ed.

Anatomy & Physiology Concepts

Learning Objectives
  • Describe basic functions of organisms.
  • Define anatomy and physiology; identify specialties.
  • Identify major organizational levels in organisms.
  • Recognize the 11 organ systems and their components.
  • Explain homeostasis, including feedback mechanisms.
Essential Terms
  • Anatomy: Science of body structures and relationships; focus on structure.
  • Physiology: Science of body functions; focus on function and workings.
Interrelation of Anatomy & Physiology
  1. Function (physiology) is tied to structure (anatomy).
  2. Structures carry out specific functions.
  3. Structural characteristics often dictate functional capabilities.
Branches of Physiology and Their Focus
  • Neurophysiology: Nerve cell functions.
  • Endocrinology: Hormonal regulation and control.
  • Cardiovascular Physiology: Heart and blood vessel operations.
  • Immunology: Body’s defenses against pathogens.
  • Respiratory Physiology: Functionality of the respiratory system.
  • Renal Physiology: Kidney functions.
  • Exercise Physiology: Changes during physical activity.
  • Pathophysiology: Changes linked to disease and aging.

Principle of Complementarity

  • Function reflects structure: Instances where specific body parts' structures suit particular functions:
    • Rigid bones for support and protection.
    • Thin-walled alveoli for effective gas exchange.
    • Muscle cells contain proteins for movement.
    • Neurons with extended processes to transmit signals.

Physiology and Physics

  • Physics aids in understanding physiological functions by explaining how body processes adhere to physical laws:
    • Electricity: Nerve impulses.
    • Force and work: Muscle contraction.
    • Fluid dynamics: Blood flow.
    • Pressure: Breathing and circulation.
    • Light: Vision.
    • Thermodynamics: Metabolism and homeostasis.

Levels of Structural Organization & Body Systems

  1. Chemical Level: Atoms and molecules (e.g., DNA).
  2. Cellular Level: Basic units of life (e.g., smooth muscle cell).
  3. Tissue Level: Groups of cells working together (e.g., smooth muscle tissue).
  4. Organ Level: Structures composed of multiple tissue types (e.g., stomach).
  5. System Level: Combined organ systems (e.g., digestive system).
  6. Organismal Level: The complete living entity.
Major Body Systems
  • Integumentary, Skeletal, Endocrine, Cardiovascular, Digestive, Muscular, Nervous, Lymphatic, Respiratory, Urinary, Reproductive.

Integumentary System

Components
  • Skin, hair, nails, sweat glands, oil glands.
Functions
  • Protects body; regulates temperature; eliminates waste; synthesizes vitamin D; detects sensations.
Clinical Examples
  • Transdermal nitroglycerin for angina, topical corticosteroids for dermatitis, Stevens-Johnson syndrome.

Skeletal System

Components
  • Bones, joints, associated cartilages.
Functions
  • Supports body; muscle attachment surface; aids movement; produces blood cells; stores minerals.
Clinical Examples
  • Alendronate for osteoporosis; Vitamin D and calcium for supplementation; chemotherapy-induced bone marrow suppression.

Muscular System

Components
  • Skeletal muscles.
Functions
  • Body movement; posture stabilization; heat generation.
Clinical Examples
  • Baclofen for muscle spasticity; neuromuscular blockers for anesthesia; statin-induced myopathy.

Nervous System

Components
  • Brain, spinal cord, nerves, sense organs.
Functions
  • Generates nerve impulses; detects changes; coordinates body functions; highly sensitive to drugs.
Clinical Examples
  • Levodopa in Parkinson’s disease; antiepileptics in seizures; opioid-induced respiratory depression.

Endocrine System

Components
  • Hormone-producing glands and cells.
Functions
  • Regulate activities through hormone release.
Clinical Examples
  • Insulin and metformin for diabetes; levothyroxine for hypothyroidism; corticosteroids can suppress adrenal function.

Cardiovascular System

Components
  • Blood, heart, blood vessels.
Functions
  • Pumps blood; transports gases, nutrients, and waste; regulates body temperature and acid-base balance.
Clinical Examples
  • ACE inhibitors for hypertension; anticoagulants for atrial fibrillation; doxorubicin-induced cardiotoxicity.

Lymphatic System and Immunity

Components
  • Lymphatic fluid, vessels, spleen, thymus, lymph nodes, tonsils.
Functions
  • Returns protein and fluid to blood; carries lipids; matures lymphocytes for immunity.
Clinical Examples
  • Vaccines; immunosuppressants in transplant patients; rituximab for lymphoma.

Respiratory System

Components
  • Lungs, air passageways.
Functions
  • Gas exchange; acid-base balance; sound production.
Clinical Examples
  • Salbutamol in asthma; inhaled anesthetics; opioid-induced respiratory depression.

Digestive System

Components
  • GI tract and accessory organs (e.g., liver, pancreas).
Functions
  • Breaks down food; absorbs nutrients; eliminates waste.
Clinical Examples
  • Omeprazole for peptic ulcers; lactulose for hepatic encephalopathy; paracetamol-induced hepatotoxicity.

Urinary System

Components
  • Kidneys, ureters, bladder, urethra.
Functions
  • Produces and eliminates urine; regulates blood composition and acid-base balance.
Clinical Examples
  • Gentamicin dosing in renal impairment; diuretics in heart failure; NSAID-induced nephrotoxicity.

Reproductive System

Components
  • Gonads and associated organs.
Functions
  • Produces gametes; regulates reproductive hormones; transports and stores gametes.
Clinical Examples
  • Oral contraceptives; oxytocin for labor; teratogenicity of thalidomide.

Basic Life Processes

Core Processes Defining Living Organisms

  1. Metabolism: Sum of all chemical reactions.

    • Catabolism: Breakdown of molecules for energy.
    • Anabolism: Synthesis of molecules for growth and repair.
    • Regulated by hormones and enzymes.

  2. Responsiveness (Irritability): Body's ability to respond to stimuli (internal and external).

  3. Movement: Involves motion of whole body or components such as muscle contractions.

  4. Growth: Increase in size through cell division and nutrient uptake.

  5. Differentiation: Unspecialized cells developing into specialized cells.

  6. Reproduction: Formation of new cells or individuals through meiosis and mitosis.

Homeostasis Control Mechanisms

Receptors, Control Centers, Effectors
  • Flow: Stimulus → Receptor (Sensor) detects change → Control Center (Integrator) compares with set point → Effector produces response to restore balance.
Feedback Mechanisms

  1. Negative Feedback: Reverses original stimulus.

    • Example: Blood glucose regulation via insulin and glucagon.

  2. Positive Feedback: Amplifies original stimulus.

    • Example: Uterine contractions during childbirth and blood clotting.
Feedforward Mechanisms
  • Anticipatory responses to disturbances; more efficient in preparation for changes.
  • Example: Increased heart rate in anticipation of exercise.

Clinical Significance of Homeostatic Imbalance

  • Conditions such as diabetes mellitus or hypertension represent failure in homeostasis.
  • Diseases alter normal control mechanisms, resulting in various health issues.
Therapeutic Strategies
  • Tailored pharmacotherapy based on specific homeostatic failures:
    • For diabetics, therapy evolves from lifestyle changes to insulin therapy.
Time Scales of Responses
  1. Rapid: Neural reflexes (seconds).
  2. Intermediate: Hormonal responses (minutes to hours).
  3. Slow: Structural and genetic changes (days to months).

Key Takeaways for Pharmacists

  • Understanding how drugs interact with homeostatic systems is essential.
  • Anticipating compensatory responses and monitoring physiological parameters is key in rational pharmacotherapy.

Summary

  • Homeostasis is critical for maintaining internal stability.
  • Negative feedback is the primary mechanism for regulation, while positive feedback drives processes to completion.
  • A decline in homeostatic function may indicate the presence of disease.